Engineering liquid crystal elastomer unlocks high thermopower for fiber-shaped ionic thermoelectric capacitors

Domain: chemistry
Published: 2025-12-30
Editorial outcome: major_revision

Abstract
Ionic thermoelectric (i-TE) have become promising candidate for harvesting low-grade thermal energy. However, the development of n-type i-TE materials still lag far behind their p-type counterparts, which impedes the application. Herein, engineering a liquid crystal elastomer (LCE) from side-chain to main-chain structure, just swollen with single LiBF4 or EMIMTFSI, enables the largest adjustable p-n (28.8 ~ −27.4 mV K−1) span among current homologous materials below 30% RH. These high n- and p-type performance further ensure the successful integration of a homogeneous π-type fiber-shaped i-TE capacitor, where three p/n pairs yield an output voltage of 402.5 mV under a tiny temperature difference of 2.5 K. The areal energy density of a per n-type fiber reaches 8.1 mJ m−2. More importantly, the i-TE materials also exhibit excellent stability under loadings of cyclic stretching, long-term testing, or temperature-controlled cycling, highlighting its potential for efficient thermal-charge energy storage in flexible electronics and smart wearables.

Introduction
Recently, the emerging ionic thermoelectric (i-TE) materials have gradually drawn extensive attention due to their ultra-high thermopower1. Among the i-TE materials, quasi-solid ionogels- that is, polymeric networks swollen with salts- have shown considerable promise for applications in heat harvesting and wearable applications due to their excellent mechanical characteristics, good thermal stability, and non-volatile2–4. And the quasi-solid TE ionogels operate in two mechanisms and correspondingly work in two modes: (1) Thermogalvanic effect and thermogalvanic cells work mode; (2) Soret effect and i-TE capacitors work mode. Among these, the Soret effect could induce a higher thermopower (>10 mV K−1), recently drawing notable interest in the field of thermal sensing and low-grade heat harvesting. Soret effect operating capacitive i-TE devices requires both p-type and n-type TE ionogels to ensure an enough voltage and thereby an efficient output energy/power. However, the current available category and performance of n-type i-TE materials still lag far behind those of p-type counterparts, and n-type and p-type characteristics in homologous materials are highly challenging, restricting the development of i-TE capacitors5–7.

The Kinetics behind the Soret effect is the generation of ionic thermoelectric potential driven by temperature gradient-inducing changes in chemical potential and entropy (Eastman entropy) between the anions and cations inside the polymeric networks. Thereby, the achievement of high-performance n-type feature requires amplifying anion-dominated mobility difference and Eastman entropy in the polymeric networks6. Pioneering studies have found the feasible n-type feature of lithium salts (lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)), sodium salts (sodium chloride (NaCl)) and transition metals (Iron(III) chloride (FeCl3), Copper(II) chloride (CuCl2)), swelling in the polymeric networks including poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(ethylene oxide) (PEO), poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and poly(vinyl alcohol) (PVA)6–12. Despite the successful realization of n-type characteristics, the overall performance of these i-TE materials is relatively low, attributing to the fact that the large size of anions and their strong interaction with the polymeric network limit the mobility of anions8,13.

To overcome the above constraints, researchers attempted to introduce another ion donor to optimize the anion migration rate via their synergistic interactions. For example, in the PVDF-HFP/1-ethyl-3-methylimidazolium bis(trifluoro-methylsulfonyl)imide (EMIM TFSI) ionogel13, the Huang group employed the synergistic effect of hydrogen bonding and ion-dipole interactions between EMIM+ and the polymer to suppress cation migration and enhance the heat of transport for the anion, resulting in a thermopower of −4 mV K−1. Furthermore, by introducing lithium tetrafluoroborate (LiBF4) and utilizing the strong coordination between Li+ and TFSI−/BF4−, the heat of transport for the anion is substantially increased, thereby boosting the thermopower to −15 mV K−1. Similarly, our group recently also enabled an improvement in the n-type performance via introducing another ion donors7. Specifically, we firstly constructed an n-type PEO/LiTFSI-based TE ionogel utilizing the strong coordination between PEO and Li+ to enlarge the migration of TFSI−, and then we induced 1-Ethyl-3-methylimidazolium tetrafluoroborate (EMIM BF4), whose BF4− could coordinate with Li+, further releasing more TFSI− and facilitating the migration of TFSI−. As a result, the thermopower was enhanced from −5.9 mV K−1 in binary ionogels to −15.2 mV K−1 in ternary ionogels. In addition to the aforementioned strategies, introducing inorganic materials, including graphene oxide (GO)14, silicon dioxide (SiO2)15, ferric chloride (FeCl3)10, et al, or upregulating the environmental conditions (humidity16,17, pH18, et al) proved to be another efficient way to expand anions migration to improve the n-type performance19.

Although all the mentioned strategies efficiently boost the n-type thermoelectrical performance, extra ion donors inevitably cause ion leakage risks, the inorganic fillers always result in a critical trade-off between TE performance and mechanical properties, and the upper humidity conditions substantially exceed typical operational environments, all of these issues severely constrain practical applications. Therefore, developing n-type TE ionogels that deliver high TE performance under low ionic loadings, while possessing favorable mechanical properties and adaptability to common low-humidity environments, represents a critically yet challenging research frontier.

Interestingly, liquid crystal elastomer (LCE) network composed of soft segments and mesogenic units may unlocks a highly feasible platform to address the above challenge, originating to the fact: (i) The designed functional group in soft segments of LCE network could interact differently with cations or anions to enable differential migration rate, ensuring n-type feature on the first level; (ii) the alignment of the mesogenic units could be designed to amplify this ions mobility difference for further enlarging the n-type performance on the second level; (iii) the linkage between the soft chain and mesogenic unit could be engineered to substantially further amplify the ions mobility difference, significantly boosting the n-type performance on the third level. Thus, engineering the LCE network is expected to unlock an exceptionally high thermopower at low humidity with single-component ionic donors, low ionic loading, and good mechanical properties at the same time.

Herein, we comprehensively explore the feasibility of the LCE network in enabling high-performance i-TE materials. Strategically engineering liquid crystal (LC) units and soft chain linkages could efficiently regulate the thermal mobility difference between cations and anions, via inducing synergistic ionic diffusion channels and ionic coordination interaction, enabling a significant increase in the thermopower. As a result, engineering the LCE structure from single-end mesogen-linked soft segments (side-chain LCE) to double-end mesogen-linked soft segments (main-chain LCE), combined with just swollen with single LiBF4, impressively enhances the n-type thermopower by 6.5 times (−27.4 mV K−1) just at low humidity blow 30% RH. Interestingly, a high p-type thermopower of 28.8 mV K−1 can also be enabled in the case of just swollen with single EMIMTFSI, achieving the largest adjustable p-n span among current homologous materials. Owing to both the p- and n-type characteristics, a π-type fiber-shaped i-TE capacitor is successfully integrated, which can output a voltage of 48.6 mV K−1 per unit, achieving the highest output in a π-type i-TE device. The areal energy density of a per n-type fiber reaches 8.1 mJ m−2. More importantly, the LCE-based i-TE materials also exhibit excellent stability under loadings of cyclic stretching, long-term testing, or temperature-controlled cycling, highlighting the potential of this system serving as efficient and practical thermal-charge energy storage. Finally, molecular dynamics simulations are employed to calculate the diffusion lengths of cations and anions in the engineering LCE system, a higher diffusion length of both Li+ (81 Å) and BF4− (122 Å) is observed inside the main-chain LCE system, in contrast with that (52 Å for Li+ and 82 Å for BF4−) inside the side-chain LCE system, elucidating the origins of the n-type thermopower and the effective enhancement of thermopower induced by engineered LCE from an ionic migration distance perspective. Overall, this work proposes a universal network for enabling high thermopower i-TE materials to solve the long-standing challenge in the i-TE field, and presents a stable, convenient, and scalable high-performance i-TE material with significant practical and commercial value.

Results
The thermopower in ionic thermoelectric materials originates from the differential migration rates of cations and anions within polymeric networks under temperature gradients. To address the challenge of scanty and low-performance n-type i-TE material, we aim to design a network intrinsically favoring anion migration. Here, LCE is selected as the substrate network, owing to its ionic selectivity interaction and ionic diffusion channel effects, a network intrinsically favoring exceptionally high thermopower, which may be unlocked. To realize this concept, we strategically designed two LCE fibers with distinct structures through careful selection of synthetic precursors and process optimization. A main-chain LCE (m-LCE) fiber is synthesized using 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene (RM82) as the liquid crystalline unit, where both terminals are incorporated into the molecular backbone (Fig. 1a). And 2,2′-(ethylenedioxy) diethanethiol (EDDET) is selected as the soft segment to potentially facilitate cation-selective interactions, owing to its ether bonds (C-O-C). As a control, we designed a side-chain LCE (s-LCE) fiber using 1,4-Bis-[4-(3-acryloyloxypropyloxy) benzoyloxy]-2-methylbenzene (RM257) as the liquid crystalline unit and EDDET as the soft segment, but the mesogens only connect one terminal to the molecular backbone, as illustrated in Fig. 1a. The m-LCE exhibits a more ordered and regular network structure, whereas the s-LCE demonstrates a more compact and disordered arrangement. These distinct network architectures are expected to yield dramatically different ionic diffusion behaviors, where the main-chain architecture is expected to potentially facilitate ionic diffusion originating from wider intermolecular spacing and more ordered ion transport channels. Hence, both the above cation-selective interactions from C-O-C of soft segments and the ordered ion transport channels from the mesogenic connection modes are conducive to boosting anion migration, indicating that rationally engineered LCE represents a promising polymeric network for high-performance n-type thermopower.

Following the above design principle of n-type i-TE materials, we firstly synthesized m/s-LCE fiber and characterized by nuclear magnetic resonance (NMR) to verify the successful engineer of two LCE architectures. As for s-LCE: 1H NMR (CDCl3, δ, ppm), 6.25–5.68 (d, 4H, CH2=CH-), 5.99 (m, 2H, CH2=CH-), 1.36 (m, 4H, -CH2-); and m-LCE: 1H NMR (CDCl3, δ, ppm), 6.04–5.48 (d, 4H, CH2=CH-), 5.79 (m, 2H, CH2=CH-), 1.47 (s, 8H, -O-CH2(CH2)2CH2-O-), 1.32 (s, 8H, -O-CH2(CH2)2CH2-O-), as shown in Fig. 1b20–22. The emergence of additional methylene peaks in the m-LCE confirms the structural distinction between the two different alkyl chains of the mesogenic units. Furthermore, in the 1H NMR spectrum of the m-LCE, the peak area ratio between olefinic protons and methylene protons is 1:10, indicating that the olefinic groups at both terminals of the mesogenic units have participated in the reaction, with both ends incorporated into the main chain, thus validating its main-chain architecture23. In contrast, the 1H NMR spectrum of the s-LCE exhibits a peak area ratio of 1:1.59 between olefinic protons and methylene protons, demonstrating that only one terminal olefinic group is connected to the molecular main chain, which is characteristic of a side-chain structure. Concurrently, two-dimensional wide-angle x-ray diffraction (2D WAXD) measurements are conducted to investigate the influence of different chain architectures on LCE molecular spacing and order parameter. As illustrated in Fig. 1c, both LCE fiber exhibit anisotropic diffraction rings in their 2D WAXD patterns. Using the interplanar spacing equation d=2π/q (1) (where d represents molecular spacing and q denotes the scattering vector), we determine that the m-LCE fiber possesses a larger molecular spacing (4.67 Å), in contrast to its side-chain counterpart (4.45 Å)24,25. This enhanced spacing provides wider channels for ionic migration within the network structure. Moreover, these different molecular chains develop distinct chain alignments induced by the shear stress from the same fiber injection molding process (Supplementary Fig. 1)26, the order parameter calculated by Hermans-Stein orientation distribution function (Supplementary Information 1)24,27 for the m-LCE (0.44) is higher than that of s-LCE (0.31). This further confirms that the m-LCE network architecture offers more favorable migration pathways, thereby is expected to accelerate free ionic diffusion.

To select a rational ion donor, density functional theory (DFT) is then employed to study the interaction between ions and the above two LCE architectures. As shown in Fig. 1d, two widespread ion donors (LiBF4 and EMIMTFSI) are analyzed here, and soft segments of two chain types. As for LiBF4, Li+ cation displays stronger binding energies with the C-O-C of soft segment than BF4− in both m/s-LCE architectures, thereby facilitating BF4− anions diffusion behavior and showing promise for n-type thermoelectric characteristics. In addition, the m-LCE exhibits a larger difference in binding energy with Li+ and BF4− compared to the s-LCE due to the variations in molecular chain structure, which is favorable for further enhancing n-type thermopower. In turn EMIMTFSI, TFSI− anions favor forming hydrogen-like non-covalent bonding interaction with soft segment (C-O-C) in all LCE architectures28, and the m-LCE also exhibits a greater difference in binding energy between EMIM+ and TFSI− compared to s-LCE. The m-LCE structure thereby shows promise not only for achieving p-type thermoelectric properties but also for enlarging the p-type thermopower. Therefore, thermopower polarity can be regulated through the interactions between C-O-C of soft segment in LCE network and different ion donors, and m-LCE structure is more conducive to thermopower enhancement owing to its structural advantages of larger molecular spacing and higher order parameter.

Based on the above theoretical insights, the thermopower of two different chain-type LCE fibers after immersion in different ionic liquids/salts (not only the above LiBF4 and EMIMTFSI, but also BMIMPF6, EMIMOAC, EMIMCl, and AMIMTFSI) is tested. The accuracy of the measurement system is ensured by performing quantitative benchmark calibration against previously reported ionic thermoelectric materials (Supplementary Figs. 2, 3)28,29. From Fig. 2a, it can be observed that the m-/s-LCE i-TE fiber exhibits identical thermoelectric polarity with the same ionic liquid, where LiBF4 and BMIMPF6 donors enable n-type characteristics, while the rest display p-type characteristics. And p/n type thermopower of m-LCE i-TE fiber has consistently proven higher than that of s-LCE structure. Notably, the thermopower polarity and performance advantages of m-LCE are consistent with the design principle in Fig. 1. Furthermore, for these n-/p-type LCE i-TE fiber, the ion donors-determined thermopower magnitude is further studied, with a focus on the influence of charge density and ionic size. In n-type materials, the higher charge density with smaller ionic size of Li+ enables strong coordination with LCE molecular chains and imposes minimal obstruction to anions migration, resulting in a substantially enlarged mobility contrast between cations and anions30,31. Conversely, in p-type materials, anions lack strong interactions with the molecular chains and preferentially form ion pairs with cations. The high charge density of Cl− and OAC− hinder ion pair dissociation, while the large ionic size of TFSI− hinders migration, amplifying the mobility difference and consequently improving the thermopower. (Supplementary Fig. 4, Supplementary Table 1).

To further verify the advantages of m-LCE structures in enhancing thermoelectric performance, the influence of soft segment content and crosslinker concentration for m/s-LCE i-TE fibers, as well as LiBF4 concentration and immersion time, on the TE performance is further studied. As shown in Supplementary Fig. 5–7, Fig. 2b, the thermopower of the m-LCE i-TE fiber consistently surpasses that of the s-LCE i-TE fiber under various parameter adjustments. Ultimately, the thermopower of the m-LCE i-TE fiber reaches −27.4 mV K−1 (voltage-temperature curve and fitting plot as shown in Supplementary Fig. 8) under conditions (EDDET: 2.2 M, PETMP: 0.26 M, immersion time: 6 h, LiBF4 concentration: 0.75 M), which is an unexpected 3.5-fold improvement compared to the side chain structure (−7.9 mV K−1). Furthermore, the conductivity of both architectures exhibits monotonic increases with increased LiBF4 concentration and immersion time, and the m-LCE i-TE fiber demonstrates great conductivity (118.7 mS m−1) at 0.75 M LiBF4 for 6 h, which is 2.6 times higher than the side-chain structure (46.5 mS m−1) (Supplementary Fig. 9). Additionally, the thermal conductivity of m-/s-LCE i-TE fiber remains at a level of 0.1–0.13 W m−1 K−1 both before and after LiBF4 solution immersion due to the intrinsic low thermal conductivity of the LCE materials, as shown in Supplementary Fig. 10.

To further emphasize the universality of m-LCE fibers for high thermoelectric performance, the thermopower of different LCE chain structures impregnated with p-type ionic donor (EMIMTFSI) is investigated. Results show that the thermopower attains 28.8 mV K−1 by optimized the impregnation concentration and time (Supplementary Fig. 11), which is 2.5 times higher than that of the side-chain variant. In summary, the structural engineering of m-LCE provides an effective strategy for the development of high-performance p- and n-type properties at homologous thermoelectric materials. In comparison with performance at humidity below 70% RH (Fig. 2c), the thermopower of −27.4 mV K−1 obtained at humidity blow 30% RH in this work sets a record for binary system thermopower. Meanwhile, the m-LCE i-TE fiber reaches the largest p-n span (56.2 mV K−1) among known homologous materials by leveraging the advantages of its intrinsic network structure5–13,18,32–42.

In addition, the humidity stability, long-term stability, and voltage-temperature cycling reversibility performance are studied. As shown in Supplementary Fig. 12, the m-LCE i-TE fiber can maintain over 88% of its thermopower within a high humidity range (30–90% RH), owing to its hydrophobic and the effective barrier against humidity provided by its highly cross-linked network43. Moreover, the voltage remains stable without significant fluctuations or decay during a 10,000 s long-term test (Supplementary Fig. 13), which is primarily attributed to the structural advantages of the m-LCE network that enable enlarged mobility differences between anions and cations without requiring additional ionic donors, thereby effectively avoiding liquid leakage and encapsulation issues, as demonstrated in Supplementary Movie 1. Additionally, the m-LCE i-TE fiber shows stable voltage responses in the cycling stability test, as illustrated in Supplementary Fig. 14. Therefore, the m-LCE i-TE fiber not only possesses excellent thermopower but also demonstrates good humidity stability, long-term voltage stability, and voltage-temperature cycling reversibility performance.

To gain deeper insights into the influence of different chain-type architectures on thermoelectric performance, we firstly conduct theoretical analysis using molecular dynamics simulation (MD) to study molecular chain conformations of m-/s-LCE at various LiBF4 concentrations. As revealed in MD snapshots (Supplementary Fig. 15), polymer chains exhibit extended quasi-linear conformations at low LiBF4 concentration, as the limited ionic content results in dominant interchain electrostatic repulsion. With increasing LiBF4 concentration, enhanced Li+ binding to molecular chains progressively reduced interchain repulsion, leading to entropically favorable spherical conformations44. This conformational evolution is quantitatively confirmed by monitoring the end-to-end distance and radius of gyration with increasing LiBF4 concentration (Fig. 2d). Both architectures demonstrate progressive coiling transitions with increasing LiBF4 concentration, while the m-LCE molecular network remains more extended than s-LCE architectures44. This relatively expanded network structure of m-LCE provides favorable migration pathways for ionic thermal diffusion, validating the reasons for the better thermopower performance of m-LCE i-TE fibers. Moreover, we further quantify the solvation structures of both systems through MD simulations to analyze the coordination interactions between liquid crystalline networks and LiBF4. The radial distribution functions (Fig. 2e, Supplementary Fig. 16) reveal pronounced peaks at 2.1 Å for both architectures45–47, confirming the incorporation of ether group (C-O-C) oxygen atoms into the inner solvation shell of Li+. Peak intensities reach maxima at LiBF4 concentrations of 0.75 M and 0.85 M for m- and s-LCE structures, respectively. Notably, the Li+-O peak amplitudes consistently exceeded those of Li+-O across all concentrations, indicating stronger coordination capability of the m-LCE architecture with Li+. Coordination number (CNs) analysis furthers substantiate these findings, revealing an average of 2.35 oxygen ions surrounding each Li+ in the m-LCE system, significantly higher than the side-chain counterpart (0.94)48. These marked differences in radial distribution functions and CNs confirm the profound impact of molecular chain architecture on ionic interactions. And this impact can be attributed to the chain conformations, where the coiling conformation of s-LCE networks introduces steric hindrance to impede O-Li+ coordination. From the diffusion coefficients (MSD) of Li+ and BF4− at various LiBF4 concentrations for both systems (Fig. 2f), it can be observed that Li+ and BF4− in m-/s-LCE architectures exhibited reduced diffusion coefficients due to limited mobile ion availability at low concentrations. Notably, the diffusion coefficients of Li+/BF4− and their difference reach their maxima at 0.75 M LiBF4, representing an optimal balance between chain conformation and ionic concentration. Conversely, both systems experienced diminished ionic transport capabilities at high LiBF4 concentrations owing to the coil of polymer networks inhibiting Li+ coordination and disrupting efficient ionic transport pathways. In addition, Li+ consistently showed lower diffusion coefficients than BF4− due to the coordination-induced mobility constraints, resulting in n-type thermopower across both systems at various LiBF4 concentrations. And m-LCE i-TE system exhibits higher diffusion coefficients of cations/anions and their difference compared to s-LCE due to the more extended structural configuration, thereby achieving enhanced thermopower performance.

Previous research on ionic thermoelectric mechanisms primarily analyzes ionic diffusion behavior through diffusion coefficients and Eastman entropy, lacking a comprehensive investigation of ionic dynamic diffusion behavior from the perspective of distance and range. In this context, the residence time (τ) of concurrent motion between adjacent species can be used to characterize the differences in diffusion behavior between species49,50, and the calculation methodology is described in Supplementary Information 2. However, as demonstrated in the Supplementary Figs. 17–21, individual ionic residence times in both systems exhibit progressive increases with increasing viscosity, limiting their utility as standalone descriptors of diffusion behavior. To address this limitation, we converted residence times into diffusion lengths (L) using the relationship L = sqrt(6 * D_ions * τ) (2) where D_ions represents the ionic diffusion coefficient, which is related to factors such as temperature, concentration, and ion size44. This transformation enables systematic and intuitive comparison of diffusion mechanisms across various concentrations, as schematically illustrated in Fig. 2g. Figure 2h illustrates the concentration-dependent diffusion lengths of Li+ and BF4− in both LCE architectures. In the m-LCE network, a progressive increase in diffusion length is observed in the low concentration range, attributed to the synergistic effects of LCE structural evolution and system viscosity modulation. The system exhibits maximum diffusion lengths at 0.75 M, reaching 122 Å for BF4− and 81 Å for Li+. Further increases in LiBF4 concentration induce substantial conformational changes in the polymer network, severely impeding ionic diffusion and migration, resulting in a dramatic reduction in diffusion lengths for both ionic species. In contrast, the s-LCE network demonstrates consistently shorter diffusion lengths for both BF4− and Li+, with a general declining trend as impregnation concentration increased. And s-LCE network exhibits maximum diffusion lengths at 0.85 M LiBF4 concentration, reaching 82 Å for BF4− and 52 Å for Li+. These values are notably lower than those observed in the main-chain system under identical conditions. This phenomenon primarily stems from the more complex and convoluted conformational structure of s-LCE, which inherently inhibits ionic migration and diffusion within the system. The diffusion length difference further validating the substantial advantages of m-LCE network architecture in facilitating ionic thermal diffusion.

To further verify the above thermoelectric mechanisms, fourier transform infrared (FTIR) spectroscopy was firstly employed to study interactions between anions/cations and different LEC polymeric networks (Supplementary Fig. 22). As shown in Fig. 3a, the m-LCE i-TE fiber exhibits a notable blue shift in the C-O-C asymmetric stretching vibration peak at 1091 cm−1, accompanied by peak splitting of the C-O-C bending vibration near 1250 cm−1 (Fig. 3b)51–53. Notably, the B-F peak at 1045 cm−1 remains unchanged, indicating coordination between the soft segment C-O-C moieties and Li+ in the m-LCE i-TE fiber, while BF4− anions show no chemical interaction with the molecular chains54–56. In contrast, the s-LCE i-TE fiber demonstrates minimal spectral changes. The C-O-C asymmetric stretching vibration peak remains stable and only minimal displacement of the bending vibration peak without peak splitting, indicating weaker coordination with Li+. Raman spectroscopic analysis further validates these findings. Figure 3c reveals that both LCE architectures displayed characteristic B-F peaks after impregnation54, the m-LCE i-TE fiber exhibits a more pronounced shift from the original B-F characteristic peak at 771 cm−1. Similarly, NMR characterization demonstrates that the original F signal at −158.574 ppm from m- and s-LCE i-TE fiber shifts to −154.058 ppm and −154.602 ppm, respectively (Fig. 3d)57. These comprehensive spectroscopic analyses confirm that BF4− dominated thermal migration occurs in both LCE structures owing to the migration hindrance of Li+ caused by strong coordination interactions, as illustrated in Fig. 3e. These selective interactions and binding strengths between anions/cations and m-/s-LCE molecular chains are consistent with the differences in ionic diffusion coefficient calculated from MD simulations, confirming the advantage of m-LCE in thermopower improvement compared to the s-LCE structure.

Beyond its excellent thermoelectric performance, the m-LCE i-TE fiber also exhibits potential for scalable industrial production, along with excellent mechanical and optical properties. As demonstrated in Fig. 4a, a continuous 4-meter-long m-LCE i-TE fiber was successfully fabricated and photographed under ambient outdoor conditions. The fiber exhibits uniform semi-transparency and structural continuity, maintaining its mechanical integrity throughout the preparation and elongation processes without any observable fractures or defects. These characteristics strongly validate its potential for industrial-scale manufacturing. Benefiting from the favorable intrinsic mechanical properties of LCE materials, m-LCE i-TE fiber demonstrates excellent weaveability. Figure 4b shows a woven rectangular textile constructed from a single fiber. Through stretching, bending, and tensile-twist deformation, the textile exhibits no fracture phenomenon and recovers to its initial state (Supplementary Movies 2, 3), underscoring its tremendous potential for applications in wearable devices. Additionally, this m-LCE i-TE fiber also exhibits exceptional elastic resilience, as evidenced in Supplementary Fig. 23, Supplementary Movie 4. After subjection to 200% tensile strain, the fiber displays immediate and complete dimensional recovery to its initial length, with no observable fracture or stress relaxation phenomena.

Furthermore, the mechanical properties of both m- and s-LCE i-TE fiber are analyzed comparatively. It can be seen from Supplementary Fig. 24 that there is a trade-off relationship between the mechanical contributions of the crosslinker and the soft segment, with the former primarily governing the stress level and the latter dominating the strain behavior of the material. As a result, through an optimal balance of soft segment and crosslinker concentrations, the optimized m-LCE fiber achieves an ultimate tensile strength of 972.1 kPa and elongation at break of 518.3%, representing remarkable improvements of 143% and 46.3%, respectively, compared to its side-chain counterpart. Despite a certain degree of compromise in mechanical properties after LiBF4 impregnation (Fig. 4c, Supplementary Fig. 25) due to swelling-induced disruption of network crosslinking structure, the m-LCE i-TE fiber maintains substantially favorable mechanical performance compared to the side-chain variant, and the m-LCE i-TE fiber delightfully exhibit practical load-bearing capability by successfully supporting a 1-kg weight (Supplementary Movie 5). This enhanced mechanical robustness can be attributed to the more ordered molecular chain alignment inherent to the main-chain architecture. The quasi-solid-state gel properties and stable internal network structure of LCE i-TE fiber are further investigated through dynamic mechanical analysis (DMA), as shown in Fig. 4d 58,59. Over a frequency range of 10−1 to 102 rad/s, both LCE architectures exhibit storage moduli (G′) consistently higher than loss moduli (G″) before and after LiBF4 solution impregnation, demonstrating stable quasi-solid-state gel characteristics and a robust crosslinked network structure7.

Meanwhile, as shown in Fig. 4e, Supplementary Figs. 26, 27, the m-LCE i-TE fiber maintains over 80% of its thermopower after stretching from a strain of 0% to 120%, as well as 1000-cycles stretching, leveraging its gel and mechanical properties. These results demonstrate the stability of the molecular chain structure and excellent practical viability of the fabricated m-LCE i-TE fiber.

As for the optical properties of the m-/s-LCE i-TE fiber, the surface morphology is analyzed using scanning electron microscopy (SEM). As shown in Fig. 4f, the m-LCE fiber exhibits ordered stripe and scale-like structures before impregnation. However, the surface stripes disappeared due to swelling after immersion in the LiBF4 solution. With prolonged impregnation time, LiBF4 crystals precipitated and aggregated on the surface. These observations are further confirmed by EDS mapping (Supplementary Fig. 28), and a similar phenomenon is also observed in s-LCE i-TE fibers (Supplementary Figs. 29, 30). In addition, the monodomain structure and birefringence of the m-/s-LCE i-TE fibers are characterized using polarized optical microscopy (POM). As shown in Supplementary Figs. 31, 32, distinct color patterns are observed in the m-/s-LCE i-TE fibers both before and after solution impregnation when fiber axis is aligned at 45° to the polarizer, while appearing dark at 0°. These observations confirm the monodomain alignment and anisotropic characteristics of m-/s-LCE fibers60,61, in which the uniformly aligned liquid crystal mesogens are favorable for ion migration and further for amplifying the thermal migration difference between cations and anions62,63, this highlight the effectiveness of the LCE polymeric network developed herein for gaining high-performance i-TE materials. In addition, densely packed, uniformly oriented striations and grooves in the m-LCE i-TE fiber (Supplementary Fig. 33) are observed by atomic force microscopy (AFM), revealing the high degree of ordering in m-LCE i-TE fiber63.

In summary, compared to previously reported ionic thermoelectric materials, m-LCE i-TE fiber demonstrates competitive comprehensive performance under low humidity conditions (below 70% RH), particularly in terms of n-type thermopower, p-n performance range, mechanical properties and fiberization capability (Fig. 4g)8,12,29,64–68. This m-LCE material represents both promising candidates for thermoelectric applications and provides effective design strategies for next-generation ionic thermoelectric materials.

Given the capacitive characteristics of ionic thermoelectric materials, the capacitive behavior of high-thermopower n-type LCE i-TE fibers is investigated. Figure 5a, b illustrates the four-stage working mechanism of the capacitor operation. Under a temperature gradient of 3.8 K, the initial stage generates an open-circuit voltage of approximately 75 mV, attributed to the diffusion and accumulation of cations and anions at the cold/hot terminals (stage I). In stage II, the connection of an external load facilitates electron flow through the circuit, neutralizing the thermoelectric potential to zero due to unsaturated electrode charges. The stage III, characterized by the removal of both temperature gradient and external load, triggers the gradual redistribution of accumulated ions to their initial random state. Consequently, electrons retained at the cold electrode generate a reverse voltage, which subsequently diminishes to zero upon reconnection of the external load (stage IV)69,70. The voltage decay characteristics during the second and fourth stages exhibit progressive retardation with increasing load resistance, as demonstrated in Fig. 5c. Then, through the calculation of stage II by equation E = (1/A) * integral(V_out^2 / R_load) dt (3) (where A is the cross section area of fiber, V_out is voltage in stage II, R_load is load resistance), the energy density (E) is calculated to be 8.1 mJ m−2 at a load resistance of 1 MΩ, as shown in Fig. 5d71.

The exceptionally high output voltage of ionic thermoelectric materials presents significant potential for thermal-charge devices and high-sensitivity sensing applications. As output voltage serves as a critical performance metric for power generation and sensing capabilities, we firstly utilize a liquid crystal display (LCD) to verify the power supply capability of m-LCE i-TE fibers. As shown in Supplementary Fig. 34, this fiber can illuminate the LCD screen to display numbers under a temperature difference of 45 K. Indeed, the startup temperature difference can be effectively reduced through connected the high-performance n-type and p-type m-LCE i-TE fiber in parallel thermally and in series electrically. As illustrated in Supplementary Fig. 35, five n-type m-LCE i-TE fibers are connected in series using silver wire interconnects, demonstrating excellent and rapid voltage responsiveness (Fig. 5e), and the output voltage per degree of temperature difference (ΔV/ΔT) of the device reaches −130.2 mV K−1 through fitting the temperature-voltage data (Supplementary Fig. 36). In addition, a π-type device integrated with p-type and n-type m-LCE i-TE fibers is further integrated, whose output performance increases with the number of p-n pairs, ultimately achieving −146.8 mV K−1 for three p-n pairs (Fig. 5f). Notably, the utilization of m-LCE architecture for both p- and n-type materials results in excellent compatibility between the polymer counterparts, manifesting in stable output voltage characteristics (Supplementary Fig. 37). The demonstrated capacitive behavior and ionic device performance validate the potential of m-LCE i-TE fiber for low-grade heat harvesting and sensing applications.

Planar or three-dimensional wearable i-TE devices are further fabricated by reasonably embedding m-LCE i-TE fiber into a LCE fiber-woven fabric, as shown in Supplementary Figs. 38, 39. It can be observed from the working principles of the two structurally distinct thermal-charge devices that the planar device (Fig. 5g) primarily relies on a temperature difference generated between one end in contact with a heat source and the opposite end to produce voltage output. In contrast, the three-dimensional thermal-charge device (Fig. 5h) creates a temperature gradient when the bottom surface contacts a heat source while the opposite side is exposed to air or another object at a different temperature. For the planar device, temperature differences of 13.5 K and 14.6 K are generated between the hot and cold ends of the fiber after attaching to the surface of a beaker with hot water and ice water, respectively, then gradually decreasing and stabilizing at 10.3 K and 7.5 K over time. At the same time, the voltage exhibits rapid response within 450 s, reaching values of 270 mV and 206.6 mV under the stable temperature difference, respectively (Fig. 5i, Supplementary Fig. 40). Meanwhile, three-dimensional device generates a voltage of ~ 44.5 mV at the temperature difference of 1.7 K (Fig. 5j, k) by attaching it onto the human arm, with one end in contact with the body and the other exposed to the ambient air. Furthermore, LCE material exhibits a maximum contraction of 18.6% at 70 °C (Supplementary Fig. 41), and DSC curves of its indicate that the liquid crystalline range of m-LCE i-TE fiber is from 42.1 °C to 90.6 °C (Supplementary Fig. 42), demonstrating great thermally-actuated potential. These experiments not only validate the feasibility of m-LCE i-TE fiber for practical applications, but also demonstrate their application potential in the domains of wearable devices and low-grade thermal energy harvesting.

Methods
Materials
1,4-bis-[4-(6-acryloyloxyhexyloxy) benzoyloxy]-2-methylbenzene (RM82, 95%) and 1,4-Bis-[4-(3-acryloyloxypropyloxy) benzoyloxy]-2-methylbenzene (RM257, 97%) were purchased from Shanghai Bide Pharmaceutical Technology Co., Ltd., 2,2′-(ethylenedioxy) diethanethiol (EDDET, 98%), pentaerythritol tetrakis(3-mercaptopropionate) (PETMP, 95%) and ethyl acetate were supplied by Shanghai Titan Scientific Co., Ltd., tri(propyleneglycol) diacrylate (TPGDA, 90%), Triethylamine (TEA, 99.5%), butylated hydroxytoluene (BHT, 99%), Dimethylformamide (DMF, 99.5%) was purchased from Sigma Aldrich. LiBF4, EMIMOAC/TFSI/Cl, BMIMPF6 and AMIMTFSI were purchased from Lanzhou Greenchem ILS, LIPC, ACS (Lanzhou, China). All reagents were used as received without any further purification.

Preparation of main/side chain LCE ionic thermoelectric fiber
The fabrication of main-/side-chain LCE i-TE fibers initially requires the preparation of main-/side-chain LCE fibers. Specifically, for main-chain LCE fibers, RM82 (2.64 g), EDDET (0.8 g), PETMP (0.25 g), TPGDA (0.4 g) and BHT (0.02 g) were dissolved in DMF (2 mL) and stirred at 70 °C for 20 min until a transparent solution was obtained. Subsequently, TEA (0.1 mL) was added to the mixture and stirred for 5 min. Then, the LCE solution was transferred into a syringe and injected into a polytetrafluoroethylene (PTFE) tube. The filled tube was then horizontally placed in a vacuum oven at 70 °C for 12 h. Finally, the LCE fiber was carefully peeled off the PTFE tube. For side-chain LCE fibers, RM257 (2.4 g), EDDET (0.7 g), and PETMP (0.1 g) were dissolved in ethyl acetate (2.4 mL) and stirred at 70 °C for 1 h. Then, DPA (9 μL) was added and stirred for 1 min to form the LCE precursor solution. Then, the LCE solution was injected into a PTFE tube via a syringe and horizontally stored at room temperature for 12 h. Finally, the side-chain LCE fiber was peeled from the PTFE tube. Then, as-synthesized m-/s-chain LCE fibers were immersed in LiBF4 (0.55–0.95 mol/L)/EMIMTFSI (0.25–1.25 mol/L) solutions for controlled periods varying from 1 to 12 h, yielding n-type and p-type main-/side-chain LCE ionic thermoelectric fibers.

Preparation of main chain LCE ionic thermoelectric devices
The assembly of main-chain LCE ionic thermoelectric devices was implemented by precisely positioning p/n-type LCE fibers on a Peltier module in thermal series and parallel configurations, with one end of each fiber placed on the hot side and the other end on the cold side. Adjacent fibers were interconnected and reinforced with silver wires and silver paste to ensure reliable electrical connections.

Preparation of planar/three-dimensional thermal-charge wearable device
The thermal-charge device consists of a substrate module and a thermoelectric module. The substrate module is fabricated by knitting a 2-meter-long m-LCE fiber into a rib-structured textile measuring 3 cm in length and 6 cm in width. The thermoelectric module comprises a separate m-LCE i-TE fiber, which is integrated into the m-LCE textile through embedding and interweaving. The planar thermal-charge device is achieved as the m-LCE i-TE fiber is fully embedded on one side of the textile, whereas a three-dimensional thermal-charge device is formed when half of the fiber is embedded on one side, and the other half is embedded on the opposite side. Silver wires serving as electrodes are similarly embedded and connected to the cold and hot ends of the fiber in a planar/three-dimensional thermal-charge wearable device.

Characterization
The micromorphology and optical properties of LCE i-TE fibers were conducted using FE-SEM (SU8010, Hitachi), AFM (Fast Scan Bio, Bruker) and POM (DM750P, Leica). The FTIR spectroscopy (Nicolet 6700, Thermo Fisher) with the attenuated total reflection accessory and Raman spectra (inVia-Reflex, Renishaw) with a 633 nm laser were recorded to analyze the ion and molecular interchain interaction. Thermopower Si was measured by a homemade equipment based on the equation Si = −ΔV/ΔT (4) here potential differences ΔV arising from temperature differences ΔT was recorded by Keithley 2182A. The linear correlation (R2) between ΔV and ΔT should be > 0.99. Test items were tested at 3 times of each sample for an average value. All samples were prepared with a standardized dimension of 2 mm in diameter and 2 cm in length. And samples were placed on a Peltier module with silver wires serving as electrodes, the diameter and length of silver wire used for testing were 0.25 mm and 4 cm, respectively, and the spacing between silver wires was 1.5 cm. The temperature at the cold and hot ends of the Peltier module was regulated by varying the input voltage, where an increase of 0.01 V in voltage achieves a precise control of 0.1 K temperature difference. The temperature change was recorded and exported using an infrared thermographic camera. The ambient humidity during testing was monitored in real time using a hygrometer. The ionic conductivity σi was calculated as follows: σi = d/(A × R) (5) where the d, A, and R in the formula represent the thickness, area, and ionic resistance, respectively. The ionic resistance was tested by electrochemical impedance spectroscopy on an electrochemical workstation (DH7006), with the frequency ranging from 0.1 to 100000 Hz. Stress-strain curves were performed on an Instron (5969) testing instrument with a speed of 50 mm min−1 at room temperature. And the gelatin properties of LCE i-TE fibers, which the angular frequency dependencies of the storage modulus (G′) and loss modulus (G″) were performed by DMA (Q800, TA).

Computational details
Modeling and Simulation Methods: All ionic species and small molecules were parameterized using the next-generation general AMBER force field (GAFF2), with specific force field parameters generated using the sobtop software. The initial configurations were constructed using the Packing Optimization for Molecular Dynamics Simulations (Packmol) program with a periodic simulation box of 40 × 40 × 40 nm3. All molecular dynamics (MD) simulations were performed using the GROMACS 2019.5 package. The simulation protocol consisted of three main stages:
1. Energy Minimization
The system was initially minimized using a combination of 5000 steps of steepest descent, followed by 5000 steps of conjugate gradient algorithms to eliminate unfavorable contacts.
2. NPT Pre-equilibration
The system was pre-equilibrated in the NPT ensemble using the V-rescale thermostat at 298 K and the Parrinello-Rahman barostat at 1 atm. Non-bonded interactions were treated with a cutoff radius of 1.2 nm, and the integration time step was set to 1 fs.
3. Production MD Simulation
Following equilibration, the temperature coupling was switched to the Berendsen thermostat. Bond lengths and angles were constrained using the LINCS algorithm. A twin-range cutoff of 1.2 nm was employed for van der Waals interactions, while long-range electrostatic interactions were handled using the particle-mesh Ewald (PME) method. Trajectory frames were saved every 10.0 ps for subsequent analysis.

The initial geometries for density functional calculation (DFT) were obtained from ChemDraw and chem3D. Moreover, the MD simulations were performed via xTB software to obtain the possible binding poses of the polymer and ionic liquids. The most stable pose was then further optimized via Gaussian 16 software with a level of b3lyp/6–31g(g,p) em=gd3bj. The results were then analyzed via Multiwfn 3.7 software, visualized via VMD software version 1.9.3. Furthermore, the charge density is evaluated by the ratio of the difference between the maximum and minimum ionic charges to the ionic size. Written and informed consent was received from all authors.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "The manuscript presents a study on molecular structure regulation of liquid crystal elastomers (LCEs), leveraging structural differences between main-chain and side-chain LCEs to modulate ion migration behavior and thermopower type. This approach enables the simultaneous realization of high-performance p-type and n-type ionic thermoelectric materials under low-humidity conditions of ≤30% RH, achieving an n-type thermopower of –27.4 mV K-1 and a p–n thermopower span approaching 50 mV K-1. Molecular dynamics simulations elucidate the correlation between ion diffusion lengths and thermoelectric performance. Finally, a homologous p-n type fibrous ionic thermoelectric capacitor device is constructed, demonstrating potential for applications in wearable energy devices. The research aligns well with the growing demand for low-grade heat harvesting and flexible wearable electronics, exhibiting significant scientific value and application potential. However, certain aspects require further elaboration to enhance the rigor and completeness of the study. Here are some comments on this manuscript that may need major revision before I can recommend acceptance for publication.\n1. The ionic liquid selection lacks sufficient justification. In other words, what’s the principle to “program” the polymer? Figure 2(a) shows that m-LCE and s-LCE exhibit n-type and p-type behavior in various ionic liquids, respectively. Still, the manuscript does not explain why specific ionic liquids induce such thermopower polarity inversion. It is recommended to include calculations of ion size, charge density, and interaction energies between the ions and the soft segments (C–O–C) of the LCEs to clarify the link mechanism between ionic liquid type and the resulting thermopower polarity.\n2. The thermoelectric properties measurement conditions require clearer specification. What’s the sample’s size? How to apply the temperature gradient? The manuscript claims that molecular structure engineering influences thermodiffusion thermopower; it is imperative to ensure the reliability of these measurements. The authors should provide detailed information on temperature control accuracy, electrode contact configuration, and the testing protocol for fiber samples. Crucially, water content in the materials should be controlled, and humidity effects during thermopower measurement need to be explicitly excluded. To confirm the reversibility of the measured thermovoltage and thus validate the intrinsic thermodiffusion thermopower, it should be demonstrated that the open-circuit voltage returns to near zero upon removal of the applied temperature gradient.\n3. The evaluation of practical performance in wearable applications is insufficient. Although Figure 5(j-l) shows voltage output from the fiber under two operational conditions, there is no demonstration of the device’s ability to power electronic components. The authors are encouraged to supplement the study with output power data and provide images or videos of the device powering actual electronic components, thereby more effectively illustrating its practical utility.\n4. The author mentioned the figure of merit (ZT) of i-TE materials in the manuscript and directly used the relevant formulas of e-TE, which is inappropriate. Because ion thermoelectric materials have difficulty continuously outputting constant electrical power under stable thermal gradients, like electronic thermoelectric materials (The four-stage discharge data in the manuscript also confirms), the efficiency calculation models and formulas for ion thermoelectric materials are significantly different from those for electronic thermoelectric materials. Therefore, the figure of merit and power factor of electronic thermoelectric materials do not apply to ion thermoelectric materials.\n5. All image quality in the manuscript needs improvement for better readability. The term liquid crystal elasticity (LCE) in the abstract may be referred to as liquid crystal elastomer (LCE) to better align with the expression of LCE in subsequent text. Consistency between figure captions and main text descriptions should be verified. Line 398, Figure 3(g) is labeled as EDS elemental mapping, whereas the main text refers to it as AFM topographical of m-LCE i-TE fibe. Additionally, on line 492, the four-stage working mechanism described in Figure 5(a) is based on n-type material, where anions predominantly accumulate at the cold side. In this context, electrons in the external circuit during the second and third stages should accumulate and remain at the hot side of the device instead of the cold side. Furthermore, the total capacitive energy density in the ion capacitor mode remains constant. (Energy Environ. Sci. 2016, 9, 1450) It is therefore recommended that long-term charge-discharge tests be provided under various load resistances, and the corresponding capacitive energy density of the device be calculated.", "reviewer_2": "This manuscript reports the fabrication of a main-chain liquid-crystalline elastomer (m-LCE) fiber. This fiber exhibits a remarkable n-type thermopower of -27.4 mV·K⁻¹ under low humidity conditions (<30% RH). However, this work is very similar with the authors’ previous work (Nat Commun 2025, 16, 5445) but does not show obvious improvement in innovation and materials performances. Here are some concerns and comments for the manuscript.\n1. Why was liquid crystal elastomer (LCE) chosen as the thermoelectric matrix instead of materials like hydrogels? As one of the most common smart materials, this paper fails to highlight LCE's stimulus responsiveness or shape-programming capabilities.\n2. The detailed preparation process for the side-chain liquid crystal fiber (s-LCE) is not mentioned. Furthermore, while s-LCE uses RM257 as the liquid crystal monomer, RM257 possesses two double bonds. How can the statement “the mesogens only one terminal connects to the molecular backbone” be ensured?\n3. The distinction between RM257 and RM82 lies solely in carbon chain length. Why was RM82 not selected for side-chain LCE fiber preparation to control variables?\n4. When molecular dynamics simulations calculated diffusion lengths for cations and anions in the programmed liquid crystal elastomer system, could the presence of numerous unreacted double bonds affect computational accuracy?\n5. During LCE fiber preparation, how does the method ensure alignment of liquid crystal units? While anisotropy in backbone LCE fibers is observable via POM, the absence of POM characterization for RM257-derived side-chain LCE fibers does not prove their liquid crystal units exhibit isotropy. Figure 1(a)'s schematic faces the same issue—side-chain liquid crystal units may not necessarily form tighter or more disordered arrangements.\n6. The m-LCE i-TE fiber prepared in this study indeed achieves the maximum p-n span under low humidity conditions. In the study “An actuatable ionogel thermoelectric fiber with aligned mesogens inducing unprecedented thermopower for four-dimensional dynamically adaptive heat harvesting. Nat Commun 2025, 16, 5445”, the p-type liquid crystal ionic-electric fiber exhibits a thermopower of 25.8 mV·K⁻¹. while the p-type thermopower of the p-type liquid crystal ionic-thermoelectric fiber in this paper is 22.5 mV·K⁻¹. Although the preparation methods are similar, the p-type thermopower does not show a significant improvement.\nSecond, the conclusion states that this liquid crystal fiber represents the highest performance among current n-type ionic thermoelectric materials under low-humidity conditions, with an n-type thermopower of -27.4 mV·K⁻¹. whereas the n-type thermopower of the ionic hydrogel synthesized in the study “Exceptional n-Type Ionic Thermoelectric Hydrogels by Synergistic Hydrophobic and Coordination Interactions, Adv. Mater. 2025, e10199” is -37.1 mV·K⁻¹, indicating that the performance does not surpass that reported in that study.", "reviewer_3": "The authors report on the use of liquid crystal elastomers (LCEs) as polymer substrates for ion-infused thermoelectrics (i-TEs). They show that the molecular structure of the mesogenic units, together with the ordered nature of the LCE network, facilitates more efficient anion and cation transport, thereby significantly enhancing the thermoelectric effect. Particularly notable is the performance of the n-type main-chain LCE/LiBF₄ configuration, which exceeds that of more conventional i-TEs. The article further compares the performance of side-chain and main-chain LCEs as i-TEs and concludes that main-chain LCEs provide a stronger thermoelectric effect, owing to their higher ordered network structure. The presented i-TEs also exhibit favourable mechanical properties, show humidity-resistant thermoelectric performance, and can be further assembled into devices to generate higher voltage outputs.\nWhile the main findings are very interesting and promising, and the materials are thoroughly, perhaps even excessively, characterised, there are several critical issues that need to be resolved.\nOverall, the manuscript is written in an overwhelming fashion, presenting in detail many results that have little to do with the thermoelectric effect or other applicative aspects, such as surface topology, optical properties, and certain mechanical properties. While these are valuable characterisations, they contribute little to the main theme of the work and would be more appropriate in the supplementary information or preparation section. Secondly, the excessive number of very small graphs and schematics makes the manuscript difficult to follow and understand. Thirdly, I would strongly recommend dividing the manuscript into sections, for example: thermoelectric mechanisms, material properties, thermoelectric devices… or something similar. This would make the article much clearer and easier to read.\nBeyond the presentation, I have concerns regarding the studied materials, specifically the side-chain LCEs. From the manuscript, it is not clear how the authors prepared the side-chain network from the reported components. In a side-chain LCE, the mesogens are attached at one end to a polymer backbone that is subsequently crosslinked. However, the authors used bifunctional mesogens and the same dithiol soft segments as in the main-chain preparation, and then state that only one end of the mesogen was attached to the backbone. This raises the question: where does the backbone come from in this case? The methods section does not describe the preparation of the side-chain LCEs at all, leaving me with the impression that the material is instead a partially reacted main-chain structure with free-floating chains. The presented NMR measurements also do not confirm the presence of a side-chain network, but merely indicate unreacted sites, which is consistent with both scenarios. Furthermore, it is not stated whether the materials were mono- or polydomain, and the preparation section likewise provides no information on this point. The only clue is a microscopy image of an m-LCE under crossed polarisers, which suggests a monodomain network. This should be explicitly addressed, since anisotropic structure affects ionic transport - a point the authors themselves emphasise on several occasions.\nIn addition to several less critical concerns, which I detail below, I unfortunately recommend a substantial rewrite and resubmission of the manuscript in order to place the findings in an appropriate context that aligns with the theme of the study and to properly address the above major issues with the studied material. As it is, I cannot recommend the article for submission.\nOther concerns and suggestions:\nPage 5, Line 188: “Moreover, the main-chain structure demonstrates a higher order parameter (0.44) compared to the side-chain structure (0.31)…” How was this value measured? Please clarify the methodology.\nFig. S5: Consider using the same y-axis scale to facilitate easier comparison. This applies to several other graphs as well.\nPage 7, Line 241: The value zTi should be defined for readers outside the field.\nFigs. S10–S13: Why not directly compare the two graphs with the results and skip the fitting plots? This would make the data much easier to follow.\nFig. S14: This schematic would fit better in the main article. I also recommend enlarging and clarifying the schematics, as the current version is hard to interpret, especially in print (colours are difficult to discern).\nFig. S15: Is there a specific reason why i-TEs from LCEs show such strong humidity resistance?\nPage 11, last paragraph: As mentioned earlier, some characterisations would be better placed in the supplementary material, with only a brief summary in the main text, since they do not contribute directly to the core theme but are still important background.\nPage 13, last paragraph: The same applies to the mechanical measurements.\nPage 13, Line 460: “Notably, the s-LCE i-TE fibre demonstrates convergence of loss modulus toward storage modulus at higher frequencies, indicating potential network structure deterioration…” This observation partly aligns with my earlier concerns about material preparation. Repeating the measurement could clarify whether the material shows fatigue. Additionally, please explain why this frequency sweep range was chosen. Without context, the reported values do not provide much useful information.\nFig. 4g: The authors compare material properties with other materials and emphasise the superior performance of LCE i-TEs. However, performance stability was not measured for the reference materials, making this comparison inappropriate.\nPage 15, Line 507: “Under a temperature gradient of 2.6 K, the device exhibits a remarkable thermopower of –110.32 mV K⁻¹, the voltage–temperature relationship is presented in Figure 5(f)...” Here the authors refer to the thermopower of an n-type series, yet the figure shows a voltage–temperature plot instead. Similar mismatches occur in several places and makes the manuscript confusing.\nPage 15, Line 520: “A self-powered wearable device is further fabricated…” In what sense is the device “self-powered”? The wording seems inaccurate: the device generates electrical potential that could serve as a power source for other devices, but this is not the same as being self-powered.\nFurthermore, the description of the device raises several questions. The manuscript states that the device is woven and that electrodes are attached to measure voltage, but it is unclear where the wires are connected. Is the device woven from a single fibre? Does the woven structure influence the voltage output (enhancing, diminishing, or leaving it unchanged)? In addition, the reported values in the text (‘…exhibits rapid response within 450 s, reaching values of 235 mV and 192 mV under these temperature differences, respectively’ and ‘…a temperature difference of 2.9 K is observed to generate a voltage of ~79 mV (Figure 5(k–l) and Supplementary Figure 26)’) do not match those shown in the corresponding graphs. Such inconsistencies is one more reason why the manuscript is difficult to follow."}, "author_response": "Responses to the Referees’ Comments\nPoint-by-point responses to the referees’ comments\nWe sincerely thank the reviewers for their constructive comments concerning\nour manuscript entitled “Programming liquid crystal elastomer unlocks\nextraordinary p- and n-type thermopower for fiber-shaped ionic thermoelectric\ncapacitors” (NCOMMS-25-63666). Those comments are all valuable and\ncritical for improving our paper. We have studied the comments very seriously\nand have addressed in full, which we hope meet with approval. Revised portion\nhave been highlighted in yellow in the manuscript. And our response to all\ncomments starts on the next page. (Comments in black, responses in blue)\nReviewer #1:\nThe manuscript presents a study on molecular structure regulation of liquid\ncrystal elastomers (LCEs), leveraging structural differences between main-\nchain and side-chain LCEs to modulate ion migration behavior and\nthermopower type. This approach enables the simultaneous realization of high-\nperformance p-type and n-type ionic thermoelectric materials under low-\nhumidity conditions of ≤30% RH, achieving an n-type thermopower of -27.4 mV\nK-1 and a p-n thermopower span approaching 50 mV K-1. Molecular dynamics\nsimulations elucidate the correlation between ion diffusion lengths and\nthermoelectric performance. Finally, a homologous p-n type fibrous ionic\nthermoelectric capacitor device is constructed, demonstrating potential for\napplications in wearable energy devices. The research aligns well with the\ngrowing demand for low-grade heat harvesting and flexible wearable\nelectronics, exhibiting significant scientific value and application potential.\nHowever, certain aspects require further elaboration to enhance the rigor and\ncompleteness of the study. Here are some comments on this manuscript that\nmay need major revision before I can recommend acceptance for publication.\nResponse:\nThank you for your thorough review and constructive comments. We have\ncarefully revised the manuscript according to your comments. The replies to\neach of your concern are listed below.\nPoint 1:\nThe ionic liquid selection lacks sufficient justification. In other words, what’s the\nprinciple to “program” the polymer? Figure 2(a) shows that m-LCE and s-LCE\nexhibit n-type and p-type behavior in various ionic liquids, respectively. Still, the\nmanuscript does not explain why specific ionic liquids induce such thermopower\npolarity inversion. It is recommended to include calculations of ion size, charge\ndensity, and interaction energies between the ions and the soft segments (C-\nO-C) of the LCEs to clarify the link mechanism between ionic liquid type and\nthe resulting thermopower polarity.\nResponse:\nSpecial thanks to you for raising this issue. The selection of ionic liquids indeed\nlacks sufficient justification. In fact, the programming principle of LCE i-TE fibers\nprimarily involves regulating the linking mode of liquid crystal mesogens within\nmolecular chains to construct main-chain and side-chain LCE molecular\narchitectures. By combining the selective interactions between LCE molecular\nchains and different cations/anions in various ionic liquids, achieving the\ndifferent of ion migration rates. These differences are further amplified by\nleveraging the variations in the order parameter and molecular spacing among\ndifferent program of LCE, ultimately leading to the optimization of thermopower.\nThe polarity reversal of thermopower in m-/s-LCE i-TE fibers primarily\nrelies on the differential cation/anion migration rates resulting from selective\ninteractions between the soft segments of LCE fibers and different\ncations/anions in various ionic liquids. Through the comparison of two typical p-\ntype and n-type LCE i-TE systems, the p-type thermopower exhibited by LCE\nfibers after impregnation with EMIM TFSI is primarily attributed to the stable\nhydrogen-bond-like non-covalent interactions between TFSI- and LCE\nmolecular chains, which constrain its migration and consequently increase the\nrelative mobility rate of EMIM+, resulting in a cation-dominated i-TE system\nunder a temperature gradient. This conclusion has been thoroughly validated\nin our previous work (Nature Communications,2025,16:5445). As for the n-type\nmaterial, the strong coordination between Li+ and LCE molecular chains\nconstrains the migration of cations, thereby enhancing the migration rate of BF -\n4\nand conferring its n-type characteristics.\nFollowing your constructive suggestions, we supplemented the interaction\nenergies between the ions and the soft segments (C-O-C) of the LCEs, ion size\nand charge density, as following:\nThrough the calculated of binding energies between LiBF (or EMIM TFSI)\n4\nand m-/s-LCE molecular chains, as shown in Figure 1(d). The calculation\nresults reveal that for LiBF , both m- and s-LCE i-TE fibers exhibit significantly\n4\nhigher binding energies with Li+ due to the strong coordination interactions\nbetween ether groups (C-O-C) of LCE molecular chains and Li+, far exceeding\nthe binding energies between the molecular chains and BF -, resulting in an\n4\nanion-dominated i-TE system. Moreover, the difference in binding energies of\nthe molecular chains with Li+ and BF - is greater in m-LCE i-TE fibers compared\n4\nto s-LCE i-TE fibers. While for EMIM TFSI, due to the hydrogen-bond-like non-\ncovalent interactions between TFSI- and LCE molecular chains, the binding\nenergies between m-/s-LCE i-TE fibers and TFSI⁻ are both higher than those\nwith EMIM+, which likewise confirms the origin of the p-type thermopower in m-\n/s-LCE i-TE fibers after EMIM TFSI impregnation. Furthermore, the difference\nin binding energies of the molecular chains with EMIM+ and TFSI- is greater in\nm-LCE i-TE fibers compared to s-LCE i-TE fibers, elucidating the reason why\nthe m-LCE i-TE fibers have higher p-type thermopower than s-LCE i-TE fibers.\nIn addition, we investigated the effects of charge density and ionic size of\ndifferent ionic liquids on the thermopower of LCE i-TE fibers. As shown in Figure\n2(a), among the six ionic liquids, LiBF and BMIM PF exhibit n-type\n4 6\ncharacteristics, with LiBF demonstrating the optimal thermopower. From the\n4\ncharge density perspective, Li+ possesses a high charge density (Energy\nStorage Materials 28 (2020) 293-299; Chemical Engineering Journal 519 (2025)\n165170) and forms strong coordination with the ether groups (C-O-C) in the\nLCE molecular chains, resulting in complete anchoring. Consequently, BF -\n4\nremains relatively free and serves as the primary charge carrier under the\ntemperature gradient. In contrast, BMIM+, due to its lower charge density,\nexhibits weakened binding energy with the molecular chains, leading to a\nreduced ionic mobility contrast between BMIM+ and PF -. From the ionic size\n6\nperspective, the small ionic size of Li+ allows it to be anchored without hindering\nthe migration of BF -. However, the BMIM⁺ obstructs the overall ionic mobility\n4\nwithin the system due to bigger ionic size, and the larger ionic size of PF -\n6\ncompared to BF - further impedes ion migration, resulting in decreased mobility.\nOAC- > TFSI- by the calculated with electrostatic potential and ion size. The\nabsence of strong interactions between these anions and LCE molecular chains\nresults in their preferential formation of stable ion pairs with the cations EMIM+\nand AMIM+. Therefore, higher charge density hinders the dissociation of ion\npairs within the system and constrains cation migration. Furthermore, from the\nionic size perspective, the order is TFSI- > OAC- > Cl-.\nThe exceptionally large\nionic size of TFSI- results in a mobility far lower than that of EMIM+ among these\nionic liquids, directly amplifying the ionic mobility contrast between anions and\ncations. On the other hand, AMIM+ exhibits lower ionic mobility than EMIM+ due\nto its larger ionic size. Therefore, considering the combined effects of charge\ndensity and ionic size, the differences of ionic mobility in ionic liquids follows\nthe order: EMIM TFSI > EMIM OAC > EMIM Cl > AMIM TFSI. This trend is\nconsistent with the experimental results shown in Figure 2(a).\nBased on the comprehensive analysis of binding energies between\ncations/anions and LCE molecular chains, ionic charge density, ionic size,\nalong with the experimental results, it can be concluded that in LCE i-TE fibers,\nthe polarity of thermopower is primarily attributed to the selective interactions\nbetween LCE molecular chains and ions, while the magnitude of thermopower\nis governed by the combined effects of ionic charge density and ionic size.\nFigure1 (d) Binding energy between soft segments and ionic donors (Li+, BF -,\n4 6\nAMIM+ and EMIM+.\nSupplementary Table 1: Ionic sizes of cations and anions in different ionic\nliquids\nIon sizes\nLength (Å) Width (Å) Height (Å)\nIon types\nBMIM+ 8.597 4.763 3.780\nAMIM+ 8.295 4.134 3.012\nEMIM+ 7.423 4.061 2.858\nTFSI- 3.118 2.576 6.614\nPF - 3.274 3.274 3.274\nOAC- 1.523 2.510 2.278\nBF - 2.131 1.867 2.186\nOur revision to the Manuscript: To more clearly elucidate the principle to\n“program” the polymer and the mechanisms to govern the magnitude and\npolarity regulation of the material’s thermopower, we have provided a detailed\nexplanation of the material programming mechanism and supplemented it with\nrelevant DFT calculations. The revised parts of the manuscript are located on\npages 4, second paragraph, line 158-161; pages 5-6, second paragraph, line\n196-213 and line 232-237, Figure 1 (d), Supplementary Figure 4 and\nSupplementary Table 1 have been modified, the revised sections have been\nhighlighted in yellow for clarity.\nPoint 2:\nThe thermoelectric properties measurement conditions require clearer\nspecification. What’s the sample’s size? How to apply the temperature gradient?\nThe manuscript claims that molecular structure engineering influences\nthermodiffusion thermopower; it is imperative to ensure the reliability of these\nmeasurements. The authors should provide detailed information on\ntemperature control accuracy, electrode contact configuration, and the testing\nprotocol for fiber samples. Crucially, water content in the materials should be\ncontrolled, and humidity effects during thermopower measurement need to be\nexplicitly excluded. To confirm the reversibility of the measured thermovoltage\nand thus validate the intrinsic thermodiffusion thermopower, it should be\ndemonstrated that the open-circuit voltage returns to near zero upon removal\nof the applied temperature gradient.\nResponse:\nThank you for raising this question. We apologize for the oversight in our\nmanuscript regarding the detailed description of the measurement conditions.\nAs illustrated in the Figure S2, the measurement samples are standardized to\na length of 2 cm and a diameter of 2 mm. Each sample is placed at the center\nof a Peltier module, with one half positions on the hot side and the other half on\nthe cold side. The temperature difference across the Peltier module is\ncontrolled by varying the applied voltage, where an increase of 0.01 V in voltage\nachieves a precise control of 0.1 K temperature difference. Therefore, the\ntemperature control in this work is accurate. Silver wires are used as electrodes\nand attaches to both the cold and hot ends of the sample, securing with double-\nsided adhesive tape to ensure tight contact between the wires and the sample,\nthe diameter and length of silver wire used for testing is 0.25 mm and 4 cm, and\nthe spacing between silver wires is 1.5 cm. The temperatures at the cold and\nhot ends are monitored and recorded using an infrared thermographic camera,\nenabling precise measurement of the surface temperature of the material. The\nentire measurement system is enclosed in an acrylic sheet chamber. The\nambient temperature of the measurement room is maintained at 26°C, and the\nrelative humidity is recorded with a hygrometer and stabilized below 30% RH.\nThese measures effectively eliminated the influence of environmental\ntemperature and humidity on the measurement results.\nTo further validate the accuracy and effectiveness of the measurement\nsystem, we synthesized bacterial cellulose (BC) films as reported in the\nliterature (Adv. Funct. Mater. 2022, 32, 2107105) and measured their\nthermopower, as described in our work (Nature Communications; (2025)\n16:5445). The measurement results were consistent with those reported in the\nliterature. Here, to further demonstrate the rigor of the measurement system,\nwe selected a fiber-based i-TE material reported in the literature (Chemical\nEngineering Journal 497 (2024) 154970) for synthesis and measurement. As\nshown in Figure S3, the synthesized PAM/LiTFSI i-TE fibers exhibited a\ntransparent appearance, matching the literature description. During\nthermopower measurement, copper was used as the electrode, and a\nthermopower of 9.01 mV K-1 was obtained, which is in excellent agreement with\nthe reported value (9.02 mV K-1). Furthermore, the performance parameters\nobtained using the thermopower measurement system employed in this study\nhave been reported and validated in publications such as Adv. Mater. 2024, 36,\n2402386 and Sci. Adv. 9, eadk2098 (2023). In conclusion, the thermopower\nmeasurement system used in this work is capable of reliably characterizing the\nperformance of ionic thermoelectric materials and demonstrates both accuracy\nand validity.\nAdditionally, water content and humidity did not affect the thermopower\nmeasurement results. The m-LCE i-TE fibers were prepared using a solution\nimmersion method with ethyl acetate as the solvent, which is highly volatile\nunder ambient conditions. During testing, all m-LCE i-TE fibers are thoroughly\ndried and contained no residual liquids. As shown in Supplementary Video 1,\nwiping the fibers with nonwoven fabric revealed no presence of liquid,\nconfirming that liquids content does not affect their performance. Furthermore,\nthe measurement environment is maintained at a constant temperature of 26 °C\nand a relative humidity below 30%, accurately monitored using a hygrometer,\nensuring no impact on the measurement results. More importantly, owing to the\nhydrophobic nature of the LCE material and its highly cross-linked network\nstructure, environmental humidity adsorption is effectively inhibited (Adv. Funct.\nMater. 2013, 23, 3070-3076). This structure reduces the material’s\nresponsiveness to external humidity and suppresses humidity diffusion,\nsignificantly minimizing performance variations of the m-LCE i-TE fibers under\nhumidity conditions. The negligible effect of humidity on thermopower\nmeasurements can be demonstrated by Supplementary Figure S12 even when\nplaced in a controlled temperature and humidity chamber at varying humidity\nlevels, the thermopower of the m-LCE i-TE fibers showed no significant change.\nTherefore, the influence of ambient humidity on the thermoelectric performance\nof the material can be ruled out.\nTo verify the reversibility of the performance of the m-LCE i-TE fiber, we\nsupplemented and tested the voltage changes under different temperature\ndifferences of materials. The results clearly demonstrate that the voltage curve\nof the m-LCE i-TE fiber responds correspondingly as the temperature difference\nincreases, and gradually returns to the initial state of 0 V upon removal of the\ntemperature difference. Furthermore, with repeated application and removal of\nthe temperature difference, the output voltage of the m-LCE i-TE fiber\nconsistently responds to the thermal changes and reverts to the initial 0 V state,\nconfirming its excellent reversibility and cycling stability, as shown in Figure S14.\nFigure S2 Physical Diagram of thermopower measurement system.\nFigure S3 PAM/LiTFSI i-TE fibers and testing physical photographs (a-b).\nVoltage-temperature curves (c) and fitting plot (d) of PAM/LiTFSI i-TE fibers.\nFigure S12 Thermopower of m-LCE i-TE fibers with various relative humidity.\nFigure S14 Voltage reversibility (a) and cycling performance (b) of m-LCE i-TE\nfiber under temperature difference.\nOur revision to the Manuscript: To provide a detailed description of the\nthermopower testing system while highlighting the water content of the tested\nmaterials and the reversibility of the thermoelectric voltage, the relevant content\nhas been revised accordingly. The revised parts of the manuscript are located\non pages 6, second paragraph, line 227-229; pages 18, third paragraph, line\n649-657; pages 7-8, first paragraph, line 281-284, Supplementary Figure 2, 3\nand 14 have been modified, the revised sections have been highlighted in\nyellow for clarity.\nPoint 3:\nThe evaluation of practical performance in wearable applications is insufficient.\nAlthough Figure 5(j-l) shows voltage output from the fiber under two operational\nconditions, there is no demonstration of the device’s ability to power electronic\ncomponents. The authors are encouraged to supplement the study with output\npower data and provide images or videos of the device powering actual\nelectronic components, thereby more effectively illustrating its practical utility.\nResponse:\nThank you for your valuable question. To address the current lack of evaluation\nof LCE i-TE materials in wearable applications, we select a liquid crystal display\n(LCD) as the electronic component and connected it in parallel to the m-LCE i-\nTE fiber. By regulating the temperatures at the cold and hot ends under a\ntemperature difference of 45 K, numerical display appears on the LCD screen.\nThis demonstrates that the output voltage generated by the m-LCE i-TE fiber\nunder temperature differences provides the necessary driving force for\nelectronic components, effectively showcasing its practical application value,\nas shown in Supplementary Figure S34.\nMeanwhile, it should also be noted that, the output current is very small of\nionic thermoelectric materials due to differences in the working mechanism and\ncharge carrier types compared to traditional electronic thermoelectric materials,\nions-the charge carriers in ionic thermoelectric materials-cannot flow through\nthe circuit via electrodes, leading to the current practicality of ionic\nthermoelectric materials being primarily evaluated based on thermopower and\nthe energy density of capacitors (Energy Environ. Sci., 2016, 9, 1450-1457; Sci.\nAdv. 9, eadk2098 (2023)). The thermopower and energy density of the m-LCE\ni-TE fiber (-27.4 mV K-1, 8.12 mJ m-2) indicates a relatively high output\nperformance. Additionally, ionic thermoelectric materials based on ion gels and\npolyelectrolytes, tend to exhibit high electrical resistance, which directly limits\ntheir output performance. Therefore, the constraints imposed by the working\nmechanism and charge carrier types on material output performance remain a\nsignificant challenge for researchers in the field of ionic thermoelectric materials\nand represent a critical frontier for future studies in this area.\nFigure S34 (a) Liquid crystal display (LCD) and (b) LCD driven by m-LCE i-TE\nfiber.\nOur revision to the Manuscript: To demonstrate the LCE’s ability to power\nelectronic components, we have supplemented the manuscript with relevant\ntests and descriptions. The revised parts of the manuscript are located on\npages 14, third paragraph, line 515-518, Supplementary Figure 34 has been\nmodified, the revised sections have been highlighted in yellow for clarity.\nPoint 4:\nThe author mentioned the figure of merit (ZT) of i-TE materials in the manuscript\nand directly used the relevant formulas of e-TE, which is inappropriate.\nBecause ion thermoelectric materials have difficulty continuously outputting\nconstant electrical power under stable thermal gradients, like electronic\nthermoelectric materials (The four-stage discharge data in the manuscript also\nconfirms), the efficiency calculation models and formulas for ion thermoelectric\nmaterials are significantly different from those for electronic thermoelectric\nmaterials. Therefore, the figure of merit and power factor of electronic\nthermoelectric materials do not apply to ion thermoelectric materials.\nResponse:\nThank you for raising this important question. We sincerely apologize for this\nissue and will ensure that zT is no longer used to characterize ionic\nthermoelectric materials in this manuscript and our future work. Indeed, we\nrecognize fundamental differences between ion thermoelectric materials and\nconventional electronic thermoelectric materials based on literature review and\nconsiderations of the ion thermoelectric mechanism (Chem. Rev. 2021, 121,\n12465-12547). While traditional thermoelectrics rely on electrons/holes as\ncharge carriers, ion thermoelectrics utilize cations and anions as thermally\ndriven carriers, operating through entirely distinct mechanisms for\nthermoelectric conversion. As a result, conventional metrics such as the\nthermoelectric figure of merit (zT) and power factor (PF) are inadequate for\nevaluating the performance of ion thermoelectrics materials. To enhance the\nscholarly rigor of our manuscript, we have therefore removed all references to\nzT and PF in the revised version.\nOur revision to the Manuscript: Since zT and PF are not suitable for\nevaluating the performance of ionic thermoelectric materials, we have removed\nthe relevant descriptions of zT and PF from the manuscript, thereby enhancing\nits professionalism.\nPoint 5:\nAll image quality in the manuscript needs improvement for better readability.\nThe term liquid crystal elasticity (LCE) in the abstract may be referred to as\nliquid crystal elastomer (LCE) to better align with the expression of LCE in\nsubsequent text. Consistency between figure captions and main text\ndescriptions should be verified. Line 398, Figure 3(g) is labeled as EDS\nelemental mapping, whereas the main text refers to it as AFM topographical of\nm-LCE i-TE fibe. Additionally, on line 492, the four-stage working mechanism\ndescribed in Figure 5(a) is based on n-type material, where anions\npredominantly accumulate at the cold side. In this context, electrons in the\nexternal circuit during the second and third stages should accumulate and\nremain at the hot side of the device instead of the cold side. Furthermore, the\ntotal capacitive energy density in the ion capacitor mode remains constant.\n(Energy Environ. Sci. 2016, 9, 1450) It is therefore recommended that long-\nterm charge-discharge tests be provided under various load resistances, and\nthe corresponding capacitive energy density of the device be calculated.\nResponse:\nThank you for raising this important question. We apologize for these oversights.\nFirst, we have revised “liquid crystal elasticity (LCE)” in the abstract to “liquid\ncrystal elastomer” and ensured consistent use of “LCE” throughout the\nmanuscript. Second, we have corrected inconsistencies between the\nmanuscript and figures, including descriptions related to EDS, AFM, and Figure\n5(e). Additionally, we have made major revisions to all figure content and layout\nto improve readability and clarity, including:\n(1) The mesogen orientation in the side-chain LCE network in Figure 1(a) and\nthe calculations of the binding energies between the two chain types and\nLiBF /EMIM TFSI were added.;\n4\n(2) Adding a schematic diagram of the diffusion length mechanism in Figure 2(g)\nas suggested by other reviewers and Figures 2(g, h) have been moved to the\nsupporting information, modifying the overall layout of Figure 2;\n(3) Moving EDS, POM, and AFM characterizations in Figure 3 to the supporting\ninformation as they are less relevant to the main focus of the article;\n(4) Transferring the small graphs and tensile performance data in Figures 4(c,\nd) and 5(e, g, i) to the supporting information, correcting the error regarding the\ncapacitor mechanism in Figure 5(a) to enhance simplicity and professionalism\nof the figures.\nMeanwhile, we reviewed the calculation of energy density for ionic\ncapacitors as reported in the literature (Energy Environ. Sci. 2016, 9, 1450),\nwhere the energy density is expressed by the formula 𝐸 = 1 𝐶𝑉2 . Here, C\n2\nrepresents the capacitance of the material, and V denotes the potential\ndifference under a temperature gradient. Since C reflects an intrinsic property\nof the material and can be considered constant, it can be determined by testing\n𝐼\nthe cyclic voltammetry (CV) curve of the material using the formula 𝐶 = (for\n𝑣\nideal capacitive behavior), where I is the current and v is the scan rate, or 𝐶 =\n𝑄\n(for non-ideal capacitive behavior), where Q is the total charge and ΔV is\n𝛥𝑉\nthe voltage window. Thus, under a constant temperature difference, the energy\ndensity of the material remains constant. Based on the capacitance calculation\nformula, we first measured the CV curve of the material at a scan rate of 1 mV/s\n(as shown in the figure below). Through integration, the total charge and\ncapacitance were determined to be 7.44*10-5 C and 3.72*10-5 F, respectively.\nSubsequently, the calculated energy density reached 9.48 mJ m2. Compared\nto the energy density reported in the manuscript (8.12 mJ m-2), this value is\nslightly higher. The discrepancy primarily arises from the fact that the energy\ndensity calculated used 𝐸 = 1 𝐶𝑉2 in the literature is the theoretical maximum\n2\nvalue of the material and does not account for energy losses during capacitor\ndischarge, while the energy density calculated in this work is the actual\nmeasured value from the charge-discharge curves during the experimental\nprocess (Nature Communications, (2023)14:3246):\n𝑉\n∫ 𝑜𝑢𝑡 𝑑𝑡\n1 𝑅\n𝑃 = 𝑙𝑜𝑎𝑑\n𝑆 𝛥𝑡\nWhere S is the effective material area, V is the voltage output in the Ⅱ stage\nout\nof the capacitor, R is the external load resistance, and Δt is the duration of\nload\nthe Ⅱ stage. This formula yields the actual output energy density of the\nmaterial in practical applications.\nMeanwhile, as illustrated in Figures 5(c-d) of the manuscript, long-term\ncharge-discharge tests under different load resistances and the corresponding\ncalculated energy densities reveal that the voltage curve during both charging\nand discharging stage decreases more gradually as the external load increases.\nFurthermore, the calculated energy density reached a peak value of 8.12 mJ m-\n2 at a load resistance of 1 MΩ.\nFigure 1. Design principle for programmed liquid crystal elastomer enabling\nhigh n-type i-TE materials.\nFigure 2. Thermoelectric Performance and Mechanism analysis.\nFigure 3. Structural Characterization.\nFigure 4. Comprehensive Performance Evaluation.\nFigure 5. Capacitive and Sensing Performance of i-TE device.\nCV curve of m-LCE i-TE fiber at a scan rate of 1 mV s-1.\nFigure 5 (c) Thermovoltage under varying loads during the Stage Ⅱ (inset:\nThermovoltage under varying loads during the Stage Ⅳ). (d) Energy density\nof i-TE capacitors with different load resistors.\nOur revision to the Manuscript: To enhance the professionalism and\nreadability of the figures in the manuscript, we have made major revisions to\nthe layout and descriptions of all figures, and have also rewritten the description\nof the long-term charge-discharge testing. The revised parts of the manuscript\nare located on pages 1, first paragraph, line 20, 31-32; pages 12, second\nparagraph, line 432-436; pages 13, first paragraph, line 470-473; pages 14,\nthird paragraph, line 508-511 and line 520-525, Figure1, 2. 3, 4, 5 have been\nmodified, the revised sections have been highlighted in yellow for clarity.\nReviewer #2:\nThis manuscript reports the fabrication of a main-chain liquid-crystalline\nelastomer (m-LCE) fiber. This fiber exhibits a remarkable n-type thermopower\nof -27.4 mV·K⁻¹ under low humidity conditions (＜30% RH). However, this work\nis very similar with the authors’ previous work (Nat Commun 2025, 16, 5445)\nbut does not show obvious improvement in innovation and materials\nperformances. Here are some concerns and comments for the manuscript.\nResponse:\nThank you for your thorough review and constructive comments. We have\ncarefully revised the manuscript according to your comments. The replies to\neach of your concern are listed below.\nPoint 1:\nWhy was liquid crystal elastomer (LCE) chosen as the thermoelectric matrix\ninstead of materials like hydrogels? As one of the most common smart materials,\nthis paper fails to highlight LCE's stimulus responsiveness or shape-\nprogramming capabilities.\nResponse: Special thanks to you for raising this issue. This manuscript selects\nLCE as the ionic thermoelectric matrix instead of other hydrogels primarily to\naddress the current challenges and limitations in the ionic thermoelectric field,\nincluding electrolyte leakage, insufficient mechanical properties, and singular\noptimization strategies. The design rationale for using LCE as the\nthermoelectric matrix is as follows:\n(1) Ionic thermoelectric materials based on hydrogels often require high-loading\nof ionic electrolytes and the addition of multi-component ionic donors to achieve\nhigh performance, leading to issues such as liquid leakage and difficulties in\nencapsulation, which limit their practical applications (Sci. Adv. 9, eadk2098\n(2023); Nat. Com. (2019)10:1093). In contrast, our work utilizes LCE as the\nmatrix and employs a solution immersion method to impart thermoelectric\nproperties. By leveraging the structural advantages of m-LCE network that\nenable enlarged mobility differences between anions and cations without\nrequiring additional ionic donors, effectively preventing ionic liquid leakage..\nMoreover, thanks to the hydrophobic nature and highly crosslinked network\nstructure of LCE, the material significantly reduces sensitivity to external\nhumidity (Adv. Funct. Mater.2013,23,3070-3076), avoiding interference with\nthermoelectric performance. As a result, LCE i-TE materials can operate at\nroom temperature without encapsulation;\n(2) Most current high-performance ionic thermoelectric materials require\nprecise regulate and optimization of their network structures, often resulting in\nmolecular chains that cannot withstand significant stress, leading to poor\nmechanical properties-typically with stress and strain levels hardly exceeding\n2022, 15, 2049-2060). This inevitably creates a trade-off between mechanical\nand thermoelectric performance. In this study, the LCE i-TE fibers inherit the\nexcellent intrinsic mechanical properties of LCE, enabling them to exhibit both\nnotable thermoelectric characteristics and robust mechanical behavior. This\nsuccessfully addresses the mechanical limitations of existing ionic\nthermoelectric materials and enhances their potential for applications in\nwearable devices and actuators fields;\n(3) Current strategies for improving the performance of ionic thermoelectric\nmaterials often rely on regulating interactions between ions and polymer\nmatrices, incorporating multicomponent doping, or controlling external\nconditions such as relative humidity and pH, such as reported in Nature\nCommunications (2022) 13:221; Adv. Mater. 2024, 36, 2402386; Energy\nEnviron. Sci., 2022, 15, 2049-2060. These approaches generally involve\ncomplex preparation processes and stringent testing conditions, resulting in\npoor reproducibility of material performance, phase separation, and insufficient\nstructural and performance stability, which limit the practical applicability of ionic\nthermoelectric materials. In this work, the use of LCE as a matrix leverages its\nprogrammable molecular chain structure to achieve a highly ordered\narrangement, which facilitates thermal-driven ion migration within the system.\nThis structural optimization intrinsically enhances the thermoelectric\nperformance of the material, offering a more practical and scalable pathway for\nadvanced applications.\nFurthermore, as a common smart material, LCE exhibits excellent stimulus\nresponsiveness and shape-programming capabilities, making it widely\napplicable in actuators, artificial muscles, and other fields. Similar to the smart\nLCE i-TE fibers reported in our previous work (Nature\nCommunications,2025,16:5445), which demonstrated integrated actuation and\nsensing capabilities under thermal stimulation, the m-LCE i-TE fibers in this\nmanuscript also exhibit thermo-actuating behavior. As shown in Figure S41, at\ndifferent temperatures, the LCE i-TE fiber undergoes transverse contraction\nmacroscopically due to the changes in the orientation of mesogens under high\ntemperature. At 70 °C, the contraction rate reached 18.6%, and the fiber\ngradually returned to its original length as the temperature decreased. DSC\nmeasurements of the LCE i-TE fiber revealed a glass transition temperature of\n42.1 °C and a clear point at 90.6 °C, indicating a liquid crystalline phase\ntemperature range of 42.1-90.6 °C (Figure S42). This suggests that deformation\ncan occur when the temperature exceeds 42.1 °C. However, the LCE i-TE fiber\npresented in this study is primarily designed for sensing applications in\nwearable thermal energy scenarios. As demonstrated in Figures 5(i-k) and\nSupplementary Figure S40, the voltage signal response under varying\ntemperature differences between the human body and the environment is used\nfor information feedback. Since the contacted heat sources in this work do not\nreach the thermal actuation range of the material, no thermally induced\ndeformation occurs.\nFigure S41 Thermal actuation behavior of m-LCE i-TE fiber.\nFigure S42 DSC curve of the m-LCE i-TE fiber.\nOur revision to the Manuscript: To highlight the advantages and thermal\nactuation properties of the LCE material, we have added relevant discussions.\nThe revised parts of the manuscript are located on pages 8, first paragraph, line\n281-289; pages 12, third paragraph, line 449-453; pages 13, second paragraph,\nline474-480, Supplementary Figure 41 and 42 have been modified, the revised\nsections have been highlighted in yellow for clarity.\nPoint 2:\nThe detailed preparation process for the side-chain liquid crystal fiber (s-LCE)\nis not mentioned. Furthermore, while s-LCE uses RM257 as the liquid crystal\nmonomer, RM257 possesses two double bonds. How can the statement “the\nmesogens only one terminal connects to the molecular backbone” be ensured?\nResponse: We sincerely appreciate your valuable suggestions. We apologize\nfor the oversight in not including the fabrication method of side-chain liquid\ncrystal elastomer (s-LCE) i-TE fibers in the manuscript. The preparation of s-\nLCE i-TE fibers follows the procedure reported in the literature (Nature\nCommunications; (2025) 16:5445), utilizing RM257 as the liquid crystal\nmesogen, EDDET and PETMP as the soft segment and crosslinker,\nrespectively, and DPA as the catalyst. Briefly, 2.4 g RM257, 0.7 g EDDET, and\n0.1 g PETMP were dissolved in 2.4 mL ethyl acetate and stirred at 70°C for 1\nh. Then, 9 μL DPA was added, and the mixture was stirred for 1 min to obtain\nthe LCE precursor solution. The solution was subsequently injected into a\npolytetrafluoroethylene (PTFE) tube (inner diameter: 2 mm) via syringe and\ncured horizontally at room temperature for 12 h. The resulting s-LCE fiber was\nthen peeled from the tube. The s-LCE i-TE fibers were prepared by immersing\nthe s-LCE fibers in an ionic liquid solution for a designated duration using the\nsolution impregnation method. This fabrication procedure has now been added\nto the materials preparation section of the manuscript.\nThe conclusion that “the mesogens only one terminal connects to the\nmolecular backbone” is primarily supported by Nuclear Magnetic Resonance\n(NMR) characterization of the material. For s-LCE: 1H NMR (CDCl₃, δ, ppm):\n6.25-5.68 (d, 4H, CH₂=CH-); 5.99 (m, 2H, CH₂=CH-); 1.36 (m, 4H, -CH₂). As\nshown in Figure 2(b), the 1H NMR spectrum of s-LCE i-TE fibers displays a\npeak area ratio of olefinic protons to methylene protons of 1:1.59, which is\nconsistent with the single-end olefin structure (Polymer 52 (2011) 5075-5084).\nThis indicates that the material contains fewer olefinic protons with only one\nterminal olefin group connected to the molecular backbone, providing direct\nevidence for the side-chain LCE structure.\nFigure 2(b) 1H NMR spectrum of s-LCE fibers.\nOur revision to the Manuscript: To enhance the professionalism of the\nmanuscript, we have supplemented the preparation method of s-LCE and the\nrelevant discussions on side-chain structure characterization. The revised parts\nof the manuscript are located on pages 17, third paragraph, line 611-619; pages\n4, first paragraph, line 166-172, the revised sections have been highlighted in\nyellow for clarity.\nPoint 3:\nThe distinction between RM257 and RM82 lies solely in carbon chain length.\nWhy was RM82 not selected for side-chain LCE fiber preparation to control\nvariables?\nResponse: We sincerely appreciate your valuable feedback. We indeed\nomitted the explanation of this part in the manuscript. The reason for not\nselecting RM82 for the synthesis of side-chain LCE fibers in this study is\nprimarily due to differences in the thermoelectric properties of the LCE fiber\nprepared from various liquid crystal mesogen. Specifically, in terms of molecular\nchain structure, RM82 contains six methylene groups, while RM257 has only\nthree. This structural difference results in a softer network formed by RM82\ncompared to that of RM257. Given the significant differences in synthesis\nprocesses between main-chain and side-chain LCE fiber, if RM82 were directly\nused to synthesize LCE fibers for ionic thermoelectric materials, the increased\nviscosity of the material system would hinder ion migration and thus adversely\naffect the ionic thermoelectric performance. To verify this, we employed the\nsynthesis process for s-LCE i-TE fibers using RM82 as the liquid crystal\nmesogen, as shown in the figure below. Furthermore, using the impregnation\nmethod described in this work, we compared the thermopower of s-LCE i-TE\nfibers synthesized with RM82 and RM257 after impregnation with LiBF and\nTE fibers synthesized with RM82 was consistently lower than that of those\nsynthesized with RM257. This can be attributed to the significantly higher\nviscosity of the s-LCE i-TE fibers prepared by RM82, which suppresses the\nthermal migration of ions within the system. Therefore, to minimize the influence\nof physical morphology differences, such as viscosity, exhibited by s-LCE i-TE\nfibers synthesized using RM82 on the thermoelectric performance, and to\nensure a valid comparison of the thermoelectric properties between m- and s-\nLCE i-TE fibers, RM82 is not used for the preparation of s-LCE i-TE fibers in\nthis work.\nRM82-based s-LCE fiber (a) and its adhesive (b) physical appearance.\nThermopower of s-LCE i-TE fibers synthesized with RM257/RM82 after\nimpregnation in 1 M EMIM TFSI (a) and 1 M LiBF (b) for different\n4\nimpregnation time.\nPoint 4:\nWhen molecular dynamics simulations calculated diffusion lengths for cations\nand anions in the programmed liquid crystal elastomer system, could the\npresence of numerous unreacted double bonds affect computational accuracy?\nResponse: We sincerely appreciate your valuable feedback. The accuracy of\ncalculations indeed significantly impacts the computational results. In the\ncalculation of diffusion length mentioned in this study, the diffusion length (L)\nfor different systems is computed using the formula 𝐿 = √6𝐷 𝜏 based on the\n𝑖𝑜𝑛𝑠\ndiffusion coefficient and residence time (ACS Cent. Sci. 2019, 5, 1250−1260).\nIn the RM257 system, the large number of unreacted double bonds primarily\naffects the overall viscosity of the system and the spatial structure of molecular\nchains. These factors have already been considered and are reflected through\nthe diffusion coefficient and residence time of ions within the system.\nIn s-LCE i-TE fibers, it is precisely the differences in viscosity and\nmolecular chain structure compared to the main-chain system that led to\nsignificant disparities in the diffusion coefficients and residence times of cations\nand anions. These differences ultimately result in variations in the diffusion\nlength. Therefore, in the calculations presented in this study, the presence of\nnumerous unreacted double bonds in the side-chain system did not\ncompromise the accuracy of the computations. Instead, it serves as strong\nevidence demonstrating the distinct ion diffusion behaviors between main-chain\nand side-chain systems.\nOur revision to the Manuscript: To clarify the accuracy of the calculations, we\nhave emphasized the computational methods and the relevant discussions.\nThe revised parts of the manuscript are located on pages 9, second paragraph,\nline 339-345, and Supplementary Information 2 has been modified, the revised\nsections have been highlighted in yellow for clarity.\nPoint 5:\nDuring LCE fiber preparation, how does the method ensure alignment of liquid\ncrystal units? While anisotropy in backbone LCE fibers is observable via POM,\nthe absence of POM characterization for RM257-derived side-chain LCE fibers\ndoes not prove their liquid crystal units exhibit isotropy. Figure 1(a)’s schematic\nfaces the same issue-side-chain liquid crystal units may not necessarily form\ntighter or more disordered arrangements.\nResponse: We sincerely appreciate you bringing up this issue. During the\npreparation of LCE fibers, the ordered alignment of the liquid crystal mesogens\nprimarily originates from the injection process. To more clearly illustrate the\nunderlying mechanism, we have provided Supplementary Figure 1 to explain\nthis process. As shown in the figure below, the liquid crystal mesogens exist in\na disordered state within the syringe. However, as the syringe is compressed\nand the injection proceeds, the applied shear stress gradually induces a\ntransition of the mesogens from a disordered to an ordered state. This\nphenomenon has also been documented in the literature (Angew. Chem. 2023,\n135, e202308793). The shear force generated at the nozzle during the injection\nmolding process is the main factor responsible for inducing the directional\nalignment of the liquid crystal mesogens.\nWe apologize for the oversight in omitting the POM characterization of the\ns-LCE i-TE fibers. Through POM testing of the s-LCE i-TE fibers prepared with\nRM257 before and after solution impregnation, it is observed that when the fiber\nand polarizing filter are oriented at 45°, the s-LCE i-TE fibers exhibit vibrant\nmulticolored patterns both before and after impregnation. In contrast, at 0°,\na completely dark scene is observed. This indicates that the s-LCE i-TE fibers\nmaintained monodomain alignment and anisotropic characteristics throughout\nthe solution impregnation process (Angew. Chem. Int. Ed. 2023, 62,\ne202214339; Adv. Sci. 2024, 11, 2400557). Based on these findings, we have\nrevised the schematic of the s-LCE fibers in Figure 1(a) to accurately reflect the\nanisotropic orientation of the liquid crystal mesogens. Additionally, the more\ndisordered and tightly packed molecular chain structure of the s-LCE fibers is\nprimarily validated using two-dimensional wide-angle XRD of both m- and s-\nLCE fibers. The results reveals that the m-LCE fiber exhibits an order parameter\nand molecular spacing of 0.44 and 4.67 Å, respectively. In comparison, the s-\nLCE fiber shows values of 0.31 and 4.45 Å, indicating smaller interchain\nspacing and lower orientation degree. This confirms that the molecular chain\nstructure of the s-LCE fiber is more disordered and tightly packed compared to\nthe m-LCE fiber. However, the depiction of the liquid crystal mesogen alignment\nin Figure 1(a) may have been exaggerated. Therefore, we have revised the\nillustration to better align with the experimental findings, enhancing the\nprofessionalism and accuracy of the figure.\nFigure S1 Schematic diagram of ordered arrangement of liquid crystal units\ninduced by injection molding.\nFigure S32 POM images of s-LCE fiber before and after LiBF impregnation.\narchitectures (m-LCE network and s-LCE network) inside fibers.\nOur revision to the Manuscript: To enhance the professionalism of the\nmanuscript and the readability of the figures, we have supplemented and\nrevised the molding method, the POM images of s-LCE, and the illustrations of\nthe side-chain structure. The revised parts of the manuscript are located on\npages 5, first paragraph, line 189-191; pages 13, first paragraph, line 461-470,\nand Figure 1(a), Supplementary Figure 1, 31, 32 have been modified, the\nrevised sections have been highlighted in yellow for clarity.\nPoint 6:\nThe m-LCE i-TE fiber prepared in this study indeed achieves the maximum p-n\nspan under low humidity conditions. In the study “An actuatable ionogel\nthermoelectric fiber with aligned mesogens inducing unprecedented\nthermopower for four-dimensional dynamically adaptive heat harvesting. Nat\nCommun 2025, 16, 5445”, the p-type liquid crystal ionic-electric fiber exhibits a\nthermopower of 25.8 mV·K⁻¹. while the p-type thermopower of the p-type liquid\ncrystal ionic-thermoelectric fiber in this paper is 22.5 mV·K⁻¹. Although the\npreparation methods are similar, the p-type thermopower does not show a\nsignificant improvement.\nSecond, the conclusion states that this liquid crystal fiber represents the highest\nperformance among current n-type ionic thermoelectric materials under low-\nhumidity conditions, with an n-type thermopower of -27.4 mV·K⁻¹. whereas the\nn-type thermopower of the ionic hydrogel synthesized in the study “Exceptional\nn-Type Ionic Thermoelectric Hydrogels by Synergistic Hydrophobic and\nCoordination Interactions, Adv. Mater. 2025, e10199” is -37.1 mV·K⁻¹, indicating\nthat the performance does not surpass that reported in that study.\nResponse: We sincerely appreciate you bringing up this issue. The\nthermopower of p-type m-LCE i-TE fiber reaches only 22.5 mV K-1 in this\nmanuscript, which is lower than the performance reported in our previous work\n(25.8 mV K-1). This is attributed to the fact that this work adopted the\nimpregnation methods from the previous article (Nat Commun 2025, 16, 5445)\nto validate that m-LCE fibers can be used for high-performance p- and n-type\nhomologous materials, and therefore the impact of different LCE chain\nstructures on thermopower is not considered. In fact, m- and s-LCE fibers\nexhibit significant differences in raw materials and fabrication processes,\nleading to substantial variations in molecular chain spatial arrangement and\nsystem viscosity, which in turn affect the binding energy and thermal migration\nrates of cations and anions. Detailed preparation methods for s-LCE fibers have\nbeen supplemented in the manuscript. Following your suggestion, we\nconducted a detailed investigation of the impregnation concentration and time\nfor p-type m-LCE i-TE fibers. The results show that the thermopower increased\nto 28.8 mV·K-1 after impregnating the m-LCE fibers in a 1 M EMIM TFSI solution\nfor 3 h, surpassing the previously reported 25.8 mV·K-1 in a shorter\nimpregnation time. This improvement is attributed to the superior ordering of\nthe m-LCE network structure, which enhances ion adsorption and infiltration,\nand facilitates ion thermodiffusion.\nIn addition, the study by Yu et al. (Adv. Mater. 2025, e10199) reports a\nthermopower of −37.1 mV⋅K−1, achieved by optimizing thermopower in a\nmulticomponent system through the synergistic effect of PVA-Cu2+ coordination\nand the hydrophobicity of poly(maleic anhydride n-butyl ester) (PMNT).\nHowever, that material requires careful consideration of the complex\ninteractions among the three components and is relatively sensitive to ambient\nhumidity. By contrast, the LCE i-TE fibers reported here leverage their intrinsic\nstructural advantages to promote ion thermodiffusion, and exhibit excellent\nhumidity resistance due to their hydrophobicity and highly crosslinked network,\nthereby offering distinct advantages. Nevertheless, this paper provides an\nimportant optimization strategy for improving the performance of\nmulticomponent ionic thermoelectric materials. Therefore, we have prominently\ncited this important reference in the introduction. In the performance\ncomparison, this article did not include that work for the following reasons: (1)\nthis manuscript submission date was August 13, whereas this Advanced\nMaterials was published on August 22, therefore, it had not yet been published\nat the time of our submission and was not included in the comparison; (2) after\ncarefully reading that paper, we found that its thermopower calculation method\ndiffers slightly from ours. They employed a segmented temperature-voltage\ntesting protocol, while our thermopower measurements follow the approach\nused in most prior studies that requires continuous voltage-temperature\nmeasurements across 3-5 plateaus followed by fitting (Science 2020, 368, 6495:\n1091–1098, DOI: 10.1126/science.aaz5045), namely a continuous voltage-\ntemperature measurement. To verify the impact of different testing methods on\nthermoelectric performance, we applied the literature’s method to our n-type m-\nLCE i-TE fibers and performed fitting. As shown in the figure below, the\nmaximum thermopower of the fibers reached −42.45 mV⋅K-1, showing that the\ntesting method greatly affects the measured thermopower. Therefore, the\nthermopower obtained using the measurements method from the literature\nsurpasses the performance reported in that literature. However, our manuscript\nrepresents a more widely recognized and commonly measurements approach,\nso the value of -27.4 mV K-1 reported in this work and the literature value of -\n37.1 mV K-1 are not directly comparable;(3) the m-LCE i-TE fibers reported here\nconstitute a binary system composed of the polymer matrix and an ionic liquid.\nAmong binary i-TE materials and under low humidity, the m-LCE i-TE fibers\nachieve the highest performance reported to date. Therefore, to ensure rigor,\nwe added the qualifier “binary system” in the performance comparison and\nrevised “the m-LCE i-TE fiber impregnated with LiBF solution achieves the\n4\nhighest reported n-type thermopower of -27.4 mV K-1 at only 30% RH” to “In\ncomparison with performance at humidity below 70% RH (Figure 2(c)), the\nthermopower of -27.4 mV K-1 obtained at humidity of 30% RH in this work sets\na record for binary system thermopower”\nFigure S11 Thermopower of m-LCE i-TE fiber with different EMIM TFSI\nimpregnation concentration (a) and time (b). Voltage-temperature curve (c)\nand fitting plot (d) of the m-LCE i-TE fiber.\nThermopower of m-LCE i-TE fibers at different temperature differences\n(a) 1.9 K, (b) 4.2 K, and (c) 6.2 K and performance fitting plot (d).\nOur revision to the Manuscript: To further optimize the performance of p-type\nionic thermoelectric materials and improve the accuracy of the manuscript\ndescriptions, we have supplemented and revised the relevant experiments and\ndiscussions. The revised parts of the manuscript are located on pages 3, first\nparagraph, line 88-89; pages 7, third paragraph, line 263-267, and\nSupplementary Figure 11 has been modified, the revised sections have been\nhighlighted in yellow for clarity.\nReviewer #3:\nThe authors report on the use of liquid crystal elastomers (LCEs) as polymer\nsubstrates for ion-infused thermoelectrics (i-TEs). They show that the molecular\nstructure of the mesogenic units, together with the ordered nature of the LCE\nnetwork, facilitates more efficient anion and cation transport, thereby\nsignificantly enhancing the thermoelectric effect. Particularly notable is the\nperformance of the n-type main-chain LCE/LiBF₄ configuration, which exceeds\nthat of more conventional i-TEs. The article further compares the performance\nof side-chain and main-chain LCEs as i-TEs and concludes that main-chain\nLCEs provide a stronger thermoelectric effect, owing to their higher ordered\nnetwork structure. The presented i-TEs also exhibit favourable mechanical\nproperties, show humidity-resistant thermoelectric performance, and can be\nfurther assembled into devices to generate higher voltage outputs.\nWhile the main findings are very interesting and promising, and the materials are\nthoroughly, perhaps even excessively, characterised, there are several critical\nissues that need to be resolved.\nResponse:\nThank you for your thorough review and constructive comments. We have\ncarefully revised the manuscript according to your comments. The replies to\neach of your concern are listed below.\nPoint 1:\nOverall, the manuscript is written in an overwhelming fashion, presenting in\ndetail many results that have little to do with the thermoelectric effect or other\napplicative aspects, such as surface topology, optical properties, and certain\nmechanical properties. While these are valuable characterisations, they\ncontribute little to the main theme of the work and would be more appropriate\nin the supplementary information or preparation section. Secondly, the\nexcessive number of very small graphs and schematics makes the manuscript\ndifficult to follow and understand. Thirdly, I would strongly recommend dividing\nthe manuscript into sections, for example: thermoelectric mechanisms, material\nproperties, thermoelectric devices…or something similar. This would make the\narticle much clearer and easier to read.\nResponse:\nThanks for your constructive feedback. Based on your suggestions, we review\nthe narrative and characterization results throughout the manuscript and\nidentified that certain data, such as EDS, POM, and AFM, are not strongly\nlinked to the main theme. Additionally, some small graphs and schematic\ndiagrams -such as those in Figure 4(c, d) and Figure 5(e, g, i)- are overly\ncluttered, making the article structurally disorganized and difficult to read. To\nimprove the overall readability and professionalism of the manuscript, we have\nundertaken a major revision of all figure layouts and streamline the related\ndescriptions. The main changes include:\n(1) The orientation of mesogens in the s-LCE fiber in Figure 1(a) has been\nmodified to better align with its anisotropic and monodomain characteristics.\nAdditionally, the binding energy between the LCE material and EMIM TFSI has\nbeen increased. These improvements enhance both the readability of the figure\nand the overall professionalism of the manuscript.\n(2) Moving the Figure 2(g, h) of original manuscript to the Supplementary\nMaterials and adding a schematic illustration of the diffusion length mechanism\n(Figure 2(g)) in the manuscript;\n(3) Relocating the SEM, EDS, POM, and AFM characterizations from the Figure\n3(f, g, h, i) of original manuscript to the Supplementary Materials, with the\ncorresponding descriptions moved to the section on mechanical and optical\nproperties of the material in Figure 4. The SEM image has been repositioned\nas Figure 4(f);\n(4) Transferring the Figure 4(c, d) of original manuscript in to the Supplementary\nMaterials, and condensing and simplifying the descriptions related to\nmechanical and optical properties in Figure 4;\n(5) Moving the Figure 5(e, g, i) of original manuscript to the Supplementary\nMaterials, and adding Figures 5(g, h) depicting the device operating principle\nto help readers better understand the working mechanism, hereby simplifying\nboth the figure layout and the accompanying content.\nAdditionally, following your suggestions, we have restructured the Results\nand Discussion section of the manuscript to enhance its clarity and conciseness.\nThe revised organization is as follows:\n(1) Fig. 1: Design principle for programmed liquid crystal elastomer enabling\nhigh n-type i-TE materials.\n(2) Fig. 2: Thermoelectric Performance and Mechanism analysis.\n(3) Fig. 3: Structural Characterization.\n(4) Fig. 4: Comprehensive Performance Evaluation.\n(5) Fig. 5: Capacitive and Sensing Performance of i-TE device.\nThis reorganization aims to improve the overall logical coherence and\nreadability of the article.\nFigure 1. Design principle for programmed liquid crystal elastomer enabling\nhigh n-type i-TE materials.\nFigure 2. Thermoelectric Performance and Mechanism analysis.\nFigure 3. Structural Characterization.\nFigure 4. Comprehensive Performance Evaluation.\nFigure 5. Capacitive and Sensing Performance of i-TE device.\nOur revision to the Manuscript: To enhance the overall readability and\nprofessionalism of the manuscript, we have made major revisions to the layout\nof all figures and the narrative content throughout the manuscript. The revised\nparts of the manuscript are located on pages 4, second paragraph, line 196-\n213; pages 7, third paragraph, line 275-289; pages 8, second paragraph, line\n323-333; pages 10, first paragraph, line 378-380; pages 11, first paragraph, line\n395-401; pages 12-13, second paragraph, line 428-480; pages 14-15, third\nparagraph, line 515-527, line 538-544 and line 547-550, and the Figure 1, 2, 3,\n4, 5 have been modified, the revised sections have been highlighted in yellow\nfor clarity.\nPoint 2:\nBeyond the presentation, I have concerns regarding the studied materials,\nspecifically the side-chain LCEs. From the manuscript, it is not clear how the\nauthors prepared the side-chain network from the reported components. In a\nside-chain LCE, the mesogens are attached at one end to a polymer backbone\nthat is subsequently crosslinked. However, the authors used bifunctional\nmesogens and the same dithiol soft segments as in the main-chain preparation,\nand then state that only one end of the mesogen was attached to the backbone.\nThis raises the question: where does the backbone come from in this case?\nThe methods section does not describe the preparation of the side-chain LCEs\nat all, leaving me with the impression that the material is instead a partially\nreacted main-chain structure with free-floating chains. The presented NMR\nmeasurements also do not confirm the presence of a side-chain network, but\nmerely indicate unreacted sites, which is consistent with both scenarios.\nFurthermore, it is not stated whether the materials were mono- or polydomain,\nand the preparation section likewise provides no information on this point. The\nonly clue is a microscopy image of an m-LCE under crossed polarisers, which\nsuggests a monodomain network. This should be explicitly addressed, since\nanisotropic structure affects ionic transport - a point the authors themselves\nemphasise on several occasions.\nResponse:\nThanks for raising this question. We apologize for the oversight in not including\nthe fabrication process of the s-LCE i-TE fiber in the manuscript, which may\nhave led to the misunderstanding that it was derived from the m-LCE i-TE fiber.\nIn fact, the preparation method and material selection for the s-LCE fiber differ\nsignificantly from those of the main-chain type. The s-LCE fiber was\nsynthesized using RM257 as the mesogen, EDDET and PETMP as the soft\nsegment and crosslinker, respectively, and DPA as the catalyst. Specifically, 2.4\ng of RM257, 0.7 g of EDDET, and 0.1 g of PETMP were dissolved in 2.4 ml of\nethyl acetate under continuous stirring at 70 °C for 1 hour. Then, 9 μl of DPA\nwas added, and stirring continued for 1 minute to obtain the LCE precursor\nsolution. This solution was injected into a polytetrafluoroethylene (PTFE) tube\nwith an inner diameter of 2 mm and left horizontally at room temperature for 12\nhours. The resulting s-LCE fiber was then peeled from the tube. The s-LCE i-\nTE fiber was subsequently obtained by immersing the s-LCE fiber in an ionic\nliquid solution for a specific duration using a solution immersion method. This\nprocedure is consistent with our group’s previously published work (Nature\nCommunications, (2025)16:5445) and has now been thoroughly detailed in the\nmaterials preparation section of the revised manuscript.\nBased on the synthesis route of the s-LCE fiber and previously reported\nliterature, the molecular backbone of the s-LCE fiber synthesized using RM257,\nEDDET, and PETMP is primarily composed of poly(methyl)acrylate (Adv. Funct.\nMater. 2025, e15319), derived from the polymerizable acrylate end groups of\nRM257. NMR results presented in the manuscript confirm that only one end of\nthe mesogenic unit is attached to the backbone in the s-LCE fiber. Furthermore,\nrepeated DMA measurements of the s-LCE i-TE fiber consistently show that the\nstorage modulus remains higher than the loss modulus in the low-frequency\nregion (0.1 rad/s). This indicates that the material exhibits quasi-solid gel\ncharacteristics due to its internally stable network structure, with no liquid-like\nbehavior suggestive of an absence of network formation. These results confirm\nthe presence of a well-defined side-chain polymer network.\nAdditionally, through the observations of POM clearly reveal that the m-\nLCE i-TE fiber exhibits colorful patterns when oriented at 45° to the polarizer,\nwhile appearing completely dark at 0°, indicating its monodomain structure and\nanisotropic nature (Angew. Chem. Int. Ed. 2023, 62, e202214339; Adv. Sci.\n2024, 11, 2400557). We apologize for not explicitly describing or emphasizing\nthis phenomenon in the manuscript. In fact, the monodomain and anisotropic\nstructure of the m-LCE i-TE fiber plays a critical role in promoting the thermally\ndriven migration of ions under a temperature gradient, which indicates that\nliquid crystal mesogens are all uniformly aligned along the same direction,\nforming nanochannels between molecular chains that are favorable for ion\nmigration with low migration resistance, enabling ions to achieve high-speed\nthermal migration and further amplifying the thermal migration difference\nbetween cations and anions, thereby optimizing thermoelectric performance\n(Adv. Mater. 2025, 2504592; Adv. Mater. 2021, 33, 2103755). To highlight this\nimportant feature, we have supplemented the POM section with a detailed\nexplanation of how the monodomain alignment and anisotropic properties\nenhance ion transport, providing further insight into the underlying mechanism.\nOur revision to the Manuscript: To more clearly explain the composition of\nthe s-LCE network structure, we have supplemented the preparation method of\ns-LCE fibers and verified the presence of the crosslinked network by DMA\ntesting. Meanwhile, we have provided more detailed discussions in the\nmanuscript to highlight the significance of monodomain alignment and\nanisotropy for thermopower enhancement. The revised parts of the manuscript\nare located on pages 17, third paragraph, line 611-619; pages 12, second\nparagraph, line 443-448; pages 13, first paragraph, line 461-470, and the Figure\n4(d) and Supplementary Figure 31, 32 have been modified, the revised sections\nhave been highlighted in yellow for clarity.\nPoint 3:\nPage 5, Line 188: “Moreover, the main-chain structure demonstrates a higher\norder parameter (0.44) compared to the side-chain structure (0.31)…” How was\nthis value measured? Please clarify the methodology.\nResponse:\nThanks for your suggestion. The calculations of order parameter for m-/s-LCE\nfibers in this manuscript are based on the Hermans-Stein orientation distribution\nfunction (Adv. Mater. 2022, 34, 2107840; Adv. Mater. 2018, 30, 1801103):\n3 < 𝑐𝑜𝑠2𝜑 > −1\n𝑆 = 𝑆1\n2\n𝜋\n∫2𝐼(𝜑)𝑠𝑖𝑛𝜑𝑐𝑜𝑠2𝜑𝑑𝜑\n< 𝑐𝑜𝑠2𝜑 >= 0 𝑆2\n𝜋\n∫2𝐼(𝜑)𝑠𝑖𝑛𝜑𝑑𝜑\nis the mean square cosine of the angle between the mesogen orientation and\nthe fiber axis. The I-φ curve was fitted using a Gaussian function, and the order\nparameter S of the m-/s-LCE fiber is derived based on Equations S1 and S2.\nOur revision to the Manuscript: To provide a detailed explanation of the\ncalculation method for LCE order parameter in the manuscript, Supplementary\nInformation 1 has been added and revised. the revised sections have been\nhighlighted in yellow for clarity.\nPoint 4:\nFig. S5: Consider using the same y-axis scale to facilitate easier comparison.\nThis applies to several other graphs as well.\nResponse:\nSpecial thanks to you for raising this issue. Your suggestion is crucial for\nimproving the readability of the figures. Accordingly, we have modified the\nperformance comparison charts in the manuscript to use a unified Y-axis scale,\nwhich allows for clearer and more intuitive interpretation of the data.\nFigure S9 Conductivity of s- (a) and m- (b) LCE i-TE fiber impregnated with\ndifferent concentrations of LiBF at various impregnation time.\n4\nimpregnation concentrations (a) and impregnation time (b).\nFigure S24 Tensile stress-strain curves at stretching rate of 50 mm·min-1 of m-\n(a) and s- (b) LCE i-TE fiber with different concentration of PETMP and\nEDDET.\nOur revision to the Manuscript: To improve the readability of the performance\ncomparisons in the figures, we have revised all figures throughout the\nmanuscript. Supplementary Information 9, 10, 24 have been modified. the\nrevised sections have been highlighted in yellow for clarity.\nPoint 5:\nPage 7, Line 241: The value zT should be defined for readers outside the field.\ni\nResponse:\nThank you for your valuable suggestion. The zT value is crucial for evaluating\ni\nthe performance of thermoelectric materials. However, due to significant\ndifferences in working mechanisms and carrier types between ionic\nthermoelectric materials and conventional electronic thermoelectric materials,\nit is inappropriate to apply the zT evaluation system-as suggested by Reviewer\ni\n1-to assess ionic thermoelectric materials. To enhance the professionalism and\nrigor of the manuscript, we have carefully reconsidered and decided to remove\nall related data and discussions regarding zT and the PF from the manuscript.\ni\nOur revision to the Manuscript: Since zT\ni\nand PF are not appropriate metrics\nfor evaluating ionic thermoelectric materials, we have removed all references\nto zT and PF from the manuscript to enhance its accuracy.\ni\nPoint 6:\nFigs. S10–S13: Why not directly compare the two graphs with the results and\nskip the fitting plots? This would make the data much easier to follow.\nResponse:\nThank you for raising this important question. Your suggestion has indeed made\nthe data much easier to follow. In response, we have significantly restructured\nthe layout of Supplementary Figures 10-13 (Now adjusts to Supplementary\nImage 17-21). Specifically, Supplementary Figure 17 now compares the\nresidence time of ions under different immersion concentrations across various\nchain types, while Supplementary Figures 18-21 provide the corresponding\nfitting diagrams. This reorganization substantially improves the logical flow and\nclarity of the data presentation.\nFigure S17 Residence time of Li+ and BF - in m- (a) /s- (b) LCE fibers at each\nLiBF impregnation concentration (a) 0.55 M, (b) 0.65 M, (c) 0.75 M, (d) 0.85\nFigure S19 Residence time fitting plots of BF --O in m-LCE i-TE fibers at each\nFigure S20 Residence time fitting plots of Li+-O in s-LCE i-TE fibers at each\nLiBF impregnation concentration (a) 0.55 M, (b) 0.65 M, (c) 0.75 M, (d) 0.85\nFigure S21 Residence time fitting plots of BF --O in s-LCE i-TE fibers at each\nOur revision to the Manuscript: To improve the readability of the figures, we\nhave revised the figure layouts. Supplementary Information 17, 18, 19, 20, 21\nhave been modified. the revised sections have been highlighted in yellow for\nclarity.\nPoint 7:\nFig. S14: This schematic would fit better in the main article. I also recommend\nenlarging and clarifying the schematics, as the current version is hard to\ninterpret, especially in print (colours are difficult to discern).\nResponse:\nThank you for your valuable suggestion. Supplementary Figure 14 is indeed a\ncentral component of this manuscript. To better highlight the innovation and\nresearch approach of our work, we have incorporated it into Figure 2 of the\nmanuscript. Accordingly, significant revisions have been made to Figure 2, as\ndetailed below:\nFigure 2. Thermoelectric Performance and Mechanism analysis.\nOur revision to the Manuscript: To highlight the importance of diffusion length,\nthe schematic illustration of the diffusion length mechanism has been added to\nFigure 2(g), and the layout of Figure 2 has been major revised.\nPoint 8:\nFig. S15: Is there a specific reason why i-TEs from LCEs show such strong\nhumidity resistance?\nResponse:\nThank you for your valuable suggestion. The strong humidity resistance of the\nm-LCE i-TE fiber primarily stems from two factors (Adv. Funct. Mater. 2013, 23,\n3070-3076):\n(1) The intrinsic hydrophobicity of the LCE material effectively prevents the\nadsorption and accumulation of external humidity, thereby mitigating its impact\non performance.\n(2) The highly cross-linked network structure of the LCE significantly restricts\nthe diffusion and plasticizing effect of environmental humidity. This reduces the\ninfluence of air humidity on the internal structure of the LCE. The structural\nstability ensures that ion migration remains largely unaffected, resulting in\nenhanced humidity resistance.\nThis property is further supported by testing under varying humidity levels,\nthe thermopower of the m-LCE i-TE fiber maintains over 85% of its original\nperformance across relative humidities ranging from 30% to 90%.\nFigure S12 Thermopower of m-LCE i-TE fibers with various relative humidity.\nOur revision to the Manuscript: To more clearly elucidate the humidity\nresistance mechanism of LCE materials, we have revised the relevant\ndescriptions in the manuscript. The revised parts of the manuscript are located\non pages 7, third paragraph, line 275-279, the revised sections have been\nhighlighted in yellow for clarity.\nPoint 9:\nPage 11, last paragraph: As mentioned earlier, some characterisations would\nbe better placed in the supplementary material, with only a brief summary in the\nmain text, since they do not contribute directly to the core theme but are still\nimportant background.\nResponse:\nThank you for your valuable suggestion. Upon reviewing the overall narrative\nand figures in the manuscript, we recognized that the characterization and\ndescriptions related to Figure 3 on page 11 are not closely aligned with the core\ntheme of the work, making the manuscript appear heavy and cumbersome. To\nenhance the readability and professionalism of the manuscript, we have\nsignificantly revised the layout and content of Figure 3. Specifically, we have\nrelocated the EDS, POM, and AFM characterizations originally included in\nFigure 3 to the Supplementary Materials. The revised Figure 3 now focuses\nentirely on illustrating the thermoelectric mechanism, as shown below.\nFigure 3. Structural Characterization.\nOur revision to the Manuscript: To improve the readability of the figure,\nwe have made major revisions to the layout and relevant descriptions of Figure 3.\nThe revised parts of the manuscript are located on pages 10-11, second\nparagraph, line 378-409, and Figure 3 has been modified, the revised sections\nhave been highlighted in yellow for clarity.\nPoint 10:\nPage 13, last paragraph: The same applies to the mechanical measurements.\nResponse:\nThank you for your valuable suggestion. The m-LCE i-TE fiber proposed in this\nwork not only achieves a significant improvement in thermoelectric\nperformance in a binary system and under low humidity conditions due to its\nintrinsic structural characteristics, but also exhibits excellent mechanical\nproperties with high stress and strain tolerance compared to existing literature,\ndemonstrating strong potential for wearable applications. Meanwhile, following\nyour suggestion, we revisit the related content and identified certain mechanical\nmeasurements results that are less relevant to the core focus. Accordingly, we\nhave moved the small graphs from Figure 4(c, d) to the Supplementary\nMaterials. We have also substantially revised the description of the mechanical\nproperties to make it more concise and focused, thereby improving the overall\nreadability of the manuscript.\nOur revision to the Manuscript: To improve the readability of the figure\npresenting mechanical properties in the manuscript, we have made major\nrevisions to both the overall layout and relevant discussions of Figure 4. The\nrevised parts of the manuscript are located on pages 12-13, second paragraph,\nline 428-493, and Figure 4 has been modified, the revised sections have been\nhighlighted in yellow for clarity.\nPoint 11:\nPage 13, Line 460: “Notably, the s-LCE i-TE fibre demonstrates convergence\nof loss modulus toward storage modulus at higher frequencies, indicating\npotential network structure deterioration…” This observation partly aligns with\nmy earlier concerns about material preparation. Repeating the measurement\ncould clarify whether the material shows fatigue. Additionally, please explain\nwhy this frequency sweep range was chosen. Without context, the reported\nvalues do not provide much useful information.\nResponse:\nThank you for your valuable suggestion. Following your suggestion, we have\nre-evaluated the DMA performance of the s-LCE i-TE fiber. As shown in Figure\n4(d), the new results differ from the initial measurements, the storage modulus\nnow consistently remains higher than the loss modulus across the frequency\nrange of 10-1 to 102 rad/s, confirming the stable quasi-solid gel characteristics\nof the material and further validating the formation of a robust internal network\nstructure in the s-LCE i-TE fiber. To ensure reliability, the experiment is repeated\nthree times, and all trials support this conclusion. After consulting with the DMA\ntesting engineer, we identified that the previously observed convergence of\nstorage and loss moduli in the high-frequency region is likely due to improper\nsample clamping or baseline calibration errors during the initial test. These\nprocedural issues introduced significant inaccuracies that did not reflect the\nintrinsic properties of the material. We sincerely apologize once again for this\noversight.\nAdditionally, the selected frequency range (10-1 to 102 rad/s) is determined\nbased on both the material’s structural responsiveness within this range and\npractical technical constraints of DMA measurement (Mechanics of Materials\n146 (2020) 103369; Journal of Applied Polymer Science 100(1), 2006:677-683):\n(1) In the low-frequency region (0.1 rad/s), the stimulus acts like a very\nslow “tap” on the material. Under such conditions, polymer chains have\nsufficient time to stretch, slide, and reorganize, reflecting macroscopic structural\nfeatures and long-term behavior. The fact that the storage modulus consistently\nexceeds the loss modulus in this regime indicates that the material does not\nflow like a liquid over extended timescales and maintains its shape due to a\nstable internal network. This behavior not only confirms the formation of a\nrobust cross-linked structure but is also characteristic of typical gels or cross-\nlinked solid materials.\n(2) In the high-frequency region (100 rad/s), the stimulus resembles a rapid\n“impact.” The material cannot adjust globally at this pace, only local segments\nrespond, reflecting microstructural behavior of the material. Here, both storage\nand loss moduli increase, indicating stronger resistance to fast deformation.\nThe polymer chains lack sufficient time to relax, leading to greater energy\nstorage. This frequency range primarily probes the rigidity and flexibility of chain\nsegments.\n(3) The intermediate frequencies serve as a transition zone bridging\nmacroscopic and microscopic responses where the material shifts from liquid-\nlike to solid-like dominance. The crossover point between storage and loss\nmoduli in this region marks the transition between viscous and elastic behavior.\nLower frequencies were avoided to prevent excessively long test durations,\nwhich can introduce increased measurement error and reduced accuracy. On\nthe other hand, higher frequencies are excluded due to the risk of amplified\ninertial effects in the clamps and sensors, which could likewise compromise\nmeasurement reliability.\nThe frequency range of 10-1 to 102 rad/s is selected for DMA measurement\nof the LCE i-TE fiber in this study primarily because it not only confirms the\nformation of a stable internal network structure but also consistently\ndemonstrates quasi-solid gel-like behavior across this span. Throughout the\nentire frequency range, the storage modulus remains higher than the loss\nmodulus, indicating that the LCE i-TE fiber maintains elasticity-dominated\nmechanical characteristics and verifies its elastomeric nature. Furthermore, this\nrange avoids technical challenges associated with extremely low or high\nfrequencies, ensuring that the test yields highly reliable data with good signal-\nto-noise ratios within a reasonable experimental timeframe.\nFigure 4(d) Dynamic mechanical curves of m- and s-LCE architecture before\nand after LiBF impregnation.\nmechanical properties of the LCE fibers, we have re-tested the DMA\ncharacteristics of the materials and revised the relevant descriptions\naccordingly. The revised parts of the manuscript are located on pages 12,\nsecond paragraph, line 443-448, and Figure 4(d) has been modified, the\nrevised sections have been highlighted in yellow for clarity.\nPoint 12:\nFig. 4g: The authors compare material properties with other materials and\nemphasise the superior performance of LCE i-TEs. However, performance\nstability was not measured for the reference materials, making this comparison\ninappropriate.\nResponse:\nThank you for your valuable suggestion. After careful consideration and\nanalysis, we conclude that since the referenced literature did not include tests\non material performance stability, the comparison of stability after cyclic\nstretching in the Figure 4(g) is not meaningful. Therefore, we have decided to\nremove the performance stability comparison from Figure 4(g). The revised\nversion of Figure 4(g) is shown below:\nFigure 4(g) Radar plots of m-LCE i-TE fiber in four areas: n-type\nthermopower, mechanical properties, fiber processability, and span of\nperformance.\nOur revision to the Manuscript: To improve the professionalism of the\nfigures in the manuscript, we have removed the discussions regarding performance\nstability. Figure 4(g) has been modified, the revised sections have been\nhighlighted in yellow for clarity.\nPoint 13:\nPage 15, Line 507: “Under a temperature gradient of 2.6 K, the device exhibits\na remarkable thermopower of -110.32 mV K⁻¹, the voltage-temperature\nrelationship is presented in Figure 5(f)…” Here the authors refer to the\nthermopower of an n-type series, yet the figure shows a voltage-temperature\nplot instead. Similar mismatches occur in several places and makes the\nmanuscript confusing.\nResponse:\nThank you for your valuable suggestion. We sincerely apologize for the\noversight that led to inconsistencies between the descriptions and figures in the\nmanuscript. After thoroughly reviewing the entire text, we have revised the\nrelevant description as follows:\n(1) “Under a temperature gradient of 2.6 K, the device exhibits a remarkable\nthermopower of -110.32 mV K-1, the voltage-temperature relationship is\npresented in Figure 5(f).” has been revised to “five n-type m-LCE i-TE fibers are\nconnected in series using silver wire interconnects, demonstrating excellent\nand rapid voltage responsiveness (Figure 5(e)), and the output voltage per\ndegree of temperature difference (ΔV/ΔT) of the device reaches -130.2 mV K-1\nthrough fitting the temperature-voltage data (Supplementary Figure 36)”\n(2) “The output characteristics demonstrated progressive improvement with\nincreasing number of parallel units, ultimately achieving 146.8 mV K-1 with three\np/n pairs under a temperature gradient of 2.5 K” has been revised to “In addition,\na π-type device integrated with p-type and n-type m-LCE i-TE fibers is further\nintegrated, whose output performance increases with the number of p-n pairs,\nultimately achieving -146.8 mV K-1 for three p-n pairs (Figure 5(f))”\n(3) “the thermopower of the m-LCE i-TE fiber reaches -27.4 mV K-1 (voltage-\ntemperature curve as shown in Supplementary Figure 8” has been revised to\n“the thermopower of the m-LCE i-TE fiber reaches -27.4 mV K-1 (voltage-\ntemperature curve and fitting plot as shown in Supplementary Figure 8) under\nconditions (EDDET: 2.2 M, PETMP: 0.26 M, immersion time: 6 h, LiBF\n4\nconcentration: 0.75 M)”\nOur revision to the Manuscript: To improve the professionalism and\nreadability of the manuscript narrative, we have conducted a comprehensive\nreview and revision of inconsistencies between the descriptions and figures\nthroughout the manuscript. The revised parts of the manuscript are located on\npages 14, third paragraph, line 520-525 and line 525-527; pages 7, second\nparagraph, line 251-255, the revised sections have been highlighted in yellow\nfor clarity.\nPoint 14:\nPage 15, Line 520: “A self-powered wearable device is further fabricated…” In\nwhat sense is the device “self-powered”? The wording seems inaccurate: the\ndevice generates electrical potential that could serve as a power source for\nother devices, but this is not the same as being self-powered. Furthermore, the\ndescription of the device raises several questions. The manuscript states that\nthe device is woven and that electrodes are attached to measure voltage, but it\nis unclear where the wires are connected. Is the device woven from a single\nfibre? Does the woven structure influence the voltage output (enhancing,\ndiminishing, or leaving it unchanged)? In addition, the reported values in the\ntext (‘…exhibits rapid response within 450 s, reaching values of 235 mV and\n192 mV under these temperature differences, respectively’ and ‘…a\ntemperature difference of 2.9 K is observed to generate a voltage of ~79 mV\n(Figure 5(k-l) and Supplementary Figure 26)’) do not match those shown in the\ncorresponding graphs. Such inconsistencies is one more reason why the\nmanuscript is difficult to follow.\nResponse:\nThank you for your valuable suggestion. “Self-powered” refers to a device that\ndoes not rely on external power sources (such as batteries or the grid), but\ninstead harvests energy from its surrounding environment and converts it into\nelectricity to meet all or part of its operational power needs. In this work, the\nmechanism of the LCE i-TE device primarily involves the conversion of low-\ngrade thermal energy into electrical energy through ionic thermodiffusion.\nHowever, it operates mainly in a capacitive mode, which differs significantly\nfrom the working mechanism of traditional electronic thermoelectric materials.\nTherefore, the term “self-powered” may not be entirely appropriate here. Based\non a review of the literature, the term “thermal-charge” is more accurate and\nprofessional for describing ionic thermoelectric materials due to their unique\ncapacitive operating mode. This expression has been widely adopted in\nnumerous published studies and is therefore considered more suitable (Nano-\nMicro Lett. (2025) 17:204).\nWe apologize for the insufficient detail in the manuscript regarding the\nstructure of the LCE device, which may have led to confusion. The device\nconsists of two integrated modules: a substrate module and a thermoelectric\nmodule. The substrate module was fabricated by weaving a 2-meter m-LCE\nfiber into a 3 cm × 6 cm rectangular textile using a rib-knitting technique. The\nthermoelectric module was integrated into this LCE textile by embedding and\ninterlacing a m-LCE i-TE fiber. Silver wires serving as electrodes were similarly\nembedded and connected to the cold and hot ends of the fiber. The tight woven\nstructure of the LCE textile ensures robust integration of the thermoelectric fiber\nand silver wires. The detailed textile structure, temperature difference utilization\nstrategy, and physical images of the device are shown in the Figure 5(g-h) and\nFigure S38-39. Meanwhile, it should be noted that the woven structure does not\naffect the output voltage of the device. As illustrated in the schematic diagram\nof the temperature difference utilization mechanism, the device is attached\ndirectly to the heat source, and its output voltage is primarily influenced by the\ntemperature difference between the cold and hot ends, rather than by variations\nin the textile weave. This observation is also supported by reports in the\nliterature (Nature Communications, (2025)16:5445).\nMeanwhile, thank you for raising this critical issue. We acknowledge that\nthere is indeed a discrepancy between the descriptions and the numerical\nvalues presented in Figure 5(i–k) and Supplementary Figure 40. This\ninconsistency arose because the initial voltage of the device during testing is\nnot 0 V, which led to the mismatch in reported values. To address this, we have\nretested the output performance of the device to ensure data accuracy and rigor.\nAs shown in the revised Figure 5(i–k) and Supplementary Figure 40, when the\ndevice is attached to a beaker and exposed to alternating cold and hot water, it\ngenerated output voltages of 270 mV and 206.6 mV under temperature\ndifferences of 10.3 K and 7.5 K, respectively. Furthermore, when affixed to the\nhuman arm, it produced an output voltage of 44.5 mV under a temperature\ngradient of just 1.7 K.\nFigure S38 Top view (a) and front view (b) of the planar structures thermal-\ncharge wearable device.\nFigure S39 Top view (a-b) and front view (c-d) of the three-dimensional\nstructures thermal-charge wearable device.\nFigure 5 (i) Voltage-temperature difference curve of the planar device\nattaching to beaker with hot water.\nFigure S40 Voltage-temperature difference curve of the planar device\nattaching to beaker with cold water.\nFigure 5 (j) (j) Physical picture and infrared thermal images of body heat\nharvesting test by three-dimensional device. (k) Voltage-temperature\ndifference curve of the three-dimensional device worn on the human arm.\nOur revision to the Manuscript: To ensure the professionalism of terminology\nin the manuscript, as well as the completeness of device fabrication methods\nand the consistency between figures and descriptions, we have supplemented\nand revised the relevant content accordingly. The revised parts of the manuscript\nare located on pages 14, third paragraph, line 512-514; pages 15, second\nparagraph, line 535-544 and line 547-550, and Figure 5(i-k),\nSupplementary Figure 38, 39, 40 have been modified, the revised sections\nhave been highlighted in yellow for clarity."}, {"round": 2, "reviewer_comments": {"reviewer_1": "The authors have addressed my comments well. Noted that the authors didn't directly reply to the other reviewer comments relative to the authors' previous paper (Nat Commun 2025, 16, 5445), which might impact their innovation of the current work. It needs clarification before it can be accepted for publication. The word \"Programming\" in the title is not an accurate description of the materials engineering strategy.", "reviewer_2": "The authors have addressed all points raised in my initial review thoroughly, thoughtfully, and with compelling experimental support. They not only clarified key conceptual issues—such as the rationale for using liquid crystalline elastomers over hydrogels and the structural distinctions between main-chain (m-LCE) and side-chain (s-LCE) architectures—but also carried out valuable additional experiments. These include POM characterization of s-LCE fibers, direct comparisons with RM82-based systems, optimization of p-type performance (now reaching 28.8 mV·K⁻¹, surpassing their prior work), and a nuanced discussion of how thermopower measurement protocols influence reported values.\nCritically, the revised manuscript reframes the study as a systematic exploration of how molecular architecture—main-chain versus side-chain—governs ionic thermoelectric behavior in LCEs. This represents a clear departure from their earlier *Nature Communications* paper, which focused on actuation–sensing integration in side-chain systems. Here, the authors present a truly binary, humidity-resistant, mechanically robust n-type i-TE fiber based on m-LCE, achieving a record thermopower of –27.4 mV·K⁻¹ under low-humidity conditions for binary systems—an advance of both fundamental and practical significance.\nAlthough the material platform builds on the authors’ previous work, the new mechanistic insights into structure–property relationships, the balanced p/n performance, and the demonstrated practical advantages (e.g., no need for encapsulation, ambient stability) collectively constitute a meaningful contribution to the field.\nAll concerns have been fully and satisfactorily addressed, and the manuscript has been substantially improved. I therefore recommend acceptance of the revised manuscript in its current form.", "reviewer_3": "The manuscript has been significantly improved and the authors have addressed all major issues. I recommend the article for publication."}, "author_response": "Responses to the Referees’ Comments\nPoint-by-point responses to the referees’ comments\nWe sincerely thank the reviewers for their constructive comments concerning\nour manuscript entitled “Programming liquid crystal elastomer unlocks\nextraordinary p- and n-type thermopower for fiber-shaped ionic thermoelectric\ncapacitors” (NCOMMS-25-63666A). Those comments are all valuable and\ncritical for improving our paper. We have studied the comments very seriously\nand have addressed in full, which we hope meet with approval. Revised portion\nhave been highlighted in yellow in the manuscript. And our response to all\ncomments starts on the next page. (Comments in black, responses in blue)\nReviewer #1:\nThe authors have addressed my comments well. Noted that the authors didn't\ndirectly reply to the other reviewer comments relative to the authors' previous\npaper (Nat Commun 2025, 16, 5445), which might impact their innovation of\nthe current work. It needs clarification before it can be accepted for publication.\nThe word \"Programming\" in the title is not an accurate description of the\nmaterials engineering strategy.\nResponse:\nSpecial thanks to you for raising this issue. We regret that we failed to\nadequately address the reviewers’ concerns regarding the innovation\ndistinction between this manuscript and our previous publication (Nat Commun\n2025, 16, 5445). In fact, the present manuscript differs substantially from the\nprevious work across three critical dimensions: material structure, performance\nenhancement, and device application. The specific details are as follows:\n1. In terms of material structure, the previous paper (Nat Commun 2025, 16,\n5445) employed side-chain LCE (s-LCE) i-TE fibers with RM257 as the liquid\ncrystalline mesogen. In contrast, the present manuscript innovatively\nintroduces main-chain LCE (m-LCE) i-TE fibers with RM82 as the liquid\ncrystalline mesogen for application in i-TE yield. These two material\narchitectures differ fundamentally not only in their synthesis methodologies but\nalso in their degree of order, network topology, and thermoelectric performance,\nwhich are entirely distinct from the previous work.\n2. Regarding thermoelectric performance, the m-LCE i-TE fibers proposed in\nthis manuscript demonstrate substantial superiority over the previous work (Nat\nCommun 2025, 16, 5445) owing to their structural advantages. In the previous\npublication, the LCE i-TE fibers exhibited a p-type thermopower of 25.8 mV K-1\nafter impregnation with the solution, while the n-type performance remained\nbelow 4 mV K-1. In contrast, the m-LCE i-TE fibers not only surpass the previous\np-type performance (28.8 mV K-1) but also achieve a remarkable n-type\nthermopower of −27.4 mV K-1 benefiting from innovations in molecular chain\narchitecture. This breakthrough represents a substantial performance\nenhancement for p-n homogeneous materials, transcending the material\nlimitation of p-type characteristics observed in previous work.\n3. Regarding device applications, the previous work (Nat Commun 2025, 16,\n5445) primarily focused on the synergistic integration of LCE i-TE fibers with\nactuation functionality, without exploring the material performance under low-\ngrade heat. In contrast, leveraging the substantial performance improvements\nof m-LCE i-TE fibers, the present manuscript not only reconstructs planar and\nthree-dimensional wearable i-TE devices but also emphasizes systematic\ninvestigation of device performance output under low-grade thermal energy,\nincluding practical daily-use scenarios and small temperature differentials\nacross the human body.\nBeyond that, through literature review and repeated verification, we also\nconcluded that using “Programming” in the title is indeed not an appropriate\ndescription. Therefore, we chose “Engineering” to express the regulation of the\nLCE material structure, as it can accurately describe the optimization strategy\nfor the material (Adv. Funct. Mater. 2024, 34, 2406847; Adv. Mater. 2025, 37,\n2506129).\nReviewer #2:\nThe authors have addressed all points raised in my initial review thoroughly,\nthoughtfully, and with compelling experimental support. They not only clarified\nkey conceptual issues-such as the rationale for using liquid crystalline\nelastomers over hydrogels and the structural distinctions between main-chain\n(m-LCE) and side-chain (s-LCE) architectures-but also carried out valuable\nadditional experiments. These include POM characterization of s-LCE fibers,\ndirect comparisons with RM82-based systems, optimization of p-type\nperformance (now reaching 28.8 mV·K⁻¹, surpassing their prior work), and a\nnuanced discussion of how thermopower measurement protocols influence\nreported values.\nCritically, the revised manuscript reframes the study as a systematic exploration\nof how molecular architecture-main-chain versus side-chain-governs ionic\nthermoelectric behavior in LCEs. This represents a clear departure from their\nearlier *Nature Communications* paper, which focused on actuation–sensing\nintegration in side-chain systems. Here, the authors present a truly binary,\nhumidity-resistant, mechanically robust n-type i-TE fiber based on m-LCE,\nachieving a record thermopower of –27.4 mV·K⁻¹ under low-humidity conditions\nfor binary systems-an advance of both fundamental and practical significance.\nAlthough the material platform builds on the authors’ previous work, the new\nmechanistic insights into structure-property relationships, the balanced p/n\nperformance, and the demonstrated practical advantages (e.g., no need for\nencapsulation, ambient stability) collectively constitute a meaningful\ncontribution to the field.\nAll concerns have been fully and satisfactorily addressed, and the manuscript\nhas been substantially improved. I therefore recommend acceptance of the\nrevised manuscript in its current form.\nResponse:\nWe sincerely appreciate the valuable suggestions you have provided. Your\nrecommendations have greatly enhanced the professionalism and readability\nof the manuscript.\nReviewer #3:\nThe manuscript has been significantly improved and the authors have\naddressed all major issues. I recommend the article for publication.\nResponse:\nWe greatly appreciate your professional suggestions and timely feedback."}]

Decision letter