Multiphase aqueous soggy sand electrolyte for zinc metal batteries applications at elevated temperatures

Domain: physics
Published: 2025-12-04
Editorial outcome: minor_revision

Abstract
Aqueous zinc metal batteries often encounter uncontrollable failure or performance decay under thermal environments, primarily due to the severe side reactions caused by aqueous electrolytes. Here, an organic-inorganic-H2O multiphase aqueous soggy sand electrolyte is reported to enhance high-temperature performance of aqueous zinc metal batteries. Soggy sand components form strong interactions between the heterogeneous phases, reconstructing hydrogen-bond networks and forming water-deficient solvation structures, which greatly limits water activity and improves thermal stability, eliminating parasitic reactions and inspiring a uniform Zn deposition at elevated temperatures. As a result, multiphase aqueous soggy sand electrolyte enables aqueous zinc metal batteries to achieve an operating temperature of 140°C, a lifespan of 1700 cycles, and a current density of 8 Ag−1. More importantly, the application of this electrolyte allows the stable cycling of Zn metal pouch cells under continuous operation at elevated temperatures. This work paves the path toward electrolyte design that enables aqueous batteries to cycle stably under thermal environments.

Introduction
The exponential growth of modern industrial systems has created an urgent demand for high-temperature (HT) resilient energy storage devices with intrinsic safety across mission-critical sectors, particularly in aerospace engineering, oil drilling and extraction, and geophysical exploration operations1,2. Compared with organic Li/Na ion batteries, aqueous zinc metal batteries (AZMBs) exhibit nonflammability, high theoretical capacity (820 mAh g−1 or 5855 mAh cm−3), and cost-effectiveness, making them highly promising for intrinsically safe electrochemical energy storage systems3,4. However, the performance of current AZMBs is hampered by side reactions inherent to aqueous electrolytes, such as hydrogen evolution reaction (HER) and zinc corrosion at the negative electrode, as well as positive electrode material dissolution5,6. These issues are kinetically accelerated at elevated temperatures due to enhanced ionic mobility and reaction kinetics7. In addition, when the working temperature rises close to the boiling point of water, gas evolution intensifies, leading to battery pack swelling and significantly curtailing the cycle life of AZMBs8. Therefore, there is an urgent need to develop long-life AZMBs capable of operating under thermal conditions.

To date, extensive research endeavors have been dedicated to enhancing the electrochemical performance of AZMBs under elevated thermal conditions, involving electrode structure modification9–11, interface coatings construction12,13, and HT-resilient electrolytes engineering5,14,15. Among these methods, improving the thermal stability of aqueous electrolytes represents a highly effective strategy to optimize the HT performance of AZMBs. Recent advancements in electrolyte formulation demonstrate that gel-based electrolytes8,16, eutectic electrolytes15,17, and cosolvent-modified electrolytes4,18 effectively mitigate the detrimental side reactions in AZMBs, enabling stable cycling performance at elevated temperatures. For instance, Liu et al. have constructed a multi-component gel electrolyte with multiple advantages of “liquid-like” high conductivity, “gel-like” robust interface, and “solid-like” high Zn2+ transfer number, enabling a lifespan of 5000 cycle lifetimes with 91.3% capacity retention at 50°C8. Yan et al. have reported a ternary deep eutectic electrolyte, effectively inhibiting water activity and promoting the interfacial stability of the electrolyte/electrode, thereby enabling long-term operation across a wide temperature range from −20°C to 70°C19. Han et al. have designed a temperature self-adaptive electrolyte by introducing tetraglyme (TG) with high thermal stability as a cosolvent, forming a carbonate-containing SEI layer conducive to inhibiting HER and electrode corrosion at elevated temperature, leading to an enhanced cycling stability at 75°C18. Previous reports demonstrate that although traditional electrolyte design strategies have made some progress, the performance of AZMBs remains unsatisfactory at high operating temperatures, especially at temperatures close to or even exceeding the boiling point of water. It is necessary to develop an electrolyte strategy to promote the application of AZMBs under thermal conditions.

Herein, we propose an electrolyte strategy of constructing an organic-inorganic-H2O multiphase aqueous soggy sand electrolyte (MASSE), which endows a high operating temperature of 140°C for AZMBs. The dual fixation of diethylene glycol solvents and Al2O3 nanoparticles greatly limits the activity of free water, as evidenced by molecular dynamics (MD) simulations, Raman, and Fourier transform infrared (FTIR). The multiphase interactions induce water-deficient solvation structures, leading to an improved thermal stability in MASSE, as confirmed by density functional theory (DFT) calculations, extended X-ray absorption fine structure (EXAFS), and in situ temperature Raman. Furthermore, MASSE effectively inhibits water-induced side reactions and facilitates uniform Zn plating/stripping behavior at elevated temperatures, as supported by in situ electrochemical impedance spectroscopy (EIS), differential electrochemical mass spectrometry (DEMS), scanning electron microscopy (SEM), and laser scanning confocal microscope (LSCM). As a result, Zn||PANI full cells exhibit a cycling lifespan of 1700 cycles, an operating temperature of 140°C, and a high current density of 8 Ag−1. Noticeably, MASSE enables the Zn metal pouch cells stable cycling at an HT of 80°C. This work presents an electrolyte design paradigm enabling AZMBs to operate stably under thermal conditions.

Results
Limited water activity and thermally robust solvation structure in MASSE
The impact of Al2O3 particle size on electrolyte stability was first investigated. The zeta potential of MASSE containing different-sized Al2O3 particles was utilized to assess the stability between the solid and liquid phases (Supplementary Fig. 1). The absolute value of the zeta potential gradually increases with decreasing Al2O3 particle size, indicating the enhanced charge density on the particle surface, which hinders Al2O3 sedimentation and phase separation through electrostatic repulsion. Optical images of MASSE further confirm that no observable phase separation occurs when the particle size is reduced to 30 nm, validating the uniformity under actual operating conditions (Supplementary Fig. 2). In addition, the ionic conductivity and viscosity of MASSE electrolytes with different sizes of Al2O3 were measured. The viscosity of Zn(OTf)2–DEG and MASSE is greatly increased compared to Zn(OTf)2–H2O due to the introduction of a large amount of DEG and Al2O3 nanoparticles, which leads to enhanced polarization at room temperature (Supplementary Fig. 3a). This phenomenon is closely related to particle size: as particle size decreases, the viscosity of MASSE electrolytes continuously increases, owing to the greater number of surface hydroxyl groups (-OH) (Supplementary Fig. 3b). The ionic conductivity reaches a maximum when 10 nm Al2O3 is added, as excessively small particles increase viscosity while overly large particles impede ion migration (Supplementary Fig. 4). Based on a comprehensive consideration of conductivity, viscosity, and stability, subsequent studies selected 10 nm Al2O3 as the standard additive component.

Water molecules exhibit three-dimensional hydrogen-bond (HB) networks characterized by diverse O–H–O geometric configurations. Elevated temperatures induce anomalous HB activation in the Zn(OTf)2–H2O, which manifests as accelerated side reactions. In contrast, our fabricated MASSE demonstrates physical and chemical stability with abundant strong HB formations (Supplementary Fig. 5). To elucidate this phenomenon, DFT calculations were performed. Electron density maps reveal the formation of HB bridges between the components (Fig. 1a and Supplementary Data 1). The H2O–H2O HBs in bulk water exhibit a binding energy of −0.314 eV. Introducing DEG or Al2O3 creates significantly stronger interactions with a more negative energy difference for H2O–DEG (−0.364 eV) and H2O–Al2O3 (−0.704 eV). These computational results demonstrate that weak H2O–H2O HBs can be effectively disrupted through competitive binding, preferentially forming robust HB networks between additives and water molecules. This synergistic interaction mechanism substantially suppresses water activity by disrupting the original HB framework. The HB populations and interaction strengths in various electrolytes were systematically investigated via MD simulations. Our analysis framework defines HBs geometrically based on two critical parameters: HB angle and HB length, with bond strength exhibiting an inverse correlation with length and direct proportionality to angle. Notably, all simulated systems demonstrate remarkably stable HB configurations, suggesting both thermodynamic and structural convergence of the systems. As illustrated in Fig. 1b, the Zn(OTf)2–H2O exhibits the highest density of H2O–H2O HBs, quantitatively correlating with the maximum water activity observed. In contrast, the Zn(OTf)2–DEG demonstrates significantly reduced HB counts between water molecules, attributable to DEG establishing additional HBs with water species. Notably, in the MASSE, Al2O3 introduces strong polar interactions with water, effectively eliminating H2O–H2O HB networks while promoting the formation of structurally optimized HB configurations. Figure 1c, d demonstrates a paradoxical phenomenon in the MASSE: While H2O-H2O HBs exhibit both elongated bond distances (increasing from ~0.262 nm in Zn(OTf)2–H2O to 0.277 nm) and contracted bond angles (reducing from 101.8° to 97.4°), these structural modifications correspond to a significant weakening of intermolecular interactions. These results reveal that introducing Al2O3 and DEG effectively establishes strong HBs with water molecules (Supplementary Figs. 6–8). This interaction disrupts the original HB networks among water molecules, ultimately leading to a marked suppression of water activity.

The reshaping effect of Al2O3 and DEG on the HB networks of H2O molecules was demonstrated by Raman spectra and FTIR spectra. The stretching vibration of O–H in the range of 3000–4000 cm−1 is deconvoluted into two peaks, corresponding to the strong H2O–H2O HBs (≈3230 cm−1) and the medium H2O–H2O HBs (≈3480 cm−1), respectively (Supplementary Fig. 9). The introduction of Al2O3 and DEG greatly attenuates the peak intensity of O–H stretching, revealing a weak water activity. In addition, with the incorporation of Al2O3 and DEG, the population of strong HBs decreases by 19% concomitantly with an 81% enhancement in medium HBs, demonstrating strong interaction between the MASSE components and water molecules (Fig. 1e). In the FTIR spectra (Fig. 1f), the O–H stretching vibration of H2O in electrolytes within the range of 3000–3800 cm−1 is deconvoluted into three peaks, assigned to “network water” (NW, 3205 cm−1), “intermediate water” (IW, 3433 cm−1), and “multimer water” (MW, 3560 cm−1). The NW depicts water molecules with strong HBs, while the MW reveals a weak HB and a poor link to the surrounding water20. The impact of the MASSE components on the HB network can be quantitatively analyzed by comparing the areal ratios of NW, IW, and MW, as displayed in Fig. 1g. The MASSE exhibit the highest proportion of MW and the lowest proportion of NW component among all electrolytes, which indicates a drastically decreased water activity and, consequently, an improved thermal stability.

The HT performance of AZMBs is fundamentally governed by the thermal robustness of the solvation structures in the electrolyte. Structural instability within these solvation complexes can trigger a cascade of detrimental electrochemical processes, including electrolyte decomposition, interfacial impedance escalation, and uncontrollable side reactions, ultimately leading to thermal runaway scenarios21. MD simulations were conducted to investigate the Zn2+ solvation shells at 80°C (Supplementary Data 2–4). As shown in Fig. 2a–c, 3D snapshots from the MD simulations demonstrate homogeneous spatial distribution of all constituent species, especially Al2O3. To quantify the local environment around Zn2+, the radial distribution function (RDF) with respect to Zn2+ and the coordination number (CN) were calculated (Supplementary Table 1). Figure 2d illustrates that H2O and OTf− in the solvation sheath are located at 1.92 Å and 1.86 Å away from Zn2+, with an average CN of 5.05 and 0.95 for Zn2+, which generates H2O-rich Zn2+ solvates for Zn(OTf)2–H2O. In the Zn(OTf)2–DEG, the CN of H2O decreases to 0.86, and DEG appears at 1.9 Å away from Zn2+ with an average CN of 3.75 (Fig. 2e). Notably, as evident from Fig. 2f, Al2O3 species with a CN of 0.68 exhibit preferential spatial association with Zn2+. The emergence of the Al2O3 RDF peak stems from the DEG-induced electrostatic interaction, which effectively bridges the interfacial gap between Zn2+ and Al2O3, enabling the periodic arrangement of Al2O3 within the Zn2+ solvation shells, thereby generating specific spectral signals characteristic of coordination (Supplementary Fig. 10). The same phenomena are also observed in SiO2 inorganics22. The primary solvation shell of Zn2+ exhibits a marginal depletion of OTf− ligands (CN=1.21) alongside a significant displacement of water molecules (CN=0.61), manifesting a water-deficient solvation structure. The representative Zn2+ solvation structures and their corresponding percentages were extracted, as shown in Supplementary Fig. 11 and Supplementary Tables 2–4. We identify the particular solvation structures in different electrolytes for subsequent discussion. X-ray absorption fine structure analysis was carried out to investigate the solvation sheath of Zn2+. The Zn K-edge X-ray absorption near-edge structure (XANES) spectra of different electrolytes are displayed in Fig. 2g. The near-edge absorption energy of MASSE shifts to lower regions, indicative of enhanced electron donation from Al2O3 ligands, which effectively lowers the Zn2+ oxidation state23. As illustrated in Fig. 2h, the contraction of the Zn–O bond length observed in MASSE correlates with enhanced ligand coordination stability, suggesting a more robust solvation network24. Additionally, the wavelet-transformed EXAFS was carried out to further elucidate the local solvation structure of Zn2+. The pink regions refer to the locations where the peaks of R-space and k-space coincide. In three electrolytes, these regions are located at low k and R values, reflecting similar Zn–O coordination, whether it involves the Zn–H2O, Zn–DEG, Zn–OTf−, or Zn–Al2O3 (Fig. 2i). These findings are consistent with FTIR and Raman spectra (Supplementary Figs. 12 and 13). The dominant solvation configuration (Zn(H2O)5(OTf−)1) in Zn(OTf)2–H2O was computationally modeled. The incorporation of Al2O3 induces structural reorganization. This leads to the replacement of the primary solvation structure, from Zn(H2O)1(DEG)5 in the Zn(OTf)2–DEG electrolyte to Zn(OTf−)1(DEG)4(Al2O3)1 in MASSE. Notably, three other solvation configurations remain consistent throughout this process. The binding energies corresponding to these three characteristic solvation structures were calculated (Fig. 2j and Supplementary Fig. 14) (Supplementary Data 1). The distinctive solvation structure in the MASSE exhibit the highest binding energy (−32.4 eV) compared to the Zn(OTf)2–H2O (−22.68 eV) and the Zn(OTf)2–DEG (−20.57 eV), demonstrating enhanced structural stability and preventing structural damage at elevated temperatures.

The configurational stability of electrolytes was systematically investigated using in situ Raman spectra under different temperatures. The Zn(OTf)2–H2O demonstrates restricted thermal stability, as evidenced by the initiation of Zn(OTf)2 crystallite precipitation at 80°C, owing to salt precipitation caused by electrolyte evaporation (Fig. 2k)20. Figure 2l demonstrates a thermo-responsive behavior of Zn(OTf)2–DEG through O–H stretching band broadening as temperature rises from 20 to 140°C. For MASSE, the O–H stretching intensity increases between 20 and 60°C and then remains stable without obvious enhancement as the heating temperature increases to 140°C. In addition, the O–H band in the MASSE electrolyte maintains much lower intensity compared to the Zn(OTf)2–H2O and Zn(OTf)2–DEG electrolyte, attributable to Al2O3-induced ligand cross-linking that stabilizes the solvation network against thermal fluctuations (Fig. 2m). Thermogravimetry curves of different electrolytes were employed in Supplementary Fig. 15. The MASSE possesses enhanced thermal stability, retaining 99.1% of its weight at 150°C, compared to 82.1% for Zn(OTf)2–DEG and 43.7% for Zn(OTf)2–H2O, which is consistent with the DFT calculations.

Suppressing parasitic reactions and Zn dendrites under elevated temperature
The thermally robust solvation structure in MASSE plays a crucial inhibitory role in the rampant parasitic reactions at HT. As shown in Fig. 3a, the corrosion behavior of the Zn negative electrode in different electrolytes was compared by Tafel plots. Compared to the Zn(OTf)2–H2O and Zn(OTf)2–DEG, the MASSE exhibits the smallest corrosion current and the highest corrosion potential at 80°C. As displayed in Fig. 3b, the potential of the Zn@Cu electrode grows dramatically once the electrolyte corrodes all of the metallic Zn14. The corrosion rate of Zn in the MASSE is 0.41 mg h−1, much slower than that in the Zn(OTf)2–H2O (3.66 mg h−1) and in the Zn(OTf)2–DEG (0.67 mg h−1), indicating a lower Zn corrosion reaction in MASSE. The protection of the Zn negative electrode from side reactions was also verified through X-ray diffraction (XRD) patterns. As shown in Fig. 3c, there are obvious characteristic peaks related to zinc triflate hydroxide hydrate (Znx+y(OTf)2y(OH)2x, ZOTH) in the Zn(OTf)2–H2O and Zn(OTf)2–DEG after 50 cycles. In contrast, the intensity of these by-products on the cycled Zn negative electrode in MASSE is significantly diminished. Subsequently, 3D Raman mapping (30×30 area) was used to spatially resolve ZOTH by-products distribution on cycled Zn negative electrodes. Characteristic strong peaks emerge in Zn(OTf)2–H2O and Zn(OTf)2–DEG, whereas MASSE displays a complete absence of these signatures, confirming effective suppression of parasitic reactions (Fig. 3d–f and Supplementary Fig. 16)25,26.

Linear sweep voltammetry (LSV) testing exhibits that MASSE demonstrate the largest electrochemical window (1.81 V < 2.24 V < 2.68 V) among all electrolytes at 25°C (Supplementary Fig. 17). At an elevated temperature of 80°C, all electrolytes exhibit marginally narrowed electrochemical windows, attributable to aggravated side reactions. Nonetheless, MASSE maintains the widest electrochemical window (1.93 V), exceeding that of both Zn(OTf)2–H2O (1.21 V) and Zn(OTf)2–DEG (1.66 V) (Fig. 3g). In situ pH monitoring over 20 h exhibit that the pH value of Zn(OTf)2–H2O increases rapidly throughout the entire cycle. This rise is caused by severe HER, which leads to higher local pH values and exacerbates the formation of ZOTH by-products at both 25°C and 80°C (Fig. 3h and Supplementary Fig. 18). The pH value of the Zn(OTf)2–DEG shows a slight easing trend but still increases. In sharp contrast, the pH values of MASSE remain relatively constant under the same conditions, indicating the substantial inhibitory effect on HER. The suppression of HER enabled by MASSE is further investigated using in situ DEMS. Figure 3i and Supplementary Fig. 19 present the quantitative DEMS results of H2 evolution during the OCP and charge process at 25°C and 80°C. Significantly reduced H2 evolution is observed at the Zn negative electrode surface utilizing the MASSE electrolyte, under room-temperature and elevated-temperature conditions. Furthermore, in situ EIS was tested to visually reflect the inhibitory effect of MASSE on parasitic reactions at 80°C (Supplementary Fig. 20). As shown in Fig. 3j and Supplementary Fig. 21, Zn(OTf)2–H2O experiences a short circuit after 12 cycles, attributable to progressive electrolyte depletion and by-products accumulation at HT. The Zn(OTf)2–DEG displays escalating electrochemical impedance during the cycling process, likely stemming from insulating deposit formation under HT (Fig. 3k and Supplementary Fig. 22). Conversely, MASSE demonstrates progressively diminishing interfacial impedance accompanied by marginally attenuated voltage hysteresis throughout cycling (Fig. 3l and Supplementary Fig. 23). This is attributable to reinforced ligand coordination frameworks. MASSE effectively inhibits the water activity at HT. Meanwhile, the effective mitigation of parasitic reactions in MASSE is also attributed to the stable and ZnF-enriched electrode/electrolyte interfaces (Supplementary Figs. 24–27).

The Zn morphology of different electrolytes at room temperature is examined by SEM. As shown in Fig. 4a, d, g, Zn deposited in MASSE exhibits a more uniform and dendrite-free morphology compared to that in Zn(OTf)2–H2O and Zn(OTf)2–DEG. The morphology of the Zn negative electrode of different electrolytes was characterized at 80°C. After Zn deposition, randomly oriented and porous clusters of Zn dendrites are observed in Zn(OTf)2–H2O and Zn(OTf)2–DEG (Fig. 4b, e). However, the surface of the Zn negative electrode in MASSE is densely packed after Zn deposition (Fig. 4h). After 50 cycles, large amounts of randomly-oriented flakes and dendrites are formed on the surface of Zn negative electrode in Zn(OTf)2–H2O and Zn(OTf)2–DEG (Fig. 4c, f), while the surface of the Zn negative electrode in MASSE is compact and relatively smooth (Fig. 4i). LSCM images exhibit a high roughness with large protrusions in the Zn(OTf)2–H2O (Fig. 4j). Despite exhibiting marginal enhancement in electrodeposition microstructure, the Zn(OTf)2–DEG retains irregular surface topography with pronounced defects (Fig. 4k). MASSE preserves a planar morphology with a low surface roughness at elevated temperature (Fig. 4l). These results demonstrate that a dendrite-suppression plating morphology is obtained in the MASSE at HT, which is attributed to thermally robust solvation structures of MASSE. Figure 4m–o systematically elucidates the underlying mechanisms of the HT stability of the MASSE, integrating the aforementioned experimental and computational insights. Ligand coordination reinforcement results in the formation of a temperature-insensitive solvation structure. The optimized HB configurations in the MASSE lead to a low water activity. Therefore, such advantages effectively inhibit parasitic reactions (HER, Zn corrosion) caused by excessive free water, and promote a uniform Zn deposition at elevated temperature.

Enhanced high-temperature performance in MASSE
Asymmetric Zn||Cu cells were assembled to evaluate the Zn plating/striping reversibility. The applied current density influences the measured CE, and high current densities can obscure the impact of HER. Therefore, a low current density of 1 mA cm−2 was used for testing at 80°C. As shown in Fig. 5a, half-cells using the Zn(OTf)2–H2O show drastic fluctuations and rapid decay in CE, lasting only 50 cycles due to severe parasitic reactions and the growth of Zn dendrites. For Zn(OTf)2–DEG, Zn||Cu cell exhibits a low average CE of 95.64% and a short cycle life. In contrast, Zn||Cu cell using MASSE exhibits a high average CE of 98.60% and a significantly extended lifespan of 1200 cycles. When the current density increases to 2 mA cm−2, enhanced cycle life and CE are also obtained in MASSE (Supplementary Fig. 28). The Zn plating/stripping behavior was also analyzed by symmetric Zn||Zn cells. As shown in Fig. 5b, the Zn||Zn cells with MASSE exhibit a lifespan of 600 h, much longer than that of Zn(OTf)2–H2O and Zn(OTf)2–DEG. Elevated-temperature electrochemical cycling presents intensified hurdles compared to ambient-condition cell operation, primarily due to accelerated interfacial degradation and thermal-driven electrolyte decomposition. MASSE with 10% Al2O3 shows the optimal cycling performance at 80°C (Supplementary Fig. 29). At a low current density of 1 mA cm−2, cells with Zn(OTf)2–H2O undergo a rapid short circuit at 9 h at 80°C. The cells with Zn(OTf)2–DEG also experience a short circuit at 920 h. The Zn||Zn symmetric cells using MASSE demonstrate stable cycling for at least 1120 h at 80°C (Supplementary Figs. 30 and 31). Similarly, at 2 mA cm−2 and 1 mAh cm−2, symmetric cells using the MASSE exhibit a stable cycling for over 900 h without significant fluctuations of overpotential, while cells with the Zn(OTf)2–H2O and Zn(OTf)2–DEG exhibit a short lifespan at 80°C (Fig. 5c and Supplementary Fig. 32). When the current density and the reversible capacity increase to 4 mA cm−2 and 2 mAh cm−2, the Zn||Zn cells using MASSE manifest a stable cycling for 140 h with a lower overpotential around 260 mV (Supplementary Fig. 33). Unfortunately, the cells using Zn(OTf)2–H2O and Zn(OTf)2–DEG experience a rapid increase of polarization voltage and a quick short circuit (14 h and 45 h). To verify the advantages of the MASSE under a high current density, the rate performance of symmetric cells was measured at 80°C (Fig. 5d). Zn||Zn cells with Zn(OTf)2–H2O fail rapidly at 2 mA cm−2, while those with Zn(OTf)2–DEG exhibit a large overpotential at 4 mA cm−2. The symmetric cells with MASSE exhibit a stable voltage profile and low voltage hysteresis even at a high current density of 8 mA cm−2 at 80°C. The cycling performance of Zn||Zn and Zn||Cu cells is further evaluated under practical conditions with a depth-of-discharge (DOD) of 50%, followed by characterization of the post-cycled negative electrodes (Supplementary Figs. 34 and 35). The significantly enhanced performance of MASSE under high current density is attributed to the rapid migration of Zn2+ (Supplementary Figs. 36 and 37 and Supplementary Table 5)27,28. Even at a boiling point temperature of 100°C, the Zn||Zn cells using MASSE demonstrate a stable cycling over 130 h (Fig. 5e). More intuitively, the wide temperature tolerance under a more stringent external environment, ranging from 25 to 140°C, was investigated. Zn||Zn cells using MASSE exhibit normal voltage curves even at operating temperatures of 140°C without short circuiting, suggesting high thermal stability of MASSE (Fig. 5f). In contrast, the symmetrical cells with Zn(OTf)2–H2O and Zn(OTf)2–DEG fail at 100°C and 120°C, respectively, demonstrating inadequate temperature tolerance under elevated thermal conditions (Supplementary Fig. 38). We compared the reported cycle life of Zn||Zn cells at elevated temperatures. Notably, this work demonstrates competitive cycling performance at high current density, large areal capacity, and a high operating temperature (Fig. 5g and Supplementary Table 6). Large-scale Zn||Zn pouch cells with an area of 25 cm2 were assembled to exemplify the practical application feasibility of MASSE at HT. The increase of the negative electrode area usually intensifies the uneven nucleation of Zn2+, dendrite growth, and by-products generation, specifically under thermal conditions. Yet, benefitting from the thermally robust Zn2+ solvation structure and confined water reactivity in MASSE, Zn||Zn pouch cells exhibit stable cycling for over 400 h at 80°C, much longer than that in Zn(OTf)2–H2O and Zn(OTf)2–DEG.

To evaluate the practical applications of the MASSE, polyaniline (PANI) was employed as a positive electrode to pair with the Zn negative electrode for full cell testing. Firstly, the performance of the MASSE-assembled full cells was tested at room temperature to verify their universality under ambient conditions. The Zn||PANI full cells employing MASSE demonstrate cycling stability of 2000 cycles, which far surpasses that of Zn(OTf)2–H2O and Zn(OTf)2–DEG (Fig. 6a). At an elevated temperature of 80°C, Zn||PANI full cells with MASSE maintain a cycle life of 1700 cycles, substantially longer than that achieved with Zn(OTf)2–H2O or Zn(OTf)2–DEG electrolytes (Fig. 6b and Supplementary Fig. 39). Furthermore, full cells with MASSE exhibit higher CE and greater reversibility during charging and discharging than those with Zn(OTf)2–H2O or Zn(OTf)2–DEG, due to inhibited side reactions at HT. The rate performance of Zn||PANI full cells with different electrolytes was tested at 80°C (Fig. 6c). The MASSE-based full cells show rate performance at a current density range from 0.8 to 8.0 Ag−1, with capacities ranging from 126 to 65 mAh g−1. When the current density is returned to 0.5 Ag−1, the specific capacity remains stable, demonstrating performance better than that of cells with Zn(OTf)2–H2O or Zn(OTf)2–DEG electrolytes (Supplementary Fig. 40). The enhanced performance difference under high current can be attributed to the rapid migration of Zn2+ in MASSE. The cycle life of MASSE was further evaluated in the full cells of Zn||PANI under more stringent testing conditions with N/P of 2 (50% DOD) (Supplementary Fig. 41). The favorable performance prompts an evaluation of the electrochemical performance at higher working temperatures. As shown in Fig. 6d, Zn||PANI full cells display a stable charge and discharge process with a gradually increasing specific capacity as the temperature increases from 25 to 140°C. Even at an HT of 140°C, the full cell still operates normally with a high specific capacity of 157 mAh g−1. Moreover, the full cells using MASSE still maintain stable cycling under high current density of a 8 Ag−1 and a high working temperature of 140°C (Supplementary Fig. 42). As summarized in Fig. 6e, Zn||PANI full cells utilizing MASSE demonstrate competitive performance against some recent relevant reports, which is attributed to their long cycle life, high-rate capability, and excellent HT tolerance (Supplementary Table 7). This comparison underscores the great advantages of MASSE for HT AZMBs. HT full cells evaluations remain predominantly limited to the coin cells due to accelerated parasitic reactions (e.g., Zn corrosion, HER, SEI dissolution) in the pouch cells under elevated temperature, which induces catastrophic capacity fade in scaled systems. Therefore, the feasibility of the MASSE was first evaluated in the pouch cells. As displayed in Fig. 6f, a large-sized pouch cell using MASSE delivers a total capacity of 37 mAh with stable cycling over 175 cycles at 80°C. Oppositely, the pouch cells using the Zn(OTf)2–H2O and Zn(OTf)2–DEG release low capacity with rapid capacity decay. Furthermore, the MASSE-assembled pouch cells can power a lamp (Supplementary Fig. 43), which shows great promise in practical applications. Considering the intimate connection between intrinsic reactions and thermal effects, the heat distribution of pouch cells during actual operation has been investigated by infrared thermal imaging. Initially, the pouch cells with different electrolytes were cycled three times at a current density of 1 Ag−1 and a temperature of 80°C, before being returned to room temperature for thermal monitoring. During the static period, the temperature varies greatly in different regions in the Zn(OTf)2–H2O and Zn(OTf)2–DEG (Supplementary Fig. 44 and Fig. 6g). A few areas have a concentrated HT, indicating that these are the sites of intensive side reactions, e.g., large-scale HER and corrosion. In contrast, the temperature of pouch cells using MASSE is uniformly distributed, which demonstrates the uniform reactions at HT (Fig. 6h). These results further demonstrate that MASSE effectively inhibits side reactions at elevated temperatures, even in the large-sized pouch cells. To verify the universality of the proposed MASSE design strategy, two parallel investigations were conducted. First, DEG solvent was replaced with various representative organic solvents (alcohols, sulfones, and esters) to systematically evaluate the HT electrochemical performance of the corresponding MASSE systems (Supplementary Fig. 45). In addition, the MASSE electrolyte was extended and applied to Zn||NVO full cell systems beyond the Zn||PANI system (Supplementary Fig. 46). The results demonstrate that the MASSE electrolyte developed in this study is not only compatible with diverse solvent systems but also adaptable to different electrode material systems, achieving long-term cycling stability under elevated temperatures in all cases.

Methods
Materials
Zinc trifluoromethylsulfonate (Zn(OTf)2, AR≥99%) was purchased from Sigma-Aldrich. Diethylene glycol (DEG, AR≥99%), alumina (Al2O3, 10 nm, AR≥99.8%), N-Methyl-2-pyrrolidone (NMP, AR≥99.5%), and polyaniline (PANI) were purchased from Aldrich. Ketjen Black, Polytetrafluoroethylene (PTFE), Zinc foil (99.9%), stainless-steel mesh (250 mesh, 0.12 mm), titanium mesh (200 mesh, 0.15 mm), and copper foil (20 μm) were all purchased from SaiBo company. The GF/F separator (thickness: 420 μm; porosity: ≥90%; average pore size: 0.7 μm) was purchased from the Whatman company.

Preparation of electrolytes and electrodes
The Zn(OTf)2–H2O and Zn(OTf)2–DEG electrolytes were prepared by directly adding Zn(OTf)2 powders to H2O and H2O–DEG (2:1, molar ratio) with molar concentrations of 2 M, respectively. MASSE was formulated by homogenizing a mixture of Zn(OTf)2–DEG electrolyte and 10 wt% Al2O3 nanoparticles using an ultrasonic cell grinder (400 W, 1 h), yielding a milky-white suspension. The PANI electrodes were prepared by combining 80 wt% active material, 10 wt% Ketjen Black, and 10 wt% PTFE dispersion in isopropanol to form a homogeneous paste, followed by rolling into free-standing films and subsequent thermal treatment at 60 °C for 8 h under vacuum conditions. Electrodes were affixed onto the stainless-steel mesh for electrochemical testing. Zinc metal was employed directly as the negative electrode without further treatment.

Characterizations
SEM measurements were performed with a Hitachi S-4800 field emission scanning electron microscope. XRD patterns of the samples were employed on an X’Pert Pro diffractometer utilizing monochromatized Cu Kα radiation (λ=1.5406 Å) at a scanning rate of 10° min−1. FTIR spectra were acquired using a Nicolet iS50 FTIR spectrometer integrated with a high-sensitivity diamond ATR accessory. Synchrotron radiation EXAFS was employed at the BL11B beamline of the Shanghai Synchrotron Radiation Facility. X-ray photoelectron spectroscopy was performed using a Thermo-Fisher Scientific ESCALAB Xi X-ray photoelectron spectrometer equipped with an Al Kα X-ray source (1486.68 eV). For depth profiling, a gas cluster ion beam source with 1 keV ion energy was employed to sputter 1×1 mm2 regions, with the analysis focused on 200×200 μm2 areas centered within these zones. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analyses were conducted using a TOF-SIMS5-100 system with a Cs+ primary ion beam operating at 1 keV energy and a sample current of ~40 nA. Secondary ion signals were acquired over 1600 s from a 50×50 µm2 analysis area, maintaining spatial resolution through controlled sputtering parameters. LSCM was performed on FV1000MPE. The in situ detection of hydrogen production was accomplished using China Education Aulight in conjunction with a gas chromatograph (GC-7920, China) equipped with detection capabilities. The temperature change of the pouch cells during charging was monitored on an infrared thermal imager (FLIR T540, Sweden).

Electrochemical measurements
The electrochemical performances of the Zn||Zn, Zn||Cu, and Zn||PANI cells were examined using CR2032-type coin cells (case and spring material: stainless steel), conducted on a battery test station (LANHE CT3001A). Zn||PANI full cells were assembled using zinc foil (Φ12 mm) as the negative electrode and PANI (Φ10 mm) as the positive electrode. For standard coin cell evaluations, a 100-μm-thick Zn foil served as the negative electrode, paired with a PANI positive electrode having a mass loading of 1 mg cm−2. For the high DOD cells tests, the 10-μm-thick Zn foil thermally pressed onto titanium mesh was used as the negative electrode, and the polyaniline (PANI) positive electrode had a loading of 12 mg cm−2, with an N/P ratio of ~2. A standardized electrolyte volume of 120 μL was dispensed into each cell. Pouch cells were assembled by stacking a positive electrode of PANI (14×11 cm2, 3 mg cm−2) with Zn foils (15×12 cm2, 10 μm). The positive electrode used stainless steel mesh as the current collector and tabs, while the negative electrode utilized zinc metal. One piece of positive electrode and two pieces of Zn foils are stacked together and encapsulated by aluminum plastic film through a vacuum final sealing machine (MSK-115A-L, Shenzhen Kejing Star Technology). The electrolyte volume of 8 mL was dispensed into each pouch cell. The stack pressure for pouch cells was ~300 kPa. The HT performance of cells was evaluated in a temperature-controlled incubator. All cells were placed in a climatic chamber for 1 h to achieve thermal equilibrium before performing electrochemical testing at different temperatures. The cut-off potentials for Zn||PANI cells were configured as 0.5 V and 1.5 V, and the current applied was varied in accordance with the experimental requirements, ranging from 0.5 to 8 Ag−1. LSV, chronoamperometry (CA), Tafel polarization test, and EIS were performed on the electrochemical workstation (CHI 760E). EIS tests were employed under potentiostatic conditions with a frequency range from 0.01 Hz to 100 kHz. The measurements were recorded with 12 data points per decade following a 2-s stabilization period at the open-circuit potential. Tafel tests were performed at a scan rate of 1 mV s−1 using Zn||Zn cells. LSV tests were conducted using Zn||Cu cells at a scan rate of 1 mV s−1 from −0.5 to 2.5 V (vs. Zn/Zn2+). CA curves were recorded at a constant overpotential of 10 mV using Zn||Zn cells. The Zn2+ transference number was calculated according to the typical Evans method, as presented by the subsequent equation:

τ = I s (ΔV − I 0 R 0 ) / I 0 (ΔV − I s R s ) (1)

where I0/Is and R0/Rs represent the initial/final current density and charge transfer resistance before and after the polarization test, ΔV (10 mV) is the constant polarization potential for the chronoamperometry test. The ionic conductivity of the electrolyte was measured using a standard 2032 coin cell with two stainless steel electrodes placed symmetrically at a set distance. AC impedance analysis from 10 mHz to 100 kHz with an amplitude of 10 mV was used, and the ionic conductivity was calculated with the following equation:

σ = L / RS (2)

Where R is the resistance, and S and L are the area and spacing between the electrodes, respectively. Data points from 20 to 140°C were measured, and the symmetrical cells remained at a set temperature controlled for 30 min prior to the test.

DFT calculations
All calculations were performed with the Gaussian 16, C01 software package. The hybrid functional PBE0, coupled with the D3 dispersion correction of Grimme featuring Becke–Johnson damping (DFT-D3BJ), was employed throughout all calculations. For geometric optimization and vibrational frequency analysis, the def2-SVPD basis set was utilized, while the def2-TZVPD basis set was adopted for single-point energy calculations. The interaction energy between H2O, DEG, and Al2O3 was calculated by the following equation:

E binding energy = E species + E slab − E slab/species (3)

Where E species and E slab were the total energy of the adsorbate and bare surface directly obtained from DFT calculations, respectively, and E slab/species was the total energy of the optimized adsorbate-surface.

MD simulations
MD simulations were executed using GROMACS software. Three system-specific simulation boxes with optimized dimensions were generated based on molecular composition and stoichiometry. Following system construction, energy minimization was performed using the steepest descent algorithm with a force tolerance of 1000 kJ mol−1 nm−1. Subsequent equilibration protocols included 100 ps temperature regulation (353.15 K) in the NVT ensemble and 100 ps pressure stabilization (1 atm) in the NPT ensemble. The production phase comprised 50 ns unconstrained MD trajectories.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "In this manuscript, the authors propose a thermally robust MASSE for enhancing high temperature performance of AZMBs. This strategy enables strong interactions between the heterogeneous phases, reconstructing hydrogen-bond networks and forming water-deficient solvation structures, which greatly improves thermal stability, and eliminating parasitic reactions at elevated temperature. This work achieved an improvement in the electrochemical performance of AZMBs, extending the operating temperature to 140 ℃. In my opinion, the result is interesting, and the paper is well organized. The manuscript can be considered for publication after revision to address the following issues.\n1. Authors claimed that elevating the operating temperature of AZMBs to 140 °C. What technical implementation fields are relevant for such extreme-temperature operational devices? Furthermore, the manuscript would benefit from a comparison of innovation with other high-temperature literatures. This would help to highlight the scientific and technical breakthroughs of this work.\n2. In the description of HB strength, the authors state that “Our analysis framework defines HBs geometrically based on two critical parameters: HB angle and HB length, with bond strength exhibiting inverse correlations with angle and direct proportionality to length.” This statement seems to contradict the subsequent description of the data.\n3. Alumina may significantly increase electrolyte viscosity due to particle aggregation, thereby restricting ion migration. It is recommended that the authors should provide more information on the viscosity and ionic conductivity of electrolytes at high temperature.\n4. While the study demonstrates superior performance of the Zn||PANI full cells at elevated temperature, it lacks room-temperature performance validation. The cycling performance of Zn||PANI full cells at room temperature should be supplemented to validate its practical applicability.\n5. The article contains several detailed errors in writing and graphical presentation. For example: (a) The mode scales in the FTIR spectra of Supplementary Fig. 8 are inconsistent, which may compromise data comparability and the rigor of graphical presentation. (b) The authors state in the “Electrochemical Measurements” section that “Tafel and LSV tests were performed at a scan rate of 1 mV s-1 using Zn||Zn cells and Zn||Cu cells, respectively”. Yet Fig. 3g labels the abscissa with the SCE reference electrode system. This creates a methodological inconsistency.", "reviewer_2": "The manuscript presents a novel multiphase soggy-sand electrolyte (MASSE) for aqueous zinc metal batteries, claiming outstanding thermal robustness up to 140 °C. The authors provide a comprehensive set of characterizations (from DFT and MD simulations to in situ electrochemical analysis) to support the claimed improvements in high-temperature performance. However, despite the extensive efforts dedicated to demonstrating elevated-temperature stability, a critical and foundational aspect has been overlooked: the room-temperature electrochemical performance. From a practical perspective, any high-temperature electrochemical system must first meet baseline performance criteria at ambient conditions to be of technological relevance. Especially considering that the vast majority of real-world applications for aqueous batteries occur within the typical terrestrial temperature range of -40 °C to 40 °C. In this manuscript, there is a striking absence of room-temperature electrochemical data such as long-term cycling stability and rate capability of Zn full batteries under room temperature. Without this information, it is impossible to assess the broader applicability, baseline stability, or trade-offs introduced by the MASSE system at normal operating conditions.\nGiven this gap, I believe the manuscript in its current form does not yet meet the publication criteria of the journal. A more balanced and rigorous evaluation spanning both room-temperature and high-temperature conditions is necessary before the proposed electrolyte system can be considered for publication.\n1. As noted above, the authors should provide electrochemical performance data at room temperature, especially for Zn full cells, to establish a meaningful baseline. Furthermore, for battery performance evaluation to be credible, Coulombic efficiency (CE) should be reported alongside capacity and cycle life. However, CE is missing in Figs. 6a, 6c, and 6f, and Fig. 6d appears to present it for only one of the electrolytes.\n2. As an electrolyte-focused study, the authors should provide a comparative analysis of the ionic conductivity for all electrolytes investigated, spanning from room temperature to high temperature.\n3. The study uses 100 μm thick Zn foil in all cells, which implies a very low depth of discharge (DOD) in the current tests. Given that the manuscript emphasizes uniform Zn deposition, it is essential to evaluate the electrolyte performance under high DOD conditions (e.g., 50% DOD) in Zn||Zn symmetric, Zn||Cu asymmetric, and full cells, to better reflect practical relevance and plating/stripping reversibility. In addition, post-cycling characterization of the Zn anode under high DOD would greatly strengthen the reliability of the conclusions.\n4. The transference number calculation used in this work is inappropriate for the MASSE system. The method assumes negligible cation-anion interactions, yet the authors' own MD results (solvation percentages) clearly show that anions are heavily involved in Zn ion solvation in MASSE. This directly violates the assumptions of the equation, rendering the reported transference number invalid. A more suitable method must be employed.\n5. The MD results shown in Fig. 2 should clearly label the coordination numbers for all Zn ion solvation environments to allow proper interpretation. Moreover, the binding energy analysis in Fig. 2j claims that MASSE has the most favorable binding energy (-32.4 eV) suggesting superior thermodynamic stability, followed by Zn(OTf)2-H2O (-22.68 eV) and Zn(OTf)2-DEG (-20.57 eV. However, this contradicts the thermal stability trend shown in Supplementary Figure 10, where MASSE < Zn(OTf)2-DEG < Zn(OTf)2-H2O in terms of weight loss. This inconsistency must be addressed and properly explained. Moreover, the schematic of the binding energy calculation in Fig. 2j is too small and lacks clarity. The authors should enlarge it and provide proper annotations to make the calculation method transparent.\n6. In Fig. 2m, there is a clear increase in O-H stretching intensity as the temperature rises from 20 °C, particularly between 20 °C and 40 °C. In fact, this variation appears even more pronounced than that observed in Figure 2l over the same temperature range. The authors should not overlook this trend when claiming thermal stability, and a proper explanation of this behavior is necessary. This further underscores the need to provide detailed electrochemical and spectroscopic data beginning from room temperature, rather than focusing solely on elevated temperatures.\n7. In Fig. 3g, the LSV curves present only one side of the electrochemical window, which is insufficient for evaluating electrolyte stability. The authors should provide the full electrochemical window for all electrolytes. These key measurements (e.g., Figs. 3g-3i) should also be performed at room temperature to demonstrate the broader applicability of the MASSE system.\n8. The authors highlight the achievement of both 8 A g-1 current density and 140 °C operating temperature, yet no cycling data is provided under these two conditions simultaneously. If the electrolyte cannot sustain operation under both extremes at once, the current presentation is misleading and overstates the system’s robustness. Clear clarification is needed.\n9. The authors should clearly report key experimental details, such as electrolyte concentration and the cathode mass loading in both coin and pouch cells, which are essential for evaluating performance and reproducibility.\n10. In Fig. 6a, the capacity of the Zn(OTf)2-H2O based cell is significantly lower than many previously reported Zn||PANI systems and far below the theoretical capacity of PANI. The authors should clarify whether this poor performance also occurs at room temperature, and explain the underlying reasons.", "reviewer_3": "This study presents a thermally stable electrolyte with a stable solvation structure at high temperatures to enhance the performance of zinc-ion batteries, particularly in high-temperature conditions. Several aspects need clarification and validation to highlight the key innovation of the work. Here are some suggestions:\n1. The electrolyte composition includes Al2O3, a novel composite material for electrolyte. Given that Al₂O₃ is a stable insulating ceramic oxide with strong bonds, how does the electrolyte ensure the uniform mixing of liquid and solid components? Is there a risk of phase separation?\n2. The impact of Al2O3 particle size on its interaction with H2O should be discussed. The simulation focuses on the molecular-scale bonding of Al2O3 with H2O, but since Al2O3 is in nano-scale, only the surface layer may affect water reactivity.\n3. As Al2O3 nanoparticles cannot dissolve in the liquid solution, the claim that Al2O3 can enter solvation structures in Fig. 4 needs clarification. This phenomenon is novel and requires further explanation.\n4. How can the polar interaction of Al2O3 be assessed in the solid-liquid phase? More discussion on this aspect is needed.\n5. The statement about electrolyte structural instability in solvation complexes leading to detrimental electrochemical processes should be supported with specific examples and references.\n6. The claim that elevated temperatures induce anomalous hydrogen bonding activation in Zn(OTf)2-H2O should specify whether this activation occurs within or outside the solvation structure.\n7. The exceptional high-temperature performance of the MASSE electrolyte, attributed to Al2O3, could be further elucidated by comparing electrolytes containing only water and Al2O3 to isolate the influence of the DEG solvent.\n8. Can this concept be applied to other aqueous systems or broader solvent and battery systems? Consider discussing the potential applicability of this approach beyond the current system.\n9. Check for grammar errors and ensure the text is clear and concise."}, "author_response": "Responses to Reviewer 1\nIn this manuscript, the authors propose a thermally robust MASSE for enhancing high temperature\nperformance of AZMBs. This strategy enables strong interactions between the heterogeneous phases,\nreconstructing hydrogen-bond networks and forming water-deficient solvation structures, which greatly\nimproves thermal stability, and eliminating parasitic reactions at elevated temperature. This work\nachieved an improvement in the electrochemical performance of AZMBs, extending the operating\ntemperature to 140 ℃. In my opinion, the result is interesting, and the paper is well organized. The\nmanuscript can be considered for publication after revision to address the following issues.\nResponse: We appreciate the reviewer for recognizing the importance and novelty of our work and\nconstructive revision advice. We have addressed the reviewer’s comments point by point.\n1. Authors claimed that elevating the operating temperature of AZMBs to 140 °C. What technical\nimplementation fields are relevant for such extreme-temperature operational devices? Furthermore, the\nmanuscript would benefit from a comparison of innovation with other high-temperature literatures. This\nwould help to highlight the scientific and technical breakthroughs of this work.\nResponse: Thank the referee very much for these comments. The core technology developed in this study,\nenabling AZMBs to operate stably at the extreme temperature of 140 °C, has potential applications\nprimarily focused on equipment operating within harsh high-temperature environments or requiring\nextreme temperature operation. Examples include power supply systems for downhole tools used in deep\ngeothermal resource exploration and power generation (enduring sustained temperatures >120 °C), high-\ntemperature power sources for unmanned rovers in the polar and equatorial regions of the moon/mars\n(experiencing extreme surface temperature fluctuations reaching ~130 °C), and self-sustaining power\nsources for embedded monitoring devices in aircraft/spacecraft operating near critical high-temperature\ncomponents like turbines.\nThis study innovatively developed a multiphase aqueous soggy-sand electrolyte system, successfully\nachieving stable cycling of AZMBs under extreme high-temperature conditions of 140 °C, thereby\novercoming the bottleneck of traditional aqueous electrolytes being unable to operate in high-temperature\nenvironments due to boiling point limitations. Compared to existing high-temperature battery systems\n(such as lithium batteries or sodium-sulfur batteries), this work addresses critical challenges such as\nR1\nelectrolyte volatilization and intensified side reactions under high temperatures through a unique organic-\ninorganic hybrid phase synergistic mechanism, while preserving the inherent safety, low cost, and\nenvironmental friendliness of aqueous batteries.\nFurthermore, regarding the current research landscape of high-temperature AZMBs systems, existing\nstrategies such as gel electrolytes, eutectic electrolytes, and co-solvent modified electrolytes primarily rely\non single modification approaches. Although these methods can partially suppress water molecule activity,\nthey struggle to fundamentally disrupt the HB network of water, leading to persistent issues such as\nevaporation of free water at high temperatures, which triggers electrode corrosion and dendrite growth.\nThe organic-inorganic hybrid phase dual-fixation mechanism proposed in this work leverages the\nsynergistic effects of nanoparticles and organic solvents. On one hand, the rigid framework of the Al O\n2 3\nphase restricts water molecule migration, while on the other hand, the intermolecular forces of the organic\nphase reconstruct the HB network, significantly reducing the activity of free water. The breakthrough of\nthis technology lies in its ability to elevate the operating temperature of aqueous batteries to 140°C for the\nfirst time, far exceeding the temperature tolerance limits of existing aqueous zinc batteries and distinctly\ndifferentiating it from highly flammable traditional high-temperature battery systems. This innovative\ndesign provides a novel solution for energy storage demands in extreme environments.\n2. In the description of HB strength, the authors state that “Our analysis framework defines HBs\ngeometrically based on two critical parameters: HB angle and HB length, with bond strength exhibiting\ninverse correlations with angle and direct proportionality to length.” This statement seems to contradict\nthe subsequent description of the data.\nResponse: Thank you for your meticulous review and valuable feedback on our manuscript. The\ndescription of the relationship between HB strength and its angle/distance is based on the reference (Angew.\nChem. Inter. Ed., 2023, 62, e202301114). The research indicates that stronger HBs correspond to shorter\nHB distances and larger HB angles. This conclusion is consistent with our experimental results.\nIn Revision: As advised by the reviewer, the following explanation ‘Our analysis framework defines HBs\ngeometrically based on two critical parameters: HB angle and HB length, with bond strength exhibiting\ninverse correlations with length and direct proportionality to angle.’ was corrected in the revised\nmanuscript.\nR2\n3. Comment: Alumina may significantly increase electrolyte viscosity due to particle aggregation, thereby\nrestricting ion migration. It is recommended that the authors should provide more information on the\nviscosity and ionic conductivity of electrolytes at high temperature.\nResponse: Thank the referee very much for these comments. As shown in Fig. R1a, the Zn(OTf) -H O\n2 2\nelectrolyte maintains relatively low viscosity in the range from 25 °C to 80 °C. However, viscosity\nmeasurements could not be continued as the system approached water’s boiling point (100 °C) due to\nsolution boiling. After introduction of DEG, the viscosity of Zn(OTf) -DEG electrolyte is greatly\n2\nincreased owing to the high molecular weight of DEG. In the MASSE electrolyte, the addition of Al O\n2 3\nfurther increases the viscosity of the electrolyte at room temperature. With increasing temperature, the\nviscosity of MASSE decreases significantly compared with Zn(OTf) -H O. In addition, the ionic\n2 2\nconductivity of electrolytes at different temperatures was also measured. The Zn(OTf) -H O electrolyte\n2 2\nexhibits a higher ionic conductivity compared to other electrolytes in the range from 25 °C to 100 °C (Fig.\nR1b). The addition of DEG and Al O lead to a reduction in the overall ionic conductivity due to lower\n2 3\nwater content. This phenomenon primarily stems from the influence of these components on the ion\ntransport pathways and solvation structure. However, this design represents a deliberate compromise made\nto balance the critical requirements of high-temperature stability against ionic conductivity. Compared to\nZn(OTf) -DEG, the addition of Al O leads to enhanced ionic conductivity, attributing to the optimized\n2 2 3\nion migration environment through interfacial effects.\nFig. R1 (a) Temperature-dependent viscosity of different electrolytes. (b) Temperature dependence of the\nionic conductivity of the different electrolytes.\nIn Revision: As advised by the reviewer, we have added more discussions on the ionic conductivity and\nthe viscosity of different electrolytes in the revised manuscript.\nR3\n4. Comment: While the study demonstrates superior performance of the Zn||PANI full cells at elevated\ntemperature, it lacks room-temperature performance validation. The cycling performance of Zn||PANI full\ncells at room temperature should be supplemented to validate its practical applicability.\nResponse: Thank you very much for your insightful comments. According to your suggestions, we have\nsupplemented the performance of the Zn||PANI full cells at room temperature. As shown in Fig. R2, the\nZn||PANI full cells employing MASSE demonstrates impressive cycling stability of 2000 cycles, which\nfar surpasses that of Zn(OTf) -H O and Zn(OTf) -DEG.\n2 2 2\nFig. R2 Cycling performance and CE of Zn||PANI full cells using different electrolytes at room temperatue.\nIn Revision: As advised by the reviewer, we replaced Fig. 6a by Fig. R2 and the corresponding\nexplanation ‘Firstly, the performance of the MASSE-assembled full cells was tested at room temperature\nto verify its universality under ambient conditions. The Zn||PANI full cells employing MASSE\ndemonstrates impressive cycling stability of 2000 cycles, which far surpasses that of Zn(OTf) -H O and\n2 2\nZn(OTf) -DEG (Fig. 6a)’ was added in the revised manuscript.\n2\n5. Comment: The article contains several detailed errors in writing and graphical presentation. For\nexample: (a) The mode scales in the FTIR spectra of Supplementary Fig. 8 are inconsistent, which may\ncompromise data comparability and the rigor of graphical presentation. (b) The authors state in the\n“Electrochemical Measurements” section that “Tafel and LSV tests were performed at a scan rate of 1\nmV s-1 using Zn||Zn cells and Zn||Cu cells, respectively”. Yet Fig. 3g labels the abscissa with the SCE\nreference electrode system. This creates a methodological inconsistency.\nResponse: Thank you for your detailed comments. We carefully checked these detailed errors in writing\nR4\nand graphical presentation. We have standardized the testing mode of FTIR spectra, uniformly switching\nto transmission mode. Meanwhile, the horizontal axis label in Fig. 3g was revised to “potential (V vs.\nZn/Zn2+)”.\nIn Revision: As advised by the reviewer, the corresponding modifications have been made, as shown in\nSupplementary Fig. 12 in the revised supporting information and Fig. 3g in the revised manuscript.\nR5\nResponses to Reviewer 2\nThe manuscript presents a novel multiphase soggy-sand electrolyte (MASSE) for aqueous zinc metal\nbatteries, claiming outstanding thermal robustness up to 140 °C. The authors provide a comprehensive\nset of characterizations (from DFT and MD simulations to in situ electrochemical analysis) to support the\nclaimed improvements in high-temperature performance. However, despite the extensive efforts dedicated\nto demonstrating elevated-temperature stability, a critical and foundational aspect has been overlooked:\nthe room-temperature electrochemical performance. From a practical perspective, any high-temperature\nelectrochemical system must first meet baseline performance criteria at ambient conditions to be of\ntechnological relevance. Especially considering that the vast majority of real-world applications for\naqueous batteries occur within the typical terrestrial temperature range of -40 °C to 40 °C. In this\nmanuscript, there is a striking absence of room-temperature electrochemical data such as long-term\ncycling stability and rate capability of Zn full batteries under room temperature. Without this information,\nit is impossible to assess the broader applicability, baseline stability, or trade-offs introduced by the\nMASSE system at normal operating conditions. Given this gap, I believe the manuscript in its current form\ndoes not yet meet the publication criteria of the journal. A more balanced and rigorous evaluation\nspanning both room-temperature and high-temperature conditions is necessary before the proposed\nelectrolyte system can be considered for publication.\nResponse: We thank Reviewer #2 for the comprehensive review and constructive criticism of our\nmanuscript. We recognize the need for significant improvements to meet the high standards of Nature\nCommunications. Following the suggestions, we have added characterizations of MASSE at room\ntemperature and incorporated room-temperature electrochemical data in the manuscript. These additions\nwill provide a more comprehensive demonstration of our experimental results and their significance. We\nbelieve that these revisions will significantly improve the quality and clarity of our manuscript, making it\nsuitable for publication in Nature Communications. Here are the steps we have taken to address your\nconcerns.\n1. Comment: As noted above, the authors should provide electrochemical performance data at room\ntemperature, especially for Zn full cells, to establish a meaningful baseline. Furthermore, for battery\nperformance evaluation to be credible, Coulombic efficiency (CE) should be reported alongside capacity\nand cycle life. However, CE is missing in Figs. 6a, 6c, and 6f, and Fig. 6d appears to present it for only\nR6\none of the electrolytes.\nResponse: Thank you very much for the insightful comments. Fig. R3a presents the cycling performance\nof Zn||PANI batteries with different electrolytes at room temperature. The PANI full cells employing\nMASSE demonstrate impressive cycling stability of 2000 cycles, which far surpasses that of Zn(OTf) -\n2 2\nat room temperature was also evaluated. As shown in Fig. R3b, the full cells employing MASSE and\nZn(OTf) -DEG display much lower specific capacity compared to that of Zn(OTf) -H O under high\n2 2 2\ncurrent densities, attributing to high viscosity and low ionic conductivity at room temperature.\nAdditionally, the CE data from Figs. 6a, 6c, and 6f, and Fig. 6d have been integrated into Fig. R4.\nFig. R3 (a) Cycling performance and CE of Zn||PANI full cells using different electrolytes at room\ntemperature. (b) The rate performance and CE of Zn||PANI full cells with different electrolytes at room\ntemperature.\nR7\nFig. R4 (a) The rate performance and CE of Zn||PANI full cells using different electrolytes at 80 ℃. (b)\nElectrochemical performance of Zn||PANI full cells using MASSE at different temperatures. (c) Cycling\nperformance and CE of Zn||PANI full cells with different electrolytes at 80 ℃. (d) Cycling performance\nand CE of Zn||PANI pouch cells using different electrolytes at 80 ℃.\nIn Revision: As advised by the reviewer, we replaced Fig. 6a by Fig. R3a. The corresponding of\nexplanation of ‘Firstly, the performance of the MASSE-assembled full cells was tested at room\ntemperature to verify its universality under ambient conditions. The PANI full cells employing MASSE\ndemonstrate impressive cycling stability of 2000 cycles, which far surpasses that of Zn(OTf) -H O and\n2 2\nZn(OTf) -DEG. (Fig. 6a).’ were added in the revised manuscript. Besides, CE have been integrated into\nFigs. 6b, 6c, and 6d and Fig. 6f.\n2. Comment: As an electrolyte-focused study, the authors should provide a comparative analysis of the\nionic conductivity for all electrolytes investigated, spanning from room temperature to high temperature.\nResponse: Thank the referee very much for these comments. We have taken your suggestions seriously\nand have incorporated new data and analyses to strengthen our manuscript. The ionic conductivity of\nelectrolytes at different temperatures was measured. The Zn(OTf) -H O electrolyte exhibits the higher\n2 2\nionic conductivity compared to other electrolytes in the range from 25 °C to 100 °C (Fig. R5). The addition\nof DEG and Al O lead to a reduction in the overall ionic conductivity. This phenomenon primarily stems\n2 3\nfrom the influence of lower water content on the ion transport pathways and solvation structure. However,\nthis design represents a deliberate compromise made to balance the critical requirements of high-\ntemperature stability against ionic conductivity. Compared to Zn(OTf) -DEG electrolyte, the addition of\n2 3\nthrough interfacial effects.\nFig. R5 Temperature dependence of the ionic conductivity of the different electrolytes.\nIn Revision: As advised by the reviewer, we have added more discussions on the ionic conductivity of\ndifferent electrolytes in the revised manuscript.\n3. Comment: The study uses 100 μm thick Zn foil in all cells, which implies a very low depth of discharge\n(DOD) in the current tests. Given that the manuscript emphasizes uniform Zn deposition, it is essential to\nR9\nevaluate the electrolyte performance under high DOD conditions (e.g., 50% DOD) in Zn||Zn symmetric,\nZn||Cu asymmetric, and full cells, to better reflect practical relevance and plating/stripping reversibility.\nIn addition, post-cycling characterization of the Zn anode under high DOD would greatly strengthen the\nreliability of the conclusions.\nResponse: Thank you for your constructive advices. According to your suggestions, the cycling\nperformance of Zn||Zn symmetric cells at a high DOD (50%) was provided. As shown in Fig. R6a-b, the\nZn(OTf) -H O based cells survive for merely 35 h and 2 h of cycling at 25 °C and 80 °C, respectively,\n2 2\nbefore a sudden short circuit occurs. Although the Zn(OTf) -DEG based cells also suffer from severe side\n2\nreactions and dendrite growth at high DOD, leading to limited cycle life (140 h at 25 °C and 13 h at 80 °C).\nIn contrast, the Zn||Zn cells using MASSE indicate a stable cycling for 450 h at 25 ℃ and 60 h at 80 ℃.\nThe cycling performance of Zn||Cu cells using different electrolytes under a high DOD of 50% were also\nevaluated. The Zn||Cu half cells using Zn(OTf) -H O show rapid decay in CE only after 30 cycles at room\n2 2\ntemperature. When Zn(OTf) -DEG is used, Zn||Cu cells exhibit a low average CE of 91.38% and a lifespan\n2\nof 100 cycles. In contrast, Zn||Cu cells using MASSE exhibits a high average CE of 99.31% with a\nsignificantly extended lifespan of 270 cycles at 25 °C (Fig. R6c). When the temperature rises to 80 °C,\nthe Zn||Cu half cells using Zn(OTf) -H O and Zn(OTf) -DEG display a drastic fluctuation with only 5\n2 2 2\ncycles (Fig. R6d). Conversely, the Zn||Cu cells using MASSE exhibit an initial CE of 89.66% and sustains\nat a high level of 95.76% over 40 cycles.\nThe MASSE was further evaluated in the full cells of Zn||PANI under practical conditions with N/P\nof 2 (50% DOD). As shown in Fig. R7a, the full cells using MASSE demonstrate an impressively lifespan\nof 250 cycles with an initial capacity of 1.45 mAh cm-2, significantly outperforming those using Zn(OTf) -\n2 2\nmaintain an areal capacity of 1 mAh cm-2 after 50 cycles with a high CE of 98.83%. In contrast, full cells\nusing Zn(OTf) -H O and Zn(OTf) -DEG exhibit negligible areal capacities and rapid capacity degradation\n2 2 2\nunder identical testing conditions (Fig. R7b). Crucially, no electrochemical data for AZMB under such\nextreme conditions (combining 80 °C operation and high DOD cycling) have been reported in the\nliterature. Our work demonstrates unprecedented areal capacity and cycle life at a such high DOD and\nworking temperature, establishing the best reported data for AZMBs to date.\nR10\nFig. R6 Cycling performance of Zn||Zn cells using different electrolytes under high DOD of 50% at (a)\n25 ℃ and (b) 80 ℃. Cycling performance of Zn||Cu cells using different electrolytes under 50% DOD at\n(c) 25 ℃ and (d) 80 ℃.\nFig. R7 Cycling performance and CE of Zn||PANI full cells using different electrolytes under N/P of 2 at\n(a) 25 ℃ and (b) 80 ℃.\nThe morphological evolution of the Zn anode after cycling under a high DOD of 50% was examined\nby SEM images. Post-cycling Zn anodes in Zn(OTf) -H O under 50% DOD show residual irregular sheets\n2 2\nR11\nand particulate aggregates attributable to parasitic side-reaction products (Fig. R8a-b). While the Zn\nanodes cycled in Zn(OTf) -DEG reduces dendrites and dead zinc to some extent, the anode surface\n2\nremains covered with randomly oriented, size-heterogeneous flaky deposits (Fig. R8c-d). In sharp contrast,\nthe surface of Zn anodes in MASSE enables compact and uniform Zn deposition. Even at high temperature\nof 80 °C, MASSE-maintained anodes retain a relatively uniform surface, despite some unavoidable side\nproducts (Fig. R8e-f). XRD characterization of cycled Zn anodes after 10 cycles under 50% DOD\nconfirms the superior parasitic reaction suppression ability of MASSE electrolyte. At room temperature\nof 25 °C, characteristic peaks related to zinc triflate hydroxide hydrate (Zn (OTf) (OH) , ZOTH)\nx+y 2y 2x\nemerge on cycled Zn anodes in the Zn(OTf) -H O electrolyte, indicating severe interfacial side reactions\n2 2\n(Fig. R8g). In contrast, Zn anodes cycled in Zn(OTf) -DEG and MASSE exhibit significantly attenuated\nZOTH peak intensity surge dramatically of cycled Zn anodes in Zn(OTf) -H O and Zn(OTf) -DEG\n2 2 2\nelectrolytes due to thermal instability, which accelerates HER and corrosion reactions (Fig. R8h).\nRemarkably, MASSE maintains minimal parasitic product signatures even under these harsh conditions,\nattributing to the restructured HB networks to collaboratively reduce free-water activity and inhibit side\nreactions.\nR12\nFig. R8 SEM images of Zn anodes after 10 cycles at 25 °C under 50% DOD in (a) Zn(OTf) -H O, (c)\n2 2\nZn(OTf) -DEG and (e) MASSE. SEM images of Zn anodes after 10 cycles at 80 °C in (b) Zn(OTf) -H O,\n2 2 2\n(d) Zn(OTf) -DEG and (f) MASSE. XRD patterns of Zn anodes after 10 cycles in different electrolytes at\n2\n(g) 25 ℃ and (h) 80 ℃ (based on Zn||Zn cells).\nIn Revision: As advised by the reviewer, we have supplemented the supplementary Fig. 31,\nsupplementary Fig. 37 and supplementary Fig. 32 in the revised supporting information. Meanwhile, we\nhave added more discussions on the electrolyte performance under 50% DOD in the revised manuscript.\n4. Comment: The transference number calculation used in this work is inappropriate for the MASSE\nsystem. The method assumes negligible cation-anion interactions, yet the authors' own MD results\n(solvation percentages) clearly show that anions are heavily involved in Zn ion solvation in MASSE. This\ndirectly violates the assumptions of the equation, rendering the reported transference number invalid. A\nmore suitable method must be employed.\nResponse: Thank you very much for your insightful comments. For transference number measurements,\nthe most commonly used method is the modified steady-state current method (Bruce-Vincent method).\nAlthough fitting high-frequency EIS impedance (R , R ) can reduce errors from interfacial side reactions,\n0 s\ncation-anion association may still lead to overestimation of transference number (e.g., incomplete anion\nblocking in high concertration systems). However, due to the operational simplicity and versatility, the\nsteady-state current method remains the mainstream approach for transference number measurements in\nliquid electrolytes (Nature Commun., 2024, 15, 9465; Nature Chem., 2024, 16, 1427-1435), solid polymer\nelectrolytes (Nature Commun., 2025, 16, 4868; Nature Commun., 2024, 15, 3748), and composite\nelectrolytes (Nature Commun., 2023, 14, 4981; Adv. Mater. 2024, 36, 2311153), through some cation-\nanion interactions are inevitable. Except for this, electrophoretic NMR (eNMR) methd directly quantify\nion correlation effects (such as ion association in high-concentration electrolytes) without neglecting\ncation-anion interactions, making it theoretically applicable to Li+, Na+, and K+ ions for transference\nnumber measurements (J. Am. Chem. Soc. 2024, 146, 11105-11114; Angew. Chem. Int. Ed., 2022, 61,\ne202205075; ACS Energy Lett., 2024, 9, 373-380). However, for Zn2+ ions, the low sensitivity of 67Zn\n(large quadrupole moment and poor signal-to-noise ratio) and rapid relaxation make accurate\nmeasurement via eNMR method impossible. Additionally, strong electric fields may disrupt Zn2+\nR13\nsolvation structures, affecting the authenticity of migration behavior.\nGiven these constraints, we calculated the self-diffusion coefficients of cations and anions through\nMD simulations and determined the cation transference number using the Nernst-Einstein equation for\nfurther verification (Phys. Rev. Lett., 2019, 122, 136001). The Nernst-Einstein equation is as follows\nD\n+\nτ =\n+ D + D\n+ -\nWhere D+ and D- were the self-diffusion coefficients of Zn2+ and OTf-, respectively. As observed from\nFig. R9 and Table R1, the trend of ion transference number calculated using this method aligns consistently\nwith the trend obtained through EIS-based method in the manuscript. The Zn2+ transference number for\nthe MASSE electrolyte is calculated to be 0.6617, which is higher than those of the Zn(OTf) -DEG\n2\n(0.5482) and the Zn(OTf) -H O system (0.4634).\n2 2\nFig. R9 The MSD curves of (a) Zn2+ and (b) OTf- obtained by MD simulation results.\nTable. R1 The self-diffusion coefficients of Zn2+ and OTf- in different electrolytes.\nElectrolytes D D τ\nZn2+ OTf- Zn2+\nZn(OTf) -H O 0.7606 0.8809 0.4634\n2 2\nZn(OTf) -DEG 0.6194 0.5105 0.5482\nIn Revision: As advised by the reviewer, we supplemented the Fig. R9 as Supplementary Fig. 34 and\nTable R1 as Supplementary Table S5 in the revised supporting information. Besides, the following\ndescription ‘As presented in Supplementary Fig. 34 and Supplementary Table 5, the self-diffusion\ncoefficient of OTf- in MASSE electrolyte is much lower than that in Zn(OTf) -DEG and Zn(OTf) -H O\n2 2 2\nR14\nelectrolyte. This phenomenon is attributed to the Al O , whose surface charge characteristics selectively\n2 3\nrepel positively charged Zn2+ while attracting negatively charged OTf-. This electrostatic modulation\neffectively promotes the migration of Zn2+ in MASSE. The Zn2+ transference numbers were calculated by\nthe aforementioned self-diffusion coefficient data and Nernst-Einstein equation:\nD\n+\nτ =\n+ D + D\n+ -\nWhere D+ and D- were the self-diffusion coefficients of Zn2+ and OTf-, respectively. The Zn2+ transference\nnumber for the MASSE electrolyte is calculated to be 0.6617, which is higher than those of the Zn(OTf) -\n2 2\ninformation.\n5. Comment: The MD results shown in Fig. 2 should clearly label the coordination numbers for all Zn ion\nsolvation environments to allow proper interpretation. Moreover, the binding energy analysis in Fig. 2j\nclaims that MASSE has the most favorable binding energy (-32.4 eV) suggesting superior thermodynamic\nstability, followed by Zn(OTf)2-H2O (-22.68 eV) and Zn(OTf)2-DEG (-20.57 eV. However, this contradicts\nthe thermal stability trend shown in Supplementary Figure 10, where MASSE < Zn(OTf)2-DEG <\nZn(OTf)2-H2O in terms of weight loss. This inconsistency must be addressed and properly explained.\nMoreover, the schematic of the binding energy calculation in Fig. 2j is too small and lacks clarity. The\nauthors should enlarge it and provide proper annotations to make the calculation method transparent.\nResponse: Thank the referee very much for these comments. According to your suggestions, the\ncoordination numbers for all Zn2+ solvation environments have been added in Fig. 2d-f and\ncomprehensively summarized in Supplementary Table 1. As shown in Fig. 2j, the distinctive solvation\nstructure in the MASSE exhibits the highest binding energy (-32.4 eV) compared to the Zn(OTf) -H O (-\n2 2\n22.68 eV) and the Zn(OTf) -DEG (-20.57 eV), demonstrating superior structural stability and preventing\n2\nstructural damage at elevated temperature. This finding is consistent with the thermogravimetric test\nresults (Supplementary Fig. 15), which demonstrates that MASSE undergoes the smallest weight loss\nwhen heated to 150 ℃, further confirming its superior thermal stability at elevated temperature.\nTo improve clarity, we have relocated the schematic of the binding energy calculation from Fig. 2j to\nFig. R10, where we have added annotations and enhanced the overall resolution for better readability. The\nreasons for selecting solvation structures are as follows: The dominant solvation configuration\nR15\n(Zn(H O) (OTf-) ) in Zn(OTf) -H O was computationally modeled. Following Al O incorporation,\n2 5 1 2 2 2 3\nstructural reorganization occurred, leading to the replacement of Zn(H O) (DEG) in Zn(OTf) -DEG with\n2 1 5 2\nZn(OTf-) (DEG) (Al O ) in MASSE, while maintaining three other consistent solvation configurations.\n1 4 2 3 1\nThe corresponding binding energy were subsequently performed on these three characteristic solvation\nstructures.\nFig. R10 The representative solvation structure in (a) Zn(OTf) -H O, (b) Zn(OTf) -DEG, (c) MASSE\n2 2 2\nobtained from MD simulations.\nIn Revision: As advised by the reviewer, in the revised supporting file, we supplemented the Fig. R10 as\nSupplementary Fig. 14 and the corresponding explanation were provided as ‘The dominant solvation\nconfiguration (Zn(H O) (OTf-) ) in Zn(OTf) -H O was computationally modeled. Following Al O\n2 5 1 2 2 2 3\nincorporation, structural reorganization occurred, leading to the replacement of Zn(H O) (DEG) in\n2 1 5\nZn(OTf) -TEG with Zn(OTf-) (DEG) (Al O ) in MASSE, while maintaining three other consistent\n2 1 4 2 3 1\nsolvation configurations. The corresponding binding energy were subsequently performed on these three\ncharacteristic solvation structures (Fig. 2j and Supplementary Fig. 14)’ in the revised manuscript.\n6. Comment: In Fig. 2m, there is a clear increase in O-H stretching intensity as the temperature rises from\n20 °C, particularly between 20 °C and 40 °C. In fact, this variation appears even more pronounced than\nthat observed in Figure 2l over the same temperature range. The authors should not overlook this trend\nwhen claiming thermal stability, and a proper explanation of this behavior is necessary. This further\nunderscores the need to provide detailed electrochemical and spectroscopic data beginning from room\ntemperature, rather than focusing solely on elevated temperatures.\nR16\nResponse: Thank the reviewer for these excellent questions. In our previous data processing method, we\nnormalized the peak intensities before plotting, which could obscure the actual intensity differences\nbetween different electrolytes. To address this issue, we have now directly plotted the peak intensities to\nensure accurate comparative analysis. The in situ Raman spectra of MASSE have been retested. The\nZn(OTf) -H O demonstrates restricted thermal stability, as evidenced by the initiation of Zn(OTf)\n2 2 2\ncrystallite precipitation at 80 °C, owing to salt precipitation caused by electrolyte evaporation (Fig. R11a).\nAs shown in Fig. R11b, the O-H stretching band in the Zn(OTf) -DEG electrolyte broadens significantly\n2\nas the temperature increases from 20 ℃ to 140 ℃, demonstrating a strong thermal response. For MASSE,\na increase in O-H stretching intensity between 20 °C and 60 °C is observed, then remains stable without\nobvious enhancement as the heating temperature increases to 140 °C. In addition, the O-H band in the\nMASSE electrolyte maintains much lower intensity compared to the Zn(OTf) -H O and Zn(OTf) -DEG\n2 2 2\nelectrolyte, attributable to Al O -induced ligand cross-linking that stabilizes the solvation network against\n2 3\nthermal fluctuations (Fig. R11c).\nFig. R11 In situ Raman spectra of O-H stretching in (a) Zn(OTf) -H O, (b) Zn(OTf) -DEG, (c) MASSE\n2 2 2\nat different temperatures.\nIn Revision: In the revised manuscript, the Fig. 2m was updated by Fig. R11c and the corresponding\nexplanation were provided. ‘For MASSE, an increase in O-H stretching intensity between 20 °C and 60 °C\nis observed, then remains stable without obvious enhancement as the heating temperature increases to\n140 °C. In addition, the O-H band in the MASSE electrolyte maintains much lower intensity compared to\nthe Zn(OTf) -H O and Zn(OTf) -DEG electrolyte, attributable to Al O -induced ligand cross-linking that\n2 2 2 2 3\nstabilizes the solvation network against thermal fluctuations (Fig. 2m).’ was added in the revised\nmanuscript.\nR17\n7. Comment: In Fig. 3g, the LSV curves present only one side of the electrochemical window, which is\ninsufficient for evaluating electrolyte stability. The authors should provide the full electrochemical window\nfor all electrolytes. These key measurements (e.g., Figs. 3g-3i) should also be performed at room\ntemperature to demonstrate the broader applicability of the MASSE system.\nResponse: Thank the reviewer for these excellent comments. According to your suggestions, full\nelectrochemical window for all electrolytes was provided. As shown in Fig R12a, MASSE displays the\nwidest electrochemical window (1.93V), exceeding those of both Zn(OTf) -H O (1.21 V) and Zn(OTf) -\n2 2 2\nDEG (1.66 V) at elevated temperature of 80 ℃. In addition, complementary tests including room-\ntemperature LSV, in-situ pH, and DEMS profiles of H evolution have been conducted to provide\n2\ncomprehensive characterization. MASSE demonstrates the largest electrochemical window (2.68 V) at\n25 ℃, surpassing Zn(OTf) -H O (1.81 V) and Zn(OTf) -DEG (2.24 V) (Fig. R12b). The in-situ pH\n2 2 2\nmonitoring over 20 hours at room temperature revealed that the pH of Zn(OTf) -H O increases rapidly\n2 2\nthroughout cycling, attributed to severe parasitic reactions. In contrast, Zn(OTf) -DEG exhibits a\n2\nmarginally increasing pH trend. Most notably, MASSE maintained a remarkably constant pH under\nidentical conditions, revealing significant suppression of the HER at 25 ℃ (Fig. R12c). Fig. R12d presents\nthe quantitative DEMS results of H evolution, during the OCP and charge process at 25 ℃. Significantly\n2\nreduced H evolution is observed at the Zn anode surface utilizing the MASSE electrolyte under room-\n2\ntemperature. This indicates that the inhibitory effect of the MASSE electrolyte on undesirable side\nreactions is not only observed under elevated-temperature but remains significant at room temperature.\nR18\nFig. R12 Electrochemical windows of different electrolytes at (a) 80 ℃ and (b) 25 ℃. (c) In-situ pH value\nin different electrolytes at 25 ℃. (d) DEMS profiles of H evolution in Zn||Zn symmetric cells in different\n2\nelectrolytes at 25 ℃.\nIn Revision: As advised by the reviewer, The Fig. 3g was updated by Fig. R12a. Figs. R12b, R12c and\nR12d were added in the revised supporting information as Supplementary Fig. 17, Supplementary Fig. 18\nand Supplementary Fig. 19, respectively. The corresponding description ‘Linear sweep voltammetry (LSV)\ntesting exhibits that MASSE demonstrates the largest electrochemical window (1.81 V  2.24 V  2.68\nV) among all electrolytes at 25 ℃ (Supplementary Fig. 17). Under elevated temperature of 80 ℃, all\nelectrolytes exhibit marginally narrowed electrochemical windows, attributable to aggravated side\nreactions at high temperature. Nonetheless, MASSE still retains the widest electrochemical window (1.93\nV), exceeding those of both Zn(OTf) -H O (1.21 V) and Zn(OTf) -DEG (1.66 V) (Fig.3g).’, ‘Following\n2 2 2\n20 h of in-situ pH monitoring exhibits that the pH value of Zn(OTf) -H O increases rapidly throughout\n2 2\nthe entire cycle, which attributes to severe HER, leads to an increase in local pH values and exacerbates\nthe formation of ZOTH by-products at both 25 ℃ and 80 ℃ (Fig. 3h and Supplementary Fig. 18). The\npH value of the Zn(OTf) -DEG shows a slight easing trend but still increases. In sharp contrast, the pH\nvalues of MASSE remain rather constant under the same conditions, indicating the substantial inhibitory\neffect on HER.’ and ‘Fig. 3i and Supplementary Fig. 19 present the quantitative DEMS results of H\n2\nevolution, during the OCP and charge process at 25 ℃ and 80 ℃. Significantly reduced H evolution is\n2\nobserved at the Zn anode surface utilizing the MASSE electrolyte, under both room-temperature and\nelevated-temperature conditions.’ were added to the revised manuscript.\n8. Comment: The authors highlight the achievement of both 8 A g-1 current density and 140 °C operating\ntemperature, yet no cycling data is provided under these two conditions simultaneously. If the electrolyte\ncannot sustain operation under both extremes at once, the current presentation is misleading and\noverstates the system’s robustness. Clear clarification is needed.\nResponse: Thank the referee very much for these comments. The MASSE electrolyte exhibits excellent\nperformance when operating either at 140 °C or under a high current density of 8 A g-1 individually.\nHowever, simultaneously imposing both extreme conditions present a significant challenge to the\nthermodynamic stability and interfacial properties of MASSE. According to your suggestions, we\nsupplemented cycling performance data at a current density of 8 A g-1 under 140 °C. As shown in Fig.\nR13, the Zn||PANI full cells using MASSE maintains stable cycling of 100 cycles under such demanding\nconditions, delivering a specific capacity of 100 mAh g-1.\nFig. R13 Cycling performance and CE of Zn||PANI full cells using MASSE electrolyte under a current\ndensity of 8 A g-1 at 140 ℃.\nIn Revision: The Fig. R13 were added to the revised supporting file as Supplementary Fig. 38 and the\ncorresponding explanation ‘More surprisingly, the full cells using MASSE still maintains stable cycling\nR20\nunder high current density of 8 A g-1 and ultra-high working temperature of 140 ℃ (Supplementary Fig.\n38).’ was added to the revised manuscript.\n9. Comment: The authors should clearly report key experimental details, such as electrolyte concentration\nand the cathode mass loading in both coin and pouch cells, which are essential for evaluating performance\nand reproducibility.\nResponse: Thank you for the detailed comments. Detailed experimental procedures for battery assembly\nare described below. For standard coin cells evaluation, Zn foil with thickness of 100 μm was employed\nas the anode, alongside a PANI electrode with a mass loading of 1 mg cm-2 serving as the cathode. For\nthe high DOD cells tests, the 10-μm-thick Zn foil thermally pressed onto titanium mesh was used as anode,\nand polyaniline (PANI) cathode had a loading of 12 mg cm-2. A standardized electrolyte volume of 120\nμL was dispensed into each cell. Pouch cells were assembled by stacking a 3 mg cm-2 of PANI cathode\nelectrode (14× 11 cm2) with Zn foils (10 μm, 15 × 12 cm2). The electrolyte volume of 8 mL was dispensed\ninto each pouch cell.\nIn Revision: As advised by the reviewer, the corresponding experimental details of ‘For standard coin\ncells evaluation, Zn foil with thickness of 100 μm was employed as the anode, alongside a PANI electrode\nwith a mass loading of 1 mg cm-2 serving as the cathode. For the high DOD cells tests, the 10-μm-thick\nZn foil thermally pressed onto titanium mesh was used as anode, and polyaniline (PANI) cathode had a\nloading of 12 mg cm-2. A standardized electrolyte volume of 120 μL was dispensed into each cell. Pouch\ncells were assembled by stacking a 3 mg cm-2 of PANI cathode electrode (14× 11 cm2) with Zn foils (10\nμm, 15 × 12 cm2). The electrolyte volume of 8 mL was dispensed into each pouch cell.’ were provided in\nthe method of electrochemical measurements part to in the revised manuscript.\n10. Comment: In Fig. 6a, the capacity of the Zn(OTf)2-H2O based cell is significantly lower than many\npreviously reported Zn||PANI systems and far below the theoretical capacity of PANI. The authors should\nclarify whether this poor performance also occurs at room temperature, and explain the underlying\nreasons.\nResponse: We sincerely apologize for this oversight. To address this issue, we have reevaluated the rate\nperformance of the Zn||PANI full cells with different electrolytes at 80 °C under identical testing\nconditions. As shown in Fig. R14a, the MASSE-based full cells show an excellent rate performance at a\nR21\ncurrent density range from 0.8 to 8.0 A g-1. However, the full cells with Zn(OTf) -H O exhibit the much\n2 2\nlower specific capacity (95 mAh g-1 to 46 mAh g-1) and abruptly fail when the current density reach 4 A\ng-1. In addition, the rate performance of Zn||PANI full cells at room temperature was also measured. As\nshown in Fig. R14b, the full cells using Zn(OTf) -H O display the higher specific capacity compared to\n2 2\nthat of MASSE and Zn(OTf) -DEG, specifically under high current densities, attributing to low viscosity\n2\nand high ionic conductivity of Zn(OTf) -H O at room temperature.\n2 2\nFig. R14 (a) The rate performance and CE of Zn||PANI full cells with different electrolytes at 80 ℃; (b)\nThe rate performance and CE of Zn||PANI full cells with different electrolytes at room temperature.\nIn Revision: As advised by the reviewer, Fig. 6c has been updated and corresponding discussions on the\nrate performance were added in the revised manuscript.\nR22\nResponses to Reviewer 3\nThis study presents a thermally stable electrolyte with a stable solvation structure at high temperatures to\nenhance the performance of zinc-ion batteries, particularly in high-temperature conditions. Several\naspects need clarification and validation to highlight the key innovation of the work. Here are some\nsuggestions:\nResponse: We thank the reviewer for the positive comments. The manuscript has been carefully revised\naccording to your comments. The detailed responses to your questions are provided as below for\nconsideration.\n1. Comment: The electrolyte composition includes Al O , a novel composite material for electrolyte. Given\n2 3\nthat Al₂O₃ is a stable insulating ceramic oxide with strong bonds, how does the electrolyte ensure the\nuniform mixing of liquid and solid components? Is there a risk of phase separation?\nResponse: Thank the reviewer very much for these insightful questions. We have confirmed the stability\nof the MASSE through molecular-level interactions and macroscopic experimental data. DEG and water\nmolecules form extensive HB with the Al O surface, achieving robust binding. MD simulations reveal\n2 3\nthat the quantity and strength of the HB network on the Al O particle surface significantly increase,\n2 3\neffectively suppressing the tendency for solid-liquid phase separation (Fig. R15). Furthermore, optical\nimages of the MASSE electrolytes containing Al O particles of varying sizes at 80 °C demonstrates that\n2 3\nphase separation decrease as the particle size reduce (Fig. R16). Notably, no observable phase separation\noccurs when the particle size was below 30 nm, validating the uniformity under actual operating conditions.\nThe zeta potential of different particle sizes has been conducted to further elucidate the stability between\nthe solid and liquid phases. As shown in Fig. R17, the absolute value of the zeta potential gradually\nincrease with decreasing Al O particle size, indicating the enhanced charge density on the particle surface,\n2 3\nwhich hinders Al O agglomeration and sedimentation through electrostatic repulsion. The synergistic\n2 3\naction of these dual mechanisms includes HB anchoring and electrostatic stabilization, collectively\nensuring the homogeneous thermodynamic and kinetic stability of the MASSE electrolyte.\nR23\nFig. R15. MD simulation results of the H O-H O HBs in different electrolytes: (a) counts, (b) distances,\n2 2\n(c) angles of the HBs.\nFig. R16 Digital photographs of MASSE electrolytes with different particle sizes of Al O captured before\n2 3\nand after static aging for 7 days at 80 ℃.\nFig. R17. Zeta potential of MASSE by adding Al O nanoparticles with different sizes.\n2 3\nR24\nIn Revision: As advised by the reviewer, in the revised supporting file, we supplemented the Fig. R16\nand Fig. R17 as Supplementary Fig. 2 and Supplementary Fig. 1, respectively.\n2. Comment: The impact of Al2O3 particle size on its interaction with H2O should be discussed. The\nsimulation focuses on the molecular-scale bonding of Al2O3 with H2O, but since Al2O3 is in nano-scale,\nonly the surface layer may affect water reactivity.\nResponse: Thank the reviewer for these excellent questions. We fully agree with the reviewer's viewpoint.\nSimulations employ ideal crystal plane models to reveal the intrinsic strength of HB interactions between\nAl O and H O (Fig. R18), elucidating the fundamental driving force by which Al O disrupts the HB\n2 3 2 2 3\nnetwork of H O. Although this mechanism fails to accurately represent the actual condition of nanoscale\n2 3\nnanoparticles dominates water reactivity. As the size of nanoparticles decreases, -OH density on the\nsurface of Al O increases exponentially, amplifying the HB interactions predicted by simulations. FTIR\n2 3\nspectra further confirms that the intensity of free water significantly weakens and obvious blue shift\nobserved with reduced particle size (Fig. R19), directly demonstrating that the size effect enhances Al O -\n2 3\nH O interfacial interaction. Furthermore, only when the Al O nanoparticle size is reduced to 30 nm could\n2 2 3\nthe MASSE electrolyte maintain phase stability at elevated temperatures, demonstrating that smaller\nnanoparticle sizes induce stronger interfacial interactions (Fig. R16).\nFig. R18 Electron density maps and energy difference of HB complexes between H O-H O, H O-DEG,\n2 2 2\nand H O-Al O .\n2 2 3\nR25\nFig. R19 The FTIR spectra of O-H stretching vibration of water molecules in MASSE electrolytes with\ndifferent sizes of Al O .\n2 3\n3. Comment: As Al2O3 nanoparticles cannot dissolve in the liquid solution, the claim that Al2O3 can\nenter solvation structures in Fig. 4 needs clarification. This phenomenon is novel and requires further\nexplanation.\nResponse: Thank the reviewer very much for these comments. Although Al O nanoparticles are insoluble\n2 3\nin the electrolyte, the high reactivity of surface atoms, particularly in particles sized 5-20 nm, endows\nthem with unique adsorption capabilities. The surface of these particles is rich in uncoordinated hydroxyl\ngroups (≡Al-OH), which can engage in surface adsorption with Zn2+ in the solution through electrostatic\ninteractions or direct coordination Zn-O bonds. In MD simulations, Zn2+ strongly adsorb onto nanoparticle\nsurfaces periodically appear near the nanoparticles (Fig. 2c). This dynamic adsorption process is\nstatistically manifested as coordination peaks in the radial distribution functions curves (Fig. 2f),\nsubstantively representing surface-mediated solvation restructuring. This mechanism aligns with recent\nresearch (Angew. Chem. Int. Ed. 2025, 64, e202501010). By introducing insoluble single-mesopore SiO\n2\n(smSiO ) to replace water molecules in the primary solvation sheath of Zn2+, they formed Zn2+-smSiO₂\n2\ncomplexes, similarly leveraging the interfacial coordination of nanoparticle surfaces instead of the\nconventional dissolution-coordination pathway.\n4. Comment: How can the polar interaction of Al2O3 be assessed in the solid-liquid phase? More\ndiscussion on this aspect is needed.\nR26\nResponse: Thank the reviewer very much for these comments. The polar interactions at the Al O\n2 3\ninterface with the electrolyte represent one of the core mechanisms for enhancing electrolyte stability and\nhigh-temperature performance. The Al O surface, rich in hydroxyl groups (-OH), gives it high polarity.\n2 3\nIt can interact with polar molecules/ions through HBs. As observed in Fig. R20, a substantial HB number\nand strength of Al O -DEG and Al O -H O is formed in the MASSE electrolyte, confirming the formation\n2 3 2 3 2\nof strong polar interactions. Meanwhile, MD simulations reveal significant adsorption of DEG and H O\n2\nmolecules near the Al O particle surfaces, further confirming the presence of strong electrostatic\n2 3\nattractive interactions (Fig. R21). Collectively, the strong polar interactions between Al O and solvents\n2 3\n(TEG and H O) establish a complex HB network within the MASSE electrolyte. This network\n2\nsignificantly restricts the activity of H O molecules, thereby suppressing side reactions at high temperature\n2\n(Fig. 3). Simultaneously, polar interactions between Al O particles promote stable particle dispersion,\n2 3\nsuppressing aggregation (Fig. R16). Through these synergistic effects derive from multiple polar\ninteractions, the electrochemical performance of aqueous zinc-ion batteries at elevated temperatures is\nsignificantly enhanced.\nFig. R20 MD simulation results of the different HBs in the MASSE electrolyte: (a) angles, (b) distances,\n(c) counts.\nR27\nFig. R21 Magnified view of local region of MD simulation in (a-c) the Zn(OTf) -DEG electrolyte and (d-\nf) the MASSE electrolyte.\n5. Comment: The statement about electrolyte structural instability in solvation complexes leading to\ndetrimental electrochemical processes should be supported with specific examples and references.\nResponse: Thank the reviewer very much for these excellent comments. In aqueous zinc-ion batteries,\nthe stability of the solvation structure directly dictates the occurrence of parasitic reactions. Specifically,\nelevated temperatures accelerate the dissociation of solvation shells, leading to increased activity of water\nmolecules. Concurrently, this instability heightens the reduction tendency of coordinated water in the\nsolvation structure, thereby triggering irreversible parasitic reactions. This not only reduces coulombic\nefficiency but also promotes zinc dendrite growth, further escalating the risk of battery short circuits.\nWu et al have proposed a “soggy-sand” electrolyte design that significantly increases the proportion of the\nsolvation structure (Zn2+-4H O-1SO 2-) with the highest binding energy by introducing inorganic\n2 4\nnanoparticles, thereby markedly reducing the occurrence of side reactions (Angew. Chem. Int. Ed. 2025,\n64, e202501010). Yu et al have identified the instability of solvation structures triggers side reaction\nthrough dynamic evolution of HB networks. By designing high-concentration electrolytes to regulate\nsolvation structures, a diluted or concentrated interface is formed upon Zn2+ desolvation and solvation,\nfundamentally inhibiting HER and dendrite formation (J. Am. Chem. Soc. 2024, 146, 17103-17113). Yao\net al have demonstrated a new electrolyte design strategy of co-reconstruction of anionic and cationic\nsolvation structures (CRACSS). The enhanced H O dissociation barriers in CRACSS leads to suppressed\nR28\nenabling high-performance AZMBs with wide-temperature operability (Nature Commun., 2024, 15, 6249).\n6. Comment: The claim that elevated temperatures induce anomalous hydrogen bonding activation in\nZn(OTf)2-H2O should specify whether this activation occurs within or outside the solvation structure.\nResponse: Thank the reviewer very much for these excellent comments. We conducted theoretical\ncalculations to analyze the difference in HB activity inside and outside the solvation structure in the\nZn(OTf) -H O electrolyte. As shown in Fig. R22a-b, the binding energy required to remove one water\n2 2\nmolecule from the Zn(H O) and Zn(H O) (OTf-) solvation shells are -0.806 eV and -1.163 eV,\n2 6 2 5 1\nrespectively. In contrast, the binding energy for H O-H O interactions among free water molecules is only\n2 2\n-0.314 eV (Fig. R22c). This significant energy contrast demonstrates that the HB network among free\nwater molecules outside the solvation shells is more readily activated upon heating. This dynamic HB\nbreaking/reformation behavior significantly enhances the reactivity of the free water molecules, thereby\nleading to occurrence of severe side reactions under elevated temperature.\nFig. R22 The binding energy required to remove one water molecule from representative solvation\nstructures of (a) Zn(H O) (OTf-) and (b) Zn(H O) in the Zn(OTf) -H O electrolyte; (c) The binding\n2 5 1 2 6 2 2\nenergy for H O-H O interactions among free water molecules.\n2 2\nR29\n7. Comment: The exceptional high-temperature performance of the MASSE electrolyte, attributed to\nAl2O3, could be further elucidated by comparing electrolytes containing only water and Al2O3 to isolate\nthe influence of the DEG solvent.\nResponse: Thank the referee very much for these insightful comments. We prepared aqueous soggy-sand\nelectrolytes containing only water and Al O (10 nm). As shown in Fig. R23, we observe rapid\n2 3\nprecipitation occurring in the DEG-free electrolyte, leading to severe phase separation. This severe\ninstability renders such an electrolyte unsuitable for battery assembly and testing. The addition of DEG\nleads to stabilizing the dispersion of Al O particles by forming robust polar interactions, ultimately\n2 3\nenabling the formation of the highly stable heterogeneous MASSE electrolyte. Furthermore, the enhanced\nhigh-temperature performance of the MASSE electrolyte is not merely attributable to the Al O\n2 3\ncomponent alone. Instead, it stems from the synergistic effect of incorporating both DEG and Al O ,\n2 3\nwhich substantially breaks the original HB network. This disruption effectively immobilizes H O molecules,\n2\nthereby enhancing battery performance at elevated temperature.\nFig. R23 Digital photographs of Zn(OTf) -H O-Al O and MASSE captured before and after static aging\n2 2 2 3\nfor 5 hours.\n8. Can this concept be applied to other aqueous systems or broader solvent and battery systems? Consider\ndiscussing the potential applicability of this approach beyond the current system.\nResponse: Thank you for your insightful comments. We have taken your suggestions seriously and have\nR30\nincorporated new data and analyses to strengthen our manuscript. To systematically validate the\nuniversality of the method proposed in this manuscript, other types of organic solvents (including alcohols,\nsulfones, and esters) were selected and designed corresponding MASSE systems. As shown in Fig. R24,\nthe Zn||PANI full cells using MASSE electrolyte with triethylene glycol (TEG), dimethyl sulfoxide\n(DMSO), and triethyl phosphate (TEP) as alternative solvents all maintain excellent cycling performance\nover 2000 cycles at 80 °C, far exceeding that of Zn(OTf) -H O. These results consistently indicates that\n2 2\nthe concept of the MASSE proposed in this work can be successfully extended and applied to multiple\nsolvent systems, demonstrating robust applicability. In addition, to evaluate the universality of MASSE,\nthe application was extended to the Zn||NVO full cell system beyond the Zn||PANI system. As displayed\nin Fig. R25, Zn||NVO full cells using the MASSE electrolyte demonstrate exceptional cycling stability of\n1500 cycles under 80 °C, which far surpasses that of Zn(OTf) -H O and Zn(OTf) -DEG. The MASSE\n2 2 2\ntechnology developed herein also enables outstanding long-cycling performance within other battery\nsystem under elevated temperature.\nFig. R24 Cycling performance and CE of Zn||PANI full cells using MASSE with different solvents.\nR31\nFig. R25 Cycling performance and CE of Zn||NVO full cells using different electrolytes.\nIn Revision: In the revised supporting file, the Fig. R24-25 have been added and renumbered as\nSupplementary Fig. 40 and Supplementary Fig. 41, with corresponding explanation provided. The\nsentences ‘To verify the universality of the proposed MASSE design strategy, two parallel investigations\nwere conducted. First, DEG solvent was replaced with various representative organic solvents (alcohols,\nsulfones, and esters) to systematically evaluate the HT electrochemical performance of the corresponding\nMASSE systems (Supplementary Fig. 40). In addition, the MASSE electrolyte was extended and applied\nto Zn||NVO full cell systems beyond the Zn||PANI system (Supplementary Fig. 41). The results\ndemonstrate that the MASSE electrolyte developed in this study is not only compatible with diverse\nsolvent systems but also adaptable to different electrode material systems, achieving outstanding long-\nterm cycling stability under elevated temperature in all cases.’ were added to the revised manuscript.\n9. Check for grammar errors and ensure the text is clear and concise.\nResponse: We sincerely appreciate the valuable feedback from the reviewer. We have meticulously\nreviewed the entire article multiple times and corrected the language errors and inaccuracies to ensure\nR32\nclarity and precision in its language expression. The revised parts have been highlighted in both the main\ntext and the supporting file. We are grateful for the reviewer's suggestions and are committed to putting in\nthe effort to ensure that every aspect of the manuscript reaches the high standards.\nR33"}, {"round": 2, "reviewer_comments": {"reviewer_1": "This MS has well revised according to the reviewers comments, and I think it becomes acceptable now.", "reviewer_2": "The revision is very good.", "reviewer_3": "Questions are properly addressed. No more questions from me."}, "author_response": ""}]

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