batterydata/battery-device-data-qa huggingface dataset:
Over the past several decades, rechargeable lithium-ion batteries (LIBs) have been widely used in the energy storage market of portable electronic devices and electric vehicles. However, the scarcity and rising costs of Li raw materials have restricted the further large-scale commercialization of LIBs, and thus have spurred extensive research in seeking cost-effective and more reliable energy storage systems. Among various promising alternatives, Na-ion batteries (NIBs) have attracted considerable attention because of the high abundance and low cost of Na resources. Of various anode candidates for NIBs, Na metal anodes are prized for their high specific capacity (1166 mA h g−1) and low electrochemical potential (−2.714 V vs. standard hydrogen electrode). However, the naturally formed solid electrolyte interphase (SEI) that originates from the instantaneous reaction between the highly reactive Na and electrolyte solvents is generally non-uniform and fragile. The heterogeneous feature easily causes uneven Na deposition and the formation of Na dendrites, and thus brings about serious safety issues. Additionally, the fragile SEI cannot tolerate huge volume changes upon the repetitive plating/stripping process, which gives rise to repeated breakdown/repair of the SEI, leading to a low coulombic efficiency (CE) and short cycle life. These issues impede the practical applications of Na metal anodes.

Question: What's the anode?
Answer: Na metal

Question: What's the electrolyte?

Question: What's the anode?
Answer: Na metal
Typical NASICON compounds (such as a NVP cathode and a NTP anode) suffering from severe performance degradation in aqueous electrolytes were employed. The crystal structures, X-ray diffraction (XRD) patterns and SEM images of the prepared NVP/C and NTP/C are shown in Fig. S7.† In Fig. S8,† all of the materials have two featured Raman shifts, in which the G-band (ordered graphitic structure) peak is at 1590 cm−1 and the D-band (disordered portion) is at 1352 cm−1. The thin carbon layer provides good electro-conductivity to NVP/C and NTP/C. In addition, the carbon content of the NVP/C and NTP/C composites measured by elemental analysis (Table S2†) and TG analysis (Fig. S9†) is approximately 3.5 wt%.

Question: What's the cathode?

Question: What's the anode?
Answer: NTP

Question: What's the electrolyte?
The nanomesh after galvanostatic EMD deposition is shown in Fig. 2c–e. The electrodeposition resulted in conformal coating of the nanowires with a 8.5 ± 1 nm thick EMD layer. Despite the limited pore size of the nanomesh, the coating was uniformly distributed throughout the depth of the nanowire network, without closing the pores within and at the top of the nanomesh (Fig. 2d). Such open porosity of the cathode is crucial to ensure its high contact area with the battery electrolyte and facilitate transport of Li+ into and out of the electrode. The excellent conformality of EMD on the nanomesh network can be ascribed to both the relatively slow diffusion of reactants through the growing oxide layer, and the pre-deposited MnO2 seed layer, which increases the homogeneity and coulombic efficiency of EMD electrodeposition. X-ray Photoemission Spectroscopy (XPS) confirmed that the as-deposited EMD consists of hydrated MnO2 (Fig. S2†), in agreement with previous observations on the hydrous nature of pristine EMD deposited from aqueous electrolytes. Note that the total thickness of the EMD-coated 3D electrode is much higher than the maximum attainable thickness of electrodeposited MnO2 on planar electrodes (500 nm on Ni and 1.5 μm on carbon-coated TiN), where the thicker EMD layers easily delaminate.

Question: What's the cathode?

Question: What's the electrolyte?
On the basis of the change in the direction of the exfoliating voltage, electrochemical exfoliation of 2D antimony, bismuth and their compounds can be divided into DC voltage exfoliation and square-wave voltage exfoliation. DC voltage exfoliation uses a DC power supply to provide the voltage, and the voltage direction does not change during the exfoliation process. The process of preparing 2D antimony, bismuth and their compounds by the DC voltage exfoliation method is similar to that of cathode exfoliation graphene. The exfoliation process was conducted by using a large block of antimony or bismuth or its compound as the cathode and platinum wire or foil as the anode and in an organic solution. This process applies a voltage to the bulk of antimony, bismuth and their compounds at the cathode, drives the insertion of cations in the electrolyte, and uses jet force that produces hydrogen to promote the peeling of antimony, bismuth and their compounds. In 2017, Li et al. illustrated the possible mechanism of cathodic exfoliation to prepare 2D Sb nanosheets in 0.5 M Na2SO4 solution. Driven by the voltage, the Na+ intercalation layer that accumulates at the negative electrode enters the interlayer of the bulk Sb crystal. Because a large amount of the Na+ intercalation layer enters the interlayer of the Sb crystal, the exfoliation of Sb is eventually promoted by the expansion force (Fig. 4a). Furthermore, the positive and negative voltage and the size of the electrolyte cations affect the efficiency of exfoliation.

Question: What's the cathode?

Question: What's the anode?

Question: What's the electrolyte?
In summary, a novel NVPF@5% rGO with in situ coated 3D carbon network has been successfully prepared via a two-step solid state CTR method and investigated for use as a cathode material for SIBs. The rGO carbon network architecture in NVPF@5% rGO could effectively construct ionic/electronic pathways and provide sufficient electrode–electrolyte contact area for rapid Na+/e− transport, which significantly improves the electrochemical performance of NaVPO4F. In addition, the stability of NVPF@5% rGO after long-term cycle testing was revealed by the results of the ex situ XRD and SEM analyses, which demonstrated the stable crystal structure of NaVPO4F and the sturdy construction of a robust carbon network. Furthermore, the results of the EIS, CV at various scan rates and GITT tests were implemented to study the electrode kinetic characteristics of NVPF@5% rGO. More importantly, the HC//NVPF@5% rGO full-cell system was fabricated with an HC anode and NVPF@5% rGO cathode, and exhibited superior high-rate capabilities (e.g., 81.8 mA h g−1 at 10C and 61.9 mA h g−1 at 20C) and ultralong cycling performance (82.71% capacity retention after 1500 cycles at 5C). Considering the easy synthesis route and impressive results, it is believed that this strategy can inspire the further development of high-rate and long-term cycle life electrode materials for SIBs.

Question: What's the cathode?
Answer: NVPF@5% rGO

Question: What's the anode?
Answer: HC

Question: What's the electrolyte?

Question: What's the cathode?
Answer: NVPF@5% rGO
Various approaches have been employed to address these issues through the engineering of ex situ deposited surface coatings, solid electrolyte interphase (SEI) transplantation, electrolyte additives, and 3D host materials. These studies have been largely empirical with limited effort directed towards a fundamental understanding of the interplay between electrolyte composition, SEI formation, and lithium metal morphology. For example, it is important to quantify the amount of lithium lost into the SEI, soluble reduction products, “dead” lithium, and corrosion, and to identify how these loss mechanisms are mitigated by using additives or surface coatings. This knowledge will enable the development of commercially viable solutions. Empirical approaches have had some success in improving coulombic efficiency and cycle life, but in most cases it is unclear which loss mechanism is mitigated and how. We consider understanding these processes mechanistically to be the “Holy Grail” of lithium anode research, knowledge that may be extensible to other battery chemistries.

Question: What's the anode?

Question: What's the electrolyte?
A few investigations are recently reported based on dual redox-additive electrolytes, responsible for improving the capacitive performance via anodic and cathodic redox-active electrolytes at negative and positive electrode interfaces, respectively. For example, Zhong et al. constructed an AC-based supercapacitor with two separate redox-additive gel polymer electrolytes: PVA/H2SO4/HQ (in the anodic region) and PVA/H2SO4/MB (in the cathodic region). This approach enhanced the specific capacitance from ∼139 F g−1 to 563.7 F g−1 and specific energy from 4.67 W h kg−1 to 18.7 W h kg−1. Frackowiak et al. reported a significantly improved supercapacitor performance based on dual redox additives KI and VOSO4 in an aqueous H2SO4 electrolyte, respectively, in anodic and cathodic regions. Similarly, Chun et al. showed the effect of dual redox additives methyl viologen chloride and KBr added into a supporting electrolyte on the supercapacitor performance. In another report, Fan et al. examined the effect of redox additives KI and VOSO4, added together in a PVA/H2SO4 polymer electrolyte. The capacitor based on this electrolyte and AC electrodes offered a significantly higher capacitance of 1232.4 F g−1 as compared to that of the PVA/H2SO4 based device (156.4 F g−1). The selection of dual redox additives for redox-active electrolytes is based on various factors. Apart from the factors, namely high solubility, reversible electron-transfer kinetics and chemical/electrochemical stability, their different redox potentials are important criteria to choose the dual redox additives. While one additive with a higher potential is used for the positive electrode, the other one functions at the negative electrode. Simultaneous redox processes at two interfaces, during charge and discharge, are responsible for a high value of the overall pseudocapacitance. Based on the same criteria discussed above, the two redox additives DPA and KI are selected in the present study, which have different redox potentials ∼0.76 V and 0.53 V versus the SHE corresponding to their possible redox reaction(s), respectively.

Question: What's the electrolyte?
Answer: PVA/H2SO4/HQ (in the anodic region) and PVA/H2SO4/MB (in the cathodic region)

Question: What's the electrolyte?
Answer: H2SO4
In summary, we have demonstrated a flexible organic–inorganic composite solid electrolyte consisting of polymer PEO, Li salt (LiTFSI), ionic liquid (BMP-TFSI), and the ceramic ion conducting LATP particles. The addition of BMP-TFSI can not only decrease the interface impedance between the polymer matrix and LATP particles, but also enhance the stability of the composite electrolyte and Li metal anode. Benefitting from the synergistic effect of the organic–inorganic complex, the PBL-CSE membrane shows improved electrochemical properties. The ionic conductivity is above 10−4 S cm−1 at 30 °C. The electrochemical stability window is up to 5.0V (vs. Li+/Li) and the Li+ transference number is 0.48. The PBL-CSE exhibits superb interface stability and impressive capacity against a Li electrode, as well as effective suppression of Li dendrite growth. The assembled solid-state LiFePO4/Li batteries demonstrated excellent cycling stability with a high specific capacity and very large capacity retention at 0.5C at 45 °C, as well as 0.3C at 30 °C. Furthermore, LiFePO4/PBL-CSE/Li all-solid-state pouch cells also demonstrate high flexibility and safety. Thus, this work represents a promising composite electrolyte for high performance, safe and high energy density all-solid-state lithium metal batteries.

Question: What's the anode?
Answer: Li metal

Question: What's the electrolyte?
The charging-discharging and cycling curves were obtained from the hybrid electrolyte cells, as displayed in Fig. 6c and d. The cells were charged/discharged with a constant current density of 0.3 mA cm−2 for the first cycle, 0.5 mA cm−2 for the second to sixth cycles, 1 mA cm−2 for the seventh to eleventh cycles and 1.4 mA cm−2 for longer cycles. The charging/discharging voltage profiles in Fig. 6c and d show that the cell with the laser-treated LLZTO sample has a relatively small overpotential even at a high current density of 1.4 mA cm−2. This result is consistent with the impedance result in Fig. 6a and b, as evident from the reduction of Nyquist curves. For the polished (pristine) LLZTO cell, the cell voltage was found to be unstable in the charging curve of the 8th cycle, implying the formation of an internal short-circuit caused by the propagation of metallic Li. In contrast, notably, the cell with the laser-treated LLZTO sample showed a stable cycling performance without any short-circuit signals (voltage noise and/or sudden drop) at a constant current density of 1.4 mA cm−2. The improved cycling stability of the laser-treated cell was confirmed from the cycling curves shown in Fig. 6e for long-term operation under 1.4 mA cm−2. The cell showed an excellent coulombic efficiency of 88.9% for 1st cycle, 100% for 3rd cycle, 100% for 7th cycle, 99.96% for 11th cycle, 99.92% for 50th cycle, 99.92% for 100th cycle, and 99.92% for 160th cycle compared with the conventional LIBs and a remarkable capacity retention of 96.7% over the 160th cycle. The mechanism to enhance the electrochemical performance in the laser-treated cell might be complicated. The surface change of LLZTO after the laser treatment includes the formation of Li2O2 and amorphous garnet, the possible reduction of LiOH and Li2CO3, and the morphological deformation. Based on our electronic structure analysis of the laser-treated LLZTO sample and its reduced electronic conductivity (Fig. S5c†), it is highly possible that the main origin of the remarkable improvement in the cycling stability of the laser-treated cell is the formation of the stable amorphous layer with a wide bandgap, which can significantly suppress the Li dendrite formation.

Question: What's the cathode?

Question: What's the anode?

Question: What's the electrolyte?
Electrochromic devices (ECDs) have been widely investigated for application in next-generation displays and smart windows thanks to their highly efficient optical transmittance modulation properties. However, several challenges such as chemical and environmental instabilities and leakage of electrolytes limit their practical applications. In this paper, we report a simple and efficient approach for synthesising ultraviolet (UV)-cured poly(methyl methacrylate) (PMMA) gels that can be used as safe electrolytes. The ECDs fabricated with the 10 min UV-cured PMMA gel electrolyte deliver remarkable device performances with a wide optical transmittance transition (ΔT) of 51.3% at a wavelength of 550 nm under −1.2–0 V bias range and fast switching times (Δt) of 1.5 s and 2.0 s for bleaching and colouration, respectively. In addition, excellent operational stability of 98.9% after 11500 cycles and environmental stability at a wide temperature range of −20 to +70 °C are exhibited. Moreover, a smart electrochromic window system, including an ECD connected with an Arduino circuit, is developed. These smart windows can change colour by simultaneously monitoring the illumination and UV intensities of sunlight.

Question: What's the electrolyte?
Answer: ultraviolet (UV)-cured poly(methyl methacrylate) (PMMA)

Question: What's the electrolyte?
Answer: UV-cured PMMA gel
Li metal is regarded as the best candidate for anode materials because of its high theoretical capacity and negative electrode potential. However, due to the continuous parasitic side reactions and messy growing Li dendrites, the practical use of the Li metal as an anode is seriously limited. An in situ formed artificial solid electrolyte interface (SEI) can commendably solve the above-mentioned problems; however, inevitable cracks and fractures are found during their long-term service due to the existence of inorganic compounds (or alloys) in the artificial-SEI. Herein, a self-repairing alloy for protecting the Li metal anode was prepared via a facile in situ reaction. A long-term cycling life of more than 1800 h and 1400 h was obtained for the self-repairing alloy protected Li metal anode at a practical current density of 2 mA cm−2 and 5 mA cm−2. Even after increasing the deposition capacity to 15 mA h cm−2, no dendrite formation was detected in the self-repairing alloy protective Li anode. This is expected to be a promising strategy in achieving a stable Li metal anode/electrolyte interface and providing a new way of thinking for the development of Li metal batteries.

Question: What's the anode?
Answer: Li metal

Question: What's the electrolyte?

Question: What's the anode?
Answer:  Li metal
As indicated by the above results, the Li/Al-ion electrolyte exhibits better cycle stability than the Al-ion electrolyte. To further investigate the electrolytes, the voltammograms of these electrolytes measured at different scan rates were analysed using the Randles–Sevick equation (Fig. S7†). The calculated Li-ion diffusion coefficients are 2.84 × 10−12 cm2 s−1 and 7.96 × 10−13 cm2 s−1 in the WO3 and the Ti-V2O5 films, and the Al-ion diffusion coefficients are 2.72 × 10−14 cm2 s−1 and 7.99 × 10−15 cm2 s−1 in the WO3 and the Ti-V2O5 films, respectively. The obtained diffusion coefficients are all two magnitudes lower for Al3+ than Li+, owing to the strong electrostatic interaction between trivalent Al3+ and the host lattice, which slows the ion diffusion in the films. For the mixed Li/Al-ion electrolyte, the obtained diffusion curves are between those of the pure Li-ion electrolyte and the pure Al-ion electrolyte (Fig. S7d, h†). Such a performance is much better compared with the coefficient of pure Al-ions in the films, indicating better ion diffusion in the lattices and promoting the cycle stabilities. Previous reports also indicated that the mixed Li/Al-ion electrolyte can promote the cycling performance in Al-anode batteries. The utilization of mixed ion electrolytes can be a promising direction and deserves further investigation.

Question: What's the anode?
Answer: Al

Question: What's the electrolyte?
Answer: Li/Al-ion

Question: What's the electrolyte?
Answer: Al-ion electrolyte.
We are able to clarify that the electrochemical doping of the polymer is still predominantly caused by the formation of ion pairs between charged polymer and PF6− anions, as DBSA itself causes irreversible doping of the polymer (Fig. 4). Fig. 4a shows the behaviour of DBSA in an electrochemical cell with no other salts present by exposing a P3HT thin film to 0.1 M DBSA in ACN electrolyte and measuring in situ ERRS. We observe the typical hole polaron signature in P3HT even at 0 V, indicating the ability of DBSA to chemically dope the polymer film when no other salts are present. We monitor the CC peak position as a function of oxidising potential and find the doping level has a minor dependence on applied bias indicated by the CC peak downshifting from 1425 cm−1 to 1417 cm−1 (Fig. 4b); the electric field causes more DBSA anions (dissociated from protons) to drift and penetrate into the P3HT film causing further doping. After discharge (0 V) the film is irreversibly doped and the CC peak position remains at 1417 cm−1 (green triangle Fig. 4a). Further evidence for irreversible p-type doping caused by DBSA is provided by changes in the UV-Vis absorbance spectra, HOMO level, and work function (see Fig. S2, ESI†). Thus, we elucidate that the mixed ionic electrolyte (with DBSA and TBA:PF6) causes reversible electrochemical doping of the polymer caused by the formation of ion pairs between charged polymer and PF6− anions. This suggests that the effect of DBSA in the mixed electrolyte is to modify the interaction between the polymer and the electrolyte allowing electrochemical doping at a lower voltage. DBSA has previously been used as a surfactant added to PEDOT:PSS formulations to improve wettability. We believe that DBSA could be having a similar effect on P3HT, interacting with the polymer and acting as a surfactant to enhance the strength of the interactions between the polymer and the electrolyte. In other words, DBSA may modulate the RED between the polymer and the solvent. We demonstrated the effect of RED between the solvent and the polymer on oxidation onset during cyclic voltammetry measurements: there is a lower RED between DCM and P3HT compared to ACN and P3HT, which results in a reduction in the oxidation onset of 0.28 V (Fig. 2). Thus, the RED between the polymer and the electrolyte solvent appears to influence the injection barrier into the film. By adding DBSA to the electrolyte, it may reduce the RED, thus causing a higher mass in the polymer film (solvent and ions), ultimately decreasing the injection barrier into the film.

Question: What's the electrolyte?
Answer: 0.1 M DBSA in ACN

Question: What's the electrolyte?
Answer: (with DBSA and TBA:PF6)
The cycle stability in terms of the charge capacity for the two kinds of films in the Li/Al-ion electrolyte was also evaluated as shown in Fig. 3a and b (details for the in situ measurement of both the charge capacity and the transmittance are provided in the ESI†). After 1000 cycles, the capacity retention was about 78% for the Ti-V2O5 film and 72% for the WO3 film. The cycle stability in terms of the electrochromic performance is obtained by monitoring the optical contrast between the colored and the bleached state of the films. As shown in Fig. 3c and d, after 1000 cycles, the Ti-V2O5 film still delivered a transmittance contrast of up to 24.8% at 400 nm, and for the WO3 film, a contrast up to 47.4% was delivered at 780 nm. These values show that 69.5% of the optical modulation can be retained for Ti-V2O5 and 65.4% can be retained for the WO3 film after 1000 cycles. As a comparison, the Al-ion electrolyte, which is commonly used in Al-based EES devices, was applied to replace the Li/Al-ion electrolyte. As shown in Fig. S6,† for both the Ti-V2O5 and the WO3 films, the optical contrast in the transmittance spectra drops rapidly within 100 cycles, indicating that the mixed ion electrolyte effectively promotes the cycle stability of the electrochromic films.

Question: What's the electrolyte?
Answer:  Li/Al-ion

Question: What's the electrolyte?
Answer:  Al-ion
The Li-metal anode is considered an essential component for obtaining the expected Li–S battery performance. This is because of Li's extremely low negative electrochemical potential, very high theoretical specific capacity, and low density. However, the Li-metal anode has additional issues. Safety concerns arise because of the possibility of cell damage or manufacturing failures due to Li-metal's high reactivity, as well as due to the dendrite formation throughout cycling processes which can cause short circuits if dendrites reach the cathode. The electrolyte (salt and solvent) plays a vital role for rapid lithium transport and providing stability even near the highly reactive lithium surface. At the Li surface, electrolyte decomposition due to reduction reactions triggered by their low electrochemical stability leads to the growth of a multicomponent passivating film. This film, known as the solid electrolyte interphase (SEI) may have beneficial passivation properties, or, quite the opposite, may be a cause of irreversible capacity loss. The specific film behavior depends on its chemical composition, structure, and thickness. Moreover, it has been found the SEI properties depend largely on the solvent, salt, and additives used as well as on the electrode structure. Therefore, understanding the role of the electrolyte in SEI formation and its properties should be a useful strategy for controlling dendrite formation, reducing the effects of anode degradation and stabilizing the surface, thus, potentially improving the performance, cycling and safety of the batteries.

Question: What's the anode?
Answer: Li-metal

Question: What's the electrolyte?

Question: What's the anode?
Answer:  Li-metal