Interface-reinforced solid-state electrochromic Li-ion batteries enabled by in-situ liquid-solid transitional plastic glues

The electrochromic Li-ion batteries(ELIBs) combine the functions of electrochromism and energy storage,realizing the display of energy-storage levels by visual signals. However, the accompanying interfacial issues including physical contact and(electro)chemical stability should be taken into account when the conventional liquid/gel electrolytes are replaced with solid-state counterparts. Herein, the in-situ liquid-solid transitional succinonitrile(SCN) plastic glues are constructed between electrodes and poly(ethylene oxide)(PEO) polymer electrolytes, enabling an interface-reinforced solid-state ELIB.Specifically, the liquid SCN precursor can adequately wet electrode/PEO interfaces at high temperature,while it returns back to solid state at room temperature, leading to seamless interfacial contact and smooth ionic transfer without changing the solid state of the device. Moreover, the SCN interlayer suppresses the direct contact of PEO with electrodes containing high-valence metal ions, evoking the improved interfacial stability by inhibiting the oxidation of PEO. Therefore, the resultant solid-state ELIB with configuration of LiMn_(2)O_(4)/SCN-PEO-SCN/WO_(3) delivers an initial discharge capacity of 111 m A h g^(-1) along with a capacity retention of 88.3% after 200 cycles at 30 ℃. Meanwhile, the electrochromic function is integrated into the device by distinguishing its energy-storage levels through distinct color changes. This work proposes a promising solid-state ELIB with greatly reinforced interfacial compatibility by introducing in-situ solidified plastic glues.

Liquid metal as an efficient protective layer for lithium metal anodes in all-solid-state batteries

Lithium metal batteries with inorganic solid-state electrolytes have emerged as strong and attractive candidates for electrochemical energy storage devices because of their high-energy content and safety.Nonetheless,inherent challenges of deleterious lithium dendrite growth and poor interfacial stability hinder their commercial application.Herein,we report a liquid metal-coated lithium metal(LM@Li)anode strategy to improve the contact between lithium metal and a Li6PS5Cl inorganic electrolyte.The LM@Li symmetric cell shows over 1000 h of stable lithium plating/stripping cycles at 2mA cm^(-2) and a significantly higher critical current density of 9.8 mAcm^(-2) at 25°C.In addition,a full battery assembled with a high-capacity composite LiNbO3@-LiNi_(0.7)Co_(0.2)Mn_(0.1)O_(2)(LNO@NCM721)cathode shows stable cycling performance.Experimental and computational results have demonstrated that dendrite growth tolerance and physical contact in solid-state batteries can be reinforced by using LM interlayers for interfacial modification.

12.6μm-Thick Asymmetric Composite Electrolyte with Superior Interfacial Stability for Solid-State Lithium-Metal Batteries

Solid-state lithium metal batteries(SSLMBs)show great promise in terms of high-energy-density and high-safety performance.However,there is an urgent need to address the compatibility of electrolytes with high-voltage cathodes/Li anodes,and to minimize the electrolyte thickness to achieve highenergy-density of SSLMBs.Herein,we develop an ultrathin(12.6μm)asymmetric composite solid-state electrolyte with ultralight areal density(1.69 mg cm^(−2))for SSLMBs.The electrolyte combining a garnet(LLZO)layer and a metal organic framework(MOF)layer,which are fabricated on both sides of the polyethylene(PE)separator separately by tape casting.The PE separator endows the electrolyte with flexibility and excellent mechanical properties.The LLZO layer on the cathode side ensures high chemical stability at high voltage.The MOF layer on the anode side achieves a stable electric field and uniform Li flux,thus promoting uniform Li^(+)deposition.Thanks to the well-designed structure,the Li symmetric battery exhibits an ultralong cycle life(5000 h),and high-voltage SSLMBs achieve stable cycle performance.The assembled pouch cells provided a gravimetric/volume energy density of 344.0 Wh kg^(−1)/773.1 Wh L^(−1).This simple operation allows for large-scale preparation,and the design concept of ultrathin asymmetric structure also reveals the future development direction of SSLMBs.

Advances in All-Solid-State Lithium-Sulfur Batteries for Commercialization

Solid-state batteries are commonly acknowledged as the forthcoming evolution in energy storage technologies.Recent development progress for these rechargeable batteries has notably accelerated their trajectory toward achieving commercial feasibility.In particular,all-solid-state lithium-sulfur batteries(ASSLSBs)that rely on lithium-sulfur reversible redox processes exhibit immense potential as an energy storage system,surpassing conventional lithium-ion batteries.This can be attributed predominantly to their exceptional energy density,extended operational lifespan,and heightened safety attributes.Despite these advantages,the adoption of ASSLSBs in the commercial sector has been sluggish.To expedite research and development in this particular area,this article provides a thorough review of the current state of ASSLSBs.We delve into an in-depth analysis of the rationale behind transitioning to ASSLSBs,explore the fundamental scientific principles involved,and provide a comprehensive evaluation of the main challenges faced by ASSLSBs.We suggest that future research in this field should prioritize plummeting the presence of inactive substances,adopting electrodes with optimum performance,minimizing interfacial resistance,and designing a scalable fabrication approach to facilitate the commercialization of ASSLSBs.

How Does Stacking Pressure Affect the Performance of Solid Electrolytes and All-Solid-State Lithium Metal Batteries?

All-solid-state lithium metal batteries(ASSLMBs)with solid electrolytes(SEs)have emerged as a promising alternative to liquid electrolyte-based Li-ion batteries due to their higher energy density and safety.However,since ASSLMBs lack the wetting properties of liquid electrolytes,they require stacking pressure to prevent contact loss between electrodes and SEs.Though previous studies showed that stacking pressure could impact certain performance aspects,a comprehensive investigation into the effects of stacking pressure has not been conducted.To address this gap,we utilized the Li_(6)PS_(5)Cl solid electrolyte as a reference and investigated the effects of stacking pressures on the performance of SEs and ASSLMBs.We also developed models to explain the underlying origin of these effects and predict battery performance,such as ionic conductivity and critical current density.Our results demonstrated that an appropriate stacking pressure is necessary to achieve optimal performance,and each step of applying pressure requires a specific pressure value.These findings can help explain discrepancies in the literature and provide guidance to establish standardized testing conditions and reporting benchmarks for ASSLMBs.Overall,this study contributes to the understanding of the impact of stacking pressure on the performance of ASSLMBs and highlights the importance of careful pressure optimization for optimal battery performance.

Atom substitution of the solid-state electrolyte Li_(10)GeP_(2)S_(12)for stabilized all-solid-state lithium metal batteries

Solid-state electrolyte Li_(10)GeP_(2)S_(12)(LGPS)has a high lithium ion conductivity of 12 mS cm^(-1)at room temperature,but its inferior chemical stability against lithium metal anode impedes its practical application.Among all solutions,Ge atom substitution of the solid-state electrolyte LGPS stands out as the most promising solution to this interface problem.A systematic screening framework for Ge atom substitution including ionic conductivity,thermodynamic stability,electronic and mechanical properties is utilized to solve it.For fast screening,an enhanced model Dop Net FC using chemical formulas for the dataset is adopted to predict ionic conductivity.Finally,Li_(10)SrP_(2)S_(12)(LSrPS)is screened out,which has high lithium ion conductivity(12.58 mS cm^(-1)).In addition,an enhanced migration of lithium ion across the LSr PS/Li interface is found.Meanwhile,compared to the LGPS/Li interface,LSrPS/Li interface exhibits a larger Schottky barrier(0.134 eV),smaller electron transfer region(3.103?),and enhanced ability to block additional electrons,all of which contribute to the stabilized interface.The applied theoretical atom substitution screening framework with the aid of machine learning can be extended to rapid determination of modified specific material schemes.

In-situ interfacial passivation and self-adaptability synergistically stabilizing all-solid-state lithium metal batteries

The function of solid electrolytes and the composition of solid electrolyte interphase(SEI)are highly significant for inhibiting the growth of Li dendrites.Herein,we report an in-situ interfacial passivation combined with self-adaptability strategy to reinforce Li_(0.33)La_(0.557)TiO_(3)(LLTO)-based solid-state batteries.Specifically,a functional SEI enriched with LiF/Li_(3)PO_(4) is formed by in-situ electrochemical conversion,which is greatly beneficial to improving interface compatibility and enhancing ion transport.While the polarized dielectric BaTiO_(3)-polyamic acid(BTO-PAA,BP)film greatly improves the Li-ion transport kinetics and homogenizes the Li deposition.As expected,the resulting electrolyte offers considerable ionic conductivity at room temperature(4.3 x 10~(-4)S cm^(-1))and appreciable electrochemical decomposition voltage(5.23 V)after electrochemical passivation.For Li-LiFePO_(4) batteries,it shows a high specific capacity of 153 mA h g^(-1)at 0.2C after 100 cycles and a long-term durability of 115 mA h g^(-1)at 1.0 C after 800 cycles.Additionally,a stable Li plating/stripping can be achieved for more than 900 h at 0.5 mA cm^(-2).The stabilization mechanisms are elucidated by ex-situ XRD,ex-situ XPS,and ex-situ FTIR techniques,and the corresponding results reveal that the interfacial passivation combined with polarization effect is an effective strategy for improving the electrochemical performance.The present study provides a deeper insight into the dynamic adjustment of electrode-electrolyte interfacial for solid-state lithium batteries.

A dynamic database of solid-state electrolyte(DDSE)picturing all-solid-state batteries

All-solid-state batteries(ASSBs)are a class of safer and higher-energy-density materials compared to conventional devices,from which solid-state electrolytes(SSEs)are their essential components.To date,investigations to search for high ion-conducting solid-state electrolytes have attracted broad concern.However,obtaining SSEs with high ionic conductivity is challenging due to the complex structural information and the less-explored structure-performance relationship.To provide a solution to these challenges,developing a database containing typical SSEs from available experimental reports would be a new avenue to understand the structureperformance relationships and find out new design guidelines for reasonable SSEs.Herein,a dynamic experimental database containing>600 materials was developed in a wide range of temperatures(132.40–1261.60 K),including mono-and divalent cations(e.g.,Li^(+),Na^(+),K^(+),Ag^(+),Ca^(2+),Mg^(2+),and Zn^(2+))and various types of anions(e.g.,halide,hydride,sulfide,and oxide).Data-mining was conducted to explore the relationships among different variates(e.g.,transport ion,composition,activation energy,and conductivity).Overall,we expect that this database can provide essential guidelines for the design and development of high-performance SSEs in ASSB applications.This database is dynamically updated,which can be accessed via our open-source online system.

Charting the course to solid-state dual-ion batteries

An electrolyte destined for use in a dual-ion battery(DIB)must be stable at the inherently high potential required for anion intercalation in the graphite electrode,while also protecting the Al current collector from anodic dissolution.A higher salt concentration is needed in the electrolyte,in comparison to typical battery electrolytes,to maximize energy density,while ensuring acceptable ionic conductivity and operational safety.In recent years,studies have demonstrated that highly concentrated organic electrolytes,ionic liquids,gel polymer electrolytes(GPEs),ionogels,and water-in-salt electrolytes can potentially be used in DIBs.GPEs can help reduce the use of solvents and thus lead to a substantial change in the Coulombic efficiency,energy density,and long-term cycle life of DIBs.Furthermore,GPEs are suited to manufacture compact DIB designs without separators by virtue of their mechanical strength and electrical performance.In this review,we highlight the latest advances in the application of different electrolytes in DIBs,with particular emphasis on GPEs.

A three-dimensional co-continuous network structure polymer electrolyte with efficient ion transport channels enabling ultralong-life all solid-state lithium metal batteries

Solid polymer electrolytes(SPEs)have emerged as one of the most promising candidates for the construction of solid-state lithium batteries due to their excellent flexibility,scalability,and interface compatibility with electrodes.Herein,a novel all-solid polymer electrolyte(PPLCE)was fabricated by the copolymer network of liquid crystalline monomers and poly(ethylene glycol)dimethacrylate(PEGDMA)acts as a structural frame,combined with poly(ethylene glycol)diglycidyl ether short chain interspersed serving as mobile ion transport entities.The preparaed PPLCEs exhibit excellent mechanical property and out-standing electrochemical performances,which is attributed to their unique three-dimensional cocontinuous structure,characterized by a cross-linked semi-interpenetrating network and an ionic liquid phase,resulting in a distinctive nanostructure with short-range order and long-range disorder.Remarkably,the addition of PEGDMA is proved to be critical to the comprehensive performance of the PPLCEs,which effectively modulates the microscopic morphology of polymer networks and improves the mechanical properties as well as cycling stability of the solid electrolyte.When used in a lithiumion symmetrical battery configuration,the 6 wt%-PPLCE exhibites super stability,sustaining operation for over 2000 h at 30 C,with minimal and consistent overpotential of 50 mV.The resulting Li|PPLCE|LFP solid-state battery demonstrates high discharge specific capacities of 160.9 and 120.1 mA h g^(-1)at current densities of 0.2 and 1 C,respectively.Even after more than 300 cycles at a current density of 0.2 C,it retaines an impressive 73.5%capacity.Moreover,it displayes stable cycling for over 180 cycles at a high current density of 0.5C.The super cycle stability may promote the application for ultralong-life all solid-state lithium metal batteries.

A gel polymer electrolyte based on IL@NH_(2)-MIL-53(Al)for high-performance all-solid-state lithium metal batteries

Solid polymer composite electrolytes possess the benefits of superior compatibility with electrodes and good thermal characteristics for more secure energy storage equipment.Herein,a new gel polymer electrolyte(GPE)containing NH_(2)-MIL-53(Al),[PP_(13)][TFSI],LiTFSI,and PVDF-HFP was prepared using a simple method of solution casting.The effects of encapsulating different ratios of ionic liquid([PP_(13)][TFSI])into the micropores of functionalized metal-organic frameworks(NH_(2)-MIL-53(Al))on the electrochemical properties were compared.XRD,SEM,nitrogen adsorption-desorption isotherms,and electrochemical measurements were conducted.This GPE demonstrates a superior ionic conductivity of 8.08×10^(-4)S·cm^(-1)at 60℃and can sustain a discharge specific capacity of 156.6 mA·h·g^(-1)at 0.2 C for over 100 cycles.This work might offer a potential approach to alleviate the solid-solid contact with the solid-state electrolyte and electrodes and broaden a new window for the creation of all-solid-state batteries.

Wet-spun poly(ionic liquid)-graphene hybrid fibers for high performance all-solid-state flexible supercapacitors

It is crucial to develop flexible and wearable electronic devices that have attracted tremendous interest due to their merits on compactness,flexibility and high capacitive properties.Herein we report the continuously ordered macroscopic poly(ionic liquid)-graphene fibers by wet spinning method via liquid crystal assembly for supercapacitor application.The fabricated all-solid-state supercapacitors exhibited a high areal capacitance(268.2 mF cm 2)and volumetric capacitance(204.6 F cm 3)with an outstanding areal energy density(9.31μWh cm-2)and volumetric energy density(8.28 mWh cm-3).The fiber supercapacitors demonstrated exceptional cycle life for straight electrodes of about 10,000 cycles(94.2%capacitance retention)and flexibility at different angles(0°,45°,90°,180°)along with a good flexible cycling stability after 6000 cycles(92.7%capacitance retention).To date,such a novel poly(ionic liquid)-graphene fiber supercapacitors would be a new platform in real-time flexible electronics.

Design strategies and recent advancements of solid-state supercapacitor operating in wide temperature range

Solid-state supercapacitors(SSCs)are emerging as one of the promising energy storage devices due to their high safety,superior power density,and excellent cycling life.However,performance degradation and safety issues under extreme conditions are the main challenges for the practical application.With the expansion of human activities,such as space missions,polar exploration,and so on,the investigation of SSC with wide temperature tolerance,high energy density,power density,and sustainability is highly desired.In this review,the effects of temperature on SSC are systematically illustrated and clarified,including the properties of the electrolyte,ion diffusion,and reaction dynamics of the supercapacitor.Subsequently,we summarize the recent advances in wide-temperature-range SSCs from the aspect of electrolyte modification,electrode design,and interface adjustment between electrode and electrolyte,especially with critical concerns on ionic conductivity and cycling stability.In the end,a perspective is presented,expecting to promote the practical application of the SSC in harsh conditions.

SEI/dead Li-turning capacity loss for high-performance anode-free solid-state lithium batteries

Anode-free solid-state lithium metal batteries(AF-SSLBs)have the potential to deliver higher energy density and improved safety beyond lithium-metal batteries.However,the unclear mechanism for the fast capacity decay in AF-SSLBs,either determined by dead Li or solid electrolyte interface(SEI),limits the proposal of effective strategies to prolong cycling life.To clarify the underlying mechanism,herein,the evolution of SEI and dead Li is quantitatively analyzed by a solid-state nuclear magnetic resonance(ss-NMR)technology in a typical LiPF6-based polymer electrolyte.The results show that the initial capacity loss is attributed to the formation of SEI,while the dead Li dominates the following capacity loss and the growth rate is 0.141 mA h cm^(−2)cycle−1.To reduce the active Li loss,the combination of inorganic-rich SEI and self-healing electrostatic shield effect is proposed to improve the reversibility of Li deposition/dissolution behavior,which reduces the capacity loss rate for the initial SEI and following dead Li generation by 2.3 and 20.1 folds,respectively.As a result,the initial Coulombic efficiency(ICE)and stable CE increase by 15.1%and 15.3%in Li-Cu cells,which guides the rational design of high-performance AF-SSLBs.

A Review on Engineering Design for Enhancing Interfacial Contact in Solid-State Lithium–Sulfur Batteries

The utilization of solid-state electrolytes(SSEs)presents a promising solution to the issues of safety concern and shuttle effect in Li–S batteries,which has garnered significant interest recently.However,the high interfacial impedances existing between the SSEs and the electrodes(both lithium anodes and sulfur cathodes)hinder the charge transfer and intensify the uneven deposition of lithium,which ultimately result in insufficient capacity utilization and poor cycling stability.Hence,the reduction of interfacial resistance between SSEs and electrodes is of paramount importance in the pursuit of efficacious solid-state batteries.In this review,we focus on the experimental strategies employed to enhance the interfacial contact between SSEs and electrodes,and summarize recent progresses of their applications in solidstate Li–S batteries.Moreover,the challenges and perspectives of rational interfacial design in practical solid-state Li–S batteries are outlined as well.We expect that this review will provide new insights into the further technique development and practical applications of solid-state lithium batteries.

Semi-interpenetrating-network all-solid-state polymer electrolyte with liquid crystal constructing efficient ion transport channels for flexible solid lithium-metal batteries

The development of the solid-state polymer electrolytes (SPEs) for Li-ion batteries (LIBs) can effectively address the hidden safety issues of commercially used liquid electrolytes.Nevertheless,the unsatisfactory room temperature ion conductivity and inferior mechanical strength for linear PEO-based SPEs are still the immense obstacles impeding the further applications of SPEs for large-scale commercialization.Herein,we fabricate a series of semi-interpenetrating-network (semi-IPN) polymer electrolytes based on a novel liquid crystal (C6M LC) and poly(ethylene glycol) diglycidyl ether (PEGDE) via UV-irradiation at the first time.The LCs not only highly improve the mechanical properties of electrolyte membranes via the construction of network structure with PEGDE,but also create stable ion transport channels for ion conduction.As a result,a free-standing flexible SPE shows outstanding ionic conductivity(5.93×10^(-5) S cm^(-1) at 30℃),a very wide electrochemical stability window of 5.5 V,and excellent thermal stability at thermal decomposition temperatures above 360℃ as well as the capacity of suppressing lithium dendrite growth.Moreover,the LiFePO_(4)/Li battery assembled with the semi-IPN electrolyte membranes exhibits good cycle performance and admirable reversible specific capacity.This work highlights the obvious advantages of LCs applied to the electrolyte for the advanced solid lithium battery.

Lithiophilic Li-Si alloy-solid electrolyte interface enabled by high-concentration dual salt-reinforced quasi-solid-state electrolyte

Solid polymer electrolytes(SPEs)are urgently required to achieve practical solid-state lithium metal batteries(LMBs)and lithium-ion batteries(LIBs),Herein,we proposed a mechanism for modulating interfacial conduction and anode interfaces in high-concentration SPEs by LiDFBOP.Optimized electrolyte exhibits superior ionic conductivity and remarkable interface compatibility with salt-rich clusters:(1)polymer-plastic crystal electrolyte(P-PCE,TPU-SN matrix)dissociates ion pairs to facilitate Li+transport in the electrolyte and regulates Li^(+)diffusion in the SEI.The crosslinking structure of the matrix compensates for the loss of mechanical strength at high-salt concentrations;(2)dual-anion TFSI^(-)_(n)-DFBOP^(-)_(m)in the Li^(+)solvation sheath facilitates facile Li^(+)desolvation and formation of salt-rich clusters and is conducive to the formation of Li conductive segments of TPU-SN matrix;(3)theoretical calculations indicate that the decomposition products of LiDFBOP form SEI with lower binding energy with LiF in the SN system,thereby enhancing the interfacial electrochemical redox kinetics of SPE and creating a solid interface SEI layer rich in LiF.As a result,the optimized electrolyte exhibits an excellent ionic conductivity of9.31×10^(-4)S cm^(-1)at 30℃and a broadened electrochemical stability up to 4.73 V.The designed electrolyte effectively prevents the formation of Li dendrites in Li symmetric cells for over 6500 h at0.1 mA cm^(-2).The specific Li-Si alloy-solid state half-cell capacity shows 711.6 mAh g^(-1)after 60 cycles at 0.3 A g^(-1).Excellent rate performance and cycling stability are achieved for these solid-state batteries with Li-Si alloy anodes and NCM 811 cathodes.NCM 811‖Prelithiated silicon-based anode solid-state cell delivers a discharge capacity of 195.55 mAh g^(-1)and a capacity retention of 97.8%after 120 cycles.NCM 811‖Li solid-state cell also delivers capacity retention of 84.2%after 450 cycles.

Structural analysis of silk using solid-state NMR

Silkworms and spiders are capable of generating fibers that are both highly durable and elastic in a short span of time,using a silk solution stored within their bodies at room temperature and normal atmospheric pressure.The dragline silk fiber,which is essentially a spider's lifeline,surpasses the strength of a steel wire of equivalent thickness.Regrettably,humans have yet to replicate this process to produce fibers with similar high strength and elasticity in an eco-friendly manner.Therefore,it is of utmost importance to thoroughly comprehend the extraordinary structure and fibrillation mechanism of silk,and leverage this understanding in the manufacturing of high-strength,high-elasticity fibers.This review will delve into the recent progress in comprehending the structure of silks derived from silkworms and spiders,emphasizing the distinctive attributes of solidstate NMR.

Li-Ion Transport Mechanisms in Selenide-Based Solid-State Electrolytes in Lithium-Metal Batteries:A Study of Li_(8)SeN_(2),Li_(7)PSe_(6),and Li_(6)PSe_(5)X(X=Cl,Br,I)

To achieve high-energy-density and safe lithium-metal batteries(LMBs),solid-state electrolytes(SSEs)that exhibit fast Li-ion conductivity and good stability against lithium metal are of great importance.This study presents a systematic exploration of selenide-based materials as potential SSE candidates.Initially,Li_(8)SeN_(2)and Li_(7)PSe_(6)were selected from 25 ternary selenides based on their ability to form stable interfaces with lithium metal.Subsequently,their favorable electronic insulation and mechanical properties were verified.Furthermore,extensive theoretical investigations were conducted to elucidate the fundamental mechanisms underlying Li-ion migration in Li_(8)SeN_(2),Li_(7)PSe_(6),and derived Li_(6)PSe_(5)X(X=Cl,Br,I).Notably,the highly favorable Li-ion conduction mechanism of vacancy diffusion was identified in Li6PSe5Cl and Li_(7)PSe_(6),which exhibited remarkably low activation energies of 0.21 and 0.23 eV,and conductivity values of 3.85×10^(-2)and 2.47×10^(-2)S cm^(-1)at 300 K,respectively.In contrast,Li-ion migration in Li_(8)SeN_(2)was found to occur via a substitution mechanism with a significant diffusion energy barrier,resulting in a high activation energy and low Li-ion conductivity of 0.54 eV and 3.6×10^(-6)S cm^(-1),respectively.Throughout this study,it was found that the ab initio molecular dynamics and nudged elastic band methods are complementary in revealing the Li-ion conduction mechanisms.Utilizing both methods proved to be efficient,as relying on only one of them would be insufficient.The discoveries made and methodology presented in this work lay a solid foundation and provide valuable insights for future research on SSEs for LMBs.

Enhanced High-Temperature Cycling Stability of Garnet-Based All Solid-State Lithium Battery Using a Multi-Functional Catholyte Buffer Layer

The pursuit of safer and high-performance lithium-ion batteries(LIBs)has triggered extensive research activities on solid-state batteries,while challenges related to the unstable electrode-electrolyte interface hinder their practical implementation.Polymer has been used extensively to improve the cathode-electrolyte interface in garnet-based all-solid-state LIBs(ASSLBs),while it introduces new concerns about thermal stability.In this study,we propose the incorporation of a multi-functional flame-retardant triphenyl phos-phate additive into poly(ethylene oxide),acting as a thin buffer layer between LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathode and garnet electro-lyte.Through electrochemical stability tests,cycling performance evaluations,interfacial thermal stability analysis and flammability tests,improved thermal stability(capacity retention of 98.5%after 100 cycles at 60℃,and 89.6%after 50 cycles at 80℃)and safety characteristics(safe and stable cycling up to 100℃)are demonstrated.Based on various materials characterizations,the mechanism for the improved thermal stability of the interface is proposed.The results highlight the potential of multi-functional flame-retardant additives to address the challenges associated with the electrode-electrolyte interface in ASSLBs at high temperature.Efficient thermal modification in ASSLBs operating at elevated temperatures is also essential for enabling large-scale energy storage with safety being the primary concern.