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Poly(ethylene oxide) (PEO)-based composite electrolytes (PCEs) are considered as promising candidates for next-generation lithium-metal batteries (LMBs) due to their high safety, easy fabrication, and good electrochemical stability. Here, we utilize operando grazing-incidence small-angle and wide-angle X-ray scattering to probe the correlation of electrochemically induced changes and the buried morphology and crystalline structure of the PCE. Results show that the two irreversible reactions, PEO-Li+ reduction and TFSI- decomposition, cause changes in the crystalline structure, array orientation, and morphology of the PCE. In addition, the reversible Li plating/stripping process alters the inner morphology, especially the PEO-LiTFSI domain radius and distance between PEO-LiTFSI domains, rather than causing crystalline structure and orientation changes. This work provides a new path to monitor a working battery in real time and to a detailed understanding of the Li+ diffusion mechanism, which is essential for developing highly transferable and interface-stable PCE-based LMBs.

The practical application of all‐solid‐state lithium metal batteries (ASSLMBs) is limited by lithium (Li) anode instability including Li dendrite formation and deteriorating interface with electrolytes. Here, a functional additive, isosorbide mononitrate (ISMN) with a non‐resonant structure (O2−N−O−) is reported, which improves its reactivity and is utilized to build a stable N‐rich solid electrolyte interface, effectively alleviating Li dendrite and side reactions for poly(vinylidene fluoride) (PVDF)‐lithium bis(trifluoromethane sulfonyl) imide (LiTFSI)‐based electrolyte (PLE‐ISMN). In addition, the ion‐dipole interaction between ISMN and Li ions facilitates the dissociation of LiTFSI to form carrier ions, improving the ionic conductivity (4.4 × 10−4 S cm−1) and transference number (0.50) of PLE‐ISMN. Consequently, the Li/Li symmetric cell delivers a high critical current density of 2.0 mA cm−2 and stable Li stripping/plating cycling over 5000 h with a capacity of 1.0 mAh cm−2. Moreover, the Li|LiFePO4 cell delivers an excellent initial discharge capacity of 154.0 mAh g−1 with an outstanding capacity retention of 88.9% after 500 cycles at 0.5 C. The Li|LiNi0.8Co0.1Mn0.1O2 cell also exhibits a good cycling performance at 4.4 V at 1 C. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries (ASSLBs) have gained enormous interest due to their potential high energy density, high performance, and inherent safety characteristics for advanced energy storage systems. Although solid-state ceramic (inorganic) electrolytes (SSCEs) have high ionic conductivity and high electrochemical stability, they experience some significant drawbacks, such as poor electrolyte/electrode interfacial properties and poor mechanical characteristics (brittle, fragile), which can hinder their adoption for commercialization. Typically, SSCE-based ASSLBs require high cell stack pressures exerted by heavy fixtures for regular operation, which can reduce the energy density of the overall battery packages. Polymer–SSCE composite electrolytes can provide inherently good interfacial contacts with the electrodes that do not require high cell stack pressures. In this study, we explore the feasibility of incorporating an electronically and ionically conducting polymer, polypyrrole (PPy), into a polymer backbone, polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), to improve the ionic conductivity of the resultant polymer–SSCE composite electrolyte (SSPE). The electronically conductive polymer-incorporated composite electrolyte showed superior room temperature ionic conductivity and electrochemical performance compared to the baseline sample (without PPy). The PPy-incorporated polymer electrolyte demonstrated a high resilience to high temperature operation compared with the liquid-electrolyte counterpart. This performance advantage can potentially be employed in ASSLBs that operate at high temperatures. In our recent development efforts, SSPEs with optimal formulations showed room temperature ionic conductivity of 2.5 × 10−4 S/cm. The data also showed, consistently, that incorporating PPy into the polymer backbone helped boost the ionic conductivity with various SSPE formulations, consistent with the current study. Electrochemical performance of ASSLBs with the optimized SSPEs will be presented in a separate publication. The current exploratory study has shown the feasibility and benefits of the novel approach as a promising method for the research and development of next-generation solid composite electrolyte-based ASSLBs. [ABSTRACT FROM AUTHOR]

The electrochemical performance of all‐solid‐state lithium batteries (ASSLBs) can be significantly improved by addressing the challenges posed by space charge layer (SCL) effect, which plays a crucial role in determining Li+ ions transport kinetic at cathodic interface. Therefore, it is critical to realize the in situ inspection and visualization of SCL behaviors for solving sluggish Li+ ions transport issues, despite remaining grant challenges. Therewith, the well‐defined model of LiNbO3‐coated NCM (NCM@LNO) cathode is constructed and assembled for the representative Li6PS5Cl‐based ASSLBs, which not only ensures excellent cathodic compatibility, but also preferably enables the better monitoring of Li+ ions transport kinetics. Combining ex situ analysis with DFT calculation, the formation and evolution mechanism of SCL are comprehensively understood, and the relationship between well‐controlled SCL configuration and Li+ electrochemical behavior has been also further illustrated and established through the operando Raman spectroscopy. On these grounds, the preferred NCM@LNO cathodes acquire the enhanced discharge capacity of 90.6% (144.8 mAh g−1) after 100 cycles and it can still deliver the exceptional capacity of 136.2 mAh g−1 after 800 cycles in ASSLBs. Hence, the research will pave up a new perspective for fundamental scientific insight of the SCL and reasonable tailoring of cathodic interface for high‐efficiency ASSLBs. [ABSTRACT FROM AUTHOR]

Halide solid electrolytes (SEs) are attracting strong attention as one of the compelling candidates for the next‐generation of inorganic SEs due to their high ionic conductivity. Nevertheless, unsatisfactory high‐voltage stability restricts the further applications of halide SEs. Herein, the anion‐engineering of F−/O2− is evolved to construct the high‐voltage stable zirconium‐based halide superionic conductors (Li2.5ZrCl5F0.5O0.5, LZCFO). Benefiting from the thermodynamic/kinetic high‐voltage stability of F‐containing SE and the disordered localized structure introduced by O2−, LZCFO displays a practical electrochemical limit of 4.87 V versus Li/Li+ and an ionic conductivity of 1.17 mS cm−1 at 30 °C. With LZCFO and NCM955, the all‐solid‐state lithium battery exhibits a high discharge capacity of 207.1 mAh g−1 at 0.1C and a capacity retention of 81.2% after 500 cycles at 0.5C. The interfacial characterization further demonstrates the formation of the F‐rich cathode–electrolyte interphase (CEI), which inhibits side reactions between the cathode and the SE and boosts excellent cycling stability. This work affords fresh insights on the engineering of SEs with high‐voltage stability, high ionic conductivity, and stable CEI in all‐solid‐state lithium batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • PTFE-based dry-processed technology is used to prepare flexible Li 6 PS 5 Cl membrane and FeS 2 composite cathode membrane. • Due to the robust adhesion of PTFE, intimate contact is obtained at 100 MPa which is one-fifth of conventional pressure. • PTFE attaches the electrochemical sluggish products to an ion–electron conductive network to improve cyclic stability. • The flexible FeS 2 -ASSLBs exhibit excellent cyclic stability under the stack pressure of 100 MPa. All-solid-state lithium batteries (ASSLBs) are considered promising energy storage systems due to their high energy density and inherent safety. However, scalable fabrication of ASSLBs based on transition metal sulfide cathodes through the conventional powder cold-pressing method with ultrahigh stacking pressure remains challenging. This article elucidates a dry process methodology for preparing flexible and high-performance FeS 2 -based ASSLBs under low stack pressure by utilizing polytetrafluoroethylene (PTFE) binder. In this design, fibrous PTFE interweaves Li 6 PS 5 Cl particles and FeS 2 cathode components, forming flexible electrolyte and composite cathode membranes. Beneficial to the robust adhesion, the composite cathode and Li 6 PS 5 Cl membranes are tightly compacted under a low stacking pressure of 100 MPa which is a fifth of the conventional pressure. Moreover, the electrode/electrolyte interface can sustain adequate contact throughout electrochemical cycling. As expected, the FeS 2 -based ASSLBs exhibit outstanding rate performance and cyclic stability, contributing a reversible discharged capacity of 370.7 mAh g−1 at 0.3C after 200 cycles. More importantly, the meticulous dQ/dV analysis reveals that the three-dimensional PTFE binder effectively binds the discharge products with sluggish kinetics (Li 2 S and Fe) to the ion–electron conductive network in the composite cathode, thereby preventing the electrochemical inactivation of products and enhancing electrochemical performance. Furthermore, FeS 2 -based pouch-type cells are fabricated, demonstrating the potential of PTFE-based dry-process technology to scale up ASSLBs from laboratory-scale mold cells to factory-scale pouch cells. This feasible dry-processed technology provides valuable insights to advance the practical applications of ASSLBs. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries (ASSLBs) are regarded as the most promising alternative to traditional liquid lithium-ion batteries due to their high-energy density and excellent safety. As an important part of ASSLBs, composite polymer electrolytes (CPEs) with excellent comprehensive performance have attracted wide attention from researchers. Herein, a series of CPEs were prepared by employing Li6.4Ga0.2La3Zr2O12 (LGLZO) submicron particles with cubic phase as fillers in polyethylene oxide (PEO) matrix. The tape-casting method was employed to prepare PEO-LiTFSI-x% LGLZO (CPE-x, where x = 0–80). In these CPE-x, the CPE-40 exhibits elevated ionic conductivity (6.20 × 10−5 S cm−1 at 20 °C and 1.88 × 10−4 S cm−1 at 60 °C), attractive Li+ transference number (0.31 at 60 °C), low activation energy barrier of lithium-ion migration, wide electrochemical window, and high critical current density of 1.3 mA cm−2. Furthermore, the LiFePO4 | CPE-40 | Li batteries deliver outstanding cycle performance (capacity retention of 85.43% after 225 cycles at 0.2C and 60 °C) and rate performance. These results show that the PEO-base solid-state electrolytes filled with submicron LGLZO particles possess a broad application prospect. [ABSTRACT FROM AUTHOR]

All-solid-state lithium-metal batteries (ASSLMBs) are widely considered as the ultimately advanced lithium batteries owing to their improved energy density and enhanced safety features. Among various solid electrolytes, sulfide solid electrolyte (SSE) Li6PS5Cl has garnered significant attention. However, its application is limited by its poor cyclability and low critical current density (CCD). In this study, we introduce a novel approach to enhance the performance of Li6PS5Cl by doping it with fluorine, using lithium fluoride nanoparticles (LiFs) as the doping precursor. The F-doped electrolyte Li6PS5Cl-0.2LiF(nano) shows a doubled CCD, from 0.5 to 1.0 mA/cm2 without compromising the ionic conductivity; in fact, conductivity is enhanced from 2.82 to 3.30 mS/cm, contrary to the typical performance decline seen in conventionally doped Li6PS5Cl electrolytes. In symmetric Li|SSE|Li cells, the lifetime of Li6PS5Cl-0.2LiF(nano) is 4 times longer than that of Li6PS5Cl, achieving 1500 h vs. 371 h under a charging/discharging current density of 0.2 mA/cm2. In Li|SSE|LiNbO3@NCM721 full cells, which are tested under a cycling rate of 0.1 C at 30 °C, the lifetime of Li6PS5Cl-0.2LiF(nano) is four times that of Li6PS5Cl, reaching 100 cycles vs. 26 cycles. Therefore, the doping of nano-LiF offers a promising approach to developing high-performance Li6PS5Cl for ASSLMBs. [ABSTRACT FROM AUTHOR]

Chlorine-rich Li-argyrodite sulfide solid electrolytes Li5.5PS4.5Cl1.5 are applied in all-solid-state batteries (ASSBs) due to the promising ionic transport and structural stability. However, the poor air/moisture stability and incompatibility to Li metal impede their practical applications. Herein, we synthesized a Li5.5PS4.5Cl1.5-based argyrodite exhibiting improved moisture stability and electrochemical performance to metallic Li, as well as high-voltage cathodes through O doping. The prepared oxygen-doped Li5.5PS4.5Cl1.5 samples (Li5.5PS4.425O0.075Cl1.5) possess significantly enhanced air stability and lower migration barrier in comparison with pristine Li5.5PS4.5Cl1.5. Moreover, Li5.5PS4.425O0.075Cl1.5 exhibits lower polarization voltage and better compatibility with lithium metal in the constant current charge-discharge tests of Li-Li symmetrical cell. This is attributed to the Cl-O coexistence coating interface that observed in the interface of Li/Li5.5PS4.425O0.075Cl1.5. To fully leverage the ultrafast ionic conductivity of Li5.5PS4.5Cl1.5, we construct ASSBs using optimized Li5.5PS4.425O0.075Cl1.5 as buffer layer between pristine LiNi0.6Mn0.2Co0.2O2 cathode materials and Li5.5PS4.5Cl1.5, leading to higher discharge capacities and elevated capacity retention. Based on above results, we further introduce LiNbO3-coated LiCoO2 as cathode, combined with Li5.5PS4.425O0.075Cl1.5 as an isolating layer between Li anode and Li5.5PS4.5Cl1.5 to suppress the growth of Li dendrite and achieve superior cyclability at wide voltage windows. Consequently, the all-solid-state lithium batteries exhibit promising application in a wide temperature range. This work provides a compelling strategy for achieving improved Chlorine-rich Li-argyrodite solid electrolytes with excellent air stability, high ionic conductivity and Li dendrite suppression capability, hence enabling all-solid-state batteries with high energy density and superior cyclability.

Halide solid‐state electrolytes (SSEs) hold promise for the commercialization of all‐solid‐state lithium batteries (ASSLBs); however, the currently cost‐effective zirconium‐based chloride SSEs suffer from hygroscopic irreversibility, low ionic conductivity, and inadequate thermal stability. Herein, a novel indium‐doped zirconium‐based chloride is fabricated to satisfy the abovementioned requirements, achieving outstanding‐performance ASSLBs at room temperature. Compared to the conventional Li2ZrCl6 and Li3InCl6 SSEs, the hc‐Li2+xZr1‐xInxCl6 (0.3 ≤ x ≤ 1) possesses higher ionic conductivity (up to 1.4 mS cm−1), and thermal stability (350 °C). At the same time, the hc‐Li2.8Zr0.2In0.8Cl6 also shows obvious hygroscopic reversibility, where its recovery rate of the ionic conductivity is up to 82.5% after 24‐h exposure in the 5% relative humidity followed by heat treatment. Theoretical calculation and experimental results reveal that those advantages are derived from the lattice expansion and the formation of Li3InCl6 ·2H2O hydrates, which can effectively reduce the migration energy barrier of Li ions and offer reversible hydration/dehydration pathway. Finally, an ASSLB, assembled with reheated‐Li2.8Zr0.2In0.8Cl6 after humidity exposure, single‐crystal LiNi0.8Mn0.1Co0.1O2 and Li‐In alloy, exhibits capacity retention of 71% after 500 cycles under 1 C at 25 °C. This novel high‐humidity‐tolerant chloride electrolyte is expected to greatly carry forward the ASSLBs industrialization. [ABSTRACT FROM AUTHOR]

Halide‐based solid electrolytes are promising candidates for all solid‐state lithium‐ion batteries (ASSLBs) due to their high ionic conductivity, wide electrochemical window, and excellent chemical stability with cathode materials. However, when tested in practice, their intrinsic electrochemical stability windows do not well match the conditions for stable operation of ASSBs. Existing literature reports halide‐based ASSBs that still operate well outside the electrochemical stability window, while ASSBs that do not operate within the window are not well studied or the studies are based on the cathode material interface. In this study, we aim to elucidate the mechanism behind all‐solid‐state battery failure by investigating how the reduction potential of Li3YCl6 solid‐state electrolyte itself changes under overcharging conditions. Our findings demonstrate that in Li‐In|Li3YCl6|Li3YCl6‐C half‐cells during the first state of charge, Cl ions participate in charge compensation, resulting in a depletion of ligands. This phenomenon significantly affects the reduction potential of Y3+, causing it to be reduced to Y2Cl3 and ultimately to Y0 at conditions far exceeding its actual reduction potential. Furthermore, we analyze the interfacial impedance induced by this process and propose a novel perspective on battery failure. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries (ASSLBs) have attracted great interest due to their promising energy density and strong safety. However, the interface issues, including large interfacial resistance between electrode and electrolyte and low electrochemical stability of solid-state electrolytes against high-voltage cathodes, have restricted the development of high-voltage ASSLBs. Herein, we report an ASSLB with stable cycling by adopting a conformal polymer interlayer in-situ formed at the Li64La3Zr14Ta0.6O12 (LLZTO)–cathode interfaces. The polymer can perfectly fill the voids and create a stable interface contact between LLZTO and cathodes. In addition, the electric field across the polymer interlayer is reduced compared with pure solid polymer electrolyte (SPE), which facilitates the electrochemical stability with high-voltage cathode. The all-solid-state Li∣LLZTO-SPE∣LiFe0.4Mn0.6PO4 (LMFP) cells achieve a low interface impedance, high specific capacity, and excellent cycling performance. This work presents an effective and practical strategy to rationally design the electrode–electrolyte interface for the application of high-voltage ASSLBs. [ABSTRACT FROM AUTHOR]

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The LiTaCl6 solid electrolyte has the lowest activation energy of ionic conduction at ambient conditions (0.165 eV), with a record high ionic conductivity for a ternary compound (11 mS cm−1). However, the mechanism has been unclear. We train machine‐learning force fields (MLFF) on ab initio molecular dynamics (AIMD) data on‐the‐fly and perform MLFF MD simulations of AIMD quality up to the nanosecond scale at the experimental temperatures, which allows us to predict accurate activation energy for Li‐ion diffusion (at 0.164 eV). Detailed analyses of trajectories and vibrational density of states show that the large‐amplitude vibrations of Cl− ions in TaCl6− enable the fast Li‐ion transport by allowing dynamic breaking and reforming of Li−Cl bonds across the space in between the TaCl6− octahedra. We term this process the dynamic‐monkey‐bar mechanism of superionic Li+ transport which could aid the development of new solid electrolytes for all‐solid‐state lithium batteries. [ABSTRACT FROM AUTHOR]

The LiTaCl6 solid electrolyte has the lowest activation energy of ionic conduction at ambient conditions (0.165 eV), with a record high ionic conductivity for a ternary compound (11 mS cm−1). However, the mechanism has been unclear. We train machine‐learning force fields (MLFF) on ab initio molecular dynamics (AIMD) data on‐the‐fly and perform MLFF MD simulations of AIMD quality up to the nanosecond scale at the experimental temperatures, which allows us to predict accurate activation energy for Li‐ion diffusion (at 0.164 eV). Detailed analyses of trajectories and vibrational density of states show that the large‐amplitude vibrations of Cl− ions in TaCl6− enable the fast Li‐ion transport by allowing dynamic breaking and reforming of Li−Cl bonds across the space in between the TaCl6− octahedra. We term this process the dynamic‐monkey‐bar mechanism of superionic Li+ transport which could aid the development of new solid electrolytes for all‐solid‐state lithium batteries. [ABSTRACT FROM AUTHOR]

The LiTaCl6 solid electrolyte has the lowest activation energy of ionic conduction at ambient conditions (0.165 eV), with a record high ionic conductivity for a ternary compound (11 mS cm−1). However, the mechanism has been unclear. We train machine‐learning force fields (MLFF) on ab initio molecular dynamics (AIMD) data on‐the‐fly and perform MLFF MD simulations of AIMD quality up to the nanosecond scale at the experimental temperatures, which allows us to predict accurate activation energy for Li‐ion diffusion (at 0.164 eV). Detailed analyses of trajectories and vibrational density of states show that the large‐amplitude vibrations of Cl− ions in TaCl6− enable the fast Li‐ion transport by allowing dynamic breaking and reforming of Li−Cl bonds across the space in between the TaCl6− octahedra. We term this process the dynamic‐monkey‐bar mechanism of superionic Li+ transport which could aid the development of new solid electrolytes for all‐solid‐state lithium batteries. [ABSTRACT FROM AUTHOR]

The LiTaCl6 solid electrolyte has the lowest activation energy of ionic conduction at ambient conditions (0.165 eV), with a record high ionic conductivity for a ternary compound (11 mS cm−1). However, the mechanism has been unclear. We train machine‐learning force fields (MLFF) on ab initio molecular dynamics (AIMD) data on‐the‐fly and perform MLFF MD simulations of AIMD quality up to the nanosecond scale at the experimental temperatures, which allows us to predict accurate activation energy for Li‐ion diffusion (at 0.164 eV). Detailed analyses of trajectories and vibrational density of states show that the large‐amplitude vibrations of Cl− ions in TaCl6− enable the fast Li‐ion transport by allowing dynamic breaking and reforming of Li−Cl bonds across the space in between the TaCl6− octahedra. We term this process the dynamic‐monkey‐bar mechanism of superionic Li+ transport which could aid the development of new solid electrolytes for all‐solid‐state lithium batteries. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries (ASSLBs) hold immense promise as next-generation energy storage systems. A crucial aspect of ASSLB development lies in achieving high energy density, which demands the high mass loadings of cathode active material. However, thick cathode with high mass loading may introduce various challenges, such as interfacial resistance between electrolytes and electrodes, suboptimal ion conduction, and limited battery lifespan. To address these challenges, composite cathode has been engineered by integrating solid-state electrolytes into conventional cathodes to enhance ion transport. Solid polymer electrolytes (SPEs), in particular, stand out for their ability to mitigate interfacial issues during cycling due to their elasticity and flexibility compared to their inorganic counterparts. This review offers a comprehensive overview of efforts to incorporate SPEs into catholytes for ASSLBs. It begins with a discussion on catholyte composition, emphasizing the properties of their constituent components. Subsequently, it provides a concise overview of electrochemical transport and measurement techniques. The review then delves into efficient and cost-effective fabrication processes, highlighting their significance. Finally, it underscores the crucial role of SPEs in advancing the development of catholytes for the future. [ABSTRACT FROM AUTHOR]

All-solid-state lithium-ion batteries (ASSLBs) have recently received significant attention due to their exceptional energy/power densities, inherent safety, and long-term electrochemical stability. However, to achieve energy- and power-dense ASSLBs, the cathode composite electrodes require optimum ionic and electrical pathways and hence the development of electrode designs that facilitate such requirements is necessary. Among the various available conductive materials, carbon black (CB) is typically considered as a suitable carbon additive for enhancing electrode conductivity due to its affordable price and electrical-network-enhancing properties. In this study, we examined the effect of different weight percentages (wt%) of nano-sized CB as a conductive additive within a cathode composite made up of Ni-rich cathode material (LiNi0.8Co0.1Mn0.1O2) and solid electrolyte (Li6PS5Cl). Composites including 3 wt%, 5 wt%, and 7 wt% CB were produced, achieving capacity retentions of 66.1%, 65.4%, and 44.6% over 50 cycles at 0.5 C. Despite an increase in electrical conductivity of the 7 wt% CB sample, a significantly lower capacity retention was observed. This was attributed to the increased resistance at the solid electrolyte/cathode material interface, resulting from the presence of excessive CB. This study confirms that an excessive amount of nano-sized conductive material can affect the interfacial resistance between the solid electrolyte and the cathode active material, which is ultimately more important to the electrochemical performance than the electrical pathways. [ABSTRACT FROM AUTHOR]

3D electrode design is proposed as an attractive approach to simultaneously increasing energy and power densities for all-solid-state thin film lithium microbatteries (TFBs). However, currently reported TFBs based on 3D electrodes prepared by atomic layer deposition or physical vapor deposition suffer from relatively low areal capacity and high fabrication cost. In this work, a 3D CuO nanowire array electrode with controllable thickness is directly prepared on a conductive substrate by a facile wet chemistry route, based on which a high-performance CuO/LiPON/Li TFB is efficiently constructed. Possessing abundant electrode/electrolyte interface contact, shortened ion diffusion length, and accommodation capability for volume change, the CuO/LiPON/Li TFB exhibits a large areal capacity (92 μAh cm−2 at 15 μA cm−2), high rate capability (11 μAh cm−2 at 960 μA cm−2), and good cycle performance (nearly no capacity loss after 70 cycles). This work establishes the great potential of preparing 3D electrodes by wet chemistry routes for realizing high-performance TFBs. [ABSTRACT FROM AUTHOR]

In the development of all‐solid‐state lithium batteries (ASSLB), progress is made with solid‐state electrolytes; however, challenges regarding compatibility and stability still exist with solid electrodes. These issues result in a low battery capacity and short cycle life, which limit the commercial application of ASSLBs. This review summarizes the recent research progress on solid‐state electrodes in ASSLBs including the solid–solid interface phenomena such as the interface between electrode materials and electrolytes. The mechanical stability problems in solid electrodes, including fracture, brittleness, and deformation of electrode materials, are also discussed, and corresponding methods to measure the solid electrode stress are provided. In addition, strategies for mitigating stress‐related issues are examined. Finally, the fabrication process of solid electrodes is introduced and their future developments, including the exploration of new electrode materials and the design of more intelligent electrode structures, are proposed. [ABSTRACT FROM AUTHOR]

Garnet‐type Li6.4La3Zr1.4Ta0.6O12 (LLZTO) suffers from instability against moist air, poor interfacial contact with anode, and serious dendrite issue, which greatly impede its practical application in all‐solid‐state lithium batteries (ASSLBs). Herein, a superlithiophilic, moisture‐resistant, and robust interlayer is demonstrated to overcome these obstacles by in situ forming an AlF3 interlayer on the LLZTO surface. Thanks to the unique property, the AlF3‐modified LLZTO offers a significantly reduced interfacial resistance by more than two orders of magnitude (from 527.5 Ω cm2 for the pristine Li/LLZTO to 1.3 Ω cm2 for the surface‐engineered interface), achieves a critical current density of 1.2 mA cm−2 and long‐term stability of over 4000–4700 h, and endows regulated Li plating/stripping behaviors. Specifically, ASSLBs coupled with LiFePO4 and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes can stably charge/discharge over 400 and 100 cycles at 0.5 and 0.2 C at 25 °C, with retentions of >80.0% and Coulombic efficiencies of >99.9%, respectively. Particularly, the NCM811‐based full ASSLB with large mass loading of 8.3 mg cm−2 also delivers a discharge‐specific capacity as high as 199.1 mAh g−1 with good rate capability, even approaching to the liquid cells. This study demonstrates a practical solution to address the interfacial challenges and paves the way for practical progress of ASSLBs. [ABSTRACT FROM AUTHOR]

Abstract Halide solid‐state electrolytes (SSEs) hold promise for the commercialization of all‐solid‐state lithium batteries (ASSLBs); however, the currently cost‐effective zirconium‐based chloride SSEs suffer from hygroscopic irreversibility, low ionic conductivity, and inadequate thermal stability. Herein, a novel indium‐doped zirconium‐based chloride is fabricated to satisfy the abovementioned requirements, achieving outstanding‐performance ASSLBs at room temperature. Compared to the conventional Li2ZrCl6 and Li3InCl6 SSEs, the hc‐Li2+xZr1‐xInxCl6 (0.3 ≤ x ≤ 1) possesses higher ionic conductivity (up to 1.4 mS cm−1), and thermal stability (350 °C). At the same time, the hc‐Li2.8Zr0.2In0.8Cl6 also shows obvious hygroscopic reversibility, where its recovery rate of the ionic conductivity is up to 82.5% after 24‐h exposure in the 5% relative humidity followed by heat treatment. Theoretical calculation and experimental results reveal that those advantages are derived from the lattice expansion and the formation of Li3InCl6 ·2H2O hydrates, which can effectively reduce the migration energy barrier of Li ions and offer reversible hydration/dehydration pathway. Finally, an ASSLB, assembled with reheated‐Li2.8Zr0.2In0.8Cl6 after humidity exposure, single‐crystal LiNi0.8Mn0.1Co0.1O2 and Li‐In alloy, exhibits capacity retention of 71% after 500 cycles under 1 C at 25 °C. This novel high‐humidity‐tolerant chloride electrolyte is expected to greatly carry forward the ASSLBs industrialization.

All-solid-state lithium batteries (ASSLBs) have gained enormous interest due to their potential high energy density, high performance, and inherent safety characteristics for advanced energy storage systems. Although solid-state ceramic (inorganic) electrolytes (SSCEs) have high ionic conductivity and high electrochemical stability, they experience some significant drawbacks, such as poor electrolyte/electrode interfacial properties and poor mechanical characteristics (brittle, fragile), which can hinder their adoption for commercialization. Typically, SSCE-based ASSLBs require high cell stack pressures exerted by heavy fixtures for regular operation, which can reduce the energy density of the overall battery packages. Polymer–SSCE composite electrolytes can provide inherently good interfacial contacts with the electrodes that do not require high cell stack pressures. In this study, we explore the feasibility of incorporating an electronically and ionically conducting polymer, polypyrrole (PPy), into a polymer backbone, polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), to improve the ionic conductivity of the resultant polymer–SSCE composite electrolyte (SSPE). The electronically conductive polymer-incorporated composite electrolyte showed superior room temperature ionic conductivity and electrochemical performance compared to the baseline sample (without PPy). The PPy-incorporated polymer electrolyte demonstrated a high resilience to high temperature operation compared with the liquid-electrolyte counterpart. This performance advantage can potentially be employed in ASSLBs that operate at high temperatures. In our recent development efforts, SSPEs with optimal formulations showed room temperature ionic conductivity of 2.5 × 10−4 S/cm. The data also showed, consistently, that incorporating PPy into the polymer backbone helped boost the ionic conductivity with various SSPE formulations, consistent with the current study. Electrochemical performance of ASSLBs with the optimized SSPEs will be presented in a separate publication. The current exploratory study has shown the feasibility and benefits of the novel approach as a promising method for the research and development of next-generation solid composite electrolyte-based ASSLBs.

All‐solid‐state lithium batteries (ASSLBs) based on sulfide solid electrolytes (SEs) are one of the most promising strategies for next‐generation energy storage systems and electronic devices. However, the poor chemical/electrochemical stability of sulfide SEs with oxide cathode materials and high interfacial impedance, particularly due to physical contact failure, are the major limiting factors to the development of sulfide SEs in ASSLBs. Herein, the composite cathode of MOF‐derived Fe7S8@C and Li6PS5Br fabricated by an infiltration method (IN–Fe7S8) with dissoluble sulfide electrolyte (dissoluble SE) is reported. Dissoluble SE can easily infiltrate the porous sheet‐type Fe7S8@C cathode to homogeneously contact with Fe7S8 nanoparticles that are embedded in the surrounding carbon matrixes and form a fast ionic transport network. Benefiting from applying dissoluble SE and Fe7S8@C, the IN‐Fe7S8‐based cells displayed a reversible capacity of 510 mAh g−1 after 180 cycles at 0.045 mA cm−2 at 30 °C. This work demonstrates a novel and practical method for the development of high‐performance all‐sulfide‐based solid state batteries. [ABSTRACT FROM AUTHOR]

All‐solid‐state lithium batteries (ASSLBs) have become a recent research hotspot because of their excellent safety performance. In order to better reflect their superiority, high‐voltage cathodes should be applied to enhance the energy density of solid batteries to compete with commercial liquid batteries. However, the introduction of high‐voltage cathodes suffers from many problems, such as low electrochemical stability, inferior interface chemical stability between cathode and electrolyte, poor mechanical contact, and gas evolution. These drawbacks significantly influence the battery performance, even causing battery failure and hindering the commercialization of solid‐state batteries. This paper first reviews the above failure mechanisms of high‐voltage cathode‐based ASSLBs from different perspectives. Then, recent advances in solid‐state electrolytes for ASSLBs are summarized, mainly including polymer solid electrolytes, sulfide solid electrolytes, and oxide solid electrolytes. In addition, the influence of the cathode materials is also highly critical, and strategies to improve electrochemical performance are put forward, which can be divided into coating protection, synthesis modification, and structure improvement. Finally, guidelines for the future development of solid‐state batteries are also discussed. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries (ASSLBs) using solid polymer electrolytes (SPEs) are believed to be future next-generation batteries aiming to replace high-risk traditional batteries using liquid electrolytes, which have a wide application range in portable electronic devices, portable power supplies, and especially in electric vehicles. Moreover, the appearance of SPEs can overcome the electrolyte leakage and flammability problems in conventional lithium-ion batteries. Nevertheless, ASSLBs still face some limitations due to the low ionic conductivity of solid-state electrolytes (SSEs) at room temperature and the poor contact electrode/electrolyte interface, which can be solved by suitable strategies. Currently, the research strategies of metal-organic frameworks that can be incorporated into solid polymer electrolytes offer a remarkable method for producing uniform solid polymer electrolytes that have good electrode/electrolyte contact interfaces and high ionic conductivity. Herein, the updates of current studies about metal-organic framework-incorporated composite solid polymer electrolytes are discussed in this mini-review.

All‐solid‐state batteries (ASSBs) are rapidly moving toward commercialization as a promising high‐performance energy storage device for portable electronics and electric vehicles. One of the most challenging problems hindering the industrialization of ASSBs is the lack of technologies for cost‐effective and large‐scale manufacturing of high‐quality solid‐state electrolytes (SSEs) with about the same thickness as the polymer separators in conventional lithium‐ion batteries. Herein, atmospheric plasma spraying (APS) is adopted as a practical route to process large‐scale, uniform, and thin SSEs to conduct Li‐ions and further to manufacture ASSBs. Garnet‐type Li7La3Zr2O12 (LLZO) films with thicknesses ranging from 30 to 300 µm are successfully manufactured with direct APS technique followed with a post annealing treatment. The electrolyte reaches a high Li‐ion conductivity of 3.82 × 10−5 S cm−1 at room temperature (25 °C). Additionally, the LLZO film with a thickness of 300 µm shows a flexural strength of 157 MPa. Li/LLZO/Li and Li/LLZO/LiFePO4 cells are assembled with the films, both showing stable cycling performance. The APS method shows scalability in solid‐state electrolyte film production, and most importantly, such a process is highly compatible with the current battery industry. [ABSTRACT FROM AUTHOR]

Sulfide electrolyte-based all-solid-state batteries (ASSBs) are potential next generation energy storage technology due to the high ionic conductivity of sulfide electrolytes and potentially improved energy density and safety. However, the performance of ASSBs at/below subzero temperatures has not been explored systematically. Herein, low temperature (LT) performance of LiNi0.8Co0.1Mn0.1O2 (NCM811)|Li9.54Si1.74P1.44S11.7Cl0.3 (LiSPSCl)|Li4Ti5O12 (LTO) ASSBs was investigated. By charging the ASSB to 6 V at −40 °C, a capacity of 100.7 mAh·g−1 at 20 mA·g−1 was achieved, which is much higher than that charged to 4.3 V (4.6 mAh·g−1) at −40 °C. Moreover, atomic resolution microscopy revealed that the NCM811 remained almost intact even after being charged to 6 V. In contrast, NCM811 was entirely destructed when charged to 6 V at room temperature. The sharp difference arises from the large internal charge transfer resistance at LT which requires high voltage to overcome. Nevertheless, such high voltage is not harmful to the active material but beneficial to extracting most energy out of the ASSBs at LT. We also demonstrated that thinner electrolyte is favorable for LT operation of ASSBs due to the reduced ion transfer distance. This work provides new strategies to boost the capacity and energy density of sulfide-based ASSBs at LT for dedicated LT applications. [ABSTRACT FROM AUTHOR]

The all‐solid‐state lithium–sulfur battery is considered to be a promising energy device due to high energy density and excellent safety. However, sulfur suffers from its insulating nature and large volume changes. Employing transition‐metal sulfide cathodes is an attractive alternative. Herein, a high energy density sulfur‐rich MoS6‐based nanocomposite is designed, where MoS6 nanospheres are homogenously anchored on carbon nanotubes (CNTs) by a wet‐chemical method, providing improved electronic conductivity and reduced volume changes. In addition, a nanosized Li7P3S11 electrolyte is in situ coated on the surface of MoS6‐CNT20 to realize intimate interface contact and form nanoscale electronic/ionic transportation networks. The resultant MoS6‐CNT20@15%Li7P3S11 composite shows high electronic conductivity (1.7 × 10−1 S cm−1) and ionic conductivity (6.7 × 10−4 S cm−1), which are eight and three orders of magnitude improved compared to those of MoS6. The Li/Li6PS5Cl/MoS6‐CNT20@15%Li7P3S11 battery exhibits an initial discharge capacity of 1034.32 mAh g−1 at 0.1 A g−1. In addition, an ultrahigh reversible energy density of 1640 Wh kg−1 for the active material can be realized, which is the highest among all transition‐metal sulfide cathodes. Moreover, it shows a reversible capacity of 550.00 mAh g−1 at 0.5 A g−1 after 1000 cycles, demonstrating that the sulfur‐rich MoS6‐based nanocomposite is a promising highenergy density cathode material for next‐generation all‐solid‐state lithium batteries. [ABSTRACT FROM AUTHOR]

Ferroelectrics can significantly boost electrochemical performances of all‐solid‐state batteries by constructing built‐in electric field to reduce the space charge layer at cathode/solid‐state electrolyte interface. However, the construction mechanism of ferroelectric built‐in electric field is poorly understood. Herein, the guanidinium perchlorate (GClO4) ferroelectrics as the cathode coatings in the LiCoO2‐based all‐solid‐state lithium battery are reported, which has state‐of‐the‐art specific capacity of 210.6 mAh g−1 (91.6% of the liquid battery). Systematic studies reveal that the flexoelectric effect originating from the lattice mismatch between GClO4 and LiCoO2 gives GClO4 coatings the single‐domain state and upward self‐polarization. Consequently, a vertically downward built‐in electric field is generated relative to the cathode, which transports the lithium ions inside the electrolyte to the three‐phase interface to alleviate the space charge layer. These findings highlight that the microstructural characteristics of ferroelectric and electrode materials are the primary concern for building an effective built‐in electric field. [ABSTRACT FROM AUTHOR]

Rare-earth (RE) halide solid electrolytes (HSEs) have been an emerging research area due to their good electrochemical and mechanical properties for all-solid-state lithium batteries (ASSBs). However, only very limited types of HSEs have been reported with high performance. In this work, tens of grams of RE-HSE Li3TbBr6 (LTbB) was synthesized by a vacuum evaporation-assisted method. The as-prepared LTbB displays a high ionic conductivity of 1.7 mS·cm−1, a wide electrochemical window, and good formability. Accordingly, the assembled solid lithium-tellurium (Li-Te) battery based on the LTbB HSE exhibits excellent cycling stability up to 600 cycles, which is superior to most previous reports. The processes and the chemicals during the discharge/charge of Li-Te batteries have been studied by various in situ and ex situ characterizations. Theoretical calculations have demonstrated the dominant conductivity contributions of the direct [octahedral]-[octahedral] ([Oct]–[Oct]) pathway for Li ion migrations in the electrolyte. The Tb sites guarantee efficient electron transfer while the Li 2s orbitals are not affected during migration, leading to a low activation barrier. Therefore, this successful fabrication and application of LTbB have offered a highly competitive solution for solid electrolytes in ASSBs, indicating the great potential of RE-based HSEs in energy devices. [ABSTRACT FROM AUTHOR]

Metal fluoride–lithium batteries with potentially high‐energy densities are regarded as promising candidates for next‐generation low‐cost rechargeable batteries. However, liquid‐electrolyte metal fluoride–lithium batteries suffer from sluggish reaction kinetics, high voltage hysteresis due to side reactions, poor rate capability, and rapid capacity drop during cycling. Moreover, the research on sulfide all‐solid‐state batteries (ASSBs) with metal fluoride cathode is still lacking. Herein, four kinds of iron fluoride materials are applied to the sulfide all‐solid‐state lithium battery system for the first time to investigate the best cathode and corresponding methods. Electrochemical tests showed the cycling performance at different current densities (0.1, 0.3, and 1 C) and rate performance of the four cathodes with the following rules: FeF3‐HT > FeF3‐RT > FeF3·0.33H2O > FeF3·3H2O. The reversible capacities of FeF3‐HT AASB are 519.9 mAh g−1 after 120 cycles at 0.3C and still maintains 340.7 mAh g−1 after 400 cycles even at a high rate of 1 C. In addition, electro impedence spectroscopy and cyclic voltammetry tests of the above four cathodes show that different contents of crystal water, morphologies, and particle sizes have a great influence on the lithium storage mechanism of cathode. Moreover, the reason for the FeF3‐HT cathode's superior specific capacity and rate performance compared with other cathodes at high current densities is revealed, according to cyclic voltammogram tests under different scan rates. The cause is that FeF3‐HT has the highest proportion of the contribution capacity of the cathode surface control process. The above research opens up a new avenue for FeF3‐HT, FeF3‐RT, FeF3·0.33H2O, and FeF3·3H2O cathodes in sulfide ASSBs. [ABSTRACT FROM AUTHOR]

Solid composite electrolytes exhibit tremendous potential for practical all-solid-state lithium metal batteries (ASSLMBs), whereas the interfacial contact between cathode and electrolyte remains a long-standing problem. Herein, we demonstrate an integrated design of a double-layer functional composite electrolyte and cathode (ID-FCC), which effectively improves interfacial contact and increases cycle stability. One composite electrolyte layer, PVDFLiFSI@LLZNTO (PL1@L), comes into contact with the LLZNTO (Li6.5La3Zr1.5Nb0.4Ta0.1O12)-containing cathode, while the other layer, PEOLiTFSI@LLZNTO (PL2@L) with a Li anode, is introduced in each. Such a design establishes a continuous network for the transport of Li+ on the interface, and includes the advantages of both PEO and PVDF for improving stability with the electrodes. The Li symmetric cells Li/PL2@L-PL1@L-PL2@L/Li steadily cycled for more than 3800 h under the current density of 0.05 mA cm−2 at 60 °C. Outstandingly, the all-solid-state batteries of LiFePO4-ID-FCC/Li showed an initial specific capacity of 161.5 mA h g−1 at 60 °C, demonstrating a remaining capacity ratio of 56.1% after 1000 cycles at 0.1 C and 74.5% after 400 cycles at 0.5 C, respectively. This work provides an effective strategy for solid-state electrolyte and interface design towards ASSLMBs with high electrochemical performance. [ABSTRACT FROM AUTHOR]

Fluorinated solid‐state electrolytes (FSSEs) exhibit good compatibility with positive materials, wide electrochemical windows, and stable chemical stability, which have been widely used in all‐solid‐state lithium batteries (ASSLBs). However, the practical application of fluorinated solid electrolytes still faces great challenges due to factors such as ionic conductivity, chemical stability, and current limitation. Herein, the development history of FSSEs is reviewed first. Subsequently, the recent advances in the improvement of ion conductivity, chemical stability, and current limit by structural design, interface regulation strategies, etc. are analyzed. Finally, the design requirements for future generations of FSSEs are prospected, focusing on the latest simple one‐step synthesis methods, improving the ionic conductivity at room temperature, and optimizing the electrochemical stability window of FSSEs. [ABSTRACT FROM AUTHOR]

Li 10 GeP 2 S 12 shows great potential as solid electrolytes for solid-state batteries due to its ultrahigh Li-ion conductivity. However, the high cost of Ge and the poor stability limit its applications. Replacing Ge with Sn can significantly lower the cost and maintains the high conductivity, while the corresponding Li 10 SnP 2 S 12 still suffers the low interfacial stability with the bare high voltage layered oxide cathodes. Herein, Li 10 SnP 2 S 12 with high Li-ion conductivity up to 4.79 mS cm−1 has been synthesized. All-solid-state battery using the cathode consisting of bare LiNi 0.6 Co 0.2 Mn 0.2 O 2 and Li 10 SnP 2 S 12 shows low capacities and poor cyclability due to side reactions between those two particles. To improve the interfacial stability, a highly conductive Li 3 InCl 6 electrolyte is introduced both in the cathode mixture and between the cathode layer and Li 10 SnP 2 S 12 solid electrolyte layer. This new configuration delivers superior electrochemical performances at different operating temperatures. It delivers high initial discharge capacities of 176.1 mAh g−1, 186.9 mAh g−1, and 73.7 mAh g−1 at 0.1C when operated at room temperature, 60 oC, and −20 oC, respectively. The superior battery performances are attributed to the excellent electrochemical stability of Li 3 InCl 6 electrolyte towards bare LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode. This work provides a guideline to design Li 10 SnP 2 S 12 -based all-solid-state lithium batteries with high energy density and long span life. [ABSTRACT FROM AUTHOR]

All‐solid‐state lithium batteries (ASSLBs) are promising due to their high‐energy output and low‐risk profile, but their development has only just begun. Atomic force microscopy (AFM) and related techniques have had an impact on ASSLBs research by elucidating the interfacial, morphological, mechanical, electrical, and electrochemical properties of a wide range of electrodes and electrolytes. However, because a cross‐section cut is necessary to define the solid–solid interface, true in situ analysis is not practical. The first part of this review will assess recent advancements in the study of ASSLBs utilizing AFM and other scanning probe microscopy techniques. The interior solid–solid interfaces can be illuminated in situ using X‐ray computed tomography (X‐CT) and other nondestructive characterization techniques, whereas, in contrast, to deepen the subject, it is further examined how X‐CT vary from the use of other instruments for solid‐state battery characterization, compare the information that various methods may give, and assess how well they can accurately reflect real batteries. This review may serve as a reference and point researchers in the direction of future study on the solid–solid interface of ASSLBs. [ABSTRACT FROM AUTHOR]

All‐solid‐state lithium batteries (ASSLBs) are considered as an alternative solution to lithium‐ion batteries, because of their safety and high theoretical energy density. Argyrodite‐based solid‐electrolytes (SEs), Li6PS5X (X = Cl, Cl0.5Br0.5 or Br), are promising candidates for ASSLBs. Most of the previous reports have used Li6PS5Cl as the default SE composition. Here, the electrochemical behavior of three different argyrodites with Cl− or Br−, or both, as the halogen is systematically studied. Using LiNi0.6Co0.2Mn0.2O2 as a model cathode, the behavior of these SEs in ASSLB cells is also studied. SEs containing Br show higher near‐room‐temperature ionic conductivity (>2 mS cm−1) and the critical current density (≥1 mA cm−2) during Li plating/stripping, and are stable up to 5 V versus Li/Li+. Li6PS5Br gives the best electrochemical performance in terms of C‐rate and long‐term cycling among the three samples. Specifically, the cathode delivers an initial reversible capacity of 156 mAh g−1, with ≈27% irreversible capacity loss and 90% capacity retention over 100 cycles, and >99% Coulombic efficiency. It delivers ≈56 mAh g−1 at 10C, 36% of its initial capacity at 0.2C, whereas Li6PS5Cl and Li6PS5Cl0.5Br0.5 deliver only 20 and 46 mAh g−1 at 10C. [ABSTRACT FROM AUTHOR]

All-solid-state lithium-ion batteries (ASSLBs) have recently received significant attention due to their exceptional energy/power densities, inherent safety, and long-term electrochemical stability. However, to achieve energy- and power-dense ASSLBs, the cathode composite electrodes require optimum ionic and electrical pathways and hence the development of electrode designs that facilitate such requirements is necessary. Among the various available conductive materials, carbon black (CB) is typically considered as a suitable carbon additive for enhancing electrode conductivity due to its affordable price and electrical-network-enhancing properties. In this study, we examined the effect of different weight percentages (wt%) of nano-sized CB as a conductive additive within a cathode composite made up of Ni-rich cathode material (LiNi0.8Co0.1Mn0.1O2) and solid electrolyte (Li6PS5Cl). Composites including 3 wt%, 5 wt%, and 7 wt% CB were produced, achieving capacity retentions of 66.1%, 65.4%, and 44.6% over 50 cycles at 0.5 C. Despite an increase in electrical conductivity of the 7 wt% CB sample, a significantly lower capacity retention was observed. This was attributed to the increased resistance at the solid electrolyte/cathode material interface, resulting from the presence of excessive CB. This study confirms that an excessive amount of nano-sized conductive material can affect the interfacial resistance between the solid electrolyte and the cathode active material, which is ultimately more important to the electrochemical performance than the electrical pathways.

Abstract All‐solid‐state Li metal batteries (ASSLMBs) have been considered the most promising candidates for next‐generation energy storage devices owing to their high‐energy density and safety. However, some obstacles such as thick solid electrolyte (SSEs) and unstable interface between the solid‐state electrolytes (SSEs) and the electrodes have restricted the practical application of ASSLBs. Here, the scalable polyimide (PI) film reinforced asymmetric ultra‐thin (~20 μm) composite solid electrolyte (AU‐CSE) with a ceramic‐rich layer and polymer‐rich layer is fabricated by a both‐side casting method and rolling process. The ceramic‐rich layer not only acts as a “securer” to inhibit the lithium dendrite growth but also redistributes Li‐ions uniform deposition, while the polymer‐rich layer improves the compatibility with cathode materials. As a result, the obtained AU‐CSE demonstrates an ionic conductivity of 1.44 × 10−4 S cm−1 at 35°C. The PI‐reinforced AU‐CSE enables Li/Li symmetric cell stable cycling over 1200 h at 0.2 mA cm−2 and 0.2 mAh cm−2. Li/LiNi0.6Co0.2Mn0.2O2 and Li/LiFePO4 ASSLMBs achieve superior performances at 35°C. This study provides a new way of solving the interface problems between SSEs and electrodes and developing high‐energy‐density ASSLMBs for practical applications.

Li+ conduction in all-solid-state lithium batteries is limited compared with that in lithium-ion batteries based on liquid electrolytes because of the lack of an infiltrative network for Li+ transportation. Especially for the cathode, the practically available capacity is constrained due to the limited Li+ diffusivity. In this study, all-solid-state thin-film lithium batteries based on LiCoO2 thin films with varying thicknesses were fabricated and tested. To guide the cathode material development and cell design of all-solid-state lithium batteries, a one-dimensional model was utilized to explore the characteristic size for a cathode with varying Li+ diffusivity that would not constrain the available capacity. The results indicated that the available capacity of cathode materials was only 65.6% of the expected value when the area capacity was as high as 1.2 mAh/cm2. The uneven Li distribution in cathode thin films owing to the restricted Li+ diffusivity was revealed. The characteristic size for a cathode with varying Li+ diffusivity that would not constrain the available capacity was explored to guide the cathode material development and cell design of all-solid-state lithium batteries.

All-solid-state lithium batteries (ASSLBs) are promising for safety and high-energy-density large-scale energy storage. In this contribution, we propose a Li3−4xZrxPS4 (LZPS) by Zr-doped β-Li3PS4 (LPS) as a novel solid electrolyte (SE) for ASSLBs based on experimental and simulation methods. The structure, electronic property, mechanical property, and ionic transport properties of LZPS (x = 0, 0.03, 0.06, and 0.1) are investigated with first-principles calculations. Meanwhile, LZPS is prepared by solid states reaction method. By combining experimental analysis and first-principles calculations, it is confirmed that a small amount of Zr4+ can be successfully doped into the framework of β-LPS composites without significantly compromising structural integrity. When the Zr4+ concentration is x = 0.03, the doped material Li2.88Zr0.03PS4 exhibits the highest ionic conductivity (5.1 × 10−4 S·cm−1) at 30 °C, and the Li-ion migration energy barrier is the lowest. The Li2.88Zr0.03PS4 SE has obtained the best mechanical properties, the good ductility, and shear deformation resistance, which can better maintain the structural stability of the battery. In addition, the Li/Li symmetrical cell is assembled, which shows excellent electrochemical stability of electrolyte against lithium. The constructed all-solid-state batteries (LiCoO2-Li6PS5Cl|Li2.88Zr0.03PS4|Li-In) delivers an initial discharge capacity of 130.4 mAh·g−1 at 0.2 C and a capacity retention of 85.1% after 100 cycles at room temperature. This study provides a promising electrolyte for the application of ASSLBs with high ionic conductivity and excellent stability against lithium. [ABSTRACT FROM AUTHOR]

The stability of Li3.8Ge0.9S0.1O4 lithium-conducting solid electrolyte versus lithium metal and Li–V bronze Li1.3V3O8 is studied in the present research. Isothermal heat treatment and thermal analysis of the mixtures of Li1.3V3O8 and Li3.8Ge0.9S0.1O4 powders indicate that there is no interaction between them below 300–350 °C. Moreover, Li3.8Ge0.9S0.1O4 solid electrolyte is stable versus lithium at 100 °C for 240 h. A model of a lithium-ion power source with a Li1.3V3O8-based cathode and a lithium metal anode is assembled and tested. The data obtained show that Li3.8Ge0.9S0.1O4 can be used in all-solid-state medium-temperature lithium and lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Sulfide electrolytes with high ionic conductivities are one of the most highly sought for all‐solid‐state lithium batteries (ASSLBs). However, the non‐negligible electronic conductivities of sulfide electrolytes (≈10−8 S cm−1) lead to electron smooth transport through the sulfide electrolyte pellets, resulting in Li dendrite directly depositing at the grain boundaries (GBs) and serious self‐discharge. Here, a grain‐boundary electronic insulation (GBEI) strategy is proposed to block electron transport across the GBs, enabling Li−Li symmetric cells with 30 times longer cycling life and Li−LiCoO2 full cells with three times lower self‐discharging rate than pristine sulfide electrolytes. The Li−LiCoO2 ASSLBs deliver high capacity retention of 80 % at 650 cycles and stable cycling performance for over 2600 cycles at 0.5 mA cm−2. The innovation of the GBEI strategy provides a new direction to pursue high‐performance ASSLBs via tailoring the electronic conductivity. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries (ASSLBs), which are consisted of Li 5.5 PS 4.5 Cl 1.5 electrolyte, metal lithium anode and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NCM811) cathode, are speculated as a promising next generation energy storage system. However, the unstable oxide cathode/sulfide-based electrolyte interface and the dendrite formation in sulfide electrolyte using the lithium metal anode hinder severely commercialization of the ASSLBs. In this work, the dendrite formation in sulfide electrolyte is investigated in lithium symmetric cell by varying the stack pressure (3, 6, 12, 24 MPa) during uniaxial pressing, and uniformly nanosized LiAlO 2 buffer layer was carefully coated on NCM811 electrode (LiAlO 2 @NCM811) to improve the cathode/electrolyte interface stability. The result shows that lithium symmetrical cell has a steady voltage evolution over 400 h under 6 MPa stacking pressure, and the assembled LiAlO 2 @NCM811/Li 5.5 PS 4.5 Cl 1.5 /Li battery under the stack pressure of 6 MPa exhibits large initial discharge specific capacity and excellent cycling stability at 0.05 C and 25 °C. The feasibility of using the lithium metal anode in all-solid-state batteries (ASSBs) under suitable stack pressure combined with uniformly nanosized LiAlO 2 buffer layer coated on NCM811 electrode supply a facile and effective measures for constructing ASSLBs with high energy density and high safety. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aminopropyl triethoxysilane is introduced to tailor the organic/inorganic interfaces in the CSSE based on the –NH 2 effect. • The hydrogen bond interaction between –NH 2 and PEO can enhance the interface interaction. • Lone pair electrons on N can react with electron-deficient -CN in solvent ACN and promote the uniform dispersion of LLZAO. • Lone pair electrons on N can complex with Li+ and promote the dissociation of Li salts and uniform Li+ diffusion. Composite solid-state electrolyte (CSSE) with integrated strengths avoids the weaknesses of organic and inorganic electrolytes, and thus become a better choice for all-solid-state lithium battery (ASSLB). However, the poor dispersion of inorganic fillers and the organic/inorganic nature difference leads to their interface incompatibility, which greatly destroys the performance of CSSE and ASSLB. Herein, silane coupling agent (SCA) aminopropyl triethoxysilane (ATS) is introduced to tailor the organic/inorganic interfaces in CSSE by the common chemical bridging effect of SCA and the special amino effect (hydrogen bond and lone pair electron effects). It is found that the hydrogen bond interaction between –NH 2 and polyethylene oxide (PEO) enhances their interface interaction. And the lone pair electrons on nitrogen atom allow it to react with solvent acetonitrile and promote the uniform dispersion of ceramic fillers. Moreover, the lone pair electrons can complex with Li+, which promotes the dissociation of Li salts, uniforms Li+ diffusion and inhibits the Li dendrite. Thanks to the above merits, the interface compatibility and stability of organic/inorganic CSSE are much enhanced by innovatively introducing ATS, showing high ionic conductivity and superior mechanical/thermal stability. The ASSLB with this modified CSSE exhibits excellent electrochemical performance with a reversible capacity of 140.9 mAh g−1 and a capacity retention of 94.4% after 280 cycles. These achievements offer a new insight into improving the stability of organic/inorganic CSSE interface and promoting their applicability into ASSLB. [ABSTRACT FROM AUTHOR]