All-solid-state Lithium Batteries Research Articles

Dendrite-Free Li5.5PS4.5Cl1.5-Based All-Solid-State Lithium Battery Enabled by Grain Boundary Electronic Insulation Strategy through In Situ Polymer Encapsulation.

Sulfide-based all-solid-state lithium batteries (ASSLBs) have attracted unprecedented attention in the past decade due to their excellent safety performance and high energy storage density. However, the sulfide solid-state electrolytes (SSEs) as the core component of ASSLBs have a certain stiffness, which inevitably leads to the formation of pores and cracks during the production process. In addition, although sulfide SSEs have high ionic conductivity, the electrolytes are unstable to lithium metal and have non-negligible electronic conductivity, which severely limits their practical applications. Herein, a grain boundary electronic insulation strategy through in situ polymer encapsulation is proposed for this purpose. A polymer layer with insulating properties is applied to the surface of the Li5.5PS4.5Cl1.5 (LPSC) electrolyte particles by simple ball milling. In this way, we can not only achieve a dense electrolyte pellet but also improve the stability of the Li metal anode and reduce the electronic conductivity of LPSC. This strategy of electronic isolation of the grain boundaries enables stable deposition/stripping of the modified electrolyte for more than 2000 h at a current density of 0.5 mA cm-1 in a symmetrical Li/Li cell. With this strategy, a full cell with Li(Ni0.8Co0.1Mn0.1)O2 (NCM811) as the cathode shows high performance including high specific capacity, improved high-rate capability, and long-term stability. Therefore, this study presents a new strategy to achieve high-performance sulfide SSEs.

Regenerative Solid Interfaces Enhance High-Performance All-Solid-State Lithium Batteries.

The performance of all-solid-state lithium batteries (ASSLBs) is significantly impacted by lithium interfacial instability, which originates from the dynamic chemical, morphological, and mechanical changes during deep Li plating and stripping. In this study, we introduce a facile approach to generate a conductive and regenerative solid interface, enhancing both the Li interfacial stability and overall cell performance. The regenerative interface is primarily composed of nanosized lithium iodide (nano-LiI), which originates in situ from the adopted solid-state electrolyte (SSE). During cell operation, the nano-LiI interfacial layer can reversibly diffuse back and forth in synchronization with Li plating and stripping. The interface and dynamic process improve the adhesion and Li+ transport between the Li anode and SSE, facilitating uniform Li plating and stripping. As a result, the metallic Li anode operates stably for over 1000 h at high current densities and even under elevated temperatures. By using metallic Li as the anode directly, we demonstrate stable cycling of all-solid-state Li-sulfur batteries for over 250 cycles at an areal capacity of >2 mA h cm-2 and room temperature. This study offers insights into the design of regenerative and Li+-conductive interfaces to tackle solid interfacial challenges for high-performance ASSLBs.

Li5.5PS4.5Cl1.5-Based All-Solid-State Battery with a Silver Nanoparticle-Modified Graphite Anode for Improved Resistance to Overcharging and Increased Energy Density.

All-solid-state lithium batteries (ASSLBs) are attracting tremendous attention due to their improved safety and higher energy density. However, the use of a metallic lithium anode poses a major challenge due to its low stability and processability. Instead, the graphite anode exhibits high reversibility for the insertion/deinsertion of lithium ions, giving ASSLBs excellent cyclic stability but a lower energy density. To increase the energy density of ASSLBs with the graphite anode, it is necessary to lower the negative/positive (N/P) capacity ratio and to increase the charging voltage. These strategies bring new challenges to lithium metal plating and dendrite growth. Here, a nano-Ag-modified graphite composite electrode (Ag@Gr) is developed to overcome these shortcomings for Li5.5PS4.5Cl1.5-based ASSLBs. The Ag@Gr composite exhibits a strong ability to inhibit lithium metal plating and fast lithium-ion transport kinetics. Ag nanoparticles can accommodate excess Li, and the as-obtained Li-Ag alloy enhances the kinetics of the composite electrode. The ASSLB with the Li(Ni0.8Co0.1Mn0.1)O2 cathode and Ag@Gr anode achieves an energy density of 349 W h kg-1. The full cell using Ag@Gr with an N/P ratio of 0.6 also highlights the rate performance. This work provides a simple and effective method to regulate the charge transport kinetics of graphite anodes and improve the cyclic performance and energy density of ASSLBs.

Developments, Novel Concepts, and Challenges of Current Collectors: From Conventional Lithium Batteries to All‐Solid‐State Batteries

AbstractWith the innovation and evolution of lithium batteries, different active materials are loaded onto the current collectors, leading to remarkable changes in the components that directly interact with the current collectors. The surface/interface of current collectors in lithium batteries is gradually becoming one of the key factors to improve the overall performance. The thickness, material composition, surface morphology, and intrinsic properties of current collectors are crucial for understanding chemo‐mechanical changes during electrochemical reactions. Despite the widely acknowledged importance of highly efficient electron transportation and improved interfacial performance of current collectors as one of the determinants of exceptional lithium battery performance, insufficient attention has been given to exploring targeted design strategies for current collectors used in various lithium batteries. Particularly, as the development of solid‐state lithium batteries in full swing, there are limited studies focused on current collectors in all‐solid‐state lithium batteries (ASSLBs). This review introduces recent advancements in current collector technology, while highlighting both similarities and differences between negative current collectors applied in conventional lithium batteries and ASSLBs. Furthermore, we propose promising prospects for utilization of alloy materials as next‐generation negative current collectors.

UV Curved PESF-LLZTO Composite Solid Electrolyte to In Situ Construct Ultrastable Interface for All Solid-State Lithium Battery

Abstract Optimizing interfacial contact between electrolyte and electrode is one of key factors to achieve stable all solid state lithium batteries (ASSLBs). In this work, UV curving technique is reported to produce ASSLBs by in situ constructing integrated interface between PESF-LLZTO composite solid electrolytes (CSEs) and LiFePO4 (LFP) cathode. Benefiting from the integral structure and ultrastable properties of the as-prepared CSE/LFP interface, the obtained ASSLBs delivers an initial discharge specific capacities of 162.8 mAh g-1 at 0.1C and 30 oC, and successfully runs over 520 cycles at 0.5 C with a discharge capacity retention ratio of 96.3 %.

Constructing Robust LiF‐Enriched Interfaces in High‐Voltage Solid‐State Lithium Batteries Utilizing Tailored Oriented Ceramic Fiber Electrolytes

AbstractThe pursuit of high‐performance energy storage devices has fueled significant advancements in the all‐solid‐state lithium batteries (ASSLBs). One of the strategies to enhance the performance of ASSLBs, especially concerning high‐voltage cathodes, is optimizing the structure of composite polymer electrolytes (CPEs). This study fabricates a high‐oriented framework of Li6.4La3Zr2Al0.2O12 (o‐LLZO) ceramic nanofibers, meticulously addressing challenges in both the Li metal anode and the high‐voltage LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode. The as‐constructed electrolyte features a highly efficient Li+ transport and robust mechanical network, enhancing both electron and ion transport, ensuring uniform current density distribution, and stress distribution, and effectively suppressing Li dendrite growth. Remarkably, the Li symmetric cells exhibit outstanding long‐term lifespan of 9800 h at 0.1 mA cm−2 and operate effectively over 800 h even at 1.0 mA cm−2 under 30 °C. The CPEs design results from the formation of a gradient LiF‐riched SEI and CEI film at the Li/electrolyte/NCM811 dual interfaces, enhancing ion conduction and maintaining electrode integrity. The coin‐cells and pouch cells demonstrate prolonged cycling stability and superior capacity retention. This study sets a notable precedent in advancing high‐energy ASSLBs.

Dry-processed technology for flexible and high-performance FeS2-based all-solid-state lithium batteries at low stack pressure

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 FeS2-based ASSLBs under low stack pressure by utilizing polytetrafluoroethylene (PTFE) binder. In this design, fibrous PTFE interweaves Li6PS5Cl particles and FeS2 cathode components, forming flexible electrolyte and composite cathode membranes. Beneficial to the robust adhesion, the composite cathode and Li6PS5Cl 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 FeS2-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 (Li2S and Fe) to the ion–electron conductive network in the composite cathode, thereby preventing the electrochemical inactivation of products and enhancing electrochemical performance. Furthermore, FeS2-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.

The effect of garnet content on the microstructure and electrochemical properties of PEO/garnet composite electrolyte

Solid-state lithium-metal batteries are one of the best candidates for next-generation energy storage devices. However, their applications are hindered by the low ionic conductivity at room temperature and the inadequate interfacial compatibility of solid-state electrolytes (SSEs). Hence, an organic/inorganic composite solid electrolyte (CSE) of Li6.25Ga0.25La3Zr2O12 (LGLZO)/polyethylene oxide (PEO) films were constructed. It's found that the crystallinity of CSE is significantly reduced and the ionic conductivity is increased to 3.57 × 10−4 S cm−1 at room temperature, which is about 60 times higher than that of the pure PEO.And the interfacial impedance is 243.84 Ω cm2, electrochemical window of 5.1 V. The assembled Li symmetric battery has excellent cycling stability more than 1000 h at 0.15 mA cm−2. The Li/PEO-LiTFSI-60 wt% LGLZO/LiFePO4 (LFP) all solid-state lithium batteries (ASSLBs) also delivers superior electrochemical performances. This work can provide a reference for the development and real-world implementation of ASSLBs at room temperature.

High-performance all-solid-state lithium batteries enabled by high-conductivity free-standing sulfide electrolyte membrane and Li-Zn/LiCl bifunctional interphase

All-solid-state lithium batteries (ASSLBs) empolying sulfide solid electrolyte and lithium metal anode can afford improved energy density and safety. However, their large-scale application is hampered by the rigidity of ceramic–based electrolyte and the inevitable growth of lithium dendrites. Herein, a novel, flexible, high-conductivity and free-standing sulfide electrolyte membrane (Li6PS5Cl-polypropylene carbonate6, (LPSCl-PPC6)) with a thickness of 60 μm is prepared via methodology of blade coating and hot pressing, which exhibits a high Li+ conductivity (3.1 × 10−3 S cm−1 at 25 °C) and a wide electrochemical window (4.7 V vs Li+/Li) at 25 °C. Additionally, a bifunctional interphase with Li-Zn/LiCl is implanted on lithium metal surface to enhance the stability of electrolyte/lithium anode, which effectively prevents the growth of lithium dendrites and the internal short circuit of lithium symmetric battery. Benefiting from the synergistic effect, the assembled ASSLBs of S-CNTs/LPSCl-PPC6/Li-Zn/LiCl|Li and LLZO@NCM93/LPSCl-PPC6/Li-Zn/LiCl|Li exhibit high initial capacity of 1183.5 mAh g−1 (193.6 mAh g−1) and exceptionally cyclic stability with capacity retention of 89.2% over 150 cycles at 0.05C (93.2% over 100 cycles at 0.1C). This highly conductive sulfide-based composite electrolyte and interface engineering provides a promising strategy for achieving high performance ASSLBs.

Enhanced all-solid-state battery performance through in-situ construction of interface modification layer

The development of high-performance all-solid-state lithium batteries (ASSLBs) relies on improving the interface stability between layered oxide cathodes and sulfide electrolytes, as well as the structural stability of cathode active materials. While coating technology is considered an effective solution, the fabrication of these coating materials using economically viable and scalable manufacturing processes remains a comprehensive and challenging task. In this study, a combination of first-principles calculations and experiments is employed to propose, for the first time, a simple and scalable aqueous process to in-situ construct an Li3VO4 (LVO) buffer coating on the surface of LiCoO2(LCO) cathode, which exhibits high ionic conductivity, relatively low electronic conductivity, and high oxidation limit. The LVO buffering coating not only facilitates the migration of lithium ions at the interface, effectively suppresses interface side reactions, and reduces interface impedance, but also enhances the mechanical and structural stability of the cathode material. As a result, the LCO/LPSC/Li-In ASSLBs with 2% LVO coating exhibit an initial discharge capacity of up to 145.6 mAh g−1 at room temperature (0.1C), with a capacity retention of 94.89% after 100 cycles. Furthermore, the ASSLBs demonstrate good capacity and cycle stability under extreme testing conditions, including high voltage, high temperature, and low temperature, especially exhibiting an initial discharge capacity of up to 114.9 mAh g−1 at −20 °C.

Improved interfacial contact and electrochemical performance of highly Ni-rich LiNixCoyMn1-x-yO2 (x>90%) cathode in all-solid-state lithium battery

Single-crystal LiNixCoyMn1-x-yO2 (SC-NCM) cathodes design is an effective solution for enhancing electrochemical performance of all-solid-state lithium battery (ASSLBs). For highly Ni-rich SC cathode (Ni>90 %), the accumulation of local stress caused by anisotropic lattice shrinkage at deeply charging state is more destructive, and even SC-NCM design can not prevent the structure damage and interfacial contact failure between cathode and solid electrolyte (SE). In this work, small-size single-crystal design and Al-doping strategy are firstly combined to synthesize LiNi0.91Co0.04Mn0.04Al0.01O2 (S-SC-NCMA) cathode. Electrochemistry test, CP-SEM, GITT and in-situ EIS techniques are combined to reveal the interfacial evolution of cathode/SE. The kinetic limitation caused by local contact failure of cathode/SE and the formation of intergranular crack under high voltage are the main reason for capacity loss of ASSLBs. Small-size single-crystal design can reduce the volumetric strain effect and Al-doping strategy can further inhibit lattice shrinkage to improve contact. This work provides an effective cathode modification strategy for highly Ni-rich NCM (Ni>90 %) cathode to improve high-voltage performance of sulfide-based ASSLBs.

Li10GeP2S12-based solid electrolyte induced by high pressure for all-solid-state batteries: A facile strategy of low-grain-boundary-resistance

Solid electrolytes (SEs) with high ionic conductivity are crucial for the collaborative design of high-performance all-solid-state lithium batteries (ASSLBs). Besides the common element substitution and doping, it is anticipated that there is still room for pressure to improve ionic conductivity in SEs by modifying their crystal structure and microstructure. Herein, we applied in-situ high pressure to monitor the effect of compression on the structure–property relation in Li10GeP2S12 (LGPS). The lattice contraction (<2%) of LG was monitored within 2 GPa, which does not affect the optimal size of the ionic channel. In contrast to the fact that the grain resistance can be markedly decreased by low pressing, grain boundary resistance is found to be minimized by virtue of 1.5 GPa, and accordingly, interfacial Li± ionic diffusion between flexible grain bodies and electrode surface is primarily facilitated by enhancing the charge carrier mobility. In addition, we report for the first time that powder LGPS could be pressed as a ceramic-sulfide pellet without breakage under 1.5 GPa and assembled as a solid electrolyte within the LiFePO4/Li10GeP2S12/Li configuration of ASSLBs. This cell exhibits improved capacity and cycling stability compared to the cell using no-pressure-treated electrolyte. The present study advances our understanding of solid electrolytes and provides an important framework for developing high-performance ASSLBs with low fabrication costs in the future.

Research Progress on the Composite Methods of Composite Electrolytes for Solid-State Lithium Batteries.

In the current challenging energy storage and conversion landscape, solid-state lithium metal batteries with high energy conversion efficiency, high energy density, and high safety stand out. Due to the limitations of material properties, it is difficult to achieve the ideal requirements of solid electrolytes with a single-phase electrolyte. A composite solid electrolyte is composed of two or more different materials. Composite electrolytes can simultaneously offer the advantages of multiple materials. Through different composite methods, the merits of various materials can be incorporated into the most essential part of the battery in a specific form. Currently, more and more researchers are focusing on composite methods for combining components in composite electrolytes. The ion transport capacity, interface stability, machinability, and safety of electrolytes can be significantly improved by selecting appropriate composite methods. This review summarizes the composite methods used for the components of composite electrolytes, such as filler blending, embedded framework, and multilayer bonding. It also discusses the future development trends of all-solid-state lithium batteries (ASSLBs).

Build a High‐Performance All‐Solid‐State Lithium Battery through Introducing Competitive Coordination Induction Effect in Polymer‐Based Electrolyte

AbstractPolymer‐inorganic composite electrolytes (PICE) have attracted tremendous attention in all‐solid‐state lithium batteries (ASSLBs) due to facile processability. However, the poor Li+ conductivity at room temperature (RT) and interfacial instability severely hamper the practical application. Herein, we propose a concept of competitive coordination induction effects (CCIE) and reveal the essential correlation between the local coordination structure and the interfacial chemistry in PEO‐based PICE. CCIE introduction greatly enhances the ionic conductivity and electrochemical performances of ASSLBs at 30 °C. Owing to the competitive coordination (Cs+…TFSI−…Li+, Cs+…C−O−C…Li+ and 2,4,6‐TFA…Li…TFSI−) from the competitive cation (Cs+ from CsPF6) and molecule (2,4,6‐TFA: 2,4,6‐trifluoroaniline), a multimodal weak coordination environment of Li+ is constructed enabling a high efficient Li+ migration at 30 °C (Li+ conductivity: 6.25×10−4 S cm−1; tLi+=0.61). Since Cs+ tends to be enriched at the interface, TFSI− and PF6− in situ form LiF‐Li3N‐Li2O‐Li2S enriched solid electrolyte interface with electrostatic shielding effects. The assembled ASSLBs without adding interfacial wetting agent exhibit outstanding rate capability (LiFePO4: 147.44 mAh g−1@1 C and 107.41mAhg−1@2 C) and cycling stability at 30 °C (LiFePO4:94.65 %@200cycles@0.5 C; LiNi0.5Co0.2Mn0.3O2: 94.31 %@200 cycles@0.3 C). This work proposes a concept of CCIE and reveals its mechanism in designing PICE with high ionic conductivity as well as high interfacial compatibility at near RT for high‐performance ASSLBs.

Build a High-Performance All-Solid-State Lithium Battery through Introducing Competitive Coordination Induction Effect in Polymer-Based Electrolyte.

Polymer-inorganic composite electrolytes (PICE) have attracted tremendous attention in all-solid-state lithium batteries (ASSLBs) due to facile processability. However, the poor Li+ conductivity at room temperature (RT) and interfacial instability severely hamper the practical application. Herein, we propose a concept of competitive coordination induction effects (CCIE) and reveal the essential correlation between the local coordination structure and the interfacial chemistry in PEO-based PICE. CCIE introduction greatly enhances the ionic conductivity and electrochemical performances of ASSLBs at 30 °C. Owing to the competitive coordination (Cs+…TFSI-…Li+, Cs+…C-O-C…Li+ and 2,4,6-TFA…Li…TFSI-) from the competitive cation (Cs+ from CsPF6) and molecule (2,4,6-TFA: 2,4,6-trifluoroaniline), a multimodal weak coordination environment of Li+ is constructed enabling a high efficient Li+ migration at 30 °C (Li+ conductivity: 6.25×10-4 S cm-1; tLi +=0.61). Since Cs+ tends to be enriched at the interface, TFSI- and PF6 - in situ form LiF-Li3N-Li2O-Li2S enriched solid electrolyte interface with electrostatic shielding effects. The assembled ASSLBs without adding interfacial wetting agent exhibit outstanding rate capability (LiFePO4: 147.44 mAh g-1@1 C and 107.41mAhg-1@2 C) and cycling stability at 30 °C (LiFePO4:94.65 %@200cycles@0.5 C; LiNi0.5Co0.2Mn0.3O2: 94.31 %@200 cycles@0.3 C). This work proposes a concept of CCIE and reveals its mechanism in designing PICE with high ionic conductivity as well as high interfacial compatibility at near RT for high-performance ASSLBs.

Vertically-Aligned Card-House Structure for Composite Solid Polymer Electrolyte with Fast and Stable Ion Transport Channels.

All-solid-state lithium batteries (ASSLBs) are highly promising as next-generation energy storage devices owing to their potential for great safety and high energy density. This work demonstrates that composite solid polymer electrolyte with vertically-aligned card-house structure can simultaneously improve the high rate and long-term cycling performance of ASSLBs. The vertical alignment of laponite nanosheets creates fast and uniform Li+ ion transport channels at the nanosheets/polymer interphase, resulting in high ionic conductivity of 8.9 × 10-4 S cm-1 and Li+ transference number of 0.32 at 60°C, as well as uniformly distributed solid electrolyte interphase. Such electrolyte is characterized by high mechanical strength, low flammability, excellent structural stability and stable ion transport channels. In addition, the ASSLB cell with the electrolyte and LiFePO4 cathode delivers a high discharge specific capacity of 124.8 mAh g-1 , which accounts for 85.6% of its initial capacity after 500 cycles at 1C. The reasonable design through structural control strategy by interconnecting the vertically-aligned nanosheets open a way to fabricate high performance composite solid polymer electrolytes.

Detection of a Cobalt-Containing Interphase at the Li6PS5Cl-NMC111 Interface by In Situ μXANES and EIS

Sulfide electrolyte all-solid-state lithium batteries (ASLBs) with uncoated Li-NixMnyCo1−x−yO2 (NMC) cathodes suffer from a large capacity loss during initial cycling and an increase in cell impedance. Decomposition reactions are known to occur at the Li6PS5Cl-NMC111 interface due to incompatibility between the two materials. If a stabilizing coating is applied to the NMC, it delivers full capacity during initial charge. However, the loss in capacity during discharge still occurs. The interface was studied by μXANES and through EIS analysis. A chemically-formed interphase was detected by μXANES, evident from reduction of Co at an uncoated NMC particle surface. This interphase was produced by decomposition at rest. To study the effect of the interphase on electrochemically active surface area, piecewise in situ EIS was performed and the data was modeled using a transmission line model (TLM). The charge transfer resistance RCT was used to estimate the volume specific active surface area (aact). The median value for aact was 296 cm−1, a factor of 7.5 lower than the theoretical value of 2216 cm−1. This provided evidence of a lower electrochemically active surface area in the ASLB.

Efficient Ion Percolating Network for High-Performance All-Solid-State Cathodes.

All-solid-state lithium batteries (ASSLBs) face critical challenges of low cathode loading and poor rate performances, which handicaps their energy/power densities. The widely-accepted aim of high ionic conductivity and low interfacial resistance seems insufficient to overcome these challenges. Here, it is revealed that an efficient ion percolating network in the cathode exerts a more critical influence on the electrochemical performance of ASSLBs. By constructing vertical alignment of Li0.35 La0.55 TiO3 nanowires (LLTO NWs) in solid-state cathode through magnetic manipulation, the ionic conductivity of the cathode increases twice compared with the cathode consisted of randomly distributed LLTO NWs. The all-solid-state LiFePO4 /Li cells using poly(ethylene oxide) as the electrolyte is able to deliver high capacities of 151mAhg-1 (2C) and 100mAhg-1 (5C) at 60°C, and a room-temperature capacity of 108mAhg-1 can be achieved at a charging rate of 2C. Furthermore, the cell can reach a high areal capacity of 3mAhcm-2 even with a practical LFP loading of 20mgcm-2 . The universality of this strategy is also presented showing the demonstration in LiNi0.8 Co0.1 Mn0.1 O2 cathodes. This work offers new pathways for designing ASSLBs with improved energy/power densities.

Experimental and Computational Study of Mg and Ta‐Doped Li7La3Zr2O12 Garnet‐Type Solid Electrolytes for All‐Solid‐State Lithium Batteries

AbstractGarnet‐type Li7La3Zr2O12 electrolytes have garnered significant attention as promising solid‐state electrolyte candidates in all‐solid‐state lithium batteries (ASSLBs). However, its susceptibility to forming Li2CO3 upon atmospheric exposure leads to performance degradation, limiting its application. This study introduces a co‐doping strategy of Mg and Ta to enhance the properties of garnet electrolytes. Pure cubic Mg and Ta‐doped LLZO electrolytes are successfully synthesized using the solid‐state reaction method. Experimental results, coupled with density functional theory (DFT) calculation, reveal that Mg2+ doping occurs primarily at the La site (24c). This substitution, given the substantial disparity in ionic radii between Mg2+ and La3+, effectively narrows the transport bottleneck for Li‐ions, resulting in a decreased ionic conductivity and an increased activation energy. Li6.6La2.8Mg0.2Zr1.4Ta0.6O12 exhibits a relative density of ≈92.6%, demonstrating outstanding performance with a room temperature ionic conductivity of 4.31 × 10−4 S cm−1 and low electronic conductivity of 2.48 × 10−8 S cm−1. Notably, after 4 months of atmospheric exposure, its ionic conductivity decreased to ≈78% of the initial value, attributable to Li2CO3 formation. Furthermore, the material demonstrated exceptional long‐term cycle stability over 1000 h at a current density of 0.1 mA cm−2 at 25 °C, indicating effective suppression of Li dendrite formation.

High‐Entropy Argyrodite‐Type Sulfide Electrolyte with High Conductivity and Electro‐Chemo‐Mechanical Stability for Fast‐Charging All‐Solid‐State Batteries

AbstractInorganic solid electrolytes offer inherently unique transport, thermal, and mechanical attributes that can potentially address the fast‐charging barriers of safety, performance, and degradation exhibited by their liquid counterparts; however, to achieve reliable fast charging while retaining long cycle life remains a challenge for all‐solid‐state lithium batteries (ASSLBs), which is hindered by the electro‐chemo‐mechanical and transport issues at solid–solid interface. Herein, a high‐entropy strategy is reported to design ideal argyrodite electrolytes for fast‐charging ASSLBs with boosted transport kinetics and mitigated electrolyte‐electrode reactions via anionic site disordering. As proof of concept, multiple aliovalent cations (Si4+/Ge4+/Sn4+) and anions (Cl−) are introduced to Li6PS5Br (LPSBr) to prepare its high‐entropy counterpart, HE‐LPSBrCl. As the configuration entropy increases from 1.35 to 2.29 R, the disordering increases by 6.83‐fold and ionic conductivity increases by nearly one order of magnitude (7.96 mS cm−1 at 30 °C for HE‐LPSBrCl). The HE‐LPSBrCl full cells deliver a high capacity of 67.7 mA h g−1 at 10 C, 61.5 times higher than that of LPSBr counterparts, and retain 85.6% of the capacity (96.2 mA h g−1 at 5 C) after 1400 cycles. Unwanted mechanical penetration of Li and interfacial delamination and particle cracking of composite cathode at high rates are successfully suppressed.