Conventional lithium-ion batteries with graphite anodes and flammable liquid electrolytes face energy density and safety limitations. All-solid-state batteries (ASSBs) offer improved safety but suffer from lithium dendrite growth and interfacial instability. Here, a LiAl solid solution anode is developed via melting isothermal processing and compaction. Among the compositions tested (LiAl-1:3, LiAl-1:4, and LiAl-1:5), LiAl-1:4 delivers optimal performance. Symmetric cells achieve a critical deposition current density of 1.35 mA cm(-2) and stable cycling for 800 h at 3 mA cm(-2). Full cells with LiNi0.9Co0.05Mn0.05O2 cathodes exhibit high-rate capability (110.4 mAh g(-1) at 30C) and outstanding longevity: 89.1% capacity retention after 1000 cycles at 1C (8.34 mg cm(-2)), over 17 000 cycles at 20C, and 12 000 cycles at 100C (2.29 mg cm(-2)). Characterization reveals that uniform Al distribution and a porous structure suppress dendrites and stabilize interfaces, while surface Li2O enhances Li+ transport. This work establishes design principles for high-power ASSBs via stoichiometric and microstructural optimization.

All-solid-state batteries (ASSBs) require solid electrolytes with both high ionic conductivity and favorable mechanical properties to maintain intimate interfacial contact with electrode particles during cycling. Herein, we report a new silicon-based solid electrolyte, Li2SiI4O, designed through theoretical calculations and subsequently synthesized experimentally. For an ideal amorphous deep-eutectic Li2SiI4O system, theoretical calculations predict a Young's modulus below 5 GPa, suggesting excellent mechanical compliance and potential plasticity. Indeed, the experimentally synthesized Li2SiI4O exhibits a Young's modulus of 19.8 GPa, lower than that of typical sulfide solid electrolytes with Young's modulus of approximately 23 GPa. This relatively low modulus is expected to improve interfacial contact between the active electrode materials and the solid electrolyte, resembling the conformal contact commonly observed at solid–liquid interfaces. Electrochemical impedance spectroscopy measurements show that Li2SiI4O exhibits an ionic conductivity of 1.23 × 10−4 S/cm at room temperature. When employed as the solid electrolyte in ASSBs, the assembled cells deliver stable cycling performance with 80% capacity retention after 800 cycles. These results demonstrate that Li2SiI4O is a promising solid electrolyte candidate for practical ASSBs by combining favorable mechanical compliance with stable electrochemical performance.

ABSTRACT The capacity utilization of all‐solid‐state sulfur cathodes reveals a significant disparity between material and electrode levels due to the high proportion of inactive components required for electro‐ionic transport. While the all‐electrochem‐active (AEA) electrode concept seeks to bridge this gap, fully realizing the energy‐density potential of sulfur‐based cathodes remains challenging. Here, we report a new strategy for co‐modulating the redox of the transition‐metal cation/sulfur anion to unlock the potential of the sulfur‐based electrode. By carefully adjusting the coordination between S anions and Ti cations, we constructed the AEA electrode with S‐anion (TiS x , x > 2)/Ti‐cation (amorphous TiS 2 ) co‐redox, where TiS x activates the redox activity of sulfur‐rich phases with narrower bandgaps through the reversible cleavage and recombination of S–S bonds, thereby enhancing the capacity utilization of anion‐redox in the electrode level, and amorphous TiS 2 serves as an electrochemically active matrix facilitating mixed ionic‐electronic conduction. This design eliminates inactive components and enables synergistic anion‐cation redox chemistry. Consequently, this designed cathode achieves an unprecedented electrode‐level energy density of 1829 Wh/kg, sustains an areal capacity of 11.6 mAh/cm 2 , and exhibits long‐term stability over 10 000 h. Device‐level demonstrations validate this synergistic approach as an effective design principle for realizing high‐energy‐density, long‐life all‐solid‐state battery cathodes under practical conditions.

Lithium metal batteries (LMBs) with gel polymer electrolytes (GPEs) are considered promising candidates for high energy-density batteries due to their high theoretical capacity and cost effectiveness. However, the complexity of the solvation structure of GPEs and their inherent flammability make it difficult for them to be widely applied. Here, we propose a strategy for reconfiguring the lithium-ion solvation structure. Based on this strategy, we designed a thermally polymerized, flame-retardant dual salt gel polymer electrolyte (TD-GPE) with controllable solvation structure and high safety. This electrolyte not only weakens the binding effect of polymer chain segments and solvated molecules on the lithium-ion, enhancing the kinetic transmission of lithium-ion in the batteries, but also further strengthens the compatibility of the electrode and electrolyte interphase, while having a certain fire-resistant effect. The battery with this electrolyte showed low-capacity degradation after 300 cycles, demonstrating excellent reversibility. Moreover, this electrolyte did not catch fire or explode during the entire process of the nail penetration test, demonstrating excellent safety. This strategy paves a new way for designing gel polymer electrolytes suitable for high safety and excellent reversible LMBs.

High-capacity Li-rich oxides are promising next-generation cathode materials for high-energy-density lithium-ion batteries. Significant efforts have been devoted to developing high-performance Li-rich cathodes, including both layered (LLRO) and disordered rock-salt (DRX) variants. However, their multiscale structural complexity, particularly associated with anionic redox reactions (ARR), has hindered a comprehensive understanding of the underlying mechanisms. Addressing these challenges requires advanced spectroscopic and structural characterization techniques that are sensitive to light elements and local atomic environments. In this Feature Article, we present our recent work employing two cutting-edge methods, resonant inelastic X-ray scattering (RIXS) and neutron pair distribution function (nPDF) analysis, to elucidate the structure-property relationships governing redox behavior and lithium diffusion in LLRO and DRX cathodes. We specifically examine ARR from a structural perspective, encompassing spectroscopic identification, local oxygen coordination, distorted oxygen pairs and spatial distribution of redox-active species. Furthermore, by combining nPDF with reverse Monte Carlo (RMC) modeling, we reveal the Li diffusion mechanisms in DRX materials across multiple scales, from local hopping channels and short-range ordering to long-range percolation pathways. These insights provide a foundation for the rational design of high-capacity and structurally stable oxide cathodes, and underscore the essential role of advanced characterization techniques in accelerating future battery research.

Na-ion batteries are promising energy storage technologies, yet cathodes suffer from structural instability during deep cycling, leading to a trade-off between energy density and long-term life. Here, we introduce a "local electron density engineering" strategy to address this intrinsic challenge. We propose that structural degradation originates from the withdrawal of electron density from lattice oxygen by a high-valence transition metal. By incorporating stable d10 (Zn2+) and d0 (Ti4+) ions, we create an electron-rich oxygen framework that acts as an "electron buffer", resisting this electron depletion. Reinforced further by Ca2+ pillars in the Na+ layers, our single-crystalline Na0.96Ca0.02Cu0.038Zn0.053Ni0.409Mn0.315Ti0.185O2 cathode exhibits a low volume change of similar to 4% under deep desodiation. In 26700 cylindrical full cells, it delivers an energy density of 181.2 Wh kg-1 and retains similar to 80% capacity rentention after 1000 cycles. These results establish a new design pathway for developing ultrastable, high-energy cathode materials for next-generation Na-ion batteries.

The precise control of sulfide solid electrolyte (SSE) particle size distribution is crucial for constructing efficient ion-conducting networks in composite cathodes of all-solid-state lithium metal batteries (ASSLBs). This work systematically investigates the effects of key particle size parameters (D10, D50, D90) of Li6PS5Cl SSE on battery performance through controlled mechanical grinding. In this study, the optimal SSE particle size composition enables exceptional electrochemical performance of ASSLB: a high reversible capacity of 202.2 mAh/g at 0.25C, superior rate capability (76% capacity retention of 5C/0.25C), and outstanding cyclability (81.5% and 80% capacity retention after 4000 cycles at 3C and 5C, respectively). Microstructural analysis indicates that the optimized SSE particle configuration, when 7.3 ≤ D50Cathode/D50SSE and 2.0 ≤ D90Cathode/D90SSE ≤ 3.5, forms a hierarchical ion-conducting network. In this configuration, the fine particles of SSE in the composite cathode can effectively fill the cathode gaps, while the medium-sized particles can provide rapid ion transport channels, resulting in excellent rate performance and reversible capacity. Larger electrolyte particles will lead to insufficient interfacial contact and "island-like" ion transport paths. Additionally, excessively lowering D90 will also result in reduced battery performance (3.5 ≤ D90C/D90SE). This study provides quantitative guiding principles for SSE particle engineering.

Sulfide solid-state electrolytes (SSEs) for all-solid-state lithium batteries (ASSLBs) have garnered significant attention due to their ultra-high ionic conductivity and favorable processing characteristics. However, their widespread adoption is severely hampered by poor compatibility with lithium metal and inadequate air stability. Herein, we develop a novel solid electrolyte, Ultra-efficient and stable Janus interface to construct high-performance sulfide-based ASSLBs (LPSC-NdO), which simultaneously achieves high ionic conductivity (8.75 mS cm-1) and outstanding electrochemical stability. This SSE demonstrates exceptional interfacial compatibility for a critical current density of 6.62mAcm-2 and stable lithium plating/stripping for over 2000 hours in symmetric cells. Full ASSLBs employing LiCoO2 (LCO) cathode exhibit remarkable cycling stability, with 95.4% capacity retention after 1000 cycles at 1C. Moreover, LPSC-NdO possesses excellent air stability, releasing only a minimal amount of H2S (0.67 cm3 g-1) upon exposure to moisture. This work presents a feasible co-doping strategy for sulfide SSEs, offering useful insights for developing SSEs that balance air stability and lithium metal interfacial compatibility toward practical-oriented development.

Safety is the most basic requirement for the application of rechargeable batteries in large-scale energy storage. Despite extensive efforts in developing non-flammable electrolytes, the elimination of thermal runaway in ampere-hour-level cells remains unachieved, while the correlation between electrolyte flame retardancy and battery safety is still unclear. Here we propose a polymerizable and non-flammable electrolyte, which leverages the synergistic anion-cation solvation effect and undergoes thermally triggered polymerization. The optimized electrode-electrolyte interfacial and a cross-linked barrier were obtained to prevent mechanical/chemical interactions between the electrodes and impede the side reactions/reductive gases generation, leading to no thermal runaway in ampere-hour-level cells. The nail-penetration tests were also passed without smoke, fire or explosion. This work brings an insight of the battery safety beyond non-flammable electrolyte design and paves the way towards safer and more efficient battery systems for energy storage.

All-solid-state Na-ion batteries (ASSNIBs) are promising for enhanced safety and energy density, but hard carbon (HC) anodes suffer from limited Na+ transport and require high electrolyte content (>30 wt %) and pressure (>1 MPa) in inorganic systems. Herein, a polymer-HC composite anode (PEO@HC) with only 5 wt % polyethylene oxide (PEO) is developed, enabling high HC loading (90 wt %) and efficient Na+ conduction under low pressure (<0.2 MPa). Synchrotron nano-CT and Small-angle X-ray scattering (SAXS) revealed a uniform PEO coating on the HC surface, reducing defects and modifying pore structures for improved ion kinetics. In Na|PEO-ASPE-Na|PEO@HC half-cells, PEO@HC delivers a high initial Coulombic efficiency (86.3 %) and reversible capacity (295.5 mAh g(-1) at 0.1C), comparable to liquid-electrolyte counterparts. The first reported pouch-type ASSNIB (PEO@HC|PEO-ASPE-Na|PEO@NVP) achieves 81 % capacity retention after 500 cycles at 0.1C. This polymer-based strategy overcomes interfacial challenges, paving the way for practical ASSNIBs in electric vehicles and stationary storage.

Thermal runaway remains the foremost safety challenge in lithium-ion batteries, spurring intensive research into its root causes and the development of intrinsic fail-safe mitigation strategies. Among the emerging strategies, thermoresponsive self-blocking electrolytes and separators represent a promising class of engineered materials whose ionic conductivity or porous microstructure undergoes rapid modulation in response to thermal excursions. By autonomously suppressing ion transport at elevated temperatures, these smart components can effectively interrupt electrochemical reactions before thermal propagation leads to catastrophic failure, thereby enabling intrinsically safe battery operation. This review critically examines the latest progress in such thermoresponsive self-blocking electrolytes and separators, emphasizing the molecular and structural design principles, underlying thermal-response mechanisms (e.g., phase transitions, pore collapse, and sol-gel switching), and their electrochemical performance in lithium battery configurations. Although these innovations have significantly advanced the field of battery safety, challenges persist in balancing a rapid thermal response with long-term interfacial stability and ionic conductivity. We outline key hurdles and propose future directions for developing multi-functional, intelligent architectures that concurrently enhance the safety and electrochemical performance, paving the way for the reliable deployment of high-energy-density batteries in electric vehicles, portable electronics, and grid-scale storage.

The development of lithium-ion battery cathode materials with higher energy density and longer cycle life is critical for advanced energy storage systems. Layered oxides are promising candidates due to their high theoretical capacity, superior cycling stability, and cost-effectiveness. However, conventional polycrystalline cathodes exhibit severe performance degradation under prolonged cycling and high-voltage operation, necessitating innovative material design strategies. Single-crystal materials, characterized by their well-defined morphological features, demonstrate distinct advantages including enhanced mechanical stability, low surface area, reduced grain boundary density, and exceptional cycling stability, effectively suppressing crack propagation and parasitic side reactions during electrochemical cycling. Nevertheless, challenges persist in single-crystal systems, including limited lithium-ion diffusion kinetics and intragranular crack formation. This review systematically summarizes the characteristics of single-crystal materials from four key aspects: synthesis methodologies, morphological control, electrochemical performance advantages, and modification strategies, establishing fundamental principles for rational material design. This work further extends the discussion to Na-ion battery systems, demonstrating the universal applicability of single-crystal engineering across battery chemistries. Finally, we outline future research directions for engineering high-performance single-crystal cathode materials, providing actionable insights for next-generation energy storage systems.

The commercialization of liquid lithium-ion batteries has revolutionized the consumer electronics industry. However, conventional lithium-ion batteries with graphite anodes and organic electrolytes are approaching their intrinsic performance limits and struggle to meet the growing demands for higher energy density, reliability, and safety in electric vehicles and large-scale energy storage. Solid-state batteries utilizing lithium or sodium metal anodes are considered promising next-generation energy storage solutions. Despite this potential, the formation of dendrites during charge–discharge cycling remains a critical challenge. Dendrite growth can initiate a destructive feedback loop of crack propagation and further dendrite intrusion, ultimately leading to battery failure and performance degradation. Previous studies have predominantly focused on single physical domains, such as electrochemical, stress, or thermal fields. However, such single-physics approach limits the understanding of dendrite evolution under realistic, coupled multiphysics conditions. This review first compares the morphological characteristics of dendrites in liquid and solid-state metal batteries. It then critically examines the key factors and predictive models of dendrite formation, initially from single-physics and subsequently from an integrated multiphysics perspective. Finally, strategies for mitigating dendrite growth via multiphysics field regulation are summarized. By establishing a comprehensive framework that integrates morphology evolution, multiphysics modeling, and suppression strategies, this work provides a foundational theoretical understanding for addressing dendrite formation in solid-state lithium and sodium metal batteries.

All-solid-state lithium batteries (ASSLBs) face critical challenges in practical applications due to excessive stack pressure requirements and interfacial degradation. To solve the solid-solid interfacial contact problem, we propose a dual interfacial engineering strategy combining nano-engineered Li6-xPS5-xCl1+x (LPSCl) electrolytes (D50 = 0.36 mu m) with a self-adaptive polyethylene-vinyl acetate/lithium difluoro(oxalato)borate (PEVA-LiDFOB) composite glue. This design establishes robust ionic networks while dynamically maintaining interfacial integrity through viscoelastic stress accommodation. The interfacial electrochemical stability on the cathode side is significantly enhanced, and the interfacial side reactions are effectively suppressed. The optimized ASSLBs with Li metal anodes achieve outstanding cyclability with 90.6% capacity retention over 1000 cycles at 1C and 61.4% after 9000 cycles at 2C at 10 MPa and RT. Practical pouch cells demonstrate 90.6% capacity retention after 100 cycles at a pressure of 2 MPa and RT. This work provides universal interfacial design principles for developing pressure-resilient ASSLB systems.

An anion-enriched solvation structure is crucial for electrolytes in establishing stable electrode-electrolyte interfaces and facilitating rapid Li+ transport kinetics. However, even a well-designed solvation structure can be sensitive to temperature variations, compromising the long-term cycling stability of batteries over wide temperature ranges. Herein, we design an electrolyte with temperature-independent anion-enriched solvation structures, by leveraging the ionic solvation/association equilibrium of Li+ in solvation structures based on the formation entropy (∂ΔG/∂T = -ΔS) counterbalancing of the mixed salts. This strategy effectively stabilizes the anion-enriched solvation structure and ensures the formation of robust inorganic interphases over a wide temperature range. Specifically, the electrolyte enables stable operation of Li||LiNi0.8Mn0.1Co0.1O2 cells from -70 to 80 °C at a high charging voltage of 4.6 V, maintaining long-term cycling stability with no observable capacity decay over 1000 cycles at -20 °C. Further toward practical application, 4.5 V Ah-level Si/C||LiNi0.9Mn0.05Co0.05O2 pouch cells achieve 92% capacity retention after 500 cycles over 250 days of operation at -20 °C. This work underscores the critical importance of understanding solvation structures from a thermodynamic perspective for the rational design of electrolytes, enabling their efficient implementation in batteries and other electrochemical systems.

Oxide and fluoride particles are widely employed to stabilize lithium metal anodes, yet the fundamental origin of their distinct interfacial behaviors remains unclear. Herein, we perform systematic density functional theory calculations to compare six representative interfaces: Li2O|Li, MgO|Li, Al2O3|Li (oxides) and LiF|Li, MgF2|Li, AlF3|Li (fluorides). The data show that interfacial adhesion, charge transfer, and work function are governed by anion charge and cation valence. The stronger interfacial hybridization enhances charge redistribution, generating larger interfacial dipoles that raise the work function. Molecular dynamics simulations reveal that these static characteristics evolve under thermal activation, with sustained Li migration into the coating, highlighting the necessity of finite-temperature assessment. These atomic-scale insights establish quantitative design principles for artificial solid electrolyte interphases.

The development of high-performance sulfide solid electrolytes necessitates materials that simultaneously exhibit superior ionic conductivity, excellent electrochemical stability, and enhanced environmental tolerance. This work reports a novel lithium solid electrolyte, Li5.3P0.98Nb0.02S4.25O0.05Cl1.7 (LPNbSOCl), which demonstrates remarkable improvements in these critical properties. The optimized composition achieves an ionic conductivity of 10.6 mS cm-1 at room temperature with an activation energy of 0.249 eV. Electrochemical characterization reveals exceptional stability against lithium metal, with a critical current density （CCD) reaching 3.82 mA cm-2 and stable cycling performance for 1000 h in symmetric cell configurations. The material exhibits significantly improved air stability, maintaining 78.4% of its initial conductivity after air exposure while substantially reducing H2S evolution compared to conventional sulfide electrolytes. Interfacial analysis indicates the formation of a stable solid electrolyte interphase containing Li─Nb alloy and Li2O at the anode. In all-solid-state battery configurations with LiCoO2 (LCO) cathodes, this electrolyte enables outstanding cycling stability over 90% capacity retention after 1000 cycles at a 1C rate and delivers 115.4 mAh g-1 at high current densities of 5C. These results demonstrate the potential of compositionally optimized lithium argyrodite materials to address the key challenges in solid-state battery technology.