Xiaona Li

All-solid-state batteries (ASSBs) are a promising next-generation energy storage technology, but their development is often constrained by the thermal instability and high cost of solid-state electrolytes (SSEs). Amorphous oxyhalide electrolytes, while mechanically deformable, are particularly susceptible to thermal degradation. Here, we report a novel and cost-effective composite SSE fabricated by embedding LaCl3 nanocrystals within an amorphous Li–Al–O–Cl (LAOC) matrix. This unique architecture synergistically combines the high ionic conductivity of the amorphous phase with the enhanced thermal and mechanical robustness imparted by the crystalline phase. The resulting Li–La–Al–O–Cl electrolyte achieves a high room-temperature ionic conductivity exceeding 1 mS cm–1 and demonstrates exceptional thermal stability, remaining a solid powder at 150 °C, a temperature at which the baseline LAOC melts. This enhanced thermal and thermo-mechanical integrity, combined with excellent deformability, enables superior interfacial contact and stability with cathodes. The Li–La–Al–O–Cl-based ASSBs maintain stable operation at 80 °C, in stark contrast to the rapid failure of LAOC-based cells. This strategy of reinforcing a soft amorphous matrix with a rigid crystalline offers a new pathway for designing thermally robust, high-performance, and commercially viable SSEs.

Halide solid electrolytes are widely regarded as promising catholytes for all‐solid‐state batteries because of their high ionic conductivity, good deformability, and relative compatibility with oxide cathodes. However, their interfacial stability has been largely evaluated under inert laboratory conditions, whereas practical battery manufacturing is typically conducted in low‐humidity dry rooms rather than inert‐atmosphere gloveboxes. Here, we demonstrate that halide solid electrolyte/oxide cathode composite electrodes can undergo severe interfacial degradation even under a low‐humidity dry‐room environment with a dew point of −40°C. Using Li ₃ InCl ₆ and LiNi _0.83 Co _0.12 Mn _0.05 O ₂ as a representative model system, we reveal that dry‐room exposure induces interfacial reactions that generate a passivation layer associated with hindered Li ⁺ transport, leading to markedly deteriorated electrochemical performance. Similar degradation behavior was also observed in several representative halide electrolyte/layered oxide combinations, suggesting that this issue is not limited to a single material pair. These findings identify a previously underappreciated processing‐induced interfacial challenge in halide‐based all‐solid‐state batteries and underscore the need to place greater emphasis on composite‐cathode stability under realistic dry‐room manufacturing conditions.

All‐solid‐state batteries (ASSBs) employing halide/sulfide bilayer electrolytes offer a promising route toward high energy density by combining the high oxidative stability of halides with the superior reductive stability of sulfides. However, severe halide–sulfide interfacial incompatibility induces continuous interfacial degradation and undermines Li ⁺ transport. Unlike conventional interfacial engineering approaches that rely on coatings or artificial buffer layers, we report a local chemistry–driven intrinsic compatibility strategy that fundamentally stabilizes halide–sulfide interfaces. By sulfurizing amorphous halide electrolytes Li ₂ O–TaCl ₅ , the short‐range coordination chemistry and medium‐range topology are simultaneously reconstructed, in which sulfur‐rich local motifs become thermodynamically more resistant to further sulfur substitution, whereas sulfur‐containing medium‐range networks exhibit stronger binding with PS ₄ units in Li ₆ PS ₅ Cl, thereby intrinsically stabilizing the halide–sulfide interface and suppressing interfacial decomposition. Simultaneously, the sulfurized framework exhibits enhanced structural heterogeneity and interconnected Li ⁺ migration pathways, achieving an ultrahigh ionic conductivity of 14.2 mS cm ⁻¹ . As a result, the assembled NCM89|8S‐LTOC|LPSC|Li‐In ASSBs exhibit outstanding electrochemical performance from −50°C to 100°C, including 131 mAh g ⁻¹ at −50°C, 2000‐cycle stability at 15 C, and high areal capacities up to 21.7 mAh cm ⁻² . This work highlights local anion chemistry regulation as an effective strategy for developing robust halide–sulfide ASSBs.

All‐solid‐state batteries (ASSBs) employing halide/sulfide bilayer electrolytes offer a promising route toward high energy density by combining the high oxidative stability of halides with the superior reductive stability of sulfides. However, severe halide–sulfide interfacial incompatibility induces continuous interfacial degradation and undermines Li ⁺ transport. Unlike conventional interfacial engineering approaches that rely on coatings or artificial buffer layers, we report a local chemistry–driven intrinsic compatibility strategy that fundamentally stabilizes halide–sulfide interfaces. By sulfurizing amorphous halide electrolytes Li ₂ O–TaCl ₅ , the short‐range coordination chemistry and medium‐range topology are simultaneously reconstructed, in which sulfur‐rich local motifs become thermodynamically more resistant to further sulfur substitution, whereas sulfur‐containing medium‐range networks exhibit stronger binding with PS ₄ units in Li ₆ PS ₅ Cl, thereby intrinsically stabilizing the halide–sulfide interface and suppressing interfacial decomposition. Simultaneously, the sulfurized framework exhibits enhanced structural heterogeneity and interconnected Li ⁺ migration pathways, achieving an ultrahigh ionic conductivity of 14.2 mS cm ⁻¹ . As a result, the assembled NCM89|8S‐LTOC|LPSC|Li‐In ASSBs exhibit outstanding electrochemical performance from −50°C to 100°C, including 131 mAh g ⁻¹ at −50°C, 2000‐cycle stability at 15 C, and high areal capacities up to 21.7 mAh cm ⁻² . This work highlights local anion chemistry regulation as an effective strategy for developing robust halide–sulfide ASSBs.

Since 2011, ionic conductivity of some sulfide‐ and halide‐based solid‐state electrolytes (SSEs) have already reached a level comparable to that of liquid electrolytes. Numerous companies worldwide have proposed diverse technical pathways for commercializing electric vehicles with ultra‐long driving ranges. However, the practical vehicular application of all‐solid‐state batteries (ASSBs) remains highly challenging and uncertain. One of the major obstacles is the requirement for high stack pressure, which typically relies on heavy metallic plates and thereby reduces the overall energy density of the module battery. This perspective compares practical all‐solid‐state pouch cells (ASSPCs) with conventional liquid batteries to analyze the origins of stack pressure requirements. The analysis is conducted from material, interfacial, and structural viewpoints, revealing the critical factors underlying this limitation. Subsequently, strategies are proposed to mitigate stack pressure from the current 20 MPa to 5 MPa for the first stage and to 2 MPa as the final target. The effect of stack pressure on cell‐to‐module energy density efficiency is also calculated to quantitative analysis. These insights provide practical suggestion from ASSPCs design to module‐level pressure management.

All‐solid‐state batteries (ASSBs) offer enhanced safety and energy density over conventional lithium‐ion batteries. However, achieving high active material loading remains challenging due to poor interfacial contact from cold‐pressing and the incompatibility of solvent‐based processing with advanced solid‐state electrolytes. Herein, we report a cellulose‐derived polymer additive (CA‐MDI) that establishes intimate solid–solid interfacial contact while ensuring continuous electron/ion transport in the composite cathodes. The efficacy of CA‐MDI is ascribed to the urethane‐linked cellulose framework, which is synthesized via the polymerization of cellulose acetate (CA) and methylene diphenyl diisocyanate (MDI). The as‐constructed ASSBs incorporating a CA‐MDI‐modified LiNi _0.89 Co _0.055 Mn _0.055 O ₂ cathode achieve a high areal capacity of 6.4 mAh cm ⁻² , delivering an initial discharge capacity of 136.6 mAh g ⁻¹ at 0.3C and retaining 91.1% of the capacity after 100 cycles, whereas additive‐free cells show rapid degradation. At a lower areal capacity of 1.8 mAh cm ⁻² , the CA‐MDI‐modified cell maintains 80% of its initial capacity for over 620 cycles at 1 C. The applicability of the CA‐MDI additive is further demonstrated using LiCoO ₂ and Li‐rich layered oxide cathodes. These results show that a mechanically adaptive polymer additive can improve the cycling stability of thick composite cathodes and provide a useful approach for developing high‐energy‐density ASSBs.

All‐solid‐state batteries (ASSBs) offer enhanced safety and energy density over conventional lithium‐ion batteries. However, achieving high active material loading remains challenging due to poor interfacial contact from cold‐pressing and the incompatibility of solvent‐based processing with advanced solid‐state electrolytes. Herein, we report a cellulose‐derived polymer additive (CA‐MDI) that establishes intimate solid–solid interfacial contact while ensuring continuous electron/ion transport in the composite cathodes. The efficacy of CA‐MDI is ascribed to the urethane‐linked cellulose framework, which is synthesized via the polymerization of cellulose acetate (CA) and methylene diphenyl diisocyanate (MDI). The as‐constructed ASSBs incorporating a CA‐MDI‐modified LiNi _0.89 Co _0.055 Mn _0.055 O ₂ cathode achieve a high areal capacity of 6.4 mAh cm ⁻² , delivering an initial discharge capacity of 136.6 mAh g ⁻¹ at 0.3C and retaining 91.1% of the capacity after 100 cycles, whereas additive‐free cells show rapid degradation. At a lower areal capacity of 1.8 mAh cm ⁻² , the CA‐MDI‐modified cell maintains 80% of its initial capacity for over 620 cycles at 1 C. The applicability of the CA‐MDI additive is further demonstrated using LiCoO ₂ and Li‐rich layered oxide cathodes. These results show that a mechanically adaptive polymer additive can improve the cycling stability of thick composite cathodes and provide a useful approach for developing high‐energy‐density ASSBs.

All‐solid‐state sodium‐ion batteries (ASSSIBs) provide a sustainable and cost‐effective solution for large‐scale energy storage. Sodium aluminosilicate (NASO) represents a resource‐sustainable electrolyte option owing to their low cost, natural abundance, and electrochemical stability. However, their strong covalent network leads to intrinsic low ionic conductivity, and poor interfacial compatibility. This work employs Cl incorporation to depolymerize the hyperconnected covalent network of NASO, forming a modified NaAlSiOCl (NASOC) structure with discrete short‐chain segments, which turns stress‐induced large‐scale cooperative rearrangement into localized deformation. Replacing a strong O─bridge with a weaker Cl─bridge further reduces the Young's modulus. Additionally, chloride doping effectively reduces the Na ⁺ migration barrier by decreasing both the elastic deformation energy and the chemical binding energy. Consequently, this Cl‐mediated depolymerization approach simultaneously reduces stiffness and improves ionic conductivity. The optimized NASOC electrolyte exhibits a low Young's modulus of ∼5 GPa and a high Na ⁺ conductivity of 0.45 mS cm ⁻¹ , which together facilitate superior ion transport and intimate electrode contact. The ASSSIBs employing NASOC retain 80.9% of their capacity after 500 cycles at 0.1 C. This work demonstrates a Cl‐mediated depolymerization strategy that concurrently enhances ionic conductivity and mechanical compliance in solid electrolytes, providing key insights for designing high‐performance and sustainable energy storage materials.

All‐solid‐state sodium‐ion batteries (ASSSIBs) provide a sustainable and cost‐effective solution for large‐scale energy storage. Sodium aluminosilicate (NASO) represents a resource‐sustainable electrolyte option owing to their low cost, natural abundance, and electrochemical stability. However, their strong covalent network leads to intrinsic low ionic conductivity, and poor interfacial compatibility. This work employs Cl incorporation to depolymerize the hyperconnected covalent network of NASO, forming a modified NaAlSiOCl (NASOC) structure with discrete short‐chain segments, which turns stress‐induced large‐scale cooperative rearrangement into localized deformation. Replacing a strong O─bridge with a weaker Cl─bridge further reduces the Young's modulus. Additionally, chloride doping effectively reduces the Na ⁺ migration barrier by decreasing both the elastic deformation energy and the chemical binding energy. Consequently, this Cl‐mediated depolymerization approach simultaneously reduces stiffness and improves ionic conductivity. The optimized NASOC electrolyte exhibits a low Young's modulus of ∼5 GPa and a high Na ⁺ conductivity of 0.45 mS cm ⁻¹ , which together facilitate superior ion transport and intimate electrode contact. The ASSSIBs employing NASOC retain 80.9% of their capacity after 500 cycles at 0.1 C. This work demonstrates a Cl‐mediated depolymerization strategy that concurrently enhances ionic conductivity and mechanical compliance in solid electrolytes, providing key insights for designing high‐performance and sustainable energy storage materials.

Epitaxial interface engineering offers a route to design thin, bonded, crystallographically correlated surface structures to stabilize high-energy cathode materials.