Self‐Dispersing Halide Catholyte Engineering for Enhanced Areal‐Capacity All‐Solid‐State Lithium Batteries

Abstract Halide electrolytes are recognized as highly promising catholytes for all‐solid‐state lithium batteries (ASSLBs) owing to their wide electrochemical windows, high ionic conductivity, and excellent compatibility with layered oxide cathodes. Despite these advantages, the practical application of halide‐based ASSLBs remains constrained by their low areal capacity, which stems from the necessity of high catholyte loadings to establish percolating Li⁺ conduction pathways within composite cathodes. Here, a self‐dispersing halide catholyte engineering is proposed to achieve a high‐loading cathode via coordinating chemistry between tetrafluorobenzoquinone (TCBQ) and Li ₃ InCl ₆ . The coordinated TCBQ molecules introduce steric hindrance effects, preventing thermodynamically driven halide particle agglomeration while achieving particle size reduction. Moreover, the dry process in thick cathode preparation further promotes particle rearrangement during thermal calendaring. Consequently, these optimizations reduce the catholyte content from the typical 30–17 wt.%, while maintaining an efficient and robust ion/electron conduction network. The optimized high‐Ni layered oxide cathode exhibits exceptional rate capability, delivering 145.8 mAh g ⁻¹ at 2C. Moreover, at a high active material loading of 12 mg cm ⁻² , the cathode achieves a remarkable initial areal capacity of 1.845 mAh cm ⁻² , while retaining 1.512 mAh cm ⁻² after 400 cycles.