Dual‐Solvent Supramolecular Assembly Enables Ampere‐Hour Halide All‐Solid‐State Pouch Cell

Halide solid electrolytes (SSEs) hold promise for next‐generation all‐solid‐state batteries (ASSBs), yet scalable fabrication of halide SSE films and ampere‐hour‐scale all‐solid‐state pouch cells (ASSPCs) via slurry coating has not been demonstrated. Here, we introduce a dual‐solvent supramolecular assembly strategy that precisely regulates the chain organization of a multiblock copolymer binder (SEEPS), enabling low‐binder, high‐viscosity slurries for uniform halide SSE film formation. Methylcyclohexane and decane are identified as chemically compatible solvents that diminish InCl 3 surface precipitation in Li 3 InCl 6 , preserving ionic conductivity. The resulting Li 3 InCl 6 /Li 6− x PS 5− x Cl 1+ x bilayer SSE film exhibits high ionic conductivity (1.26 mS/cm), mechanical robustness, and electrochemical stability. ASSBs using NCM88 cathodes and micro‐silicon anodes retain 71.3% capacity after 600 cycles at 0.5 C, while the first ten‐layer ampere‐hour‐scale halide ASSPC delivers 1.45 Ah at 0.2 C with 95.1% capacity retention over 100 cycles. This approach establishes a practical and scalable pathway for fabricating halide ASSPCs, bridging laboratory innovations and commercial deployment.