Site‐Selective Anion‐Cation Regulation of Sulfide Electrolyte Enables Low‐Pressure Dendrite‐Suppressed All‐Solid‐State Lithium Metal Batteries

ABSTRACT Achieving stable sulfide‐based all‐solid‐state lithium batteries with Li metal anodes and high‐capacity cathodes under low stack pressure is highly desirable for high‐energy‐density energy storage, but remains challenging because of unstable solid‐solid interfaces and dendrite‐induced short circuits. Here, we develop a site‐selective anion‐cation regulation strategy for argyrodite Li 6 PS 5 Cl electrolyte to couple framework stabilization with interphase chemistry, enabling long‐term dendrite‐suppressed cycling under low stack pressure. Al 3+ substitution for P 5+ forms AlS 4 ‐related local units and strengthens local Al–S bonding, stabilizing the sulfide framework against redox decomposition. Cl − incorporation into the 4 a /4 d anion sublattice promotes Li + transport, delivering a high room‐temperature ionic conductivity of 7.22 mS cm −1 . More importantly, F/Cl regulation redirects the interfacial decomposition pathway from a Li 2 S‐rich/LiCl interphase toward a LiF/LiCl‐rich and Li 2 S‐poor passivation layer, with exposed LiF/LiCl (200) planes that exhibit stronger interfacial adhesion with Li metal. Benefiting from this coupled framework‐interphase regulation, Li | LAPSCF‐Cl | Li symmetric cells cycle for over 8000 h at 0.5 mA cm −2 at 3 MPa and support stable cycling of both NCM811 and sulfur cathodes paired with Li metal under a relatively low pressure of 30 MPa.