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

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 Li6PS5Cl electrolyte to couple framework stabilization with interphase chemistry, enabling long-term dendrite-suppressed cycling under low stack pressure. Al3+ substitution for P5+ forms AlS4 -related local units and strengthens local Al-S bonding, stabilizing the sulfide framework against redox decomposition. Cl- incorporation into the 4a/4d 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 Li2S-rich/LiCl interphase toward a LiF/LiCl-rich and Li2S-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.