Design Unique Air-Stable and Li–Metal Compatible Sulfide Electrolyte via Exploration of Anion Functional Units for All-Solid-State Lithium–Metal Batteries

The marriage of solid-state sulfide electrolytes (SSSEs) with Li-anode and oxide-based cathodes can multiply the energy density of all-solid-state Lithium–metal batteries (ASSLMBs). However, hydrolysis in the air, reduction at the Li/SSSE interface, and growth of Li-dendrites inside SSSEs collectively block the route of sulfide-based ASSLMBs. Herein, a novel Li_2.96P_0.98S_3.92O_0.06-Li₃N glass–ceramic electrolyte (GCE) is developed, wherein O and N substitution produce POS₃^3– and Li₃N unique functional units enable superior σ_Li+ 1.58 mS cm^–1 at RT. Notably, POS₃^3– units in Li_2.96P_0.98S_3.92O_0.06-Li₃N excellently prevent the structural degradation against moisture @45–50%. The critical current density of Li_2.96P_0.98S_3.92O_0.06–Li₃N reaches 1 mA cm^–2/1 mAh cm^–2 @ RT. Moreover, Li//Li cells realize unprecedented Li-plating/stripping >1000 h at 0.3 mA cm^–2/0.3 mAh cm^–2 and 0.5 mA cm^–2/0.5 mAh cm^–2 at RT. ToF-SIMS and depth-X-ray photoelectron spectroscopy (XPS) confirm the formation of Pre-solid-electrolyte interphase (SEI) enriched with thermodynamically stable Li₂O and Li₃N species at Li/Li_2.96P_0.98S_3.92O_0.06–Li₃N interface, suppressing the interfacial reactions and growth of Li-dendrites inside Li_2.96P_0.98S_3.92O_0.06–Li₃N. Furthermore, LiNbO₃@NCA/Li_2.96P_0.98S_3.92O_0.06–Li₃N/Li cells deliver a remarkable initial discharge capacity of 177.3, 177.6, and 177.8 mAh g^–1 with 7.50, 16.50, and 21.50 mg cm^–2 of NCA loading. Thus, the novel Li_2.96P_0.98S_3.92O_0.06–Li₃N GCE addresses all key challenging issues and has tremendous potential to be used in sulfide-based high-energy ASSLMBs.