Antimony and Tellurium Dual-Doped Li ₁₀ GeP ₂ S ₁₂ Solid Electrolyte with Superior Air Stability and Lithium Compatibility for All-Solid-State Lithium Batteries

Li10GeP2S12 solid electrolyte has gained extensive attention due to its ultrahigh ionic conductivity (>10 mS cm–1). However, its poor stability against moisture, solvents, and lithium metal severely impedes its practical application in all-solid-state batteries. Herein, an antimony and tellurium (Sb–Te) dual-doped Li10GeP2S12 with enhanced chemical and electrochemical stability is synthesized. The optimized Li10.02Ge0.98Sb0.02P2S11.97Te0.03 exhibits a high cold-pressed ionic conductivity of 6.97 mS cm–1 at room temperature and demonstrates superior air stability and heptyl butyrate tolerance. After exposure to 40% relative humidity air for 120 min, it generates only 0.128 cm3 g–1 H2S gas, which is merely one-quarter of that produced by pristine Li10GeP2S12. The ionic conductivities remain at 1.07 and 4.76 mS cm–1 after exposure to humid air for 20 min and placed in a dry room at a dew point of −60 °C for 24 h, respectively, much higher than those of Li10GeP2S12 with 0.32 and 2.53 mS cm–1. Meanwhile, it retains 90.7% of its ionic conductivity after soaking in heptyl butyrate for 40 min, enabling a solid electrolyte membrane with a high ionic conductivity of 2.83 mS cm–1. Moreover, the Li10.02Ge0.98Sb0.02P2S11.97Te0.03-based Li|Li symmetric battery exhibits a high critical current density of 2.2 mA cm–2 and maintains stable lithium plating/stripping for over 900 h at 0.1 mA cm–2/0.1 mA h cm–2. The assembled LiCoO2|Li all-solid-state pouch cell delivers an initial discharge capacity of 121.02 mA h g–1, with a high capacity retention of 92.98% after 100 cycles at 0.1 C and 60 °C.