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

Li 10 GeP 2 S 12 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 Li 10 GeP 2 S 12 with enhanced chemical and electrochemical stability is synthesized. The optimized Li 10.02 Ge 0.98 Sb 0.02 P 2 S 11.97 Te 0.03 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 cm 3 g –1 H 2 S gas, which is merely one-quarter of that produced by pristine Li 10 GeP 2 S 12 . 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 Li 10 GeP 2 S 12 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 Li 10.02 Ge 0.98 Sb 0.02 P 2 S 11.97 Te 0.03 -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 LiCoO 2 |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.