Li7P3S11 double-layer electrolyte for silicon-based all-solid-state batteries: Interface SiS2-doping

Sulfide solid electrolytes is indispensable for developing all-solid-state batteries with Si-based anode for its superior ionic conductivity and excellent mechanical ductility. However, the unfriendly interface between sulfide and silicon still leads to poor cycling performance. Herein, we report a SiS₂-doping Li₇P₃S₁₁ (LPS-xSi) membrane sandwiched between Li₇P₃S₁₁ electrolyte and Si electrode to form double-layer sulfide electrolyte (LPS-xSi|LPS). LPS-xSi|LPS double-layer contacts well with Si anode and forms Li-Si alloys at the interface to eliminate the adverse side reactions and promote the Li⁺ transmission of the interface. The LPS-2Si|LPS possesses the highest ionic conductivity of 5.4 × 10⁻⁴ S cm⁻¹ at 30 °C. LiIn | LPS-2Si|LPS | LiIn cell works steadily for more than 1000 h at 30 ℃ with 0.1 mA cm⁻². The assembled 99 wt.% Si | LPS-2Si|LPS | LiIn cell exhibits an initial discharge capacity of 2208.7 mAh g⁻¹ and remains 339.5 mAh g⁻¹ after 100 cycles.