Ge–O Dual-Doping toward a Highly Conductive, Air-Stable, and Lithium-Compatible Argyrodite Solid Electrolyte for All-Solid-State Lithium Batteries

Despite high ionic conductivity and good mechanical deformability, the application of argyrodite solid electrolytes for all-solid-state lithium batteries (ASSLBs) is greatly limited by its moisture sensitivity and electrode/electrolyte interface compatibility. Herein, a Li_6.2Ge_0.1P_0.9S_4.8O_0.2Cl electrolyte with high ion conductivity, excellent air stability, superior lithium dendrite suppression capability is synthesized by Ge–O dual doping into typical Li₆PS₅Cl (LPSC) argyrodites. The NCM811/Li ASSLBs using the Li_6.2Ge_0.1P_0.9S_4.8O_0.2Cl electrolyte deliver a high specific capacity of 164.2 mA h g^–1 at 0.1 C and an excellent long-term cycling performance at room temperature (86% capacity retention after 300 cycles with a Coulombic efficiency of almost 99.7% at 0.5 C). This rationally designed Ge,O codoped LPSC electrolyte is highly expected to pave the road for the practical application of ASSLBs to deepen the understanding of the dopant substitution mechanism.