Transition metal dichalcogenides in alliance with Ag ameliorate the interfacial connection between Li anode and garnet solid electrolyte

Abstract Solid-state batteries (SSBs) exhibit a promising prospect due to their potential in terms of safety and energy densities. As an oxide electrolyte, cubic garnet solid electrolyte (cubic-Li7La3Zr2O12) attracts wide attention due to the high ionic conductivity. However, the problem of poor contact between garnet solid electrolyte and lithium impairs the development of solid electrolytes. Herein, we demonstrate an effective modification method to cope with the interface issue between electrolyte and Li metal by introducing an Ag@WSe2 composite layer. By applying this method, the interfacial resistance between the garnet electrolyte and Li metal is reduced to ~12.5 Ω cm2, which is nearly 150 times lower than the value of 1900 Ω cm2 before modification. The WSe2 acts as a framework to immobilize Ag, while Ag forms an Ag–Li alloy with lithium for lithium ions transportation. And other Ag@TMDs (transition metal dichalcogenides) composites have also been proven to have similar effects. In addition, the Li | Ag@WSe2-LLZO | LFP full cell demonstrates a satisfactory capacity and excellent cycle stability (500 cycles with 90% capacity retention rate) at room temperature.