Solid Electrolyte/Lithium Anodes Stabilized by Reduced Graphene Oxide Interlayers: Implications for Solid-State Lithium Batteries

Poor interfacial compatibility between the solid polymer electrolyte and lithium anode is one of bottleneck issues for the wide application of solid-state lithium batteries. In this work, a strategy to improve the stability of a solid electrolyte/anode interface by applying graphene oxide (GO) coating on the surface of the poly(propylene carbonate) (PPC) solid electrolyte membrane to react with metal Li and spontaneously reducing in situ to form a reduced graphene oxide (rGO) interface-modified layer was proposed. The rGO interlayer contributes to the combination of an interface and inhibition of lithium dendrites. The GO-modified composite solid electrolyte (GO-SE) shows a wide electrochemical window of up to 4.8 V, high room temperature ionic conductivity reaching 2.22 × 10–4 S·cm–1, and a high ion migration number of 0.9. This GO-SE is suitable for high-voltage solid-state lithium batteries, and the assembled NCM622/GO-SE/Li cells have an initial specific capacity of about 160 mA h/g at 0.5 C, and the specific capacity remains above 100 mA h/g after 200 cycles, much more stable than that of the battery with an unmodified SE membrane at different rates from 0.1 to 2 C. This interface modification method is promising to be widely applied in the solid-state lithium batteries.