Stabilizing lithium plating-stripping reaction between a lithium phosphorus oxynitride glass electrolyte and copper thin film by platinum insertion

Abstract

Lithium (Li) plating-stripping reaction properties at the lithium phosphorus oxynitride glass electrolyte (LiPON)/copper thin film (Cu) interface is improved by the insertion of nano-thickness platinum (Pt) layer at the interface. The LiPON films are formed on mirror-polished lithium-ion conductive solid electrolyte sheets, and current collector thin films of Li, Cu–Pt multi layer, and Cu are formed on the LiPON films. The plating-stripping reactions at the LiPON/current collector films interface are carried out by galvanostatic and potential sweep measurements. Galvanostatic measurements reveal that Pt layer insertion reduces the overvoltage of the reaction and improves its coulomb efficiency. Also, cyclic voltammetry measurement suggests formation of Li–Pt alloys at higher voltages than 0 V (vs. Li/Li +) during the lithium plating process. Scanning electron microscopy observation clarifies that platinum insertion moderate non-uniform lithium plating reaction. Most probably, Li–Pt alloys increase the reaction sites, resulting in both the stabilization of current collector and the reduction of the overvoltage of the lithium plating-stripping reaction upon cycling. The results shown here will be useful in improving the anode reaction of the “Li-free” all-solid-state lithium batteries.