Nanostructure of Si-Sn Thick-Film Electrodes to Improve the Energy Density of Oxide-Based All-Solid-State Lithium-Ion Batteries

Abstract

Charge and discharge characteristics of Si-Sn composite thick-film electrodes on a garnet-type solid electrolyte were studied systematically. Charge/discharge cycle performance of 0.1 μm-thick Si-Sn thin-film electrodes simply depended on the Si:Sn composition ratio, while the thick-film electrodes with a thickness of 1 μm delivered the most outstanding performance at a specific Si/Sn atomic ratio of 7:3. The Si7-Sn3 composite film had a unique nanostructure to promote the charge/discharge reactions of Si and to maintain the interfacial contact with the solid electrolyte. These results can provide a clue to the design of Si-based negative electrodes for all-solid-state lithium ion batteries with high energy density.