Fabrication of amorphous LiPON, LiAlGePO, and GeSn films in low-temperature plasma sputtering process for all-solid-state Li+-ion battery

Abstract Plasma-sputtered amorphous films for all-solid-state Li + -ion batteries are investigated. In LiPON electrolyte films, the amount of N incorporated into LiPO films is controlled by the sputtering discharge gas. Ionic conductivity increases with increasing N 2 gas proportion in Ar/N 2 discharge, reaching a maximum of 2.7 × 10 −6 S cm −1 at Li 2.39 PO 3.71 N 0.13 . In amorphous LiAlGePO electrolyte films, the amounts of Al and Ge incorporated into LiPO films are controlled in a combinatorial approach using two-source co-sputtering. The P/Ge ratio varies over a wide range from 23.3 to 1.61 at the radial substrate positions, and the highest ionic conductivity of 4.32 × 10 −5 S cm −1 is achieved at Li 4.80 Al 0.80 Ge 1.16 P 3 O 13.1 . We evaluate all-solid-state Li + -ion batteries fabricated using the developed amorphous LiPON electrolyte and GeSn anode films, where GeSn films with about 50 nm nanograins are fabricated by high-gas-pressure sputtering at 500 mTorr. A maximum capacity of 2.86 μ Ah cm −2 is attained for all-solid state Li + -ion battery.