LiAlO 2 -Modified Li Negative Electrode with Li 10 GeP 2 S 12 Electrolytes for Stable All-Solid-State Lithium Batteries.

Lithium (Li) metal has an ultrahigh specific capacity in theory with an extremely negative potential (versus hydrogen), receiving extensive attention as a negative electrode material in batteries. However, the formation of Li dendrites and unstable interfaces due to the direct Li metal reaction with solid sulfide-based electrolytes hinders the application of lithium metal in all-solid-state batteries. In this work, we report the successful fabrication of a LiAlO 2 interfacial layer on a Li/Li 10 GeP 2 S 12 interface through magnetic sputtering. As LiAlO 2 can be a good Li + ion conductor but an electronic insulator, the LiAlO 2 interface layer can effectively suppress Li dendrite growth and the severe interface reaction between Li and Li 10 GeP 2 S 12 . The Li@LiAlO 2 200 nm/Li 10 GeP 2 S 12 /Li@LiAlO 2 200 nm symmetric cell can remain stable for 3000 h at 0.1 mA cm -2 under 0.1 mAh cm -2 . Moreover, unlike the rapid capacity decay of a cell with a pristine lithium negative electrode, the Li@LiAlO 2 200 nm/Li 10 GeP 2 S 12 /LiCoO 2 @LiNbO 3 cell delivers a reversible capacity of 118 mAh g -1 and a high energy efficiency of 96.6% after 50 cycles. Even at 1.0 C, the cell with the Li@LiAlO 2 200 nm electrode can retain 95% of its initial capacity after 800 cycles.