LiAlO<sub>2</sub>-Modified Li Negative Electrode with Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> Electrolytes for Stable All-Solid-State Lithium Batteries
Xinshuang Chang, Wei Weng, Mengqi Li, Ming Wu, George Z. Chen, Kam Loon Fow, Xiayin Yao
Abstract
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.