Air exposure towards stable Li/Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> interface for all-solid-state lithium batteries
Wei Weng, Dong Zhou, Gaozhan Liu, Lin Shen, Mengqi Li, Xinshuang Chang, Xiayin Yao
Abstract
Abstract Moist air is a great challenge for manufacturing sulfide-based all-solid-state lithium batteries as the water in air will lead to severe decomposition of sulfide electrolytes and release H 2 S gas. However, different with direct reaction with water, short-period air exposure of Li 10 GeP 2 S 12 sulfide electrolyte with controlled humidity can greatly enhance the stability of Li 10 GeP 2 S 12 against lithium metal, thus realizing stable Li 10 GeP 2 S 12 based all-solid-state lithium metal batteries. During air exposure, partial hydrolysis reaction occurs on the surface of Li 10 GeP 2 S 12 pellets, rapidly generating a protective decomposition layer of Li 4 P 2 S 6 , GeS 2 and Li 2 HPO 3 in dozens of seconds. This ionically conductive but electronically insulation protecting layer can effectively prevent the severe interface reaction between Li 10 GeP 2 S 12 and lithium metal during electrochemical cycling. The Li/40s-air-exposed Li 10 GeP 2 S 12 /Li cell shows long cycling stability for 1000 h. And the LiCoO 2 /40s-air-exposed Li 10 GeP 2 S 12 /Li batteries present good rate capability and long cyclic performances, showing capacity retention of 80% after 100 cycles.