Fluorinated Li <sub>10</sub> GeP <sub>2</sub> S <sub>12</sub> Enables Stable All‐Solid‐State Lithium Batteries
Yuming Jin, Qinsheng He, Gaozhan Liu, Zhi Gu, Ming Wu, Tianyu Sun, Zhihua Zhang, Liang‐Feng Huang, Xiayin Yao
Abstract
Abstract The instability of Li 10 GeP 2 S 12 toward moisture and that toward lithium metal are two challenges for the application in all‐solid‐state lithium batteries. In this work, Li 10 GeP 2 S 12 is fluorinated to form a LiF‐coated core–shell solid electrolyte LiF@Li 10 GeP 2 S 12 . Density‐functional theory calculations confirm the hydrolysis mechanism of Li 10 GeP 2 S 12 solid electrolyte, including H 2 O adsorption on Li atoms of Li 10 GeP 2 S 12 and the subsequent PS 4 3− dissociation affected by hydrogen bond. The hydrophobic LiF shell can reduce the adsorption site, thus resulting in superior moisture stability when exposing in 30% relative humidity air. Moreover, with LiF shell, Li 10 GeP 2 S 12 shows one order lower electronic conductivity, which can significantly suppress lithium dendrite growth and reduce the side reaction between Li 10 GeP 2 S 12 and lithium, realizing three times higher critical current density to 3 mA cm −2 . The assembled LiNbO 3 @LiCoO 2 /LiF@Li 10 GeP 2 S 12 /Li battery exhibits an initial discharge capacity of 101.0 mAh g −1 with a capacity retention of 94.8% after 1000 cycles at 1 C.