Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
Adv Mater. 2023 May;35(19):e2211047. doi: 10.1002/adma.202211047. Epub 2023 Mar 27.
The instability of Li GeP S toward moisture and that toward lithium metal are two challenges for the application in all-solid-state lithium batteries. In this work, Li GeP S is fluorinated to form a LiF-coated core-shell solid electrolyte LiF@Li GeP S . Density-functional theory calculations confirm the hydrolysis mechanism of Li GeP S solid electrolyte, including H O adsorption on Li atoms of Li GeP S and the subsequent PS 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 GeP S shows one order lower electronic conductivity, which can significantly suppress lithium dendrite growth and reduce the side reaction between Li GeP S and lithium, realizing three times higher critical current density to 3 mA cm . The assembled LiNbO @LiCoO /LiF@Li GeP S /Li battery exhibits an initial discharge capacity of 101.0 mAh g with a capacity retention of 94.8% after 1000 cycles at 1 C.
LiGePS 对水分和金属锂的不稳定性是其在全固态锂电池中应用的两大挑战。在这项工作中，LiGePS 被氟化形成 LiF 包覆的核壳固体电解质 LiF@LiGePS。密度泛函理论计算证实了 LiGePS 固体电解质的水解机制，包括 H2O 在 LiGePS 上 Li 原子的吸附以及随后受氢键影响的 PS 解离。疏水性 LiF 壳可以减少吸附位点，从而在暴露于 30%相对湿度空气中时表现出优异的水分稳定性。此外，具有 LiF 壳的 LiGePS 表现出一个数量级更低的电子电导率，这可以显著抑制锂枝晶生长并减少 LiGePS 与锂之间的副反应，实现 3 倍更高的临界电流密度至 3 mA cm。组装的 LiNbO@LiCoO/LiF@LiGePS/Li 电池在 1 C 下循环 1000 次后，初始放电容量为 101.0 mAh g，容量保持率为 94.8%。
