Oxygen doped argyrodite electrolyte for all-solid-state lithium batteries

Abstract

Highly conductive argyrodite electrolytes are considered to be one of the most prospective solid electrolytes for all-solid-state batteries. However, poor electrochemical compatibility with a Li anode restrains their application. Herein, oxygen doping is adopted to improve the chemical and electrochemical performance of the argyrodite electrolyte. Meanwhile, the Cl−/S2− ratio is increased to enhance the lithium ionic conductivity. The resultant Li6.05PS4.9O0.1Cl1.05 electrolyte exhibits a high conductivity of 7.49 mS cm−1. Benefitting from the stable Li3OCl formed at the electrolyte/Li interface and the low electronic conductivity arising from the oxygen doping, a Li6.05PS4.9O0.1Cl1.05 electrolyte shows excellent interfacial stability and lithium dendrites suppression capability. A Li/Li6.05PS4.9O0.1Cl1.05/Li cell can maintain stable Li plating/stripping for 13 000 h at 0.1 mA cm−2. Moreover, a high critical current density up to 1.3 mA cm−2 of Li6.05PS4.9O0.1Cl1.05 is realized. Consequently, the LiCoO2/Li6.05PS4.9O0.1Cl1.05/Li batteries achieve remarkable better cycling stability than that using pristine Li6PS5Cl, possessing a reversible capacity of 104.6 mAh g−1 at 1C with a capacity retention of 86.7% after 300 cycles.