Charge compensation mechanisms in Li‐substituted high‐entropy oxides and influence on Li superionic conductivity

Abstract The charge compensation mechanisms that occur when Li + substitutes a 2+ element in superionic conductor (MgCoNiCuZn)O high‐entropy oxide have been studied using a combination of thermogravimetric analysis and X‐ray photoemission spectroscopy. Depending on the concentration of Li + in the compound, the charge compensation involves first partial oxidation of Co 2+ into Co 3+ for low fraction of Li + , and then a combination of both the oxidation of cobalt and the formation of oxygen vacancies for large fraction of Li + .