The Strategy of Surface Oxygen Vacancy Stabilization for High-Performance Lithium-rich Cathode Materials

Abstract

Lithium-rich materials exhibit high capacity and high voltage properties due to the charge compensation mechanism, but the disadvantages such as material voltage decay and poor cycling stability limit their practical application. The fixation and stabilizations of surface lattice oxygen is considered the most challenging problem the materials. We have successfully prepared a lithium-rich cathode material with a triad of oxygen vacancies, surface spinel and polyanionic SO4 2− doping by a mild surface pre-activation treatment, and systematically investigated the stabilization mechanism of surface oxygen vacancies in the materials. The VS-LR0.25 material with multiple stabilizations of oxygen vacancies exhibited excellent cycling stability and rate performance, with an initial Coulomb efficiency of 82.7%, and capacity retention of 95.1% after 200 cycles at 1 C.