Suppressing oxygen vacancies on the surface of Li-rich material as a high-energy cathode via high oxygen affinity Ca0.95Bi0.05MnO3 coating

Abstract

Because of high energy density and work voltage, the Li-rich materials are considered to be one of the most promising next-generation lithium-ion batteries. However, the commercial applications are limited by the capacity loss, poor rate capability, and voltage decay during cycling. Herein, functionalizing the surface of Li1.2Mn0.54Ni0.13Co0.13O2 by Ca0.95Bi0.05MnO3 is proposed, which suppresses the formation of the oxygen vacancies and maintains structural stability by high oxygen affinity and alleviative electrolyte corrosion. Electrochemical tests demonstrate that this admirable electrode delivers excellent cycling stability. The Li-rich electrode decorated with 5 wt.% Ca0.95Bi0.05MnO3 exhibits a stable capacity retention of 86.5% at 0.1C after 200 cycles and an excellent full cell performance with the energy retention of 95.4% at 0.1C after 100 cycles. Moreover, the voltage decay of the modified material is restrained from 5.02 to 3.07 mV per cycle over 200 cycles. The finding here sheds new light on the development of the better Li-rich cathodes for improving electrochemical performance of electrode materials.