LiPO2F2 electrolyte additive for high-performance Li-rich cathode material

Li-rich layered oxide cathodes have received considerable attention because of the high operating potential and specific capacity. However, the structural instability and parasitic reactions at high potential cause severe degradation of the electrochemical performance. In our studies, the cycling stability of Li1.14Ni0.133Co0.133Mn0.544O2 cathode is improved with LiPO2F2 electrolyte additive. After 500 cycles, the capacity retention is increased from 53.6% to 85% at 3C by LiPO2F2 modification. This performance is mainly attributed to the enhanced interfacial stability of the Li-rich cathode. Based on systematic characterization, LiPO2F2 additive was found to promote a stable interface film on the cathode surface during the cycling and mitigates the interfacial side reactions. This study provides new insights for improving high-potential Li-rich layered oxide batteries. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.