Enhanced Cycling Performance of a Li-Excess Li2CuO2Cathode Additive by Cosubstitution Nanoarchitectonics of Ni and Mn for Lithium-Ion Batteries

The adoption of Li2CuO2has drawn interest as a Li-excess cathode additive for compensating irreversible Li+loss in anodes during cycling, which would move forward high-energy-density lithium-ion batteries (LIBs). Li2CuO2provides a high irreversible capacity (>200 mAh g–1) in the first cycle and an operating voltage comparable with commercial cathode materials, but its practical use is still restricted by the structural instability and spontaneous oxygen (O2) evolution, resulting in poor overall cycling performance. It is thus crucial to reinforce the structure of Li2CuO2to make it more reliable as a cathode additive for charge compensation. Pursuing the structural stability of Li2CuO2, herein, we demonstrate cosubstitution by heteroatoms, such as nickel (Ni) and manganese (Mn), for improving the structural stability and electrochemical performance of Li2CuO2. Such an approach effectively enhances the reversibility of Li2CuO2by suppressing continuous structural degradation and O2gas evolution during cycling. Our findings provide new conceptual pathways for developing advanced cathode additives for high-energy LIBs.