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

The adoption of LiCuO has 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). LiCuO provides a high irreversible capacity (>200 mAh g) 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 (O) evolution, resulting in poor overall cycling performance. It is thus crucial to reinforce the structure of LiCuO to make it more reliable as a cathode additive for charge compensation. Pursuing the structural stability of LiCuO, herein, we demonstrate cosubstitution by heteroatoms, such as nickel (Ni) and manganese (Mn), for improving the structural stability and electrochemical performance of LiCuO. Such an approach effectively enhances the reversibility of LiCuO by suppressing continuous structural degradation and O gas evolution during cycling. Our findings provide new conceptual pathways for developing advanced cathode additives for high-energy LIBs.