Surface coating engineering of prelithiation cathode additives for lithium-ion batteries

Abstract

The active lithium ions loss during the initial charge and discharge process of lithium ion batteries seriously hampers its increasement of energy density. Pre-lithiation, involving the pre-storage of active lithium ions prior to cycling, emerges as a promising and effective strategy to offset this loss. Li6CoO4 has been identified as a candidate capable of releasing adequate lithium ions to compensate for such loss. However, its poor air stability renders it susceptible to side reactions in the atmosphere, leading to the formation of residual lithium and consequently affecting its electrochemical performance. In this study, we propose application of a lithium aluminate (LiAlO2) coated onto the surface of lithium cobalt oxide (Li6CoO4) to mitigate the presence of residual lithium. Meanwhile, with decreasing of residual lithium, the rate capability is also enhanced. The research results demonstrate that samples treated with this coating layer exhibit an enhanced energy density in the full cell, indicating the efficacy of this approach in optimizing the electrochemical performance of prelithiation additives.