A low-carbon strategy for revival of degraded single crystal LiNi_0.6Co_0.2Mn_0.2O₂

Abstract: Single crystal LiNi_0.6Co_0.2Mn_0.2O₂ is currently widely used due to the outstanding cycle stability and safety. However, its sensitivity to the environment and the high residual alkali makes the electrochemical performance and processing property severely degraded after long-term storage, especially for the Ni-rich single crystal material. Therefore, it is highly urgent to develop a cost-effective strategy for the revival of degraded Ni-rich cathode materials. Here, a low-carbon strategy is proposed to revive the degraded single crystal LiNi_0.6Co_0.2Mn_0.2O₂ (SCNCM622) through water washing. The solid–liquid reaction mechanism of SCNCM622 and water was revealed and the strong dependence of the recovery effect on the washing time was clarified. Under optimized conditions, the sample with a washing time of 24 h shows 31.2% reduction in viscosity, 18.4% improvement in discharge capacity, 15.3% enhancement in cycle life, and excellent rate performance compared to the blank sample. Therefore, this strategy can achieve higher utilization of single crystal Ni-based cathode materials with a lower cost. Graphical abstract: [Figure not available: see fulltext.]