Revealing the Relationships between Washing/Recalcination Processes and Structure Performance of Ni-Rich Layered Cathode Materials

Abstract

Ni-rich layered oxides are the most promising cathode materials for Li-ion batteries due to their high specific capacity and reasonable cost. Unfortunately, undesired residual Li compounds (RLCs) tend to form on the surface of Ni-rich materials, causing severe limitations to their commercialization. In this work, water washing and subsequent recalcination strategies were adopted to eliminate surface RLCs as well as guarantee the cycling stability of LiNi0.83Co0.11Mn0.06O2 materials. The washing/recalcination processes not only induced the migration of Li+ and the redox of Ni2+/Ni3+ but also contributed to the variation of the specific surface area. Combined with the electrochemical properties, we found that these structure evolutions showed different impacts on the performance as the recalcination temperatures changed. Taking capacity and cycling stability into account, the optimal recalcination condition was selected. More importantly, the relationships between washing/recalcination processes and structure performance were established. This work reinforces the understanding of modified Ni-rich materials and motivates the development of advanced cathodes for batteries.