单晶型镍锰钴三元正极材料的形成和失效机理研究进展

Single crystal cathode materials have become one of the most promising materials due to their high cycling and high pressure density. Single crystal material is an improvement on secondary spherical particles. Understanding the formation and cycling mechanism of single crystal has a good guiding role in the preparation of single crystal. In this paper, the structural characteristics of single crystal materials were firstly analyzed. Both single crystal oxides and spherical secondary particle oxides have layered structures. Then, the stability mechanism of single crystal was described. Single crystal has no internal grain boundary and there is no intercrystal breakage during the cycle. In this paper, the formation and cyclic failure mechanism of single crystal cathode materials were summarized. In addition, the formation mechanism of dissolution and recrystallization of the secondary particle precursor disintegrating and the primary particle gradually growing into the single crystal particle during the synthesis process of the single crystal cathode material was emphasized. When the cutoff voltage is less than 4.3 V, the slippage is reversible and there are slippage traces after multiple charging and discharging. When the cutoff voltage is greater than 4.3 V, the intragranular fracture occurs after several cycles and the battery performance deteriorates.