However, the ternary materials may suffer from some potential disadvantages, including poor cycle performance and more severe gas production. Generally, used as positive electrode materials in batteries are secondary particles of ternary materials which are composed of a plurality of primary particles of the ternary materials. The positive electrode material which contains ternary materials may contact with electrolyte. During the charging of the battery, the ternary materials in the positive electrode material may undergo side reactions with electrolyte, such as the dissolution of metal ions. Side reactions can indirectly lead to a decrease in the particle strength of the positive electrode material, with cracks gradually increasing and expanding in the primary particles or at the interface thereof, and even breakage of the particles of the positive electrode material. It in turn may expose more surfaces of the positive electrode material to electrolyte, causing more side reactions. Accordingly, it may form a vicious cycle. Correspondingly, battery performances, especially cycle performance, are adversely affected.

To solve those problems, the currently proposed improving measures mainly include controlling particle size and structural morphology, coating, doping, monocrystallization, and the like. For example, doping can enhance the strength of particles of ternary materials per se. Coating can limit the contact of electrolyte with ternary materials.

The development of new energy electric vehicles and large capacity energy storage systems is driving the development of secondary batteries with further improvement in performances. Therefore, there is still a demand on developing positive electrode materials with further improvements to enhance cycle performance of a battery.