Synthesis and Modification of Single-Crystal High-Nickel Ternary Cathode Materials
With the rapid development of portable electronic products and electric vehicles,the demand for high energy density lithium-ion batteries is increasing.High-nickel ternary materials with nickel content higher than 0.6(include)(e.g.,LiNi0.6Co0.2Mn0.2O2,LiNi0.8Co0.1Mn0.1O2 and LiNi0.9Co0.05Mn0.05O2),which can deliver a high reversible specific capacity of more than 200 mAh·g-1 at an upper cut-off voltage of 4.3 V vs Li+/Li,are an important development direction of cathode material with high specific capacity.However,the weak mechanical strength,low compaction density of polycrystal ternary materials and the anisotropy of primary grains lead to intergranular cracks in the polycrystal particles during the charging and discharging process.The electrolyte will penetrate into the polycrystal particles along the intergranular cracks,thus aggravating the side reaction between the electrode and electrolyte and deteriorating the cycle performance and safety of the battery.The design of single crystal material without grain boundary can reduce the formation of intergranular cracks,effectively suppress the side reaction at the interfaces and improve the cycle stability.In this study,the advantages and problems of single-crystal high-nickel ternary materials are reviewed,and their synthesis methods and modification strategies are analyzed.Finally,the application prospects and challenges of single-crystal high-nickel ternary materials are reviewed and prospected.
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