Synthesis of "Double Modified" Cathode Materials for High Energy Lithium Ion Batteries

The nickel-rich ternary cathode material is considered to be one of the most ideal cathode materials for the next generation of high energy density lithium ion power batteries due to its high reversible capacity and low cost. However, problems such as poor interface stability and declining internal structure of secondary particles have seriously hindered the large-scale application of such positive electrode materials.

Recently, Li Lingjun, an associate professor at Changsha University of Science and Technology, has completed a collaboration with professors and teams at Xiamen University, Zhang Qiaobao, Argonne National Laboratory Lu Jun, University of Nebraska-Lincoln, Brookhaven National Laboratory, and other domestic and foreign professors and teams. Work, through the first-principles calculation as a guide, synthesize a "double-modified" nickel-rich ternary cathode material coated with titanium doped and lanthanum nickel lithium oxide. This simple and efficient synthesis method is expected to greatly reduce the production threshold of high-performance nickel-rich ternary materials. The results were published in the international journal Advanced Functional Materials.

From the analysis of the migration barrier of titanium and niobium on the surface of nickel-rich ternary materials, the team found that titanium is incorporated into the bulk phase and escapes to the surface state, which is the state with the lowest energy of the system. According to the theoretical calculation results, they rationally designed and synthesize the "double-modified" nickel-rich ternary materials. The material exhibits good thermal stability, structural stability and excellent electrochemical properties. After 150 cycles at 60 °C, the capacity retention of the dual-modified material was nearly double that of the pure phase nickel-rich material. After full-field transmission X-ray microscopy was used to visualize the positive/back cycle of the positive electrode material, the team demonstrated that “dual modification” can inhibit the generation of microcracks in the secondary particles of the positive electrode material and the microcrack propagation during the cycle. The uneven distribution of Ni3+ between the secondary particles of the post-rich nickel material is effectively suppressed, thereby significantly improving the structural stability of the secondary particles of the material.

This discovery provides new ideas and theoretical guidance for the development and application of nickel-rich ternary materials, and contributes to the development of high energy density lithium ion power batteries.


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