LR41 battery!Chinese and foreign R&D teams synthesize "double modification" cathode materials for high-energy lithium-ion batteries

Recently, Li Lingjun, associate professor at Changsha University of Science and Technology, collaborated with professors and teams at home and abroad such as Zhang Qiaobao of Xiamen University, Lu Jun of Argonne National Laboratory, the University of Nebraska-Lincoln, and Brookhaven National Laboratory to complete a project Working under the guidance of first-principles calculations, a titanium-doped, lanthanum-nickel-lithium oxide-coated "double-modified" nickel-rich ternary cathode material was simultaneously synthesized.

Nickel-rich ternary cathode materials are considered to be one of the most ideal cathode materials for the next generation of high-energy-density lithium-ion power batteries due to their high reversible capacity and low cost. However, problems such as poor interface stability and decay of the internal structure of secondary particles have seriously hindered the large-scale application of this type of cathode materials.

Recently, Li Lingjun, associate professor at Changsha University of Science and Technology, collaborated with professors and teams at home and abroad such as Zhang Qiaobao of Xiamen University, Lu Jun of Argonne National Laboratory, the University of Nebraska-Lincoln, and Brookhaven National Laboratory to complete a project Working under the guidance of first-principles calculations, a titanium-doped, lanthanum-nickel-lithium oxide-coated "double-modified" nickel-rich ternary cathode material was simultaneously synthesized. This simple and efficient synthesis method is expected to greatly lower the production threshold of high-performance nickel-rich ternary materials. The results were recently published in the international journal "Advanced Functional Materials".

"Among commercial cathode materials, nickel-rich ternary materials with layered structures have high energy density (the specific energy of a single cell can reach 280Whkg-1) and low cost, and are increasingly favored by the market. However, nickel-rich ternary cathodes The material still has problems such as poor interface stability and decay of the internal structure of secondary particles, which seriously hinders its large-scale application." Li Lingjun said.

To this end, the scientific research team focused on high-capacity nickel-rich cathode materials for lithium-ion batteries. After three years of analyzing the migration barriers of titanium and lanthanum on the surface of nickel-rich ternary materials, they found that titanium was incorporated into the bulk phase and lanthanum was enriched. The state on the surface is the state with the lowest energy of the system, that is, the stable state. Based on the theoretical calculation results, they rationally designed and simultaneously synthesized a dual-modified nickel-rich ternary material doped with titanium and coated with lanthanum nickel lithium oxide.

Li Lingjun said that the material exhibits good thermal stability, structural stability and excellent electrochemical properties. "At a high temperature of 60 degrees Celsius, after 150 cycles, the capacity retention rate of the dual-modified material is nearly twice that of the pure-phase nickel-rich material. It can effectively suppress the nanoscale structural degradation of the surface of the nickel-rich material during the cycle. This enhances the surface stability of nickel-rich materials."

In addition, the research team used full-field transmission X-ray microscopy to conduct visual studies on the cathode material before and after cycling, proving that the double modification inhibited the generation of microcracks in the secondary particles of the cathode material and the expansion of microcracks during cycling, and revealed After circulation, the uneven distribution of Ni3+ among the secondary particles of the nickel-rich material is suppressed, and the structural stability of the secondary particles of the material is significantly improved.

This discovery provides new ideas and theoretical guidance for the development and application of nickel-rich ternary materials, and is helpful for the development of high-energy-density lithium-ion power batteries. This research was supported by multiple funds from the National Natural Science Foundation of China, National Key Research and Development Projects, Changsha Outstanding Innovative Youth Training Program, and the U.S. Department of Energy.