In recent years, the application of lithium-ion batteries has made rapid progress, and the world can do everything. Especially in the application of electric vehicles and energy storage in small power grids, it has achieved remarkable results. But as the scope of application is wider, people's requirements for energy density, cycle performance and rate performance are becoming higher and higher.
In the internal structure of a lithium battery, there are many factors that affect its performance improvement, and the four materials of positive and negative materials, separator and electrolyte are particularly critical. Among them, the positive electrode material of the lithium ion battery is an important part of limiting the increase of its energy density.
Compared with the currently commercialized lithium cobalt oxide, lithium iron phosphate and ternary materials, the high nickel layered material has the advantages of high capacity and low cost, and is one of the first choices for the next-generation power battery cathode material. However, its poor cycle stability and rate performance become the main factors restricting its commercial application. This has a great relationship with the surface structure and chemical properties of high nickel cathode materials.
The good news is that China has made new progress in research on the surface structure and chemical properties of high-nickel cathode materials.
Recently, the Clean Energy Center research team led by Professor Pan Feng of the School of New Materials, Peking University Shenzhen Graduate School cooperated with Professor Wang Feng and Professor Bai Jianming of Brookhaven National Laboratory in the United States to use in-situ synchrotron radiation X-ray diffraction spectrum and X-ray Absorption spectroscopy (XPS), scanning transmission microscopy-electron energy loss spectroscopy (STEM-EELS) combined with electrochemical characterization, the surface reconstruction phenomenon and related mechanisms of high nickel layered oxide materials in lithium ion batteries during the preparation process were deeply studied Research, this work was recently published in the well-known journal "Advanced Energy Materials" (Advanced Energy Materials, IF = 24.884) in the field of energy materials.
In addition, the use of synchrotron radiation technology has carried out in-depth systematic research on the effect and mechanism of surface reconstruction on the cation disorder (lithium-nickel mixed discharge) in the preparation process of high-nickel layered oxide materials for lithium batteries, and related work was published in famous journals "Journal of Materials Chemistry A".
At present, high-nickel ternary materials are one of the mainstream development directions for battery materials. It is of great significance to study the surface structure of high-nickel materials and find out the structural origin and mechanism that affect their electrochemical performance, so as to improve the electrochemical performance of high-nickel materials and speed up their industrialization.