Positive electrode material and preparation method thereof, lithium battery positive electrode and lithium battery

Abstract

The invention discloses a positive electrode material and a preparation method thereof, a lithium battery positive electrode and a lithium battery. The positive electrode material comprises an inner core and a coating layer coating the inner core, and a transition layer is formed between the inner core and the coating layer; the inner core is a positive electrode active material, and the coating layer is a boron-phosphorus dimerization compound; the positive electrode active material is lithium-containing compound particles of LixMyOzFk, and the boron-phosphorus dimerization compound is MaBPbOc. According to the invention, the bipolymer with a B-O-P bond is introduced to coat the positive electrode material, so that the influence of traditional phosphate coating on the reduction of the rate capability of the material is solved, and the cycling stability and the rate of the material are both improved. The coating layer can effectively prevent contact between the material and an electrolyte, inhibit decomposition of the electrolyte and generation of surface side reactions under high voltage, reduce dissolution and precipitation of ions on the surface of the material, improve the stability of the surface structure of the material and the thermal stability and safety of the material and the battery, and further improve the cycle performance and rate capability of the material. And the self-discharge performance of the material is improved.