There are mainly four kinds of olivine phosphate LiMPO4 (M represents metal, mainly iron Fe, nickel Ni, manganese Mn and cobalt Co); The voltages are 3.4~3.5V (iron), 5.0~5.4V (nickel), 4.0~4.2V (manganese) and 4.7~4.8V (cobalt) respectively. At the same time, the four phosphates can be doped with each other to form multiple olivine series materials. The charge-discharge curves and cyclic voltammetry curves of the multi-element system can be simply regarded as the linear superposition of the charge-discharge curves and cyclic voltammetry curves of the four separate olivines. Since the voltage of lithium nickel phosphate exceeds the current upper limit of electrolyte stability, cobalt is not the main constituent element. On the contrary, manganese is friendly to the environment, and the working voltage of lithium manganese phosphate is ideal (at 4.1V), which can be matched with the existing commercial electrolytic solution.

Lithium manganese iron phosphate (LMFP) is a new cathode material obtained by adding manganese on the basis of lithium iron phosphate. On the one hand, it can improve the voltage of the material system and make up for the low energy density caused by the low voltage of lithium iron phosphate; on the other hand, it can improve the conductivity by surface coating carbon material conductive agent.