The invention discloses a preparation method of a
lithium iron phosphate cathode material. The preparation method comprises the following steps of (1), dispersing
iron phosphate into a dispersing agent, so as to obtain dispersion liquid A of the
iron phosphate; (2), dispersing a
lithium carbonate and
magnesium chloride doping agent into a dispersing agent, so as to obtain
lithium source-
magnesium source
doping agent dispersion liquid B; (3), slowly adding the dispersion liquid A of the iron
phosphate into the lithium source-
magnesium source
doping agent dispersion liquid B, enabling an obtained first mixture to react to make a coarse material of a
lithium iron phosphate material; (4),
grinding and uniformly mixing the coarse material of the
lithium iron phosphate material and carbon-source glucose in a dispersing medium
ethanol,
drying an obtained second mixture,
sintering the second mixture for 12h to 24h at a temperature of 700 to 750 DEG C in a protective
atmosphere of a
nitrogen gas, and naturally cooling the second mixture to a
room temperature, so as to obtain the
lithium iron phosphate cathode material. The non-in-situ
carbon coating is adopted by the preparation method; meanwhile, the
carbon coating is carried out in a
sintering process; the increment of a
crystal particle of the lithium iron
phosphate material in a long-time high-temperature
sintering process is limited; the
electronic conductivity and the
ion diffusion rate of the material are further improved; the lithium iron
phosphate cathode material has better rate charging and discharging performance.