Preparation method for low-temperature nanometer lithium iron phosphate cathode material

The present invention discloses a method for preparing low-temperature nano-lithium iron phosphate cathode material. The lithium source compound, a trivalent iron source compound, a phosphorus source compound in proportion mixed with water, then add the metal ion-doped mixed oxide and a carbon source, a high energy ultra-fine grinding process for 2-3 hours, spray-dried powders with sieving; powder pretreated in an inert atmosphere at a temperature range of 300-500 deg.] C for 2-10 hours, water was added and cooling the secondary carbon, stirring, after the second high energy superfine grinding process, the slurry spray dried to obtain spherical powder, sieved; spherical powder was jet milled, in an inert gas atmosphere 500-600 ℃ 6-30 hours, and then high temperature heat treatment 600-900 ℃ 10-30 hours, cooled to give a low temperature 60 ~ 70nm nano when the lithium iron phosphate cathode material for lithium ion battery positive electrode, excellent low-temperature discharge performance of the battery.