High-performance lithium iron manganese phosphate positive electrode material, low-cost preparation method thereof and lithium ion battery

The invention discloses a high-performance lithium iron manganese phosphate positive electrode material, a low-cost preparation method thereof and a lithium ion battery, and the preparation method comprises the following steps: adjusting the pH value of a manganese source containing iron impurities or an iron source containing manganese impurities to weak acidity, and then filtering to obtain a lithium iron manganese phosphate precursor; adding the lithium manganese iron phosphate precursor, a lithium source and a carbon source into water, and uniformly mixing to obtain mixed slurry; grinding the mixed slurry, and performing spray drying to obtain a spray material; and carrying out high-temperature sintering on the spray material to obtain the high-performance lithium iron manganese phosphate positive electrode material. The low-cost lithium manganese iron phosphate positive electrode material is prepared from the manganese source containing the iron impurities or the iron source containing the manganese impu