High-compaction lithium manganese iron phosphate positive electrode material as well as preparation method and application thereof

The invention discloses a high-compaction lithium manganese iron phosphate positive electrode material as well as a preparation method and application thereof. The method comprises the following steps: firstly, by taking manganese salt, ferrous salt and phosphate as raw materials, carrying out coprecipitation under different conditions to obtain manganese ferric ammonium phosphate slurry, mixing the manganese ferric ammonium phosphate slurry with different properties according to a certain ratio, carrying out liquid-solid separation to obtain a solid-phase product, and drying, roasting and dehydrating to obtain manganese ferric ammonium phosphate powder. Putting the manganese ferric ammonium phosphate powder, a lithium source, a carbon source, a ball milling auxiliary agent and zirconium oxide beads into a ball milling tank according to a certain proportion for ball milling; and separating the zirconium beads after the ball milling is completed, drying, calcining and grinding the obtained mixture, and finally