Aluminum phosphate double-modified high-nickel cobalt-free polycrystalline positive electrode material and preparation method thereof

The preparation method comprises the following steps: (A) preparing a high-nickel cobalt-free polycrystalline positive electrode material precursor through a coprecipitation method, carrying out reaction aging, collecting a precipitate, washing, filtering and collecting a filter cake; (B) adding a phosphorus-containing source and an aluminum source into the filter cake to obtain a high-nickel cobalt-free polycrystalline positive electrode material precursor uniformly doped and coated with aluminum phosphate; (C) uniformly mixing the high-nickel cobalt-free polycrystalline positive electrode material precursor uniformly doped and coated with aluminum phosphate with lithium salt; and (D) calcining the mixture at high temperature to obtain the aluminum phosphate double-modified high-nickel cobalt-free polycrystalline positive electrode material. A high-nickel cobalt-free polycrystalline positive electrode material precursor uniformly doped and coated with aluminum phosphate is realized through a semi-wet package