CATHODE ACTIVE MATERIAL AND PREPARATION METHOD THEREOF, POSITIVE ELECTRODE PLATE, BATTERY, AND ELECTRICAL DEVICE

Provided are a cathode active material and a preparation method thereof, a positive electrode plate, a battery, and an electrical device. The present disclosure relates to the technical field of batteries. A change An in a content of Fe in the cathode active material satisfies Δn≥0.1 and Δn=n1−n2; n1 is a content of Fe in the cathode active material prior to charging, and n2 is a content of Fein the cathode active material when charging to 4.0 V; and the content of Fe=amount of Fe substance in the cathode active material/(the amount of Fe substance in the cathode active material+amount of Fe substance in the cathode active material). Therefore, by using the cathode active material, a battery loaded with the cathode active material can have excellent energy density.