Positive electrode active material and preparation method thereof, positive electrode plate, lithium-ion secondary battery, and battery module, battery pack, and apparatus containing such lithium-ion secondary battery

Abstract

A positive electrode active material and a preparation method thereof, a positive electrode plate, a lithium-ion secondary battery, and a battery module, battery pack, and apparatus containing such lithium-ion secondary battery are disclosed. The positive electrode active material includes a lithium nickel cobalt manganese oxide. In the lithium nickel cobalt manganese oxide, the number of moles of nickel accounts for 50% to 95% of the total number of moles of nickel, cobalt, and manganese. The lithium nickel cobalt manganese oxide has a layered crystal structure with a space group R3m. The lithium nickel cobalt manganese oxide includes a doping element. When the positive electrode active material is in a 78% delithiated state, the doping element has two or more different valence states, and the amount of doping element in a highest valence state accounts for 40% to 90% of the total amount of doping element.

Dependencies are inferred from the claim text.