POSITIVE ELECTRODE ACTIVE MATERIAL, PREPARATION METHOD THEREFOR, POSITIVE ELECTRODE PLATE, LITHIUM ION SECONDARY BATTERY, AND BATTERY MODULE, BATTERY PACK AND DEVICE COMPRISING LITHIUM ION SECONDARY BATTERY

A positive electrode active material and a preparation method thereof, a positive electrode plate, a lithium-ion secondary battery (5), and a battery module (4), a battery pack (1), and apparatus containing the lithium-ion secondary battery (5) are provided. The positive electrode active material includes secondary particles formed by agglomeration of primary particles, where the primary particles include a layered nickel-containing lithium composite oxide, and the nickel-containing lithium composite oxide includes a doping element; and when the positive electrode active material is charged from an 11% delithiated state to a 78% delithiated state at a rate of 0.1C, a lattice of the primary particles has a maximum shrinkage rate satisfying Δa ≤ 3.00% in an a-axis direction, and a maximum swelling rate satisfying Δc ≤ 3.02% in a c-axis direction.