POSITIVE ACTIVE MATERIAL, POSITIVE ELECTRODE PLATE, LITHIUM-ION BATTERY, AND ELECTRICAL DEVICE

Provided are a positive active material, a positive electrode plate, a lithium-ion battery, and an electric device. The positive active material includes lithium iron phosphate particles. A volume percentage of the lithium iron phosphate particles having a particle size smaller than 1 μm is x, and a volume percentage of the lithium iron phosphate particles having a particle size greater than 5 μm is z, z/x ranging from 0.5 to 2.8.