Lithium-ion secondary battery, battery apparatus, electric apparatus, preparation method for positive electrode active material, and preparation method for positive electrode plate

Abstract

The disclosure relates to a lithium-ion secondary battery, a battery apparatus, an electric apparatus, and methods for preparing a positive electrode active material and a positive electrode plate. The lithium-ion secondary battery includes a positive electrode plate, a negative electrode plate, and an electrolyte. The positive electrode plate comprises a current collector and a film layer disposed on at least one side of the current collector. The film layer comprises a positive electrode active material including lithium-containing transition metal phosphate particles, at least part of the surfaces of which are coated with a carbon material. In a section of the film layer along the electrode plate thickness direction, an area proportion of particles with a particle size greater than or equal to 1.5 μm is 8.0% to 20.0%. In a cumulative distribution curve of graphitization degree, a median C50 of the film layer ranges from 0.95 to 1.20.