a crystal size D₁₀₄ of the positive electrode material and a particle size distribution change rate ΔPSD of the positive electrode material satisfy: 50 nm≤D₁₀₄×ΔPSD≤450 nm, where ΔPSD is a particle size distribution change rate calculated according to the formula ΔPSD=(D_v90?D_v10)/D_v50 through volume particle distribution measurement on the positive electrode material, D₁₀₄ is a crystal size obtained by fitting a peak value of a 104 crystal plane through XRD ray diffraction testing on the positive electrode material, and D₁₀₄ is measured in nm.

The positive electrode material in this application uses a mixed material of a large-particle lithium-nickel transition metal oxide A (large-particle high-nickel ternary polycrystalline positive electrode material) and a small-particle lithium-nickel transition metal oxide B (small-particle high-nickel ternary monocrystalline positive electrode material). A degree of crystallinity and particle size distribution of the mixed high-nickel active material can be controlled to effectively mitigate the particle crushing problem during cold pressing and cycling, improve the compacted density of the high-nickel powder, and also ensure lower gassing and good cycle performance.

In the positive electrode material provided in this application, monocrystalline-like means that the primary particles are larger than 1 μm in size, but the primary particles are agglomerated. Monocrystalline means that the primary particles are larger than 1 μm in size, but are not agglomerated obviously.

In the positive electrode material provided in this application, a range of D₁₀₄×ΔPSD is optionally 50 nm to 450 nm, 50 nm to 80 nm, 80 nm to 120 nm, 80 nm to 250 nm, 120 nm to 250 nm, 250 nm to 350 nm, or 350 nm to 450 nm.