POSITIVE ELECTRODE MATERIAL AND PREPARATION METHOD AND USE THEREFOR, LITHIUM-ION BATTERY POSITIVE ELECTRODE POLE PIECE, AND LITHIUM-ION BATTERY

The present disclosure relates to the technical field of secondary battery, and discloses a positive electrode material and a preparation method and use therefor, a lithium-ion battery positive electrode poly piece, and a lithium-ion battery. The positive electrode material comprises multicrystal particles A and single crystal particles or quasi single crystal particles B; the particle diameters D5, D50 and D95 of the cathode material satisfy the relationship shown in Formula I: 1.5≤K95=D95−D5/D50≤2.5 The positive electrode material comprises multicrystal particles A and single crystal particles or quasi single crystal particles B, whereby it can significantly suppress generation of micro-cracks in the cathode material, and enhance particle strength of the positive electrode material, so that the positive electrode material has a high compaction density and a high compressive strength, thereby ensuring that a battery comprising the positive electrode material has a high volumetric energy density and a relatively long cycle life.