POSITIVE ELECTRODE PLATE, LITHIUM ION BATTERY, AND ENERGY STORAGE DEVICE

Provided are a positive electrode plate, a lithium ion battery, and an energy storage device. The positive electrode plate includes a positive current collector and a positive active substance layer. The positive active substance layer is disposed on at least part of a surface of the positive current collector. The positive active substance layer contains a positive active substance doped with a metal element M. A doping amount of the metal element M in the positive active substance of the positive active substance layer gradually decreases in a thickness direction away from the positive current collector. A ratio of a doping amount of the metal element M in the positive active substance of the positive active substance layer closest to the positive current collector to a doping amount of the metal element M in the positive active substance of the positive active substance layer farthest from the positive current collector is less than or equal to 8. According to the present disclosure, resistance of lithium ions to diffuse in the positive electrode plate is significantly reduced, while polarization of the lithium ions in a diffusion process of the positive electrode plate is inhibited, thereby improving cycle performance and energy efficiency of the lithium ion battery.