POSITIVE ACTIVE MATERIAL, POSITIVE ELECTRODE PLATE, ELECTROCHEMICAL ENERGY STORAGE APPARATUS, AND APPARATUS

This application provides a positive active material, a positive electrode plate, an electrochemical energy storage apparatus, and an apparatus. The positive active material is LiNiCoMMeOAor LiNiCoMMeOAwhose surface is provided with a coating layer. The positive active material is secondary particles, and a particle size D10 of the positive active material satisfies: 0.5 μm≤D10≤3 μm. In this application, particle morphology of the positive active material and the amount of micro powder in the positive active material are properly controlled, to effectively reduce side reactions between the positive active material and an electrolyte, decrease gas production of the electrochemical energy storage apparatus, and improve storage performance of the electrochemical energy storage apparatus without deteriorating energy density, cycle performance and rate performance of the electrochemical energy storage apparatus.