Positive electrode active material, positive electrode plate, electrochemical energy storage apparatus, and apparatus

A positive active material, wherein

• the positive active material is LixNiyCozMkMepOrAm, or LixNiyCozMkMepOrAm with a coating layer on its surface, wherein 0.85≤x≤1.15, 0<y<1, 0<z<1, 0<k<1, 0≤p≤0.1, 1≤r≤2, 0≤m≤1, m+r≤2, M is selected from one or two of Mn and Al, Me is selected from one or more of Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Sr, Sb, Y, W, and Nb, and A is selected from one or more of N, F, S, and Cl;
• and
• the positive active material is single crystal or quasi-single crystal particles, and a particle size Dn10 of the positive active material satisfies:
• 0.3 μm≤Dn10≤2 μm, wherein
• Dn10 is a corresponding particle size when a cumulative number distribution percentage of the positive active material reaches 10%, wherein
• the particle size Dn10 of the positive active material measured in μm and a particle size Dv10 of the positive active material measured in μm satisfy:
• 0.15≤Dn10×Dv10≤6, and
• Dv10 is a corresponding particle size when a cumulative volume distribution percentage of the positive active material reaches 10% the particle size Dv10 of the positive active material is 0.5 μm to 3 μm.