Positive electrode active material, secondary battery, battery module, battery pack and power consuming device

A positive electrode active material, comprising

• an active material A having a composition formula of
• Lix1Nia1Cob1Mnc1O2-y1Qy1 I
• wherein in formula I:
• 0.95≤x1≤1.3, 0.7≤a1≤0.99, 0.01≤b1≤0.15, 0.01≤c1≤0.3, a1+b1+c1=1, and 0≤y1≤0.1;
• and
• Q is one or more selected from S, N, F, Cl, Br, and I;
• an active material B having a composition formula of
• Lix2Nia2COb2Mnc2O2-y2Qy2 II
• wherein in formula II:
• 0.95≤x2≤1.3, 0.7≤a2≤0.99, 0.01≤b2≤0.15, 0.01≤c2≤0.3, a2+b2+c2=1, and 0≤y2≤0.1;
• and
• Q is one or more selected from S, N, F, Cl, Br and I;
• and
• an active material C having a composition formula of
• Lix3Nia3Cob3Mnc3O2-y3Qy3 III
• wherein in formula III:
• 0.95≤x3≤1.3, 0.3≤a3≤0.7, 0.01≤b3≤0.15, 0.01≤c3≤0.5, a3+b3+c3=1, and 0≤y3≤0.1;
• and
• Q is one or more selected from S, N, F, Cl, Br and I,
• wherein an average particle size Dv50 of the active material A is greater than both an average particle size Dv50 of the active material B and an average particle size Dv50 of the active material C.