Positive electrode active material composition, positive electrode plate, battery and electric device

The invention provides a positive active material composition, a positive pole piece, a battery and an electric device. The positive electrode active material composition comprises a first positive electrode active material and a second positive electrode active material, wherein the first positive electrode active material comprises an inner core Li < a > A < b > Mn < f > B < 1-f > P < 1-d > R < d > O < 4-n > D < n > and a coating layer coating the inner core, the second positive electrode active material comprises a compound Li < Ni < x > Co < y > M < 1-x-y > O < 2 >, and z is more than or equal to 0.018 m + 0.003 f and less than or equal to 0.02 m + 0.02 f.