The invention relates to a positive
electrode active material, a battery, and a method for manufacturing the positive
electrode active material. Provided is a positive
electrode active material capable of achieving low battery resistance. A positive electrode active material having particles of a
compound A having a composition represented by LixNiaCobMncOy and particles of a compound B having a composition represented by MdOe, in the particles of the compound B, the abundance ratio of an element having an
ion radius alpha of # imgabs0 # is 45 mol% or more, and the content of the element having an
ion radius alpha of # imgabs0 # relative to the total of the particles of the
compound A and the particles of the compound B is 5 mol% or more. The
area ratio X of the particles of the compound B is 0.8% < = X < = 19.6%. Wherein 0.1 < = x < = 1.5, 0.5 < = a < = 1.0, 0 < = b < = 0.3, 0 < = c < = 0.3, a + b + c = 1.0, and 1.5 < = y < = 2.1, 0.001 < = d < = 0.2, and 0.002 < = e < = 0.4, and M represents at least one element selected from the group consisting of Ti, Zr, Ta, Pr, K, La, Ba, Y, Sr, Ce, Se, Hf, and Rh.