POSITIVE ELECTRODE ACTIVE MATERIAL, POSITIVE ELECTRODE, BATTERY, BATTERY PACK, ELECTRONIC DEVICE, ELECTRIC MOTOR VEHICLE, POWER STORAGE DEVICE AND ELECTRIC POWER SYSTEM

PROBLEM TO BE SOLVED: To provide a positive electrode active material which enables the increase in volume density of an active material in a positive electrode.SOLUTION: A positive electrode comprises first active material particles, second active material particles and third active material particles. The second active material particles are cohering particles resulting from the agglomeration of primary particles. The average particle diameter D1 of the first active material particles, the average particle diameter D2 of the second active material particles, and the average particle diameter D3 of the third active material particles satisfy the following relation: D1>D2>D3. The particle collapse rate α1 of the first active material particles and the particle collapse rate α2 of the third active material particles are 20% or less, and the particle collapse rate β of the second active material particles is 70% or more.SELECTED DRAWING: Figure 1 【課題】正極における活物質の体積密度を向上できる正極活物質を提供する。【解決手段】正極は、第１活物質粒子と、第２活物質粒子と、第３活物質粒子とを含み、第２活物質粒子が、一次粒子が凝集した凝集粒子である。第１活物質粒子の平均粒径Ｄ１、第２活物質粒子の平均粒径Ｄ２および第３活物質粒子の平均粒径Ｄ３が、Ｄ１＞Ｄ２＞Ｄ３の関係を満たす。第１活物質粒子の粒子崩壊率α１および第３活物質粒子の粒子崩壊率α２は、２０％以下であり、かつ第２活物質粒子の粒子崩壊率βは、７０％以上である。【選択図】図１