MATÉRIAU ACTIF DE CATHODE POUR BATTERIE SECONDAIRE, SON PROCÉDÉ DE PRÉPARATION ET BATTERIE SECONDAIRE AU LITHIUM COMPRENANT CELUI-CI

摘要

The present invention provides a positive electrode active material for a secondary battery, the positive electrode active material being a lithium cobalt-based oxide including a doping element M, wherein a lithium cobalt-based oxide particle containing the doping element M in an amount of 3,000 ppm or more, wherein in a bulk portion corresponding to 90% of a core side among the radius from a core of the particle to a surface thereof, the doping element M in the lithium cobalt-based oxide particle is contained at a constant concentration, and in a surface portion from the surface of the particle to 100 nm in a core direction, the doping element M is contained at a concentration equal to or higher than that in the bulk portion and has a concentration in which the concentration thereof is gradient gradually decreased in the core direction from the surface of the particle.