Method for preparing positive electrode active material

Abstract

One aspect of the present invention relates to a positive electrode active material that is stable in high potential and / or high temperature conditions. To provide a method for producing quality, or a positive electrode active material whose crystal structure is resistant to breakdown even after repeated charging and discharging. To provide a method for producing quality. [Solution] The structure is designed to be resistant to deformation and cleavage under stress in the c-axis direction. To suppress the occurrence of cracks, one aspect of the present invention is a composite containing lithium and cobalt. The positive electrode has an oxide-containing positive electrode active material, and the positive electrode active material is doped (also called an additive element) The positive electrode has nickel in the interior (or center) and magnesium on the surface. .

Claims

1. A secondary battery having a positive electrode and a negative electrode, The positive electrode has particles of a composite oxide containing lithium and cobalt. The aforementioned particle is a secondary particle composed of aggregates of multiple primary particles, It has primary particles in the surface layer and primary particles in the central part located inside the surface layer, The primary particles in the surface layer are cobalt oxide CoO, whose crystalline structure is the O3 phase. ２ It has magnesium between its layers, The primary particles in the central part are cobalt oxide CoO, whose crystal structure is the O3 phase. ２ A secondary battery having nickel between its layers.

2. A secondary battery according to claim 1, wherein, after charging and discharging the secondary battery, the number of cracks in the primary particles in the central part is less than the number of cracks in the primary particles per unit area of ​​the primary particle cross-section of the surface part.

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