Cathode active material precursor particle, cathode active material particle for lithium secondary battery and lithium secondary battery

A lithium secondary battery cathode active material particle, which is formed as a secondary particle that is a mass of a plurality of single-crystal primary particles of a lithium-nickel-based complex oxide having a layered rock salt structure, characterized in that:

• the primary particles have a mean particle size of 0.01 to 5 μm, and
• the secondary particle has an aspect ratio, which is expressed as a value calculated by dividing a long axis diameter by a short axis diameter, of 1.0 or more and less than 2 and a mean particle size of 1 to 100 μm, wherein the (003) planes of the second particle are substantially uniaxially oriented.

A lithium secondary battery comprising a cathode including a cathode active material layer, and an anode including an anode active material layer, characterized in that:

• the cathode active material layer contains a cathode active material particle formed as a secondary particle which is a mass of a plurality of single-crystal primary particles of a lithium-nickel-based complex oxide having a layered rock salt structure,
• the primary particles have a mean particle size of 0.01 to 5 μm, and
• the secondary particle has an aspect ratio, which is expressed as a value calculated by dividing a long axis diameter by a short axis diameter, of 1.0 or more and less than 2 and a mean particle size of 1 to 100 μm, wherein the (003) planes of the second particle are substantially uniaxially oriented.