Lithium metal composite oxide, positive electrode active material for lithium secondary batteries, positive electrode and lithium secondary battery
AssigneeSumitomo Chemical Company, Limited
InventorKenji Takamori
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Abstract
A lithium metal composite oxide composed of secondary particles that are aggregates of primary particles, and single particles that exist independently from the secondary particles, wherein the lithium metal composite oxide is represented by a compositional formula (1), and satisfies requirements (A), (B) and (C).
Claims20
A lithium metal composite oxide composed of secondary particles that are aggregates of primary particles, and single particles that exist independently from the secondary particles, wherein the lithium metal composite oxide is represented by a compositional formula (1) shown below, and satisfies requirements (A), (B) and (C) described below:
- Li[Lix(Ni(1-y-z-w)CoyMnzMw)1-x]O2 (1)
- (wherein M is at least one element selected from the group consisting of Fe, Cu, Ti, Mg, Al, W, B, Mo, Nb, Zn, Sn, Zr, Ga and V, −0.1≤x≤0.2, 0<y≤0.4, 0≤z≤0.4 and 0≤w≤0.1)
- (A) a BET specific surface area of the lithium metal composite oxide is less than 2 m2/g,
- (B) the lithium metal composite oxide has at least two peaks in a number-based circularity distribution of circularity determined using a formula (2) shown below:
- Circularity=4πS/L2 (2)
- (wherein S is a projected surface area in a projected image of a particle that constitutes a powder of the metal composite oxide, and L is a circumference of the particle), and
- (C) an average particle size D50 of the lithium metal composite oxide is at least 2 μm but not more than 20 μm.
Dependencies are inferred from the claim text.