Nickel manganese composite hydroxide particles and manufacturing method thereof, cathode active material for a non-aqueous electrolyte secondary battery and manufacturing method thereof, and a non-aqueous electrolyte secondary battery
Provided are nickel manganese composite hydroxide particles having a small and uniform particle size and having a double structure which enables to obtain a cathode active material having a hollow structure, and a manufacturing method thereof. When obtaining the nickel manganese composite hydroxide by a reaction crystallization, using an aqueous solution for nucleation, which includes at least a metallic compound that contains nickel, a metallic compound that contains manganese and an ammonium ion donor and controlling the pH value that is measured at a standard solution temperature of 25° C. is 10.5 to 12.0, nucleation is performed in an oxidizing atmosphere in which the oxygen concentration is greater than 1% by volume, and then nuclei are grown by switching the atmosphere from the oxidizing atmosphere to a mixed atmosphere of oxygen and inert gas in which the oxygen concentration is 1% by volume or less.
1. A cathode active material for a non-aqueous electrolyte secondary battery comprises lithium nickel manganese composite oxide particles having a layered hexagonal crystal structure and expressed by a general formula of Li 1+u Ni x Mn y Co z M t O 2 (where −0.05≤u≤0.50, x+y+z+t=1, 0.3≤x≤0.7, 0.1≤y≤0.55, 0≤z≤0.4, 0≤t≤0.1, M is one or more added elements that are selected from among Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo and W), the cathode active material having an average particle size of 2 to 8 μm, a value [(d90−d10)/average particle size], which is an index indicating an extent of particle size distribution thereof, of 0.60 or less, and having a hollow structure provided with an outer shell section of aggregated sintered primary particles and a hollow section inside the outer shell section,
wherein a ratio of the thickness of the outer shell section
with respect to the particle size of the lithium nickel
manganese composite oxide particles is 5 to 45%.
2. The cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the ratio of the thickness of the outer shell section with respect to the particle size of the lithium nickel manganese composite oxide particles is 8 to 38%.
3. A non-aqueous electrolyte secondary battery, the cathode thereof being formed using the cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 .
4. The cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the average particle size is 3 to 6.5 μm, and the value [(d90−d10)/average particle size] is 0.55 or less.
5. The cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the ratio of the thickness of the outer shell section with respect to the particle size of the lithium nickel manganese composite oxide particles is 8 to 14%.
6. The cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the absolute value of the thickness of the outer shell section is 0.5 to 2.5 μm.