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 that are a precursor for forming cathode active material comprising lithium nickel manganese composite oxide having hollow structure of particles having a small and uniform particle size for obtaining a non-aqueous electrolyte secondary battery having high capacity, high output and good cyclability. When obtaining the nickel manganese composite hydroxide particles from a crystallization reaction, an aqueous solution for nucleation, which includes at least a metallic compound that contains nickel and a metallic compound that contains manganese, and does not include a complex ion formation agent that forms complex ions with nickel, manganese and cobalt, is controlled so that the temperature of the solution is 60° C. or greater, and so that the pH value that is measured at a standard solution temperature of 25° C. is 11.5 to 13.5, and after nucleation is performed, an aqueous solution for particle growth, which includes the nuclei that were formed in the nucleation step and does not substantially include a complex ion formation agent that forms complex ions with nickel, manganese and cobalt, is controlled so that the temperature of the solution is 60° C. or greater, and so that the pH value that is measured at a standard solution temperature of 25° C. is 9.5 to 11.5, and is less than the pH value in the nucleation step.
1. A cathode active material for a non-aqueous electrolyte secondary battery, the cathode active material comprising:
spherical secondary particles formed with aggregated primary particles of a lithium nickel manganese composite oxide, the lithium nickel manganese composite oxide expressed by the general formula Li 1+u Ni x Mn y Co z M t O 2
wherein
−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 an added element selected from one or more elements from among Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo and W;
wherein the secondary particles comprise
a layered hexagonal crystal structure,
an average particle size of 3 to 6.5 μm,
a value of 0.55 or less of index ((d90−d10)/average particle size) indicating an extent of a particle size distribution,
a specific surface area of 1 to 1.8 m 2 /g, and
a hollow structure comprising a hollow section formed in a center section of the secondary particles and an outer shell section on the outside of the hollow section, the thickness of the outer shell section being 0.5 to 2 μm; and
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 0.05 to 0.38.
2. A non-aqueous electrolyte secondary battery, the battery comprising:
a cathode comprising a cathode active material,
the cathode active material comprising
spherical secondary particles formed with aggregated primary particles of a lithium nickel manganese composite oxide, the lithium nickel manganese composite oxide expressed by the general formula Li 1+u Ni x Mn y Co 2 M t O 2
wherein
−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 an added element selected from one or more elements from among Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo and W;
wherein the secondary particles comprise
a layered hexagonal crystal structure,
an average particle size of 3 to 6.5 μm,
a value of 0.55 or less of index ((d90−d10)/average particle size) indicating an extent of a particle size distribution,
a specific surface area of 1 to 1.8 m 2 /g, and
a hollow structure comprising a hollow section formed in a center section of the secondary particles and an outer shell section on the outside of the hollow section, the thickness of the outer shell section being 0.5 to 2 μm; and
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 0.05 to 0.38.