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 manufacturing method for manufacturing 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, and
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 crystalline structure,
an average particle size of 2 to 8 μm,
a value of 0.60 or less of index [(d90−d10)/average particle size] indicating an extent of a particle size distribution,
a specific surface area of 1 to 2 m 2 /g, and
a hollow structure comprising a hollow section inside in a center section of the secondary particles and an outer shell section on the outside of the hollow section formed with the aggregated primary particles and the thickness of the outer shell section being 0.5 to 2.5 μm;
the manufacturing method comprising:
a mixing step of mixing a lithium compound into nickel manganese composite hydroxide particles,
the nickel manganese composite hydroxide particles comprising:
spherical secondary particles formed with aggregated primary particles of a nickel manganese composite hydroxide, the nickel manganese composite hydroxide expressed by the general formula:
Ni x Mn y Co z M t (OH) 2+a
wherein
x+y+z+t=1,
0.3≤x≤0.7, 0.1≤y≤0.55,
0≤z≤0.4,
0≤t≤0.1,
0≤a≤0.5, and
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 nickel manganese composite hydroxide particles comprise
an average particle size of 3 to 7 μm,
a value of 0.55 or less of index [(d90−d10)/average particle size] indicating an extent of a particle size distribution, and
a layered structure comprising a center section formed with fine primary particles, and an outer shell section on the outside of the center section formed with plate shaped or needle shaped primary particles that are larger than the fine primary particles, and the thickness of the outer shell section being 0.3 to 3 μm; and
a calcination step of performing calcination of a mixture of the lithium compound and the nickel manganese composite hydroxide particles formed in the mixing step in an oxygen atmosphere at a temperature of 800° C. to 980° C.
2. The manufacturing method for manufacturing the cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein
the mixture is adjusted so that a ratio of the sum of the number of metal atoms other than lithium included in the mixture and the number of lithium atoms is 1:0.95 to 1.5.
3. The manufacturing method for manufacturing the cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein
the nickel manganese composite hydroxide particles have already been heat-treated before the mixing step at a temperature of 105° C. to 750° C.
4. The manufacturing method for manufacturing the cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein
temporary calcination has already been performed on the mixture after the mixing step and before the calcination step at a temperature of 350° C. to 800° C.
5. The manufacturing method for manufacturing the cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein
The calcination step is performed under an oxygen atmosphere having an oxygen content of 18% by volume to 100% by volume.