Nickel-cobalt composite hydroxide and method and device for producing same, cathode active material for non-aqueous electrolyte secondary battery and method for producing same, and non-aqueous electrolyte secondary battery
To improve cycling characteristics of a non-aqueous electrolyte secondary battery by obtaining a nickel-cobalt composite hydroxide having a sharp particle size distribution as a precursor, a slurry including a nickel-cobalt composite hydroxide obtained by continuously supplying an aqueous solution that includes at least nickel and cobalt, an ammonium ion donor aqueous solution and a caustic alkali aqueous solution to a reaction vessel and reacting, is continuously extracted and separated into a large particle size portion and s small particle size portion by classification, and the small particle size portion is continuously returned to the reaction vessel. As a result, a nickel-cobalt composite hydroxide is obtained that is expressed by the general formula: Ni 1-x-y Co x M y (OH) 2 (where, 0.05≤x≤0.50, 0≤y≤0.10, 0.05≤x+y≤0.50, and M is at least one kind of metal element selected from among Al, Mg, Mn, Ti, Fe, Cu, Zn and Ga, and that satisfies the relationships (D50−D10)/D50≤0.30, and (D90−D50)/D50≤0.30 among D10, D50 and D90 of this composite hydroxide.
1. In combination, a nickel-cobalt composite hydroxide and a production device for producing the nickel-cobalt composite hydroxide, the combination comprising:
the nickel-cobalt composite hydroxide comprising
a general formula: Ni 1-x-y Co x M y (OH) 2 (where, 0.05≤x≤0.50, 0≤y≤0.10, 0.05≤x+y≤0.50, and M is at least one kind of metal element selected from among Al, Mg, Mn, Ti, Fe, Cu, Zn and Ga,
an average particle size of within a range from 10 μm to 30 μm, and
(D50−D10)/D50≤0.30, and (D90−D50)/D50≤0.30 among D10, D50 and D90 of the nickel-cobalt composite hydroxide; and
the production device comprising
a reaction vessel;
a constant volume pump for continuously supplying an aqueous solution including nickel and cobalt, an aqueous solution including an ammonium ion donor, and a caustic alkali aqueous solution to the reaction vessel;
a constant volume pump for with an extraction nozzle for continuously extracting nickel-cobalt composite hydroxide generated by a reaction inside the reaction vessel from the reaction vessel by way of the extraction nozzle;
a separation apparatus separating the extracted nickel-cobalt composite hydroxide into a large particle size portion and a small particle size portion by classification; and
a reflux apparatus continuously returning the small particle size portion separated out to the reaction vessel.
2. The combination of claim 1 , wherein the nickel-cobalt composite hydroxide has a tap density of 2.0 g/cm 3 or greater.