Nickel composite hydroxide, cathode active material for non-aqueous electrolyte secondary battery, and methods for producing these
A nickel composite hydroxide having a volume-average particle size of the secondary particles of 8.0 μm to 50.0 μm is obtained, by obtaining a nickel composite hydroxide slurry in a primary crystallization process by providing an aqueous solution having at least a nickel salt and a neutralizer into a reaction vessel while continuously stirring in a state of not containing a complex ion formation agent, and controlling the crystallization reaction so that the ratio of the volume-average particles size of secondary particles with respect to that of the secondary particles finally obtained is 0.2 to 0.6, and producing the nickel composite hydroxide in a secondary crystallization process by continuing the crystallization process while keeping the amount of the obtained slurry constant, continuously removing only the liquid component of the slurry, and performing control so that the slurry has a temperature of 70° C. to 90° C. and a pH value at a standard liquid temperature of 25° C. of 10.0 to 11.0.
1. A method for producing a nickel composite hydroxide,
a nickel composite hydroxide comprising spherical shaped secondary particles of nickel composite hydroxide, the secondary particles formed by an aggregation of plural needle shaped or plate shaped primary particles, with a length in a short-diameter direction of the primary particles being 0.1 μm or less, the volume-average particle size (MV) of the secondary particles being 9.0 μm to 50.0 μm, and (D90-D10)/MV that indicates a relationship of the particles size distribution to the volume-average particle size (MV) being less than 0.5
the method comprising a step of providing an aqueous solution including at least a nickel salt and a neutralizer into a reaction vessel while continuously stirring, forming a reaction aqueous solution and producing the nickel composite hydroxide by a crystallization reaction in a state of not containing a complex ion formation agent for forming complex ions with metal elements in the reaction aqueous solution,
the step comprising:
a primary crystallization process of obtaining a nickel composite hydroxide slurry while controlling the crystallization reaction so that a ratio of a volume-average particles size (MV) of secondary particles of nickel composite hydroxide generated in the reaction vessel with respect to a volume-average particle size (MV) of secondary particles of nickel composite hydroxide that are finally obtained is 0.2 to 0.6; and
a secondary crystallization process of continuing the crystallization reaction by keeping an amount of the slurry obtained in the primary crystallization process constant by continuously removing only a liquid component of the slurry while maintaining the state of not containing the complex ion formation agent, and performing control so that a temperature of the slurry is in a range of 70° C. to 90° C., and a pH value at a standard liquid temperature of 25° C. of the slurry is in a range of 10.0 to 11.0 until the volume-average particle size (MV) of the secondary particles of nickel composite hydroxide becomes 8.0 μm to 50.0 μm.
2. The method for producing nickel composite hydroxide according to claim 1 , wherein in the primary crystallization process control is performed so that a temperature of the slurry is in a range of 70° C. to 90° C., and a pH value at a standard liquid temperature of 25° C. is in a range of 10.0 to 11.0.
3. The method for producing nickel composite hydroxide according to claim 1 , wherein a composition of the aqueous solution including the nickel salt is adjusted so that the nickel composite hydroxide has a composition ratio that is expressed by a general expression: Ni 1-x-y Co x M y (OH) 2+A , where 0≦x≦0.35, 0≦y≦0.35, 0≦A≦0.5, and M is at least one additional element selected from Mn, V, Mg, Al, Ti, Mo, Nb, Zr and W.
4. The method for producing nickel composite hydroxide according to claim 1 , wherein a composition of the aqueous solution including the nickel salt is adjusted so that the nickel composite hydroxide has a composition ratio that is expressed by a general expression: Ni 1-x-y Co x M y (OH) 2+A , where 0≦x≦0.22, 0≦y≦0.15, x+y<0.3, 0≦A≦0.5, and M is at least one additional element selected from Mn, V, Mg, Al, Ti, Mo, Nb, Zr and W.
5. The method for producing nickel composite hydroxide according to claim 2 , wherein in the secondary crystallization process, crystallization is continued until the volume-average particle size (MV) of the nickel composite hydroxide becomes 18.0 μm to 50.0 μm.
6. The method for producing nickel composite hydroxide according to claim 1 , wherein in the secondary crystallization process, a cross-flow filtration unit is used to keep the amount of slurry fixed.
7. The method for producing nickel composite hydroxide according to claim 6 , wherein a ceramic filter is used as a filter material of the cross-flow filtration unit.
8. A nickel composite hydroxide comprising:
spherical shaped secondary particles of nickel composite hydroxide, the secondary particles formed by an aggregation of plural needle shaped or plate shaped primary particles, with a length in a short-diameter direction of the primary particles being 0.1 μm or less, the volume-average particle size (MV) of the secondary particles being 9.0 μm to 50.0 μm, and (D90−D10)/MV that indicates a relationship of the particles size distribution to the volume-average particle size (MV) being less than 0.5.
9. The nickel composite hydroxide according to claim 8 having a composition that is expressed by a general expression: Ni 1-x-y Co x M y (OH) 2+A , where 0≦x≦0.35, 0≦y≦0.35, 0≦A≦0.5, and M is at least one additional element selected from Mn, V, Mg, Al, Ti, Mo, Nb, Zr and W.
10. The nickel composite hydroxide according to claim 8 having a composition that is expressed by a general expression: Ni 1-x-y Co x M y (OH) 2+A , where 0≦x≦0.22, 0≦y≦0.15, x+y<0.3, 0≦A≦0.5, and M is at least one additional element selected from Mn, V, Mg, Al, Ti, Mo, Nb, Zr and W.
11. The nickel composite hydroxide according to claim 8 , wherein the volume-average particle size (MV) is 18.0 μm to 50.0 μm.