Nickel-manganese composite hydroxide, method for producing the same, positive electrode active material for nonaqueous electrolyte secondary battery, method for producing the same, and nonaqueous electrolyte secondary battery
Provided are a positive electrode active material with which a nonaqueous electrolyte secondary battery having a high energy density can be obtained, a nickel-manganese composite hydroxide suitable as a precursor of the positive electrode active material, and production methods capable of easily producing these in an industrial scale. Provided is a nickel-manganese composite hydroxide represented by General Formula (1): Ni x Mn y M z (OH) 2+α and containing a secondary particle formed of a plurality of flocculated primary particles. The nickel-manganese composite hydroxide has a half width of a diffraction peak of a (001) plane obtained by X-ray diffraction measurement of at least 0.10° and up to 0.40° and has a degree of sparsity/density represented by [(void area within secondary particle/cross section of secondary particle)×100](%) of at least 0.5% and up to 10%. Also provided is a production method of the nickel-manganese composite hydroxide.
1. A positive electrode active material for a nonaqueous electrolyte secondary battery, the positive active material comprising: a lithium-nickel-manganese composite oxide represented by General Formula (2): Li 1+t Ni x Mn y M z O 2+β in Formula (2), M is at least one additional element selected from Co, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, Fe, and W; and t, x, y, z, and β satisfy −0.05≤t≤0.5, 0.1≤x≤0.9, 0.05≤y 0.8, 0≤z≤0.8, x+y+z=1.0, and 0≤β≤0.5 and containing a secondary particle formed of a plurality of flocculated primary particles, wherein
a degree of sparsity/density represented by [(void area within secondary particle/cross section of secondary particle)×100](%) is at least 0.5% and up to 12%, and a DBP absorption amount measured in accordance with JIS K6217-4 is at least 12 cm 3 /100 g and up to 20 cm 3 /100 g, and
[(D90−D10)/average particle diameter] that is an indicator to represent a spread of particle size distribution is at least 0.7.
2. The positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein a tap density is at least 2.0 g/cm 3 and up to 2.7 g/cm 3 .
3. The positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein a ratio I(003)/I(104) of a diffraction peak intensity I(003) of a 003 plane to a peak intensity I(104) of a 104 plane, obtained by X-ray diffraction measurement, is at least 1.7.
4. The positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein when an arbitrary radial direction from a center of a cross section of the secondary particle toward an outside thereof is regarded as an x-axis direction and a direction perpendicular to the x-axis direction is regarded as a y-axis direction, an orientation rate of a crystal ab plane measured by an electron backscatter diffraction method is at least 55% in each of the x-axis direction and the y-axis direction.
5. A nonaqueous electrolyte secondary battery comprising the positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 for a positive electrode thereof.