1. A positive-electrode active material precursor for a nonaqueous electrolyte secondary battery, the positive-electrode active material precursor comprising:
a nickel-cobalt-manganese carbonate composite represented by a general formula of NixCoyMnzMtCO3where x+y+z+t=1, 0.05≤x≤0.3, 0.1≤y≤0.4, 0.55≤z≤0.8, and 0≤t≤0.1 are satisfied; and M represents one or more additive elements selected from among Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W,
wherein the positive-electrode active material precursor includes secondary particles having an average particle diameter greater than or equal to 4 μm and less than or equal to 9 μm, and
wherein the secondary particle includes a sparse central portion and a dense outer shell portion outside of the central portion, formed of primary particles.
secondary particles
average particle diameter
greater than or equal to 4 μm and less than or equal to 9 μm
μm