Coated Nickel Hydroxide Powder for Positive Electrode Active Material of Alkaline Secondary Battery, and Evaluation Method for Coating Adhesion Properties of Coated Nickel Hydroxide Powder

摘要

Provided are a coated nickel hydroxide powder that has a cobalt compound coating having improved uniformity and adhesion properties on the surface of particles thereof and is therefore suitable for use as a positive electrode active material of alkaline secondary battery, and an evaluation method for the adhesion properties of the coating.;The coated nickel hydroxide powder for a positive electrode active material of alkaline secondary battery is obtained by coating the surface of nickel hydroxide particles with a cobalt compound, and has a. transmittance ratio of 30% or higher as determined by (A−Bmax)/(B0−Bmax). The transmittance A (coated nickel hydroxide powder), the transmittance B0 (nickel hydroxide powder), or the transmittance Bmax (nickel hydroxide powder and cobalt compound containing cobalt in an amount corresponding to the amount of cobalt contained in the coating) can be determined by measuring the transmittance of a tubular transparent cell after shaking the tightly-closed transparent cell containing each powder for a certain time and then taking the contents out of the transparent cell.

主权项

1. A coated nickel hydroxide powder for a positive electrode active material of alkaline secondary battery, comprising nickel hydroxide particles having a coating made of a cobalt compound on a surface thereof, wherein when a transmittance A, a transmittance B0, and a transmittance Bmax are defined as follows, a transmittance ratio (%) represented by (A−Bmax)/(B0 Bmax)×100 is 30% or higher,
transmittance A: transmittance of a tubular transparent cell measured after shaking the tubular transparent cell containing the coated nickel hydroxide powder for a predetermined time and then taking the contents out of the tubular transparent cell; transmittance B0: transmittance of a tubular transparent cell measured after shaking the tubular transparent cell containing a nickel hydroxide powder for a predetermined time and then taking the contents out of the tubular transparent cell; and transmittance Bmax: transmittance of a tubular transparent cell measured after shaking the tubular transparent cell, for a predetermined time, containing the nickel hydroxide powder and a cobalt compound powder containing cobalt in an amount corresponding to an amount of cobalt contained in the coating of the coated nickel hydroxide powder and then taking the contents out of the tubular transparent cell.