Nickel electrode material,and production method therefor, and nickel electrode and alkaline battery

摘要

Subjects for the invention are to provide a nickel electrode material having a satisfactory tap density and capable of attaining a sufficient reduction in discharge reserve and a process for producing the nickel electrode material, and to provide a nickel electrode and an alkaline storage battery having a high capacity and excellent internal-pressure characteristics. For accomplishing the subjects, the invention provides a nickel electrode material for use in a nickel electrode, wherein the positive-electrode material constituting the electrode material comprises: positive active material particles which comprise as the main component either a nickel hydroxide or a solid solution in a nickel hydroxide of one or more other elements and in which part of the nickel hydroxide has been oxidized; and a coating layer formed on the surface of the positive active material particles and comprising as the main component a high-order cobalt compound in which the cobalt has an oxidation number larger than 2, the average oxidation number of the nickel in the positive active material particles and the cobalt in the coating layer being from 2.04 to 2.40, and the positive-electrode material having a tap density of 2.0 g/cm<3 >or higher. The invention further provides a process for producing the electrode material, a nickel electrode employing the electrode material, and an alkaline storage battery having the nickel electrode.