| 摘要 |
PROBLEM TO BE SOLVED: To improve the utilization factor of an active material, suppress an overvoltage rise at the terminal stage of a discharge, and increase the capacity of a battery by dissolving at least one of four elements such as Mn in the Ni oxide powder which is the principal constituent of a positive electrode active material, and covering the surface and/or surface vicinity of powder grains with a high-conductivity material containing oxycobalt hydroxide with the specific resistance of a specific value or below. SOLUTION: For the manufacture of a positive electrode active material, at least one element selected from among Mn, Al, Cr, Ca is dissolved in Ni oxide powder to synthesize active material grains. The active material grain surface is covered with high-conductivity oxycobalt hydroxide having the specific resistance of 15 Ω.cm or below and low crystallinity. A positive electrode additive mainly made of bivalent Co oxide is added to the surface and/or surface vicinity of the active material grains by mechanical kneading method or reaction crystal deposition method, the powder or aqueous solution of one or more hydroxides of Na, K, Li is added, and the oxidation process is applied in a range >=80 deg.C to <=120 deg.C in the oxidation atmosphere. |
