| 摘要 |
PROBLEM TO BE SOLVED: To improve the utilization factor of an active material and to maintain the high utilization factor in long-term charging/discharging cycles by wetting the cobalt hydroxide synthesized from a cobalt salt aqueous solution and an alkaline aqueous solution under the existence of a reducing agent with the alkaline aqueous solution, then heating it in the open air, and adding the obtained oxycobalt hydroxide to the powder mainly made of nickel hydroxide of a positive electrode. SOLUTION: When Co(OH)2 is obtained by the neutralization reaction of cobalt salt and an alkaline aqueous solution, generation of an inert high-order cobalt oxide on the surface by dissolved oxygen is suppressed by a reducing agent. Co(OH)2 is heated in the open air after being wetted by the alkaline aqueous solution, then it is efficiently converted into trivalent oxycobalt hydroxide forming a conductive network in a positive electrode. The oxycobalt hydroxide obtained from Co(OH)2 having the BET specific surface area of 20-30 m<2> /g is preferably used, or it may be immersed in an aqueous solution mainly containing lithium hydroxide, and an electrochemically stable conductive network having high conductivity is formed. |
