Nickel electrode active material for alkaline storage batteries and nickel positive electrode using the same

Abstract

Disclosed is an active material for constituting a nickel electrode for alkaline storage batteries which has a high utilization at high ambient temperatures and therefore realizes a battery of higher energy density and a longer cycle life. The nickel electrode active material comprises a nickel hydroxide powder prepared from nickel sulfate and contains SO 4 2− at 0.4 wt % or less in the crystal of the powder. The nickel hydroxide is preferably solid solution nickel hydroxide incorporating therein at least one element selected from the group consisting of cobalt, cadmium, zinc and magnesium.

1 . A nickel electrode active material for alkaline storage batteries comprising a nickel hydroxide having a content of sulfate ions in a crystal of nickel hydroxide of 0.4 wt % or less, wherein the sulfate ions have been removed from the crystal of nickel hydroxide with an alkaline solution having a pH of 13.0 to 14.0.  
     
     
         2 . The nickel electrode active material according to  claim 1 , wherein the nickel hydroxide is a solid solution nickel hydroxide and incorporates at least one element selected from the group consisting of cobalt, cadmium, zinc and magnesium.  
     
     
         3 . A pasted nickel positive electrode for alkaline storage batteries comprising a nickel hydroxide having a content of sulfate ions in a crystal of nickel hydroxide of 0.4 wt % or less, wherein the sulfate ions have been removed from the crystal of nickel hydroxide with an alkaline solution having a pH of 13.0 to 14.0.  
     
     
         4 . The pasted nickel positive electrode according to  claim 3 , wherein the nickel hydroxide is a solid solution nickel hydroxide and incorporates at least one element selected from the group consisting of cobalt, cadmium, zinc and magnesium.