Nickel electrode

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PROBLEM TO BE SOLVED : To restrict the lowering of the charging efficiency in the high temperature without lowering discharging electric potential so as to provide an electrode having the excellent charging and discharging efficiency by containing a rare earth element in the nickel hydroxide as a main component of the active material in the solid solution condition. SOLUTION : In a nickel electrode for an alkaline storage battery, of which active material is mainly composed of nickel hydroxide, rare earth element such as Yb, Eu, Er is contained in the nickel hydroxide in the solid solution condition. Or, furthermore, cobalt or zinc is contained in the solid solution condition. The active material desirably has the composition formula expressed with (Ni1-a Xb Coc Znd )(OH)2 . X means one or more kinds of Yb, Eu, Er, a=b+c+d, 0.02<=a<=0.20, 0<=c<0.20, 0<=d<0.20. Oxygen overvoltage of the nickel hydroxide can be raised by including the rare earth element in the nickel hydroxide in the solid solution condition. Furthermore, charging reactive electric potential in the high temperature condition can be lowered in a range, in which the discharging electric potential of the nickel electrode is not lowered, by containing the cobalt.