Production method of sintered-type nickel positive electrode for alkaline secondary battery

A method for producing a sintered-type nickel positive electrode for an alkaline secondary battery, comprising:

• a step (1) of soaking a sintered nickel substrate in an acidic solution containing cobalt ions and at least one metal ions selected from the group consisting of magnesium ions, iron ions and manganese ions, and drying thus soaked substrate to prepare a metal salt carried-substrate A;
• a step (2) of soaking said substrate A in an alkaline solution to deposit cobalt hydroxide and at least one selected from the group consisting of magnesium hydroxide, iron hydroxide and manganese hydroxide in pores of and on surface of said substrate, to prepare a hydroxide carried-substrate B;
• a step (3) of oxidizing said cobalt hydroxide to produce cobalt oxide having a mean cobalt valence of over 2, to prepare an oxide carried-substrate C;
• and
• a step (4) of filling an active material comprising nickel hydroxide in pores of said substrate C by repeating a series of steps of soaking said substrate C in a solution containing nickel nitrate dissolved therein, drying thus soaked substrate C, and then soaking thus dried substrate C in an alkaline solution, to prepare an active material carried-substrate D.