Nickel active material for use in alkali storage cells and its manufactuiring method

An alkali storage cell, comprising:

• a positive electrode made up of a substrate filled with a nickel active material in particle form comprises of a covering layer formed on a surface of a mother particle comprising nickel hydroxide, wherein the covering layer includes a cobalt compound and at least one of the following metal compounds;
• an aluminum compound, a magnesium compound, an indium compound and a zinc compound, and wherein the cobalt compound in the covering layer is converted into cobalt compound where an oxidization number of cobalt is higher than 2 by heat treatment of the nickel active material in the presence of oxygen and alkali;
• a negative electrode arranged so as to face the positive electrode with a separator in-between;
• and
• an alkali electrolyte which is in contact with both the positive electrode and the negative electrode.

A manufacturing method for nickel active material for an alkali storage cell, including:

• dispersing mother particles comprising nickel hydroxide to form a dispersed solution;
• adding an alkali solution and a multiple component solution containing a cobalt compound and metal compound made up of at least one of an aluminum compound, a magnesium compound, an indium compound and a zinc compound to the dispersed solution whilst adjusting pH with a weak base, thereby using the mother particles as a base and covering a surface of the mother particles by precipitating a multiple component precipitate made up of the cobalt compound and the metal compound;
• and
• placing the mother particles covered in the covering step into alkali metal solution and heat treating with oxygen present.

A manufacturing method for an alkali storage cell, comprising:

• a positive electrode manufacturing step which comprises:
• dispersing mother particles comprising nickel hydroxide to form a dispersed solution;
• adding an alkali solution and a multiple component solution containing a cobalt compound and metal compound made up of at least one of an aluminum compound, a magnesium compound, an indium compound and a zinc compound to the dispersed solution whilst adjusting pH with a weak base, thereby using the mother particles as a base and covering a surface of the mother particles by precipitating a multiple component precipitate made up of the cobalt compound and the metal compound;
• and
• placing the mother particles covered in the covering step into alkali metal solution and heat treating with oxygen present,
• arranging the positive electrode formed in the positive electrode manufacturing step and a negative electrode so as to face each other with a separator in-between and assembling a cell by pouring in an alkali electrolyte.