Abstract: The production method is a method for producing a positive electrode active material for a lithium ion secondary battery which contains at least nickel and lithium, the method including: a firing process in which a mixture of a nickel compound powder and a lithium compound powder is fired; and a water washing process in which a lithium-nickel composite oxide powder obtained in the firing process is washed with water, wherein the firing process is performed under conditions such that a value obtained by dividing a ratio of an amount-of-substance of lithium to a total amount-of-substance of transition metals other than lithium in the lithium-nickel composite oxide powder after the washing with water by a ratio of an amount-of-substance of lithium to a total amount-of-substance of transition metals other than lithium in the lithium-nickel composite oxide powder before the washing with water exceeds 0.95.

Abstract: A nickel complex oxide having a carbon content of 0.15% by mass or lower.

Abstract: The production method is a method for producing a positive electrode active material for a lithium ion secondary battery which contains at least nickel and lithium, the method including: a firing process in which a mixture of a nickel compound powder and a lithium compound powder is fired; and a water washing process in which a lithium-nickel composite oxide powder obtained in the firing process is washed with water, wherein the firing process is performed under conditions such that a value obtained by dividing a ratio of an amount-of-substance of lithium to a total amount-of-substance of transition metals other than lithium in the lithium-nickel composite oxide powder after the washing with water by a ratio of an amount-of-substance of lithium to a total amount-of-substance of transition metals other than lithium in the lithium-nickel composite oxide powder before the washing with water exceeds 0.95.

Abstract: A coated nickel hydroxide powder that has improved dispersibility in a paste to inhibit agglomeration and can be densely packed in a three-dimensional metal porous body in the preparation of a positive electrode for alkaline secondary battery includes nickel hydroxide particles and a coating layer made of a cobalt compound and formed on a surface of the nickel hydroxide particles, wherein when 10 mL of water is added to 10 g of the coated nickel hydroxide powder to prepare a suspension, a total amount of eluted ions except for oxonium ions, hydroxide ions, and carbonate ions in the suspension is 6.5 mmol/L or less. The coated nickel hydroxide powder obtained through a crystallization step, a coating step, and a washing step is dried in a drying step in a decarbonated atmosphere whose partial pressure of a carbon-containing gas is 15 Pa or less.

Abstract: A nickel complex oxide having a carbon content of 0.15% by mass or lower.

Abstract: A coated nickel hydroxide powder that has improved dispersibility in a paste to inhibit agglomeration and can be densely packed in a three-dimensional metal porous body in the preparation of a positive electrode for alkaline secondary battery includes nickel hydroxide particles having a coating layer made of a cobalt compound formed on a surface of the nickel hydroxide particles, wherein when 10 mL of water is added to 10 g of the coated nickel hydroxide powder to prepare a suspension, the suspension has a pH of 10.2 or higher (as measured at 25° C.). The coated nickel hydroxide powder obtained through a crystallization step and a coating step is washed in a washing step until an amount of ammonium ions eluted into a suspension obtained by adding 10 mL of water to 10 g of the coated nickel hydroxide powder becomes 0.35 mmol/L or less.

Abstract: The present invention provides nickel-cobalt-manganese composite hydroxide and a method for manufacturing same, the nickel-cobalt-manganese composite hydroxide as a precursor allowing a positive electrode active material having excellent battery characteristics and a high-density to be manufactured. The nickel-cobalt-manganese composite hydroxide is represented by a general formula: Ni1-x-y-zCoxMnyMz(OH)2 (wherein 0<x?1/3, 0<y?1/3, 0?z?0.1, and M is at least one element selected from Mg, Al, Ca, Ti, V, Cr, Zr, Nb, Mo, and W) and serves as a precursor of a positive electrode active material for nonaqueous electrolyte secondary batteries; wherein the specific surface area measured by a nitrogen adsorption BET method is 1.0 to 10.0 m2/g, the carbon content measured by a high frequency combustion infrared absorption method is not more than 0.1% by mass, and the half-value width of a plane in X-ray diffraction is not more than 1.5°.

Abstract: A coated nickel hydroxide powder that has improved dispersibility in a paste to inhibit agglomeration and can be densely packed in a three-dimensional metal porous body in the preparation of a positive electrode for alkaline secondary battery includes nickel hydroxide particles and a coating layer made of a cobalt compound and formed on a surface of the nickel hydroxide particles, wherein when 10 mL of water is added to 10 g of the coated nickel hydroxide powder to prepare a suspension, the suspension having a pH of 10.2 or higher (as measured at 25° C.). The coated nickel hydroxide powder obtained through a crystallization step and a coating step is washed in a washing step until an amount of ammonium ions eluted into a suspension obtained by adding 10 mL of water to 10 g of the coated nickel hydroxide powder becomes 0.35 mmol/L or less.

Abstract: A coated nickel hydroxide powder that has improved dispersibility in a paste to inhibit agglomeration and can be densely packed in a three-dimensional metal porous body in the preparation of a positive electrode for alkaline secondary battery includes nickel hydroxide particles and a coating layer made of a cobalt compound and formed on a surface of the nickel hydroxide particles, wherein when 10 mL of water is added to 10 g of the coated nickel hydroxide powder to prepare a suspension, a total amount of eluted ions except for oxonium ions, hydroxide ions, and carbonate ions in the suspension is 6.5 mmol/L or less. The coated nickel hydroxide powder obtained through a crystallization step, a coating step, and a washing step is dried in a drying step in a decarbonated atmosphere whose partial pressure of a carbon-containing gas is 15 Pa or less.

Abstract: The present invention provides nickel-cobalt-manganese composite hydroxide and a method for manufacturing same, the nickel-cobalt-manganese composite hydroxide as a precursor allowing a positive electrode active material having excellent battery characteristics and a high-density to be manufactured. The nickel-cobalt-manganese composite hydroxide is represented by a general formula: Ni1-x-y-zCoxMnyMz(OH)2 (wherein 0<x?1/3, 0<y?1/3, 0?z?0.1, and M is at least one element selected from Mg, Al, Ca, Ti, V, Cr, Zr, Nb, Mo, and W) and serves as a precursor of a positive electrode active material for nonaqueous electrolyte secondary batteries; wherein the specific surface area measured by a nitrogen adsorption BET method is 1.0 to 10.0 m2/g, the carbon content measured by a high frequency combustion infrared absorption method is not more than 0.1% by mass, and the half-value width of a plane in X-ray diffraction is not more than 1.5°.