Positive electrode active material for non-aqueous electrolyte secondary battery and production method for same, precursor for positive electrode active material, and non-aqueous electrolyte secondary battery using positive electrode active material
Provided is a cathode active material for a non-aqueous electrolyte secondary battery capable of obtaining high initial discharge capacity and good output characteristics at low temperature. In order to achieve this, a cathode active material that is a lithium nickel composite oxide composed of secondary particles that are an aggregate of primary particles is expressed by the general expression: Li w (Ni 1-x-y Co x Al y ) 1-z M z O 2 (where 0.98≦w≦1.10, 0.05≦x≦0.3, 0.01≦y≦0.1, 0≦z≦0.05, and M is at least one metal element selected from a group consisting of Mg, Fe, Cu, Zn and Ga), and where the crystallite diameter at (003) plane of that lithium nickel composite oxide that is found by X-ray diffraction and the Scherrer equation is within the range of 1200 Å to 1600 Å is used as the cathode material.
1. A precursor of a cathode active material for a non-aqueous electrolyte secondary battery, comprising:
a nickel composite hydroxide expressed by the general expression:
(Ni 1-x-y Co x Al y ) 1-z M z (OH) 2
where 0.05≦x≦0.3, 0.01≦y≦0.1, 0<z≦0.05, and M is at least one metal element chosen from Mg, Fe, Cu, Zn and Ga,
where the precursor is composed of secondary particles formed by an aggregate of primary particles, and
where a half width at (101) plane found by X-ray diffraction of the nickel composite hydroxide is 0.45° to 0.8°.
2. The precursor of a cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the precursor is obtained by covering the surface of a hydroxide composed of Ni, Co and M given by the expression above with aluminum hydroxide.
3. The precursor of a cathode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein by mixing the precursor for obtaining a cathode active material for a non-aqueous electrolyte secondary battery with a lithium compound, or by mixing the precursor after oxidizing roasting with a lithium compound, and performing calcination of the obtained mixture in an oxidizing atmosphere, the cathode active material for a non-aqueous electrolyte secondary battery is obtained.
4. A manufacturing method for a cathode active material for a non-aqueous electrolyte secondary battery, comprising:
mixing the precursor according to claim 1 , or an oxide of the precursor that is obtained by performing oxidizing roasting of the precursor, with a lithium compound; and
calcinating the obtained mixture in oxidizing atmosphere to obtain a lithium nickel composite oxide that is expressed by the general expression:
Li w (Ni 1-x-y CO x Al y ) 1-z M z O 2
where 0.98≦w≦1.10, 0.05≦x≦0.3, 0.01≦y≦0.1, 0<z≦0.05, and M is at least one metal element chosen from Mg, Fe, Cu, Zn and Ga, and
where a crystallite diameter at (003) plane of the lithium nickel composite oxide that is found by X-ray diffraction and the Scherrer equation is within the range of 1200 Å to 1600 Å.
5. The manufacturing method for a cathode active material for a non-aqueous electrolyte secondary battery according to claim 4 , wherein the calcination temperature is within the range of 700° C. to 760° C.
6. The manufacturing method for a cathode active material for a non-aqueous electrolyte secondary battery according to claim 4 , wherein the lithium compound is lithium hydroxide.