| 摘要 |
PROBLEM TO BE SOLVED: To provide a positive electrode active material to obtain a nonaqueous electrolyte secondary battery having large discharge capacity, excellent initial charge-discharge efficiency and excellent high-rate discharge characteristics, a method for manufacturing the same, and a new lithium-transition metal composite oxide for the positive electrode active material.SOLUTION: A positive electrode active material for a nonaqueous electrolyte secondary battery contains a lithium-transition metal composite oxide, and the lithium-transition metal composite oxide is composed of Li and transition metal elements containing Co, Ni, and Mn, and represented by the formula: LiCoNiMnO, where a+x+y+z=2. The molar ratio Li/Me (a/(x+y+z)) of Li to the total transition metal element Me is in the range of 1.25 to 1.40, the molar ratio Co/Me (x/(x+y+z)) is in the range of 0.020 to 0.230, the molar ratio Mn/Me (z/(x+y+z)) is in the range of 0.625 to 0.719, the BET specific surface area is 0.88 m/g or greater, and the tap density is 1.25 g/cc or greater. A method for manufacturing the positive electrode active material for a nonaqueous electrolyte secondary battery comprises the steps of manufacturing a precursor by coprecipitating a compound containing Co, Ni, and Mn in a solution, and burning the precursor and a lithium compound after mixing them. The pH is in the range of 8.5 to 9.4 in the precursor manufacturing step, and the burning temperature is in the range of 800 to 940°C. |
