| 摘要 |
PROBLEM TO BE SOLVED: To provide a positive electrode active material with high performance and high capacity excellent in the charging/discharging cycle and accomplish a secondary battery incorporating this positive electrode active material. SOLUTION: This positive electrode active material comprises a compound expressed by the chemical equation Li1- X-a AXNi1- Y-b BYO2 , where A is strontium or barium, B is at least one of transition metal elements, and X and Y should meet the conditions 0<X<=0.10 and 0<Y<=0.30 while a and b should meet the conditions -0.10<=a<=0.10 and -0.15<=b<=0.15, provided that X represents the total mol number of strontium or barium while Y represents the total mol number of all transition metal elements other than Ni in case B comprises two or more sorts of transition metal elements, wherein the positive electrode active material forms secondary particles as a coagulation of primary particles having mean particle size between 0.01 and 5.0μm, and the mean particle size of the secondary particles ranges from 5.0 to 50μm. |
