| 摘要 |
PROBLEM TO BE SOLVED: To provide a positive electrode active material for a secondary battery with long life, improved high capacity, and high structural stability by coating the surface of a compound containing Li, Ni, and Co as the main component with a metal oxide. SOLUTION: A compound selected from among LiaNI1-x-yCoxMyO2, LiaNi1-x-yCoxMyO2-zFz, or LiaNi1-x-yCoxMyO2-zS2 [M is Al, Mg, Sr, La, Ce, V, or Ti; x is 0-1, y and z are 0.01-0.1; (a) is 1.00-1.1] is coated with a 1-100 nm thickness metal oxide of preferably Mg, Si, Ti, Al, V, Co, K, Ca, An, or B. The compound in the formula is obtained, in such a way that, LiaCoxMy(OH)2 is synthesized, LiOH and LiF or NaS powder is added to the compound and stirred, the obtained mixture is heat-treated by blowing dry air in a furnace at 700-900 deg.C, surface-treated with a metal alkoxide solution, dried, and then heat-treated under air atmosphere. |
