| 摘要 |
PROBLEM TO BE SOLVED: To reduce internal resistance and increase battery capacity, by adding one or more kinds among B, Bi, Mo, P, Cr, V, and W, to a lithium manganate spinel used as a positive-electrode active material. SOLUTION: Preferably, the amount of respective elements added to a spinel compound expressed by LiMn2O4, etc., low in material cost, and having a large output density, is 0.1 to 20 mol.%, especially, 1.5 to 10 mol.%, of Mn. The elements added improve electronic conductivity by their dissolution, reduce contact resistance between particles as sintering assistants, or contribute to conductivity owing to products by reaction with LiMn2O4, thereby lowering internal resistance, reducing a conductive assistant, and enabling a positive- electrode active material to be increased. The addition of the elements of the fixed amount does not degrade the cycle characteristics. It is preferable to make the positive-electrode active material by firing a mixture made by mixing, at a fixed ratio, salts, such as carbonates and acetates, not generating harmful decomposition gases, with an oxide, in an oxidizing atmosphere at 700 to 900 deg.C for 5 to 50 hours. |
