| abstract |
There is obtained an active material for a lithium secondary battery that has a wide usable voltage range, a high charge-discharge cycle durability, a high capacity and high safety and availability. n The particles of a lithium-nickel-cobalt-manganese-fluorine-containing composite oxide having an R-3m rhombohedral structure represented by a general formula Li p Ni x Mn 1-x-y Co y O 2-q F q (where 0.98≦p≦1.07, 0.3≦x≦0.5, 0.1≦y≦0.38, and 0≦q≦0.05), and the particles of the lithium-nickel-cobalt-manganese-fluorine-containing composite oxide characterized in that the half-width of the diffraction peak of a (110) plane whose 2θ is 65±0.5° in the X-ray diffraction using a Cu—Kα line is, 0.12 to 0.25° are used as an active substance for a positive electrode. |