U.S. Patent No. 6,686,093 - Positive Electrode Active Material For Nonaqueous Electrolytic Solution Secondary Battery And Nonaqueous Electrolytic Solution Secondary Battery Therewith (Feb. 3, 2004)

A positive electrode active material for nonaqueous electrolytic solution secondary batteries is substantially made of a Li containing transition metal composite oxide, which has a composition expressed by Li.sub.x M.sub.y S.sub.z O.sub.2 (wherein M is a transition metal, such as Co, Ni, Mn, Fe and V, and 0.9.ltoreq.x.ltoreq.1.15, 0.8.ltoreq.y.ltoreq.1.00, and 0<z<0.001). Such positive electrode active material is excellent in particle size controllability (miniaturization and sharpening of the particle size distribution). A nonaqueous electrolytic solution secondary battery comprises a positive electrode, a separator, a negative electrode, a battery case accommodating these, and a nonaqueous electrolytic solution filled in the battery case. The positive electrode contains the positive electrode active material for the nonaqueous electrolytic solution secondary battery expressed by the aforementioned general formula.