Provided are a positive electrode active material for nonagueous secondary batteries, the material having a narrow particle-size distribution and a monodisperse property and being capable of increasing a battery capacity; an industrial production method thereof; and a nonaqueous secondary battery using the positive electrode active material and having excellent electrical characteristics. The positive electrode active material is represented by a general formula: Li.sub.1+uNi.sub.xCo.sub.yMn.sub.zM.sub.tO.sub.2+ (wherein, 0.05u0.95, x+y+z+t=1, 0x0.5, 0y0.5, 0.5z<0.8, 0t0.1, and M is an additive element and at least one element selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W), has an average particle diameter of 3 to 12 um, and has [(d.sub.90d.sub.10)/average particle diameter], an index indicating a scale of particle-size distribution, of 0.60 or less.

A battery includes a positive electrode including a positive electrode active material, a negative electrode, and an electrolytic solution including a nonaqueous solvent. The positive electrode active material includes a compound having a crystal structure belonging to a space group FM3-M and represented by Compositional Formula (1): Li.sub.xMe.sub.yO.sub.F.sub., where, Me is one or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr; and subscripts x, y, , and satisfy the following requirements: 1.7x2.2, 0.8y1.3, 12.5, and 0.52. The nonaqueous solvent includes a solvent having at least one fluoro group.

A positive-electrode active material contains a compound that has a crystal structure belonging to a space group FM3-M and that is represented by the composition formula (1) and a lithium ion conductor,
Li.sub.xMe.sub.yO.sub.F.sub.(1) wherein Me denotes one or two or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr, and the following conditions are satisfied.
1.7x2.2
0.8y1.3
12.5
0.52

Provided is a battery including: a positive electrode containing a positive electrode active material; a negative electrode; and an electrolyte solution containing a nonaqueous solvent. The positive electrode active material contains a compound represented by composition formula (1) below and having a crystal structure belonging to space group FM3-M: Li.sub.xMe.sub.yO.sub.F.sub.. (1) Here, Me is one or two or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and C. x, y, , and satisfy the following conditions: 1.7x2.2, 0.8y1.3, 12.5, and 0.52, respectively. The nonaqueous solvent includes at least one solvent selected from hydrofluoroethers, phosphazenes, phosphates, and perfluoropolyethers.

A composite oxide powder including a composition formula (1), wherein the ratio / of a surface area value (m.sup.2/g) calculated by a BET one-point method to a surface area value (m.sup.2/g) calculated from a formula (2) is greater than 1.0 and equal to or less than 1.5 and the surface area value is equal to or less than 20 m.sup.2/g. ABO.sub.3- (1) (wherein A is one or more types of elements (La, Sr, Sm, Ca and Ba), B is one or more types of elements (Fe, Co, Ni and Mn) and 0<1); and surface area value (m.sup.2/g)=specific surface area value -surface area value (2) (the specific surface area value (m.sup.2/g) is a value in a total pore size range measured by a mercury intrusion method. The specific surface area value (m.sup.2/g) is a value in a range of pore sizes that are larger than a 50% cumulative particle size.

A highly active trimetallic mixed transition metal oxide material has been developed. The material may be sulfided to generate metal sulfides which are used as a catalyst in a conversion process such as hydroprocessing. The hydroprocessing may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

A positive-electrode active material contains a compound that has a crystal structure belonging to a space group FM3-M and contains is represented by the composition formula (1) and an insulating compound,
Li.sub.xMe.sub.yO.sub.F.sub.(1) wherein Me denotes one or two or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr, and the following conditions are satisfied.
1.7x2.2
0.8y1.3
12.5
0.52

A battery includes a positive electrode including a positive electrode active material, a negative electrode, and an electrolytic solution including a lithium hexafluorophosphate and an additive. The positive electrode active material includes a compound having a crystal structure belonging to a space group FM3-M and represented by Compositional Formula (1): Li.sub.xMe.sub.yO.sub.F.sub.. The additive is at least one selected from the group consisting of difluorophosphates, tetrafluoroborates, bis(oxalate)borate salts, bis(trifluoromethanesulfonyl)imide salts, and bis(fluorosulfonyl)imide salts.

A positive-electrode active material containing a compound that has a crystal structure belonging to the space group FM-3M and is represented by the composition formula (1):
Li.sub.xMe.sub.yO.sub.F.sub.(1) wherein Me denotes one or two or more elements selected from the group consisting of Mn, Co, Ni, Fe, and Al, and the following conditions are satisfied. 1.3x2.2 0.8y1.3 12.93 0.072

A battery includes a positive electrode including a positive electrode active material, a negative electrode, and an electrolytic solution including an additive. The positive electrode active material includes a compound having a crystal structure belonging to a space group FM3-M and represented by Compositional Formula (1): Li.sub.xMe.sub.yO.sub.F.sub., where, Me is one or more elements selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V, and Cr; and subscripts x, y, , and satisfy the following requirements: 1.7x2.2, 0.8y1.3, 12.5, and 0.52. The additive is at least one selected from dinitrile compounds and diisocyanate compounds.