Cathode active material for a nonaqueous electrolyte secondary battery and manufacturing method thereof, and a nonaqueous electrolyte secondary battery that uses cathode active material

1. A cathode active material for a nonaqueous secondary battery mainly comprising:

a lithium nickel composite oxide that is represented by the compositional formula LiNi 1−a M a O 2 ; wherein

M is at least one kind of element selected from among a transitional metal other than Ni, a group 2 element and group 13 element;

‘a’ is within the range 0.01≦a≦0.5,

the cathode active material further comprising fine particles of a manganese composite oxide that contains lithium, wherein the fine particles of the manganese composite oxide that contains lithium are needle shaped and/or plate shaped fine particles,

wherein the lithium nickel composite oxide is composed of spherical shaped powder comprising secondary particles having an average particle radius of greater than or equal to 8 μm and less than or equal to 20 μm, each of the secondary particles formed with aggregated primary particles having an average particle radius of greater than or equal to 1 μm and less than or equal to 3 μm,

wherein the fine particles of the manganese composite oxide that contains lithium adhere to a surface of the primary particles such that the fine particles adhere to a surface of the spherical shaped powder of the lithium nickel composite oxide as an aggregate, and

wherein a manganese coating ratio D(s), which is an atomic ratio, (Mn/(Ni+M)), between Mn in the manganese composite oxide that contains lithium, and the Ni and the element M in the lithium nickel composite oxide, is 0.003 to 0.02.

2. The cathode active material for a nonaqueous electrolyte secondary battery of claim 1 , wherein the cathode active material is obtained by adding a manganese solution to a slurry of which the lithium nickel composite oxide is suspended in a solvent keeping a pH of greater than 9 and less than or equal to 13.5 so that the fine particles of a manganese hydroxide that contains lithium is adhered to the surface of the spherical shaped powder of the lithium nickel composite oxide as an aggregate of needle shaped and/or plate shaped minute particles, and baking a lithium nickel composite oxide to which the fine particles of the manganese hydroxide that contains lithium is adhered at a temperature of 400 to 600° C. for 3 to 10 hours.

3. The cathode active material for a nonaqueous electrolyte secondary battery of claim 1 , wherein the element M includes at least one element from among Co, Al and Ti.

4. The cathode active material for a nonaqueous electrolyte secondary battery of claim 1 , wherein the fine particles of the manganese composite oxide that contains lithium uniformly covers the surface of the spherical shaped powder of the lithium nickel composite oxide.

5. A nonaqueous electrolyte secondary battery in which the cathode active material for a nonaqueous electrolyte secondary battery of any one of the claims 1 , 2 , 3 , and 4 is used.

6. The nonaqueous electrolyte secondary battery of claim 5 , wherein the battery is a 2032 type coin battery having an initial discharge capacity of 166.3 mAh/g or more.

7. A manufacturing method of the cathode active material for a nonaqueous electrolyte secondary battery of claim 1 , comprising steps of:

suspending a lithium nickel composite oxide in a solvent to obtain a slurry;

adding a solution in which a manganese salt is dissolved to the slurry;

adhering manganese hydroxide that contains lithium to the surface of the particles of lithium nickel composite oxide; and

baking the lithium nickel composite oxide to which manganese hydroxide that contains lithium adheres to the surface thereof, to obtain a lithium nickel composite oxide to which lithium manganese composite oxide adheres to the surface thereof.

8. The manufacturing method of the cathode active material for a nonaqueous electrolyte secondary battery of claim 7 , wherein

at least one from among nitrate salt, sulfate salt, chloride salt and acetate salt is used as the manganese salt.

9. The manufacturing method of the cathode active material for a nonaqueous electrolyte secondary battery of claim 7 , wherein manganese sulfate is used as the manganese salt.

10. The manufacturing method of the cathode active material for a nonaqueous secondary battery of claim 7 , wherein a lithium compound is added to the solvent beforehand, and the lithium nickel composite oxide is suspended in the solvent in which the lithium compound has been added.

11. The manufacturing method of the cathode active material for a nonaqueous secondary battery of claim 10 , wherein

the solution in which the manganese salt is dissolved is added to the solvent so that the atomic ratio between the Mn in the lithium manganese composite oxide and the Ni and element M in the lithium nickel composite oxide becomes 0.003 to 0.02, and an amount of the lithium compound is added to the solvent to satisfy the reaction formula MnSO 4 +2tLiOH→tMn(OH) 2 +(1−t)MnSO 4 +tLi 2 SO 4 (0<t≦1.2).

12. The manufacturing method of the cathode active material for a nonaqueous secondary battery of any one of the claims 7 to 11 , wherein the baking is performed at a temperature of 400 to 600° C. for 3 to 10 hours in an atmosphere of oxygen or air.