Positive electrode active material for lithium ion battery, positive electrode for lithium ion battery, and lithium ion battery

1. A positive electrode active material for a lithium ion battery which is represented by the following composition formula:

Li(Li x Ni 1-x-y M y )O 2+α

wherein M represents Co as an essential component and at least one selected from Sc, Ti, V, Cr, Mn, Fe, Ge, Cu, Zn, Ga, Ge, Al, Bi, Sn, Mg, Ca, B, and Zr;

wherein 0≦x≦0.1, 0<y≦0.7, and α>0;

wherein ratio of peak strength (Ps104) on (104) plane to peak strength (Ps003) on (003) plane, which is (Ps104/Ps003), is 0.9 or less and 2θ of (110) plane is 64.6° or more according to powder X-ray diffraction.

2. The positive electrode active material for a lithium ion battery of claim 1 , wherein M is at least one selected from Mn and Co.

3. The positive electrode active material for a lithium ion battery of claim 1 or 2 , wherein α>0.05 in the composition formula.

4. The positive electrode active material for a lithium ion battery of claim 3 , wherein α>0.1 in the composition formula.

5. The positive electrode active material for a lithium ion battery of claim 1 or 2 , wherein ratio of peak strength (Ps104/Ps003) is 0.85 or less.

6. The positive electrode active material for a lithium ion battery of claim 5 , wherein 28 of (110) plane is 64.7° or more.

7. The positive electrode active material for a lithium ion battery of any one of claim 1 or 2 , wherein 2θ of (018) plane is 64.45° or less and difference in 2θ between (018) plane and (110) plane is more than 0.1°.

8. A positive electrode for a lithium ion battery in which the positive electrode active material for a lithium ion battery of claim 1 or 2 is used.

9. A lithium ion battery in which the positive electrode for a lithium ion battery of claim 8 is used.