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 x Ni 1−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, Cu, Zn, Ga, Ge, Bi, Sn, Mg, Ca, B, and Zr:

wherein 0.9≦x≦1.2, 0<y≦0.7, and α≧0.1:

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 2⊖ 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 comprises Mn and Co.

3. The positive electrode active material for a lithium ion battery of claim 1 or 2 , wherein α>0.15 in the composition formula.

4. The positive electrode active material for a lithium ion battery of claim 3 , wherein α>0.20 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 2⊖ of (110) plane is 64.7° or more.

7. The positive electrode active material for a lithium ion battery of claim 1 or 2 , wherein 20 of (018) plane is 64.45° or less and difference in 2⊖ 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.