Cathode active material, cathode therewith and nonaqueous electrolyte secondary battery

1. A cathode active material for non-aqueous electrolyte secondary battery, comprising:

a particle containing a cathode material capable of absorbing and releasing lithium; and

a film that is disposed at least partially to the particle and contains a metal salt represented by a formula (2):

where R2 represents a chain saturated hydrocarbon group, a chain unsaturated hydrocarbon group or a ring saturated hydrocarbon group, where M2 represents lithium, and where a2, b2, c2, d2 and e2 each represent an integer of 1 or more.

2. The cathode active material for non-aqueous electrolyte secondary battery according to claim 1 , wherein the metal salt represented by the formula (2) is at least one kind selected from the group consisting of lithium 2-hydroxypropane sulfonate and lithium 2-hydroxypropene sulfonate.

3. The cathode active material for non-aqueous electrolyte secondary battery according to claim 1 , wherein the film contains an alkali metal salt or an alkaline earth metal salt different from the metal salt represented by the formula (2).

4. The cathode active material for non-aqueous electrolyte secondary battery according to claim 1 , wherein the particle at least contains lithium and at least one transition metal.

5. The cathode active material for non-aqueous electrolyte secondary battery according to claim 4 , wherein the particle contains cobalt Co and has a layered structure.

6. The cathode active material for non-aqueous electrolyte secondary battery according to claim 4 , wherein the particle contains a main transition metal element that is largest in a ratio among transition metals constituting the particle, and wherein at least one element different from the main transition metal element is present at least partially on a surface of the particle.

7. The cathode active material for non-aqueous electrolyte secondary battery according to claim 6 , wherein the particle contains at least one of nickel Ni, manganese Mn and phosphorus P as an element different from the main transition metal element.

8. A cathode for non-aqueous electrolyte secondary battery, comprising:

a conductive base material; and

a cathode active material layer that is disposed on the conductive base material and at least contains a cathode active material, wherein

the cathode active material includes:

a particle containing a cathode material capable of absorbing and releasing lithium; and

a film that is disposed at least partially on the particle and contains a metal salt represented by a formula (2):

where R2 represents a chain saturated hydrocarbon group, a chain unsaturated hydrocarbon group or a ring saturated hydrocarbon group, where M2 represents lithium, and where a2, b2, c2, d2 and e2 each represent an integer of 1 or more.

9. A non-aqueous electrolyte secondary battery comprising:

a cathode having a cathode active material;

an anode;

a separator; and

an electrolyte,

wherein the cathode active material includes:

a particle containing a cathode material capable of absorbing and releasing lithium; and

a film that is disposed at least partially on the particle and contains a metal salt represented by a formula (2):

where R2 represents a chain saturated hydrocarbon group, a chain unsaturated hydrocarbon group or a ring saturated hydrocarbon group, where M2 represents lithium, and where a2, b2, c2, d2 and e2 each represent an integer of 1 or more.

10. The non-aqueous electrolyte secondary battery according to claim 9 , wherein the upper limit charge voltage is 4.25 V or more and 4.80 V or less and the lower limit charge voltage is 2.80 V or more and 3.00 V or less.