Cathode active material, cathode therewith and nonaqueous electrolyte secondary battery

1. A cathode active material, comprising:

a particle containing a cathode material capable of absorbing and releasing an electrode reactive material; and

a film that is disposed at least partially to the particle and contains a metal salt represented by a formula (1),

where R1 represents a (a1+b1+c1) valent group and M1 represents a metallic element, where a1, d1, e1 and n each represent an integer of 1 or more and b1 and c1 each represent an integer of 0 or more, where b1 and c1 satisfy a relationship such that (b1+c1)≧1.

2. The cathode active material according to claim 1 , wherein the R1 in the formula (1) is a chain saturated hydrocarbon group, a chain unsaturated hydrocarbon group, a ring saturated hydrocarbon group or a group obtained by halogenating one of the groups.

3. The cathode active material according to claim 1 , wherein a metallic element of the metal salt is an alkali metal element or an alkaline earth metal element.

4. The cathode active material according to claim 1 , wherein the metal salt represented by the formula (1) is a metal salt represented by a formula (2),

where R2 represents a (a2+b2) valent group and M2 represents a metallic element, and

where a2, b2, c2, d2 and e2 each represent an integer of 1 or more.

5. The cathode active material according to claim 1 , wherein the metal salt represented by the formula (1) is a metal salt represented by a formula (3),

where R3 represents a (a3+b3) valent group and M3 represents a metallic element, and

where a3, b3, c3, d3 and e3 each represent an integer of 1 or more.

6. The cathode active material according to claim 1 , wherein the metal salt represented by the formula (1) is at least one kind selected from a group consisting of lithium 2-hydroxypropane sulfonate, lithium 2-hydroxypropene sulfonate, lithium 4-hydroxy butyrate, lithium 4-hydroxy-2-butenate, magnesium 2-hydroxyethane sulfonate, magnesium 2-hydroxyethene sulfonate, magnesium 4-hydroxy butyrate, magnesium 4-hydroxy-2-butenate, calcium 2-hydroxyethane sulfonate, calcium 2-hydroxyethene sulfonate, calcium 4-hydroxy butyrate and calcium 4-hydroxy-2-butenate.

7. The cathode active material 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 (1).

8. The cathode active material according to claim 1 , wherein the particle at least contains lithium and at least one transition metal.

9. The cathode active material according to claim 8 , wherein the particle contains cobalt and has a layered structure.

10. The cathode active material according to claim 8 , 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.

11. The cathode active material according to claim 10 , wherein the particle contains at least one of nickel, manganese and phosphorus is as an element different from the main transition metal element.

12. A cathode, 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 an electrode reactive material; and

a film that is disposed at least partially on the particle and contains a metal salt represented by a formula (1),

where R1 represents a (a1+b1+c1) valent group and M1 represents a metallic element,

where a1, d1, e1 and n each represent an integer of 1 or more and b1 and c1 each represent an integer of 0 or more, and

where b1 and c1 satisfy a relationship such that(b1+c1)≧1.

13. 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 an electrode reactive material; and

a film that is disposed at least partially on the particle and contains a metal salt represented by a formula (1),

where R1 represents a (a1+b1+c1) valent group and M1 represents a metallic element,

where a1, d1, e1 and n each represent an integer of 1 or more and b1 and c1 each represent an integer of 0 or more, and

where b1 and c1 satisfy a relationship such that(b1+c1)≧1.

14. The non-aqueous electrolyte secondary battery according to claim 13 , wherein an upper limit charge voltage is 4.25 V or more and 4.80 V or less and a lower limit discharge voltage is 2.00 V or more and 3.30 V or less.