Lithium secondary battery, positive electrode active material, positive electrode, electric tool, electric vehicle, and power storage system

1. A lithium secondary battery, comprising:

a positive electrode;

a negative electrode; and

an electrolyte solution,

wherein the positive electrode comprises a positive electrode active material that comprises an element M2 incorporated in a crystal structure in a surface layer area of a complex oxide,

wherein the element M2 is carbon,

wherein the complex oxide comprises an element M1 and is represented by formula (1):

Li 1+a (Mn b Co c Ni 1−b−c ) 1−a M1 d O 2−e   (1),

wherein the element M1 is at least one of aluminum, magnesium, zirconium, titanium, barium, boron, silicon, or iron, and

wherein a satisfies 0<a<0.25, b satisfies 0.5≦b<0.7, c satisfies 0≦c<1−b, d satisfies 0.01≦d≦0.2, and e satisfies 0≦e≦1.

2. The lithium secondary battery according to claim 1 , wherein an amount of the element M2 in the positive electrode active material is 0.01 mol % to 5 mol % with respect to an amount of lithium.

3. The lithium secondary battery according to claim 1 ,

wherein the element M1 is at least one of aluminum, magnesium, or titanium.

4. The lithium secondary battery according to claim 3 ,

wherein the element M1 is aluminum.

5. The lithium secondary battery according to claim 1 , wherein the a satisfies 0.1<a<0.25.

6. The lithium secondary battery according to claim 1 ,

wherein a compound that comprises the element M2 is deposited on the surface layer area of the complex oxide by a mechanochemical reaction, and

wherein the positive electrode active material is burned based on the deposited element M2 on the surface layer area.

7. The lithium secondary battery according to claim 6 , wherein the compound is a solid solution with the complex oxide.

8. The lithium secondary battery according to claim 1 ,

wherein a negative electrode active material of the negative electrode comprises a metal-based material, and

wherein the metal-based material comprises at least one of silicon or tin as a constituent element.

9. The lithium secondary battery according to claim 8 ,

wherein the negative electrode active material is a silicon oxide SiO v , and

wherein v satisfies 0.2<v<1.4.

10. The lithium secondary battery according to claim 1 , wherein at least one of the positive electrode, the negative electrode, or the electrolyte solution comprises at least one of a heteropoly acid or a heteropoly acid compound.

11. The lithium secondary battery according to claim 1 ,

wherein at least one of the positive electrode or the negative electrode is provided with a gel coating,

wherein the gel coating comprises at least a compound,

wherein the compound is at least one of an amorphous polyacid compound or a polyacid salt compound, and

wherein the amorphous polyacid compound comprises at least one poly-element.

12. The lithium secondary battery according to claim 11 , wherein the gel coating is based on at least one of a heteropoly acid or a heteropoly acid compound.

13. The lithium secondary battery according to claim 12 , wherein the at least one of the amorphous polyacid compound or the polyacid salt compound comprises one of hexavalent poly-atom ions or poly-atom ions with a valence less than six.

14. The lithium secondary battery according to claim 10 ,

wherein the at least one of the heteropoly acid or the heteropoly acid compound is at least a compound selected from one of compounds represented by formulas (2) to (5):

H x A y (BD 6 O 24 ). z H 2 O  (2),

wherein A is at least one of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, aluminum, ammonium, ammonium salt, or phosphonium salt,

wherein B is at least one of silicon, arsenic, or germanium,

wherein D is at least one of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, zirconium, niobium, molybdenum, technetium, rhodium, cadmium, indium, tin, tantalum, tungsten, rhenium, or thallium,

wherein x satisfies 0≦x≦8, y satisfies 0≦y≦8, and z satisfies 0≦z≦50, and

wherein at least one of the x or they is greater than 0;

H p A g (BD 12 O 40 ). z H 2 O  (3),

wherein p satisfies 0≦p≦4, q satisfies 0≦q≦4, and

wherein at least one of the p or the q is greater than 0;

H x A y (B 2 D 18 O 62 ). z H 2 O  (4); and

H j A k (B 5 D 30 O 110 ). z H 2 O  (5),

wherein j satisfies 0≦j≦15, k satisfies 0≦k≦15, and

wherein at least one of the j or the k is greater than 0.

15. The lithium secondary battery according to claim 10 , wherein the heteropoly acid is at least one of phosphomolybdic acid, phosphotungstic acid, silicomolybdic acid, or silicotungstic acid.

16. A positive electrode active material, comprising:

an element M2 incorporated in a crystal structure in a surface layer area of a complex oxide,

wherein the element M2 is carbon,

wherein the complex oxide comprises an element M1 and is represented by formula (1):

Li 1+a (Mn b Co c Ni 1−b−c ) 1−a M1 d O 2−e   (1),

wherein the element M1 is at least one of aluminum, magnesium, zirconium, titanium, barium, boron, silicon, or iron, and

wherein a satisfies 0<a<0.25, b satisfies 0.5≦b<0.7, c satisfies 0≦c<1−b, d satisfies 0.01≦d≦0.2, and e satisfies 0≦e≦1.

17. A positive electrode, comprising:

a positive electrode active material that comprises an element M2 incorporated in a crystal structure in a surface layer area of a complex oxide,

wherein the element M2 is carbon,

wherein the complex oxide comprises an element M1 and is represented by formula (1):

Li 1+a (Mn b Co c Ni 1−b−c ) 1−a M1 d O 2−e   (1),

wherein the element M1 is at least one of aluminum, magnesium, zirconium, titanium, barium, boron, silicon, or iron, and

wherein a satisfies 0<a<0.25, b satisfies 0.5≦b<0.7, c satisfies 0≦c<1−b, d satisfies 0.01≦d≦2, and e satisfies 0≦e≦1.

18. An electric tool, comprising:

a lithium secondary battery to supply power to the electric tool,

wherein the lithium secondary battery comprises a positive electrode, a negative electrode, and an electrolyte solution,

wherein the positive electrode comprises a positive electrode active material that comprises an element M2 incorporated in a crystal structure in a surface layer area of a complex oxide,

wherein the element M2 is carbon,

wherein the complex oxide comprises an element M1 and is represented by formula (1):

Li 1+a (Mn b Co c Ni 1−b−c ) 1−a M1 d O 2−e   (1),

wherein the element M1 is at least one of aluminum, magnesium, zirconium, titanium, barium, boron, silicon, or iron, and

wherein a satisfies 0<a<0.25, b satisfies 0.5≦b<0.7, c satisfies 0≦c<1−b, d satisfies 0.01≦d≦2, and e satisfies 0≦e≦1.

19. A power storage system, comprising:

a lithium secondary battery as a power storage source,

wherein the lithium secondary battery comprises a positive electrode, a negative electrode, and an electrolyte solution,

wherein the positive electrode comprises a positive electrode active material that comprises an element M2 incorporated in a crystal structure in a surface layer area of a complex oxide,

wherein the element M2 is carbon,

wherein the complex oxide comprises an element M1 and is represented by formula (1):

Li 1+a (Mn b Co c Ni 1−b−c ) 1−a M1 d O 2−e   (1),

wherein the element M1 is at least one of aluminum, magnesium, zirconium, titanium, barium, boron, silicon, or iron, and

wherein a satisfies 0<a<0.25, b satisfies 0.5≦b<0.7, c satisfies 0≦c<1−b, d satisfies 0.01≦d≦0.2, and e satisfies 0≦e≦1.