Anode and secondary battery

1. An anode comprising:

an anode active material layer on an anode current collector, the anode active material layer including a plurality of anode active material particles,

wherein,

the average particle area of the plurality of anode active material particles observed from a surface of the anode active material layer is within a range of and including 1 μm 2 to 60 μm 2 , and

the ratio of the total of particle areas of anode active material particles having a particle area of and including 20 μm 2 to 30 μm 2 to the total of the particle areas of the plurality of anode active material particles is within a range of and including 10% to 58%.

2. The anode according to claim 1 , wherein the average particle area is within a range of and including 2 μm 2 to 40 μm 2 .

3. The anode according to claim 2 , wherein the average particle area is within a range of and including 5 μm 2 to 17 μm 2 .

4. The anode according to claim 1 , wherein the average circularity of the plurality of anode active material particles is within a range of and including 0.4 to 0.8.

5. The anode according to claim 1 , wherein the anode active material layer is formed by a vapor-phase method, a liquid-phase method, a sintering method or a spraying method.

6. The anode according to claim 1 , wherein the anode active material particles include at least one kind selected from the group consisting of a simple substance, alloys and compounds of silicon.

7. The anode according to claim 1 , wherein the anode active material layer includes a plurality of layers of two kinds having different oxygen contents in a thickness direction.

8. The anode according to claim 1 , wherein the anode active material layer is alloyed with the anode current collector.

9. A secondary battery comprising:

a cathode;

an anode; and

an electrolyte,

wherein,

the anode includes an anode active material layer on an anode current collector, the anode active material layer including a plurality of anode active material particles,

the average particle area of the plurality of anode active material particles observed from a surface of the anode active material layer is within a range of and including 1 μm 2 to 60 μm 2 and,

the ratio of the total of particle areas of anode active material particles having a particle area of and including 20 μm 2 to 30 μm 2 to the total of the particle areas of the plurality of anode active material particles is within a range of and including 10% to 58%.

10. The secondary battery according to claim 9 , wherein the average particle area is within a range of and including 2 μm 2 to 40 μm 2 .

11. The secondary battery according to claim 10 , wherein the average particle area is within a range of and including 5 μm 2 to 17 μm 2 .

12. The secondary battery according to claim 9 , wherein the average circularity of the plurality of anode active material particles is within a range of and including 0.4 to 0.8.

13. The secondary battery according to claim 9 , wherein the anode active material layer is formed by a vapor-phase method, a liquid-phase method, a sintering method or a spraying method.

14. The secondary battery according to claim 9 , wherein the anode active material particles include at least one kind selected from the group consisting of a simple substance, alloys and compounds of silicon.

15. The secondary battery according to claim 9 , wherein the anode active material layer includes a plurality of layers of two kinds having different oxygen contents in a thickness direction.

16. The secondary battery according to claim 9 , wherein the anode active material layer is alloyed with the anode current collector.