Electrode structure having rolled graphene film

1. An electrode structure comprising:

a rolled graphene film which is wound about a central axis, and

a nanomaterial dispersed on a surface of the rolled graphene film, the nanomaterial providing a space between facing surfaces of the rolled graphene film,

wherein the nanomaterial comprises carbon nanotubes, fullerene, carbon nanowires, carbon nanofibers, or a combination thereof.

2. The electrode structure of claim 1 , wherein the graphene film comprises:

a single graphene sheet or a laminate of a plurality of graphene sheets.

3. The electrode structure of claim 2 , wherein the graphene sheet is a single atomic layer graphene sheet, a network sheet having graphene flakes connected to one another, or a combination thereof.

4. The electrode structure of claim 1 , wherein an average thickness of the graphene film is about 1,000 micrometers or less.

5. The electrode structure of claim 1 , wherein the graphene film is porous.

6. The electrode structure of claim 1 , wherein the nanomaterial has a shape of a discrete particle, a tube, a wire, a rod, a fiber or a non-uniform, non-discrete bulk unit, or a combined shape thereof.

7. The electrode structure of claim 1 , wherein an average diameter of the nanomaterial is in a range of about 1 nanometer to about 200 nanometers.

8. The electrode structure of claim 1 , wherein the nanomaterial is dispersed on the surface of the graphene film without agglomeration.

9. The electrode structure of claim 1 , wherein a content of the nanomaterial is in a range of about 1 wt % to about 50 wt % based on a total weight of the nanomaterial and the graphene film.

10. The electrode structure of claim 1 , wherein a top or bottom surface of the electrode structure has a shape of in a circular form, an elliptical form or a polygonal form.

11. The electrode structure of claim 1 , wherein a thickness of the electrode structure is in a range of about 10 micrometers to about 1,000 micrometers, taken along the central axis.

12. The electrode structure of claim 1 , wherein a density of the electrode structure is in a range of about 0.1 gram per cubic centimeter to about 1.5 grams per cubic centimeter.

13. An electric device comprising:

an electrode, the electrode comprising:

a current collector; and

the electrode structure of claim 1 , on the current collector.

14. The electric device of claim 13 , wherein

a top or bottom surface of the electrode structure is inclined with respect to the central axis, and contacts the current collector, and

flow paths are defined between facing graphene film surfaces of the rolled graphene film, elongated along the central axis and substantially perpendicular to the current collector.

15. The electric device of claim 13 , wherein the electric device is a supercapacitor, a secondary battery, a fuel cell or a solar cell.