Nanocomposite of graphene and metal oxide materials
Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10 C.
1. A method comprising:
providing graphene layers in a first mixture, the graphene layers having a first surface and a second surface and thicknesses of 0.5 to 50 nm;
dispersing the graphene layers with a surfactant;
adding a metal oxide precursor to said dispersed graphene layers to form a second mixture; and
precipitating the metal oxide from the second mixture on surfaces of the dispersed graphene layers to form a nanocomposite material comprising a metal oxide bonded directly to the first and second surfaces of a graphene layer with the metal oxide substantially uniformly distributed throughout the nanocomposite material.
2. The method of claim 1 wherein the graphene layers consist essentially of functionalized graphene sheets.
3. The method of claim 1 wherein the graphene layers consist essentially of 1 to 147 graphene sheets.
4. The method of claim 1 further comprising providing graphene layers prepared by thermal expansion before providing the graphene layers in the first mixture.
5. The method of claim 1 wherein the first mixture is an aqueous suspension.
6. The method of claim 1 wherein the surfactant is sodium dodecyl sulfate.
7. The method of claim 1 further comprising the step of heating the second mixture from 50 to 500° C. to condense the metal oxide such that the metal oxide is bonded directly to the surface of the graphene layer and remove the surfactant.
8. A method comprising:
providing graphene layers in a first mixture, the graphene layers having a first surface and a second surface, and consisting essentially of 1 to 147 functionalized graphene sheets;
dispersing the graphene layers with an anionic surfactant;
adding a metal oxide precursor to said dispersed graphene layers to form a second mixture; and
condensing the metal oxide from the second mixture on surfaces of the dispersed graphene layers and removing the surfactant to form a nanocomposite material comprising a metal oxide bonded directly to the first and second surfaces of the graphene layers with the metal oxide substantially uniformly distributed throughout the nanocomposite material.
9. The method of claim 1 wherein the graphene layers have thicknesses of 2 to 10 nm.
10. The method of claim 9 wherein the graphene layers consist essentially of functionalized graphene sheets.
11. The method of claim 1 wherein the surfactant is sodium dodecyl sulfate.