Provided is a lithium or sodium metal battery having an anode, a cathode, and a porous separator and/or an electrolyte, wherein the anode contains a graphene-metal hybrid foam composed of multiple pores, pore walls, and a lithium- or sodium-attracting metal residing in the pores; wherein the metal is selected from Au, Ag, Mg, Zn, Ti, Na (or Li), K, Al, Fe, Mn, Co, Ni, Sn, V, Cr, or an alloy thereof and is in an amount of 0.1% to 90% of the total hybrid foam weight or volume, and the pore walls contain single-layer or few-layer graphene sheets, wherein graphene sheets contain a pristine graphene or non-pristine graphene selected from graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof.

The present invention relates to preparation of a highly dispersible graphene powder. Further, the present invention includes providing an electrode for a lithium ion battery having good output characteristics and cycle characteristics by utilizing a highly dispersible graphene powder. The present invention also includes providing a graphene powder having a specific surface area of 80 m.sup.2/g or more to 250 m.sup.2/g or less as measured by BET measurement, and an oxygen-to-carbon element ratio of 0.09 or more to 0.30 or less as measured by X-ray photoelectron spectroscopy.

The present invention relates to preparation of a highly dispersible graphene powder. Further, the present invention includes providing an electrode for a lithium ion battery having good output characteristics and cycle characteristics by utilizing a highly dispersible graphene powder. The present invention also includes providing a graphene powder having a specific surface area of 80 m.sup.2/g or more to 250 m.sup.2/g or less as measured by BET measurement, and an oxygen-to-carbon element ratio of 0.09 or more to 0.30 or less as measured by X-ray photoelectron spectroscopy.

In one aspect of the invention, a dye sensitized solar cell has a counter-electrode including carbon-titania nanocomposite thin films made by forming a carbon-based ink; forming a titania (TiO.sub.2) solution; blade-coating a mechanical mixture of the carbon-based ink and the titania solution onto a substrate; and annealing the blade-coated substrate at a first temperature for a first period of time to obtain the carbon-based titania nanocomposite thin films. In certain embodiments, the carbon-based titania nanocomposite thin films may include solvent-exfoliated graphene titania (SEG-TiO.sub.2) nanocomposite thin films, or single walled carbon nanotube titania (SWCNT-TiO.sub.2) nanocomposite thin films.

In one aspect of the invention, a dye sensitized solar cell has a counter-electrode including carbon-titania nanocomposite thin films made by forming a carbon-based ink; forming a titania (TiO.sub.2) solution; blade-coating a mechanical mixture of the carbon-based ink and the titania solution onto a substrate; and annealing the blade-coated substrate at a first temperature for a first period of time to obtain the carbon-based titania nanocomposite thin films. In certain embodiments, the carbon-based titania nanocomposite thin films may include solvent-exfoliated graphene titania (SEG-TiO.sub.2) nanocomposite thin films, or single walled carbon nanotube titania (SWCNT-TiO.sub.2) nanocomposite thin films.

Provided is a photosensitizer that can make a compound having a polymerizable group be efficiently cured by irradiation with an active energy ray. A photosensitizer comprising graphene, the graphene having a number average molecular weight (Mn) in terms of polystyrene of 500 or more and 1,000,000 or less, the number average molecular weight measured by gel permeation chromatography.

The invention provides a method of producing graphene. The method comprising: A) mixing graphite powders with a silk fibroin nanofiber solution, performing mechanical stirring to exfoliate graphite to form graphene flakes; wherein the silk fibroin nanofibers in the silk fibroin nanofiber solution have a crystallinity of 40% or above; the silk fibroin nanofibers have a diameter of 10 to 30 nm; the silk fibroin nanofibers have a length of 100 nm to 3 μm; the mechanical stirring has a shearing speed of 1,000 to 50,000 rpm; and the duration of the mechanical stirring is 10 min to 6 h; B) centrifuging the solution obtained in step A) after exfoliation to remove unexfoliated graphite; and C) centrifuging the centrifuged solution obtained in step B), and separating graphene from the silk fibroin nanofibers to obtain the graphene.

The invention provides a method of producing graphene. The method comprising: A) mixing graphite powders with a silk fibroin nanofiber solution, performing mechanical stirring to exfoliate graphite to form graphene flakes; wherein the silk fibroin nanofibers in the silk fibroin nanofiber solution have a crystallinity of 40% or above; the silk fibroin nanofibers have a diameter of 10 to 30 nm; the silk fibroin nanofibers have a length of 100 nm to 3 μm; the mechanical stirring has a shearing speed of 1,000 to 50,000 rpm; and the duration of the mechanical stirring is 10 min to 6 h; B) centrifuging the solution obtained in step A) after exfoliation to remove unexfoliated graphite; and C) centrifuging the centrifuged solution obtained in step B), and separating graphene from the silk fibroin nanofibers to obtain the graphene.

An improved method for concentrating dispersions of graphene oxide, coating a substrate with a layer of a graphene oxide solution, and producing a supported graphene membrane stabilised by controlled deoxygenation; and graphene-based membranes that demonstrate ultra-fast water transport, precise molecular sieving of gas and solvated molecules, and which show great promise as novel separation platforms.

The present disclosure provides supercapacitors that may avoid the shortcomings of current energy storage technology. Provided herein are electrochemical systems, comprising three dimensional porous reduced graphene oxide film electrodes. Prototype supercapacitors disclosed herein may exhibit improved performance compared to commercial supercapacitors. Additionally, the present disclosure provides a simple, yet versatile technique for the fabrication of supercapacitors through the direct preparation of three dimensional porous reduced graphene oxide films by filtration and freeze casting.