Water soluble graphene oxide nanoparticles (GO) are provided having graphene sheets containing carboxylic and hydroxyl groups. The diameter of the GO when present in a closed form ranges from about 40 nm to 120 nm. Eco-friendly methods are provided for producing the GO. Methods for reversible encapsulation of a molecule within water soluble carbon nanoparticles (wsCNP) including the GO nanoparticles are provided that allow for delivery of the wsCNP loaded with therapeutic and/or imaging agents to a subject in need by releasing the therapeutic/imaging agent upon an increase in pH above about 7.2. The wsCNP have been shown to cross the blood brain barrier in a mouse model of vascular dementia, and methods are provided for delivering the wsCNP loaded with a therapeutic and/or imaging molecule to the brain.

This can be a method of making a high strength composite reinforcing fiber using flat GO flakes coated on a conventional reinforcing fiber. This maintains some the flexibility of the fiber and aligns the flat graphene flakes along the surface of the fiber; this dramatically increases the strength of the fiber. It also allows bonding between overlapping flakes, in contrast to flakes being uniformly dispersed in a host material that is being reinforced and dramatically increases the strength of the host material.

This can be a method of making a high strength composite reinforcing fiber using flat GO flakes coated on a conventional reinforcing fiber. This maintains some the flexibility of the fiber and aligns the flat graphene flakes along the surface of the fiber; this dramatically increases the strength of the fiber. It also allows bonding between overlapping flakes, in contrast to flakes being uniformly dispersed in a host material that is being reinforced and dramatically increases the strength of the host material.

The present invention is an improved method of production of graphenic materials used to store energy and the energy storage systems using such produced graphenic materials. Provided herein is a method of producing graphene oxide that includes oxidizing graphite powder in a mixture of H.sub.3PO.sub.4 and H.sub.2SO.sub.4 in the presence of KMnO.sub.4, wherein the ratio of graphite powder to KMnO.sub.4 is about 1:9 by weight and the ratio of H.sub.3PO.sub.4 to H.sub.2SO.sub.4 is about 1:9 by volume, to produce graphene oxide; dispersing the graphene oxide in water at an acidic pH (e.g., about 0) to form a solution; adjusting the solution to about a neutral pH; and isolating the graphene oxide. An energy storage device is provided herein that includes the graphene oxide made by the disclosed methods or that includes the population (plurality) of reduced graphene oxide particles having the properties disclosed herein, such as batteries and supercapacitors.

The present invention is an improved method of production of graphenic materials used to store energy and the energy storage systems using such produced graphenic materials. Provided herein is a method of producing graphene oxide that includes oxidizing graphite powder in a mixture of H.sub.3PO.sub.4 and H.sub.2SO.sub.4 in the presence of KMnO.sub.4, wherein the ratio of graphite powder to KMnO.sub.4 is about 1:9 by weight and the ratio of H.sub.3PO.sub.4 to H.sub.2SO.sub.4 is about 1:9 by volume, to produce graphene oxide; dispersing the graphene oxide in water at an acidic pH (e.g., about 0) to form a solution; adjusting the solution to about a neutral pH; and isolating the graphene oxide. An energy storage device is provided herein that includes the graphene oxide made by the disclosed methods or that includes the population (plurality) of reduced graphene oxide particles having the properties disclosed herein, such as batteries and supercapacitors.

Provided are a method for directly preparing expanded graphite or graphene under normal temperature and normal pressure, a graphene material, and a product. The method comprises the following specific steps: firstly dispersing graphite in an acidic medium containing an oxidizing agent, and then enabling obtained suspension liquid to stand under normal temperature and normal pressure, thus obtaining expanded graphite. The method does not involve any high-temperature high-pressure reaction process, is safe in operation, low in energy consumption and high in efficiency, and is environmentally-friendly. Obtained expanded graphite can realize 50-1500 times of volume expansion, and an sp2 hybridization structure of a graphene sheet layer is basically not damaged; and the obtained expanded graphite can be widely applied to the fields of energy storage, heat management, photoelectronic devices, solar cells, anti-corrosive materials, various composite materials, and the like. The prepared expanded graphite can also be used as a precursor for preparing high-quality graphene, and the high-quality graphene basically containing no defects can be obtained by peeling off the expanded graphite.

Provided are a method for directly preparing expanded graphite or graphene under normal temperature and normal pressure, a graphene material, and a product. The method comprises the following specific steps: firstly dispersing graphite in an acidic medium containing an oxidizing agent, and then enabling obtained suspension liquid to stand under normal temperature and normal pressure, thus obtaining expanded graphite. The method does not involve any high-temperature high-pressure reaction process, is safe in operation, low in energy consumption and high in efficiency, and is environmentally-friendly. Obtained expanded graphite can realize 50-1500 times of volume expansion, and an sp2 hybridization structure of a graphene sheet layer is basically not damaged; and the obtained expanded graphite can be widely applied to the fields of energy storage, heat management, photoelectronic devices, solar cells, anti-corrosive materials, various composite materials, and the like. The prepared expanded graphite can also be used as a precursor for preparing high-quality graphene, and the high-quality graphene basically containing no defects can be obtained by peeling off the expanded graphite.

The present invention belongs to the field of new materials technology and discloses a green method for preparing functionalized carbon materials. The present invention can use potassium ferrate(VI) as an oxidant and mechanical milling as a reaction technique for oxidizing carbon materials in a preparation of functionalized carbon materials having oxygen-containing functional groups. Compared with the prior art, the present invention provides a method that combines an environmentally friendly oxidant with an environmentally friendly reaction process. The oxidant potassium ferrate(VI) is a green oxidant without producing any toxic byproducts. The reaction process is solvent-free, facilitated by milling the solid mixture of carbon materials and the oxidant. Thus, the present invention provides an environmentally friendly method for preparing oxidatively functionalized carbon materials, which is of promotion value.

The present invention belongs to the field of new materials technology and discloses a green method for preparing functionalized carbon materials. The present invention can use potassium ferrate(VI) as an oxidant and mechanical milling as a reaction technique for oxidizing carbon materials in a preparation of functionalized carbon materials having oxygen-containing functional groups. Compared with the prior art, the present invention provides a method that combines an environmentally friendly oxidant with an environmentally friendly reaction process. The oxidant potassium ferrate(VI) is a green oxidant without producing any toxic byproducts. The reaction process is solvent-free, facilitated by milling the solid mixture of carbon materials and the oxidant. Thus, the present invention provides an environmentally friendly method for preparing oxidatively functionalized carbon materials, which is of promotion value.

To provide a manufacturing method of graphene oxide that allows mass production through a relatively simple process, at low costs, and with safety and efficiency. A hydrogen peroxide solution, sulfuric acid, and flake graphite are put in a reaction container, and the mixture is stirred to obtain expansion graphite. The synthesized expansion graphite is washed not with pure water but with a saturated aqueous solution of magnesium sulfate (MgSO.sub.4) or an organic solvent, whereby a large amount of sulfuric acid is contained between graphite layers. The expansion graphite is subjected to heat treatment or microwave irradiation to form expanded graphite, and a graphite layer is peeled by ultrasonic treatment and then oxidized to form a graphene compound.