Abstract: The purpose of the present invention is to provide a graphene dispersion which has high dispersibility and which is capable of exhibiting high electrical conductivity and ionic conductivity when used as a raw material for producing an electrode material. The present invention provides a graphene dispersion including a graphene, an amine compound having a molecular weight of 150 or less, and an organic solvent, wherein the mass ratio of an amine compound to the graphene is 0.005 or more and 0.30 or less.

Abstract: In order to prepare a highly conductive and highly dispersible graphene powder and to obtain an electrode for a lithium ion battery with excellent performance utilizing the highly conductive and highly dispersible graphene, a graphene powder and a preparation method thereof is provided. The graphene powder comprises a compound having a catechol group adsorbing on the surface of graphene in a weight ratio of 5-50% relative to the grapheme and the element ratio of oxygen to carbon in the graphene powder measured by X-ray photoelectron spectroscopy is 0.06 or more and 0.20 or less. The method for producing a graphene powder comprise the step of reducing a graphite oxide with a reducing agent having no catechol group in the presence of a compound having a catechol group.

Abstract: The purpose of the present invention is to provide a graphene dispersion which has high dispersibility and which is capable of exhibiting high electrical conductivity and ionic conductivity when used as a raw material for producing an electrode material. The present invention provides a graphene dispersion including a graphene, an amine compound having a molecular weight of 150 or less, and an organic solvent, wherein the mass ratio of an amine compound to the graphene is 0.005 or more and 0.30 or less.

Abstract: In order to prepare highly conductive and highly dispersible graphene and obtain an electrode for a lithium ion battery with good output characteristics and cycle characteristics, there is provided a graphene composition containing thiourea, the element ratio of sulfur to carbon being 0.04 or more and 0.12 or less in X-ray photoelectron spectroscopy measurement.

Abstract: Provided are a graphene powder, a production method thereof, and an electrochemical device comprising the same. The graphene powder has an elemental ratio of oxygen atoms to carbon atoms of not less than 0.07 and not more than 0.13 and an elemental ratio of nitrogen atoms to carbon atoms of not more than 0.01. In the production method, the graphene powder is produced by using a dithionous acid salt as a reducing agent. Since the graphene has a low content of nitrogen atoms and a proper amount of oxygen atoms and a proper defect, the graphene is provided with good performance of both dispersibility and conductive property, and is usable as a good conductive additive, such as the one for a lithium ion battery electrode. The production method has the advantages of low cost, high efficiency and low toxicity.

Abstract: In order to prepare highly conductive and highly dispersible graphene and obtain an electrode for a lithium ion battery with good output characteristics and cycle characteristics, there is provided a graphene composition containing thiourea, the element ratio of sulfur to carbon being 0.04 or more and 0.12 or less in X-ray photoelectron spectroscopy measurement.

Abstract: In order to prepare a highly conductive and highly dispersible graphene powder and to obtain an electrode for a lithium ion battery with excellent performance utilizing the highly conductive and highly dispersible graphene, a graphene powder and a preparation method thereof is provided. The graphene powder comprises a compound having a catechol group adsorbing on the surface of graphene in a weight ratio of 5-50% relative to the grapheme and the element ratio of oxygen to carbon in the graphene powder measured by X-ray photoelectron spectroscopy is 0.06 or more and 0.20 or less. The method for producing a graphene powder comprise the step of reducing a graphite oxide with a reducing agent having no catechol group in the presence of a compound having a catechol group.

Abstract: Provided are a graphene powder, a production method thereof, and an electrochemical device comprising the same. The graphene powder has an elemental ratio of oxygen atoms to carbon atoms of not less than 0.07 and not more than 0.13 and an elemental ratio of nitrogen atoms to carbon atoms of not more than 0.01. In the production method, the graphene powder is produced by using a dithionous acid salt as a reducing agent. Since the graphene has a low content of nitrogen atoms and a proper amount of oxygen atoms and a proper defect, the graphene is provided with good performance of both dispersibility and conductive property, and is usable as a good conductive additive, such as the one for a lithium ion battery electrode. The production method has the advantages of low cost, high efficiency and low toxicity.