# US 11,111,148 B2 · Graphene, preparation method thereof and supercapacitor electrode and supercapacitor containing the graphene > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,111,148 B2 - Document ID: US11111148B2 - Status: Granted - Kind: B2 - Application number: 16/312,851 - Filed: 2017-03-10 - Published: 2019-07-11 - Granted: 2021-09-07 - Earliest claimed: 2016-06-24 - Assignees: Institute of Electrical Engineering, Chinese Academy of Sciences - Applicants: Institute of Electrical Engineering, Chinese Academy of Sciences - Inventors: Yanwei Ma; Chen Li; Xiong Zhang - Web page: https://patentgrep.com/patent/US11111148B2 ## CPC - C01B 32/184: Preparation - C01B 2204/22: Electronic properties - C01P 2002/72: by d-values or two theta-values, e.g. as X-ray diagram - C01P 2004/03: obtained by SEM - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS ## Abstract Provided are a graphene and a preparation method therefor. The method for preparing a graphene comprises following steps: i) placing a mixture of a magnesium powder and a solid oxide powder in a carbon dioxide-containing environment; and ii) heating the mixture to enable the magnesium powder to react with carbon dioxide, thereby obtaining a graphene. The specific surface area of the grapheme is 350-750 m2/g, and the pore volume is 1-2 cm3/g. The method for preparing a graphene in the present invention is simple and easy to carry out, and has a low cost and a high yield; and the graphene product has few impurities, a high carbon-oxygen ratio, and excellent capacitance performance and electrochemical stability. ## Claims ### Claim 1 A method for preparing a graphene, comprising the following steps: i) placing a mixture comprising a magnesium powder and a solid oxide powder in a carbon dioxide-containing environment, wherein the pressure of carbon dioxide in the environment is above 0.125 MPa; ii) heating said mixture to enable the magnesium powder to react with carbon dioxide, thereby obtaining a graphene. ### Claim 2 (depends on 1) The method according to claim 1, further comprising following steps: iii) removing magnesium oxide and/or said solid oxide from the product of Step ii). ### Claim 3 (depends on 2) The method according to claim 2, wherein Step iii) comprises: washing the product of Step ii) with an acid. ### Claim 4 (depends on 2) The method according to claim 2, further comprising following steps: iv) subjecting the product of Step iii) to one or more operations of washing, filtration or drying. ### Claim 5 (depends on 1) The method according to claim 1, wherein Step i) comprises placing a mixture comprising a magnesium powder and a solid oxide powder in a sealed container filled with carbon dioxide. ### Claim 6 (depends on 5) The method according to claim 5, wherein in Step i), at least one of the following is satisfied: the solid oxide powder has an average particle diameter of 0.1˜1000 μm; the magnesium powder has an average particle diameter of 9˜9000 μm. ### Claim 7 (depends on 1) The method according to claim 1, wherein in Step i), a mass ratio of the magnesium powder to the solid oxide powder is 1:0.1˜10. ### Claim 8 (depends on 1) The method according to claim 1, wherein said solid oxide is a metal oxide. ### Claim 9 (depends on 8) The method according to claim 8, wherein said solid oxide is magnesium oxide. ### Claim 10 (depends on 1) The method according to claim 1, wherein said solid oxide is an alkaline earth metal oxide. ### Claim 11 (depends on 1) The method according to claim 1, wherein in Step i), at least one of the following is satisfied: the carbon dioxide in the environment has a pressure of 0.125˜10 MPa; the carbon dioxide in the environment is above 90 volume %. ### Claim 12 (depends on 1) The method according to claim 1, comprising one or more of the following steps: a) mixing a magnesium powder with a magnesium oxide powder homogeneously to obtain a mixed powder, placing said mixed powder in a sealed pressure-resistant container, and embedding a tungsten coil in said mixed powder; b) reducing gas pressure in the sealed pressure-resistant container to 2×10−4 Pa, introducing carbon dioxide gas into said sealed pressure-resistant container until the pressure in said sealed pressure-resistant container is 0.125˜10 MPa; c) applying a direct current of 0.5˜30 A to said tungsten coil by using a direct current power supply, for a period of 5-30 s, whereby a reaction between the magnesium powder and the carbon dioxide is initiated by heat generated from said tungsten coil, thereby obtaining a powder after reaction; d) placing the powder product in Step c) in a dilute acid solution, followed by standing for 6.about.48 h, then washing said powder with deionized water by sucking filtration, collecting a filtrate, and freeze-drying the filtrate to obtain a graphene. ### Claim 13 A method for preparing a mesoporous graphene, comprising the following steps: Step 1, mixing a magnesium powder with a magnesium oxide powder homogeneously to obtain a mixed powder, placing said mixed powder in a sealed pressure-resistant container, and embedding a tungsten coil in said mixed powder; Step 2, reducing pressure in said sealed pressure-resistant container to 2×10−4 Pa by using a molecular pump, and introducing carbon dioxide gas into said sealed pressure-resistant container until the pressure in said sealed pressure-resistant container is 0.125-10 MPa; Step 3, applying a direct current of 0.5-30 A to said tungsten coil by using a direct current power supply, for a period of 5-30 s, whereby a reaction between the magnesium powder and the carbon dioxide is initiated by heat generated from the tungsten coil, and after the reaction proceeding for 1-2 min, obtaining a black powder; Step 4, placing said black powder in a dilute acid solution, followed by standing for 6-48 h, then washing said black powder with deionized water by sucking filtration until the powder is neutral, thereby obtaining a filter cake, and freeze-drying said filter cake to obtain a mesoporous graphene powder. ### Claim 14 (depends on 13) The method for preparing a mesoporous graphene according to claim 13, wherein in Step 1, said magnesium powder has an average particle diameter of 1-1000 μm, and said magnesium oxide powder has an average particle diameter of 0.1-1000 μm. ### Claim 15 (depends on 13) The method for preparing a mesoporous graphene according to claim 13, wherein in Step 1, said mixed powder has a mass ratio of the magnesium powder to the magnesium oxide powder of 1:0-1:10. ### Claim 16 (depends on 13) The method for preparing a mesoporous graphene according to claim 13, wherein said dilute acid solution is a dilute hydrochloric acid, a dilute sulfuric acid or a dilute nitric acid, each having a concentration of 0.2-2 M. ### Claim 17 (depends on 13) The method for preparing a mesoporous graphene according to claim 13, wherein said sealed pressure-resistant container is a sealed pressure-resistant steel container with a volume of 10-200 L. ### Claim 18 (depends on 13) The method for preparing a mesoporous graphene according to claim 13, wherein said freeze-drying in Step 4 comprises following steps: Step 4.1, placing said filter cake in a plastic beaker, adding deionized water to said plastic beaker, and then carrying out an ultrasonic treatment and a stirring step, thereby obtaining a paste; Step 4.2, freezing said paste in a cryogenic liquid for 30 min to obtain a black solid; Step 4.3, drying said black solid in a freeze drier to obtain said mesoporous graphene powder. ### Claim 19 (depends on 18) The method for preparing a mesoporous graphene according to claim 18, wherein in Step 4.1, a mass ratio of said deionized water to said filter cake is 1:1-8:1. ### Claim 20 (depends on 18) The method for preparing a mesoporous graphene according to claim 18, wherein the cryogenic liquid in Step 4.2 is liquid nitrogen, liquid helium or liquid argon.