Production of graphene

Patent metadata

Field	Value
Publication number	US-2018282164-A1
Application number	US-201615765062-A
Country	US
Kind code	A1
Filing date	Oct 7, 2016
Priority date	Oct 8, 2015
Publication date	Oct 4, 2018
Grant date	—

Abstract

Methods for the production in an electrochemical cell of graphene and graphite nanoplatelet structures having a thickness of less than 100 nm in a cell having a negative electrode which is graphitic and an electrolyte which consists of ions in a solvent, where the cations are sulfur-containing ions or phosphorus containing ions, wherein the method comprises the step of passing a current through the cell to intercalate ions into the graphitic negative electrode so as to exfoliate the graphitic negative electrode.

First claim

1 . A method for the production in an electrochemical cell of graphene and graphite nanoplatelet structures having a thickness of less than 100 nm, wherein the cell comprises:
(a) a negative electrode which is graphitic; (b) a positive electrode which may be graphitic or another material; and (c) an electrolyte which consists of ions in a solvent, where the cations are sulfur-containing ions; and wherein the method comprises the step of passing a current through the cell to intercalate ions into the graphitic negative electrode so as to exfoliate the graphitic negative electrode.

2 . A method according to claim 1 , wherein the sulfur-containing cations are organosulfur cations.

3 . A method according to claim 2 , where the organosulfur cations are sulfonium ions.

4 . A method according to claim 3 , wherein the sulfonium ions are trialkyl sulfonium ions, suitably selected from triethyl sulfonium and trimethyl sulfonium.

5 . A method according to claim 1 , wherein the counteranions are selected from bis(trifluoromethylsulfonyl)imide, bromide, tetrafluoroborate (BF 4 − ), perchlorate (ClO 4 − ) and hexafluorophosphate (PF 6 − ).

6 . A method according to claim 1 , wherein the solvent is a non-aqueous solvent, suitably selected from dimethyl sulfoxide, N-methyl-2-pyrrolidone, N,N′-dimethyl formamide and mixtures thereof.

7 . A method for the production in an electrochemical cell of graphene and graphite nanoplatelet structures having a thickness of less than 100 nm, wherein the cell comprises:
(a) a negative electrode which is graphitic; (b) a positive electrode which may be graphitic or another material; and (c) an electrolyte which consists of ions in a solvent, where the cations are phosphorous-containing ions and wherein the electrolyte is substantially free of metal cations; and wherein the method comprises the step of passing a current through the cell to intercalate ions into the graphitic negative electrode so as to exfoliate the graphitic negative electrode.

8 . A method according to claim 7 , wherein the phosphorous-containing cations are phosphonium ions.

9 . A method according to claim 8 , where the phosphonium ions are tetraalkyl phosphonium ions.

10 . A method according to claim 9 , wherein the tetraalkyl phosphonium ions are selected from tetrabutyl phosphonium, tetraethyl phosphonium and tetramethyl phosphonium.

11 . A method according to claim 7 , wherein the counteranions are selected from hydroxide, bromide, tetrafluoroborate (BF 4 − ), perchlorate (ClO 4 − ) and hexafluorophosphate (PF 6 − ).

12 . A method according to claim 7 , wherein the solvent is a non-aqueous solvent, suitably selected from dimethyl sulfoxide, N-methyl-2-pyrrolidone, N,N′-dimethyl formamide, and mixtures thereof.

13 . A method according to claim 7 , wherein the negative electrode is an electrode comprising one or more selected from highly ordered pyrolytic graphite, natural graphite and synthetic graphite.

14 . A method according to claim 7 , which is carried out a temperature from 20° C. to 150° C.

15 . A method according to claim 7 , wherein the graphene or graphite nanoplatelet structures having a thickness of less than 100 nm are separated from the electrolyte by at least one technique selected from:
(a) filtering; (b) using centrifugal forces to precipitate the graphene or graphite nanoplatelet structures; and (c) collecting the graphene or graphite nanoplatelet structures at the interface of two immiscible solvents.

16 . A method according to claim 7 , wherein the electrochemically exfoliated graphene or graphite nanoplatelet structures are further treated using ultrasonic energy and/or thermal energy.

17 . A method according to claim 7 , wherein the method further includes the step of isolating the graphene or graphite nanoplatelet structures.

Assignees

• Univ Manchester

Inventors

• Abdelkader Amr
• Kinloch Ian
• Dryfe Robert

Classifications

• C01B32/22

  Intercalation · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• C01B2204/04

  Specific amount of layers or specific thickness · CPC title

• C01B32/215

  Purification; Recovery or purification of graphite formed in iron making, e.g. kish graphite · CPC title