Humic acid-based supercapacitors

• US 10,332,693 B2
• Filed: 07/15/2016
• Issued: 06/25/2019
• Est. Priority Date: 07/15/2016
• Status: Active Grant

• Current Assignee: Nanotek Instruments Group, LLC
• Original Assignee: Nanotek Instruments, Inc.
• Inventors: Chai, Song-Hai, Zhamu, Aruna, Jang, Bor Z.
• Primary Examiner(s): Ha, Nguyen T
• Application Number:
  US15/211,209
• Publication Number:
  US 20180019070A1
• Time in Patent Office: 1,075 Days
• CPC Class Codes: C01B 19/04 Binary compounds including binary selenium-tellurium compounds C01B19/004, C01B19/005, C01B19/007 take precedence
• CPC Class Codes: C01B 32/19 by exfoliation
• CPC Class Codes: C01B 32/23 Oxidation
• CPC Class Codes: C01G 39/06 Sulfides
• CPC Class Codes: C01G 45/02 Oxides; Hydroxides
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C07G 1/00 Lignin; Lignin derivatives
• CPC Class Codes: C08G 2261/3223 containing one or more sulfur atoms as the only heteroatom, e.g. thiophene
• CPC Class Codes: C08G 2261/77 grafting
• CPC Class Codes: C08G 61/126 with a five-membered ring containing one sulfur atom in the ring
• CPC Class Codes: C08H 6/00 Macromolecular compounds derived from lignin, e.g. tannins, humic acids
• CPC Class Codes: C11B 1/10 by extracting
• CPC Class Codes: H01G 11/02 using combined reduction-oxidation reactions, e.g. redox arrangement or solion
• CPC Class Codes: H01G 11/04 Hybrid capacitors
• CPC Class Codes: H01G 11/06 with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
• CPC Class Codes: H01G 11/24 characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor
• CPC Class Codes: H01G 11/36 Nanostructures, e.g. nanofibres, nanotubes or fullerenes
• CPC Class Codes: H01G 11/38 Carbon pastes or blends; Binders or additives therein
• CPC Class Codes: H01G 11/42 Powders or particles, e.g. composition thereof
• CPC Class Codes: H01G 11/46 Metal oxides
• CPC Class Codes: H01G 11/48 : Conductive polymers
• CPC Class Codes: H01G 11/52 : Separators
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

A supercapacitor electrode comprising a mixture of graphene sheets and humic acid, wherein humic acid occupies 0.1% to 99% by weight of the mixture and the graphene sheets are selected from a pristine graphene material having essentially zero % of non-carbon elements, or a non-pristine graphene material having 0.001% to 5% by weight of non-carbon elements wherein said non-pristine graphene is selected from graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, chemically functionalized graphene, or a combination thereof; and wherein said mixture has a specific surface area greater than 500 m²/g.

Claims

1. A supercapacitor electrode comprising a mixture of graphene sheets and humic acid, wherein said humic acid occupies 0.1% to 99% by weight of the mixture and said graphene sheets are selected from a pristine graphene material having essentially zero % of non-carbon elements, or a non-pristine graphene material having 0.001% to 5% by weight of non-carbon elements wherein said non-pristine graphene is selected from the group consisting of graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, chemically functionalized graphene, and a combination thereof;

and wherein said mixture has a specific surface area greater than 500 m²/g.

2. The supercapacitor electrode of claim 1, wherein said electrode comprises multiple particulates that are porous and each particulate is composed of multiple humic acid molecules and graphene sheets that are packed into a spherical or ellipsoidal shape.

3. The supercapacitor electrode of claim 1, wherein said graphene sheets comprise single-layer graphene.

4. The supercapacitor electrode of claim 1, wherein said graphene sheets contain few-layer graphene having an average thickness no greater than 2 nm or no more than 5 graphene planes per sheet.

5. The supercapacitor electrode of claim 1, wherein said humic acid contains isolated single molecules.

6. The supercapacitor electrode of claim 1, wherein said mixture has a specific surface area greater than 1,500 m²/g.

7. The supercapacitor electrode of claim 1, wherein said mixture has a specific surface area greater than 2,000 m²/g.

8. The supercapacitor electrode of claim 1, wherein said graphene sheets or humic acid molecules are functionalized with one or more of conducting polymers, transition metal oxides, or transition metal sulfides.

9. The supercapacitor electrode of claim 1, wherein said graphene sheets are chemically or physically activated.

10. A supercapacitor comprising an anode, a cathode, a porous separator disposed between said anode and said cathode, a liquid electrolyte in ionic contact with said anode and said cathode, wherein at least one of said anode and said cathode contains said supercapacitor electrode of claim 1.

11. The supercapacitor as defined in claim 10, wherein said graphene sheets and/or said humid acid molecules are bonded by or bonded to a conductive binder material selected from the group consisting of a conducting polymer, a polymeric carbon, an amorphous carbon, a petroleum pitch, a coal tar pitch, a meso-phase pitch, and combinations thereof.

12. The supercapacitor as defined in claim 10, wherein said graphene sheets are activated, surface-functionalized, or surface-coated with functional materials or chemical groups for enhanced capacitance.

13. The supercapacitor as defined in claim 10 wherein said graphene sheets are functionalized with one or more conducting polymers, transition metal oxides, or transition metal sulfides.

19. The supercapacitor of claim 10, which is selected from a symmetric supercapacitor, an asymmetric supercapacitor, a redox supercapacitor, a lithium-ion capacitor, or a sodium-ion capacitor.

14. A supercapacitor comprising an anode, a cathode, a porous separator disposed between said anode and said cathode, a liquid electrolyte in ionic contact with said anode and said cathode, wherein at least one of said anode and said cathode contains a supercapacitor electrode comprising a mixture of graphene sheets and humic acid, wherein said humic acid occupies 0.1% to 99% by weight of the mixture and said graphene sheets are selected from a pristine graphene material having essentially zero % of non-carbon elements, or a non-pristine graphene material having 0.001% to 5% by weight of non-carbon elements wherein said non-pristine graphene is selected from the group consisting of graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, chemically functionalized graphene, and a combination thereof and wherein said mixture has a specific surface area greater than 500 m²/g, wherein said anode or cathode further contains a redox pair partner material selected from a metal oxide, a conducting polymer, an organic material, a non-graphene carbon material, an inorganic material, or a combination thereof, wherein said partner material, in combination with graphene sheets or humic acid, forms a redox pair for pseudo-capacitance.

15. The supercapacitor of claim 14, wherein said metal oxide is selected from RuO₂, IrO₂, NiO, MnO₂, VO₂, V₂O₅, V₃O₈, TiO₂, Cr₂O₃, Co₂O₃, Co₃O₄, PbO₂, Ag₂O, or a combination thereof.

16. The supercapacitor of claim 14, wherein said inorganic material is selected from a metal carbide, metal nitride, metal boride, metal dichalcogenide, or a combination thereof.

17. The supercapacitor of claim 14, wherein said metal oxide or inorganic material is selected from an oxide, dichalcogenide, trichalcogenide, sulfide, selenide, or telluride of niobium, zirconium, molybdenum, hafnium, tantalum, tungsten, titanium, vanadium, chromium, cobalt, manganese, iron, or nickel in a nanowire, nano-disc, nano-ribbon, or nano platelet form.

18. The supercapacitor of claim 14, wherein said inorganic material is selected from nano discs, nano platelets, nano-coating, or nano sheets of an inorganic material selected from:

(a) bismuth selenide or bismuth telluride, (b) transition metal dichalcogenide or trichalcogenide, (c) sulfide, selenide, or telluride of niobium, zirconium, molybdenum, hafnium, tantalum, tungsten, titanium, cobalt, manganese, iron, nickel, or a transition metal;

(d) boron nitride, or (e) a combination thereof;

wherein said discs, platelets, or sheets have a thickness less than 100 nm.