Continuous process for producing electrodes for supercapacitors having high energy densities

Patent metadata

Field	Value
Publication number	US-9922775-B2
Application number	US-201514756777-A
Country	US
Kind code	B2
Filing date	Oct 13, 2015
Priority date	Oct 13, 2015
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

A process for producing a supercapacitor cell, comprising: (a) Continuously feeding a conductive porous layer to a cathode material impregnation zone, wherein the conductive porous layer contains interconnected electron-conducting pathways and at least 70% by volume of pores; (b) Impregnating a wet cathode active material mixture (containing a cathode active material and an optional conductive additive mixed with a liquid electrolyte) into pores of this porous layer to form a cathode electrode; (c) Preparing an anode electrode in a similar manner; and (d) Stacking an anode electrode, a porous separator, and a cathode electrode to form the supercapacitor, wherein the anode electrode and/or the cathode electrode has a thickness no less than 100 μm; and/or wherein the anode or cathode active material constitutes an electrode active material loading no less than 7 mg/cm 2 in the anode or the cathode.

First claim

We claim:

1. A process for producing a supercapacitor cell, said process comprising:
(A) continuously feeding a first electrically conductive porous layer to a cathode material impregnation zone, wherein said first conductive porous layer has two opposed porous surfaces and contains interconnected electron-conducting pathways and at least 70% by volume of pores;
(B) impregnating a wet cathode active material mixture into said first electrically conductive porous layer from at least one of said two porous surfaces to form a cathode electrode, wherein said wet cathode active material mixture contains a cathode active material and an optional conductive additive mixed with a first liquid electrolyte;
(C) continuously feeding a second electrically conductive porous layer to an anode material impregnation zone, wherein said second conductive porous layer has two opposed porous surfaces and contains interconnected electron-conducting pathways and at least 70% by volume of pores;
(D) impregnating a wet anode active material mixture into said second electrically conductive porous layer from at least one of said two porous surfaces to form an anode electrode, wherein said wet anode active material mixture contains an anode active material and an optional conductive additive mixed with a second liquid electrolyte; and
(E) stacking said anode electrode, a porous separator, and said cathode electrode to form said supercapacitor cell, wherein said anode electrode and/or said cathode electrode has a thickness no less than 100 μm; and/or wherein said anode active material or said cathode active material constitutes an electrode active material loading no less than 7 mg/cm 2 in said anode or said cathode.

2. The process of claim 1 , wherein step (A) and step (B) include delivering said wet cathode active material mixture to said at least one porous surface through spraying, printing, coating, casting, conveyor film delivery, and/or roller surface delivery; and/or wherein step (C) and step (D) include delivering said wet anode active material mixture to said at least one porous surface through spraying, printing, coating, casting, conveyor film delivery, and/or roller surface delivery.

3. The process of claim 1 , wherein said anode active material and/or said cathode active material contains multiple particles of a carbon material and/or multiple graphene sheets, wherein said multiple graphene sheets contain single-layer graphene or few-layer graphene each having from 1 to 10 graphene planes and said multiple particles of carbon material have a specific surface area no less than 500 m 2 /g when measured in a dried state.

4. The process of claim 3 , wherein said graphene sheets are selected from the group consisting of pristine graphene, graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, boron-doped graphene, nitrogen-doped graphene, chemically functionalized graphene, physically or chemically activated or etched versions thereof, and combinations thereof.

5. The process of claim 3 , wherein said anode active material or cathode active material 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 or a carbon material, form a redox pair for pseudo-capacitance.

6. The process of claim 5 , wherein said metal oxide is selected from RuO 2 , IrO 2 , NiO, MnO 2 , VO 2 , V 2 O 5 , V 3 O 8 , TiO 2 , Cr 2 O 3 , Co 2 O 3 , Co 3 O 4 , PbO 2 , Ag 2 O, or a combination thereof.

7. The process of claim 5 , wherein said inorganic material is selected from a metal carbide, metal nitride, metal boride, metal dichalcogenide, or a combination thereof.

8. The process of claim 5 , 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, nanodisc, nanoribbon, or nanoplatelet form.

9. The process of claim 5 , wherein said inorganic material is selected from nanodiscs, nanoplatelets, nano-coating, or nanosheets of an inorganic material selected from: (a) bismuth selenide or bismuth telluride, (b) transition metal dichalcogenide or trichalcogenide, (c) sulfide, selenide, or telluride of a transition metal; (d) boron nitride, or (e) a combination thereof; wherein said nanodiscs, nanoplatelets, or nanosheets have a thickness less than 100 nm.

10. The process of claim 3 , wherein said carbon material is selected from activated carbon, activated meso-carbon micro beads, activated graphite, activated or chemically etched carbon black, activated hard carbon, activated soft carbon, carbon nanotube, carbon nanofiber, activated carbon fiber, activated graphite fiber, exfoliated graphite worms, activated graphite worms, activated expanded graphite flakes, or a combination thereof.

11. The process of claim 1 , wherein said first and/or second electrically conductive porous layer has a thickness no less than 200 μm, has at least 85% by volume of pores, and/or said electrode active material loading is no less than 10 mg/cm 2 .

12. The process of claim 1 , wherein said first and/or second electrically conductive porous layer has a thickness no less than 300 μm, has at least 90% by volume of pores, and/or said electrode active material loading is no less than 15 mg/cm 2 .

13. The process of claim 1 , wherein said first and/or second electrically conductive porous layer has a thickness no less than 400 μm, has at least 95% by volume of pores, and/or said electrode active material loading is no less than 20 mg/cm 2 .

14. The process of claim 1 , wherein said first and/or second electrically conductive porous layer is selected from metal foam, metal web or screen, perforated metal sheet-based 3-D structure, metal fiber mat, metal nanowire mat, conductive polymer nano-fiber mat, conductive polymer foam, conductive polymer-coated fiber foam, carbon foam, graphite foam, carbon aerogel, carbon xerogel, graphene foam, graphene oxide foam, reduced graphene oxide foam, carbon fiber foam, graphite fiber foam, exfoliated graphite foam, or a combination thereof.

15. The process of claim 1 , wherein said anode or said cathode contains graphene sheets as the only electrode active material and does not contain any other electrode active material.

16. The process of claim 1 , wherein said anode or said cathode contains the following materials as the only electrode active material in said anode or cathode: (a) graphene sheets alone; (b) graphene sheets mixed with a carbon material; (c) graphene sheets mixed with a partner material that forms a redox pair with said graphene sheets to develop pseudo-capacitance; or (d) graphene sheets and a carbon material mixed with a partner material that forms a redox pair with said graphene sheets or said carbon material to develop pseudo-capacitance, and wherein there is no other electrode active material in said anode or cathode.

17. The process of claim 1 , wherein a volume ratio of said anode active material-to-said liquid electrolyte in said wet anode active material mixture is from 1/5 to 20/1 and/or a volume ratio of said cathode active material-to-said liquid electrolyte in said wet cathode active material mixture is from 1/5 to 20/1.

18. The process of claim 1 , wherein a v

Assignees

• Zhamu Aruna
• Jang Bor Z
• Nanotek Instruments Inc

Inventors

• Zhamu Aruna
• Jang Bor Z

Classifications

• H01G11/26

  characterised by their structure, e.g. multi-layered, porosity or surface features · CPC title

• H01G11/58

  Liquid electrolytes · CPC title

• H01G11/50 Primary

  specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation · CPC title

• H01G11/36

  Nanostructures, e.g. nanofibres, nanotubes or fullerenes · CPC title

• H01G11/46

  Metal oxides · CPC title