Process for producing a porous carbon electrode

Patent metadata

Field	Value
Publication number	US-11145469-B2
Application number	US-201716473980-A
Country	US
Kind code	B2
Filing date	Dec 27, 2017
Priority date	Dec 27, 2016
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

A method for producing a porous carbon electrode includes preparing a slurry by mixing a porous, particulate, conductive carbon powder with a solution of a polymer binding agent for the particulate carbon powder in a solvent for the polymer binding agent, forming a precursor electrode by casting the slurry as a layer and subjecting the cast layer to a wet phase inversion to realize porosity in the cast layer, subjecting the thus obtained precursor electrode to a thermal treatment to cause oxidative stabilization, carbonization, dehydrogenation or cyclisation of the polymer binding agent or a combination of two or more of the afore mentioned phenomena by heating the precursor electrode and converting the polymer binding agent into a conductive binding agent binding the particles of the conductive carbon powder together.

First claim

What is claimed is:

1. A method for producing a porous carbon electrode, comprising:
preparing a slurry by mixing a porous, particulate, conductive carbon powder with a solution of a polymer binding agent for the carbon powder in a solvent for the polymer binding agent;
forming a precursor electrode by casting the slurry as a layer and subjecting a cast layer to a wet phase inversion to create porosity in the cast layer; and
subjecting said precursor electrode to a thermal treatment by heating the precursor electrode to a temperature with the purpose of converting the polymer binding agent into a conductive binding agent binding said porous, particulate, conductive carbon powder together,
wherein the polymer binding agent is a polymer material having a degradation temperature which is lower than the melting temperature.

2. A method according to claim 1 , wherein the thermal treatment comprises a first step of heating the precursor electrode in the presence of an oxidizing agent to a temperature which is equal to or lower than the melting temperature of the polymer binding agent.

3. A method according to claim 2 , wherein the thermal treatment comprises a first thermal treatment step which is carried out at a temperature of between 50° C. and 300° C.

4. The method of claim 2 , wherein the thermal treatment of the precursor electrode is carried out in the presence of an oxygen containing gas.

5. A method according to claim 2 , wherein the thermal treatment of the precursor electrode comprises a second thermal treatment step of heating the precursor electrode in an inert atmosphere to a temperature of between 250° C. and 600° C., wherein the second step is carried out after the first thermal treatment step.

6. A method according to claim 3 , wherein the first thermal treatment step is carried out for a period of time of between 20 minutes and 240 minutes.

7. A method according to claim 1 , wherein the polymer binding agent is selected from the group consisting of nitrile polymers.

8. A method according to claim 1 , wherein the polymer binding agent comprises one or more polymers selected from the group consisting of polyacetates and cellulose compounds.

9. A method according to claim 1 , wherein the weight ratio of the polymer binding agent to the conductive carbon powder varies from 70.0: 30.0 to 90.0:10.0.

10. A method according to claim 1 , wherein the solvent for the polymer material is selected from the group consisting of N,N-dimethylformamide (DMF), formamide, dimethylsulphoxide (DMSO), N,N-dimethylacetamide (DMAC), acetonitrile, acetamide, trichloroethylene, chloroform, dichloromethane, N-methyl-pyrrolidinone (NMP), N-ethyl-pyrrolidinone (NEP), methyletherketone, dioxane, triethylphosphate, aceton, diethylenetriamine and mixtures of two or more hereof.

11. A method according to claim 10 , wherein the solvent comprises a co-solvent selected from the group consisting of tetrahydrofuran (THF), tetramethyl urea (TMU), N,N-dimethylpropylene urea (DMPU), trimethyl phosphate (TMP), triethyl phosphate (TEP), tri-n-butyl phosphate (TBP), tricresyl phosphate (TCP), acetone, aniline ; a ketone; a chlorinated hydrocarbon; aromatic fluids and chloroform and a mixture of two or more of the afore-mentioned co-solvents.

12. A method according to claim 1 , wherein the cast layer of the slurry after having been subjected to the thermal treatment has a thickness of 500 micron or less.

13. A method according to claim 1 , wherein the slurry is subjected to degassing before being subjected to the thermal treatment.

14. A method according to claim 1 , wherein the slurry is cast on at least one side of an electrically conductive carrier.

15. A method according to claim 1 , wherein the porous carbon electrode comprises a current collector and the slurry is applied to both opposite sides of the current collector.

16. A method according to claim 1 , wherein the slurry is applied to an electrically conductive carrier using impregnation.

17. A method according to claim 16 , wherein said electrically conductive carrier is made of a material or a combination of materials selected from the group consisting of a sheet material and a felt material comprising conductive carbon fibers and reticulated vitreous carbon.

18. A method according to claim 17 , wherein a current collector is positioned between two layers of a sheet material impregnated with the slurry.

19. A method according to claim 1 , wherein the porous carbon powder has a BET surface area of at least 250 m2/g.

20. A porous carbon electrode, comprising a porous active layer which contains particles of a porous conductive carbon powder, wherein at least part of the particles are connected by a porous residue of a polymer binding agent that has been subjected to a thermal treatment according to claim 1 .

21. An electrochemical cell containing at least one porous carbon electrode obtained with the method of claim 1 .

22. A method for desalination of water, wherein an aqueous solution containing one or more salts is subjected to desalination in an electrochemical cell according to claim 21 .

23. A method for capacitive de-ionization of water, wherein an aqueous solution containing one or more salts is subjected to capacitive de-ionization in an electrochemical cell according to claim 22 .

Assignees

• Vito Nv

Inventors

• Doyen Willy
• Cardoen Dennis
• Helsen Joost
• Claes Andre-Viktor

Classifications

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• H01G11/24

  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 title

• H01G11/38

  Carbon pastes or blends; Binders or additives therein · CPC title

• C02F2001/46161

  Porous electrodes · CPC title

• C02F2001/46138

  Electrodes comprising a substrate and a coating · CPC title