Microscale-bipolar-interface-enabled pH gradients in electrochemical devices

Patent metadata

Field	Value
Publication number	US-11616246-B2
Application number	US-201916379212-A
Country	US
Kind code	B2
Filing date	Apr 9, 2019
Priority date	Apr 9, 2018
Publication date	Mar 28, 2023
Grant date	Mar 28, 2023

Abstract

Among the various aspects of the present disclosure is the provision of method of inducing or providing a pH gradient in electrochemical or chemical systems. Briefly, the pH gradient is induced by use of coated particles or films with an ion exchange ionomer.

First claim

What is claimed is:

1. A method of inducing or providing a pH gradient in an electrochemical or a chemical system comprising:
(i) coating a first catalytic particle, a plurality of catalytic particles, or a catalytic film with an ion exchange ionomer, resulting in a first ionomer-coated catalytic particle, a first ionomer-coated plurality of catalytic particles, or a first ionomer-coated catalytic film;
(ii) placing the first ionomer-coated catalytic particle, the first ionomer-coated plurality of catalytic particles, or the first ionomer-coated catalytic film in contact with an ion exchange membrane (IEM);
(iii) coating a second catalytic particle, a plurality of catalytic particles, or a catalytic film with an ion exchange ionomer, resulting in a second ionomer-coated catalytic particle, a second ionomer-coated plurality of catalytic particles, or a second ionomer-coated catalytic film; and
(iv) placing the second ionomer-coated catalytic particle, the second ionomer-coated plurality of catalytic particles, or the second ionomer-coated catalytic film in contact with the IEM;
wherein
the IEM is a cation membrane (CEM) or an anion exchange membrane (AEM);
the first ionomer-coated catalytic particle, ionomer-coated plurality of particles, or ionomer-coated catalytic film is an anion exchange ionomer (AEI)-coated catalytic particle, AEI-coated plurality of catalytic particles, or AEI-coated catalytic film; and
the second ionomer-coated catalytic particle, ionomer-coated plurality of catalytic particles, or ionomer-coated catalytic film is a cation exchange ionomer (CEI)-coated catalytic particle, CEI-coated plurality of catalytic particles, or CEI-coated catalytic film;
the AEM or AEI comprises a material selected from one or more of the group consisting of polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene tri-block copolymer-based backbone, poly (phenylene oxide)-based backbone, polysulfone-based backbone, poly(N,N-diallylazacycloalkane)-based backbone, bromoalkyl-tethered poly(biphenyl alkylene)-based backbone, multiblock copoly(arylene ether)-based backbone, poly (vinylbenzyl chloride)-based backbone, and cardo-polyetherketone-based backbone; and
the material comprises a functional group selected from one or more of the group consisting of benzyl-trimethylammonium, benzyl-imidazolium, guanidium, benzyl-tris (2, 4, 6-trimethoxyphenyl) phosphonium, permethyl cobaltocenium, 1,4-dimethylpiperazinium, and benzyl-trimethylphosphonium.

2. The method of claim 1 , wherein the IEM is a CEM.

3. The method of claim 1 , wherein the first or second catalytic particle, plurality of catalytic particles, or catalytic film comprises a material selected from one or more of the group consisting of Ni; CoO; a noble metal; a metal alloy thereof; a metal mixture thereof; and combinations thereof.

4. The method of claim 3 , wherein the noble metal is Ag, Au, Ir, Pd, or Pt.

5. The method of claim 1 , wherein the CEM or CEI comprises a material selected from one or more of the group consisting of a perfluorosulfonic acid (PFSA)/polytetrafluoroethylene (PTFE) copolymer, sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene tri-block copolymer, sulfonated poly (phenylene oxide), sulfonated poly(quinoxaline), poly(ethylene-co-tetrafluoroethylene)-graft-poly(styrene sulfonic acid), poly(vinylidene fluoride)-graft-poly(styrene sulfonic acid), sulfonated poly(arylene ether ketone), sulfonated poly( 4 -phenoxybenzoyl-1,4-phenylene), and sulfonated polysulfone.

6. The method of claim 1 , further comprising
introducing either a reducing agent or an oxidizing agent to a first electrode or a second electrode comprising a first ionomer-coated catalytic film, a first ionomer-coated catalytic particle, or a first ionomer-coated plurality of catalytic particles; or
introducing either an oxidizing agent or a reducing agent to a second ionomer-coated catalytic film, a second ionomer-coated catalytic particle, or a second ionomer-coated plurality of catalytic particles.

7. The method of claim 6 , wherein,
the first electrode and the second electrode are separated by the IEM;
a reaction with a reduced or oxidized species from the first electrode and an oxidized or reduced species from the second electrode occurs at an interface between the the first or second ionomer-coated catalytic film, the first or second ionomer-coated catalytic particle, or the first or second ionomer-coated plurality of catalytic particles and the IEM, wherein the reaction results in splitting water, forming water, forming compounds produced by half-cell reactions occurring at the first electrode and the second electrode, or forming a compound produced by an overall full cell reaction;
the reducing agent comprises a material selected from one or more of the group consisting of: sodium borohydride, methanol, hydrazine, hydrogen, water, and ethanol; or
the oxidizing agent comprises a material selected from one or more of the group consisting of hydrogen peroxide, water, and oxygen.

8. The method of claim 6 , wherein the reducing agent or the oxidizing agent is fed contacted with the first electrode or the second electrode in a single-pass mode or in a recycle mode.

9. The method of claim 1 , wherein the CEI comprises a material selected from one or more of the group consisting of sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene tri-block copolymer, perfluorosulfonic acid (PFSA)/polytetrafluoroethylene (PTFE) copolymer solution, sulfonated poly (phenylene oxide), sulfonated polysulfone, sulfonated poly (arylene ether ether ketone), and sulfonated poly(4-phenoxybenzoyl-1,4-phenylene).

10. The method of claim 1 , wherein the ion exchange ionomer coating:
(i) increases the pH gradient between the IEM and the first or second ionomer-coated catalytic film, the first or second ionomer-coated catalytic particle, or the first or second ionomer-coated plurality of catalytic particles compared to the pH gradient without the ion exchange ionomer coating;
(ii) provides a pH gradient of about 1 pH unit per nm between the IEM and the first or second ionomer-coated catalytic film, the first or second ionomer-coated catalytic particle, or the first or second ionomer-coated plurality of catalytic particles; or
(iii) prevents catholyte contact with an anode active site.

11. A method of electrochemical conversion from combining a reducing agent and an oxidizing agent, comprising:
introducing either a reducing agent or an oxidizing agent to a first electrode comprising a first catalyst coated by a first ion exchange ionomer; or
introducing either an oxidizing agent or a reducing agent to a second electrode comprising a second catalyst coated by a second ion exchange ionomer
wherein
the first electrode and the second electrode are separated by an ion exchange membrane (IEM);
the IEM is a cation exchange membrane (CEM) or an anion exchange membrane (AEM);
the first ion exchange ionomer and second ion exchange ionomer are independently selected from an anion exchange ionomer (AEI) or a cation exchange ionomer (CEI);
the AEM or AEI comprises a material selected from one or more of the group consisting of a polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene tri-block copolymer-based backbone, poly (phenylene oxide)-based backbone, polysulfone-based backbone, poly(N,N-diallylazacycloalkane)-based backbone, bromoalkyl-tethered poly(biphenyl alkylene)-based backbone, multiblock copoly(arylene ether)-based backbone, poly (vinylbenzyl chloride)-based backbone, and cardo-polyetherketone-based backbone; and
the material comprises a functional group selected from one or more of the group consisting of benz

Assignees

• Ramani Vijay K
• Wang Zhongyang
• Parrondo Javier
• SANKARASUBRAMANIAN Shrihari
• Washington University St Louis

Inventors

• Ramani Vijay K
• Wang Zhongyang
• Parrondo Javier
• SANKARASUBRAMANIAN Shrihari

Classifications

• H01M2300/0082

  Organic polymers · CPC title

• H01M4/92

  Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence) · CPC title

• Y02E60/50

  Fuel cells · CPC title

• H01M2300/0014

  Alkaline electrolytes · CPC title

• H01M4/881 Primary

  Electrolytic membranes · CPC title