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EP-4737615-A1 - SEPARATOR AND ELECTROCHEMICAL CELL COMPRISING SAME

EP4737615A1EP 4737615 A1EP4737615 A1EP 4737615A1EP-4737615-A1

Abstract

The present invention relates to a separation membrane having an anode catalyst layer coated on one surface of a porous substrate, and more particularly, to a separation membrane which enables ions to move smoothly through the pores of a porous substrate, and has a low overvoltage by coating the anode catalyst layer on one surface of the separation membrane, and an electrochemical cell including the same.

Inventors

  • HAN, YU JIN
  • NOH, TAE GEUN

Assignees

  • LG Chem, Ltd.

Dates

Publication Date
20260506
Application Date
20240829

Claims (13)

  1. A separation membrane including: a porous substrate and an anode catalyst layer, wherein the anode catalyst layer includes metal particles and a binder, and the anode catalyst layer is coated on any one surface of the porous substrate.
  2. The separation membrane according to claim 1, wherein the pores of the porous substrate have an average diameter of 10 nm or more and 500 nm or less.
  3. The separation membrane according to claim 1, wherein the porosity of the porous substrate is 50% by volume or more and 95% by volume or less.
  4. The separation membrane according to claim 1, wherein the thickness of the porous substrate is 10 µm or more and 500 µm or less.
  5. The separation membrane according to claim 1, wherein the porous substrate is at least one selected from the group consisting of polyethersulfone, polytetrafluoroethylene, polyethylene, polypropylene, polyethylene terephthalate, polyester, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethylenenaphthalene, polyvinylidene fluoride, cellulose acetate, and nylon.
  6. The separation membrane according to claim 1, wherein the content per unit area of the oxidation catalyst in the anode catalyst layer is 0.1 mg/cm 2 or more and 3.0 mg/cm 2 or less.
  7. The separation membrane according to claim 1, wherein the thickness of the anode catalyst layer is 1 µm or more and 30 µm or less.
  8. The separation membrane according to claim 1, wherein the metal particles have an average particle diameter of primary particles (D SEM ) of 20 nm or more and 30 nm or less.
  9. The separation membrane according to claim 1, wherein the metal particles have an average particle diameter of secondary particles (D 50 ) of 100 nm or more and 2,000 nm or less.
  10. An electrochemical cell including: the separation membrane according to claim 1 and a cathode, wherein the cathode is in contact with the other surface of the separation membrane on which the anode catalyst layer is not coated.
  11. The electrochemical cell according to claim 10, wherein the cathode has a cathode catalyst layer coated on one surface of a gas diffusion layer.
  12. A method for manufacturing an electrochemical cell, the method including the steps of: (S10) manufacturing a separation membrane by coating an anode catalyst layer on any one surface of a porous substrate; and (S20) disposing a cathode to contact the other surface of the separation membrane which is not coated with the anode catalyst layer in step (S10), wherein the anode catalyst layer includes metal particles and a binder.
  13. The method for manufacturing an electrochemical cell according to claim 12, wherein the step (S10) includes the steps of: (S11) preparing an anode catalyst ink by mixing metal particles, a binder, and a solvent; (S12) applying the anode catalyst ink to a transfer film to prepare an anode catalyst layer; and (S13) transferring the anode catalyst layer to any one surface of the porous substrate to coat the anode catalyst layer.

Description

[Technical Field] CROSS-REFERENCE TO RELATED APPLICATION Th present application claims the benefit of priority to Korean Patent Application No. 10-2023-0116359 filed on September 1, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field The present invention relates to a separation membrane and an electrochemical cell including the same. [Background Art] Carbon dioxide is a greenhouse gas that causes global warming and must be reduced. Methods such as capture, chemical conversion, or electrochemical conversion are known as methods of reducing carbon dioxide. Among them, the electrochemical conversion method can precisely control the components so that other synthetic gases can be produced, resulting in economic benefits over simply removing carbon dioxide. In addition, carbon dioxide can be electrolyzed with water to obtain organic substances such as carbon monoxide, ethylene, methane, formic acid, formate, various hydrocarbons, and aldehyde or alcohol. The process of electrochemically decomposing and converting carbon dioxide using an electrochemical cell is as follows. When current is applied while supplying water to an anode, water is decomposed to generate oxygen gas and at the same time hydrogen ions and electrons, wherein the electrons move to a cathode through an external conductive wire. Carbon dioxide and water vapor are supplied to the cathode, wherein the carbon dioxide and water vapor react with the electrons transferred from the anode and decompose into carbon monoxide and hydroxide ions. The generated hydroxide ions move to the anode through a separation membrane, and the moved hydroxide ions are oxidized to generate oxygen gas and at the same time water and electrons. Through the above process, the electrochemical decomposition reaction of carbon dioxide proceeds. Meanwhile, an ion separation membrane such as a Nafion separation membrane is widely used as a separation membrane applied to the electrochemical cell, but the Nafion separation membrane has disadvantages in that it is expensive and have limited pH conditions that can be used as a cation exchange separation membrane. Specifically, when the Nafion separation membrane is used under basic or neutral electrolyte conditions used for carbon dioxide electrolysis, there is a problem that the performance of the electrochemical cell deteriorates, such as a slow ion permeation rate and a high overvoltage. On the other hand, since an anion exchange membrane that can be used suitably with a basic electrolyte is more expensive than the Nafion separation membrane, it is uneconomical in mass production and commercialization. Therefore, it is necessary to develop a separation membrane that has performance equivalent to or higher than that of the ion exchange membrane such as the cation exchange membrane or the anion exchange membrane and is also inexpensive. [Disclosure] [Technical Problem] The present invention has been devised to solve the problems of the prior art as mentioned above, and aims to provide a separation membrane that uses an inexpensive porous substrate as a material for the separation membrane, and also has performance equivalent to or higher than that of a conventional ion exchange membrane by coating an anode catalyst layer on one surface of the porous substrate. Another object of the present invention is to provide an electrochemical cell including the separation membrane. [Technical Solution] In order to solve the problems, the present invention provides a separation membrane and an electrochemical cell including the same. (1) The present invention provides a separation membrane including a porous substrate and an anode catalyst layer, wherein the anode catalyst layer includes metal particles and a binder, and the anode catalyst layer is coated on any one surface of the porous substrate.(2) The present invention provides the separation membrane according to (1) above, wherein the pores of the porous substrate have an average diameter of 10 nm or more and 500 nm or less.(3) The present invention provides the separation membrane according to (1) or (2) above, wherein the porosity of the porous substrate is 50% by volume or more and 95% by volume or less.(4) The present invention provides the separation membrane according to any one of (1) to (3) above, wherein the thickness of the porous substrate is 10 µm or more and 500 µm or less.(5) The present invention provides the separation membrane according to any one of (1) to (4) above, wherein the porous substrate is at least one selected from the group consisting of polyethersulfone, polytetrafluoroethylene, polyethylene, polypropylene, polyethylene terephthalate, polyester, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethylenenaphthalene, polyvinylidene fluoride, cellulose acetate, and nylon.(6) The present invention provides the separation membrane according to any one of (1) to (5) abo