Search

KR-20260066806-A - Method of using diaphragms, alkaline water electrolysis cells, and porous membranes for alkaline water electrolysis

KR20260066806AKR 20260066806 AKR20260066806 AKR 20260066806AKR-20260066806-A

Abstract

The objective of the present invention is to provide a diaphragm for alkaline water electrolysis that can realize a diaphragm capable of stably performing water electrolysis while maintaining high ion permeability and high gas barrier properties even when used for a long time as a diaphragm for alkaline water electrolysis. The diaphragm for alkaline water electrolysis of the present invention is characterized by having a porous membrane comprising a polyolefin, and having a peel strength in the membrane thickness direction of the porous membrane of 2.0 N or more.

Inventors

  • 나가노 다로
  • 무라타 히로시
  • 다카미 히데후미
  • 다이카이 가즈히로

Assignees

  • 아사히 가세이 가부시키가이샤

Dates

Publication Date
20260512
Application Date
20250325
Priority Date
20240326

Claims (19)

  1. As a diaphragm for alkaline water electrolysis, A diaphragm for alkaline water electrolysis characterized by having a porous membrane comprising a polyolefin, wherein the peel strength of the porous membrane in the membrane thickness direction is 2.0 N or higher.
  2. In paragraph 1, The above porous membrane is a diaphragm for alkaline water electrolysis, comprising the above polyolefin as a main component.
  3. In paragraph 1, A diaphragm for alkaline water electrolysis, wherein the porous membrane comprises 90 mass% or more of the polyolefin.
  4. In paragraph 1 or 2, The above polyolefin is a polyethylene with a viscosity average molecular weight of 900,000 or more, a diaphragm for alkaline water electrolysis.
  5. In paragraph 1 or 2, A diaphragm for alkaline water electrolysis, wherein the peel strength in the membrane thickness direction of the above porous membrane is 3.0 N or higher.
  6. In paragraph 1 or 2, A diaphragm for alkaline water electrolysis, wherein the thickness of the porous membrane is 25 μm or more and 500 μm or less.
  7. In paragraph 1 or 2, A diaphragm for alkaline water electrolysis, wherein the porosity of the above porous membrane is 30% or more and 80% or less.
  8. In paragraph 1 or 2, A diaphragm for alkaline water electrolysis, wherein the permeability of the above porous membrane is 10 seconds or more and 2000 seconds or less in terms of 100 μm.
  9. In paragraph 1 or 2, A diaphragm for alkaline water electrolysis, wherein the protrusion strength of the porous membrane is 200 gf or more and 10,000 gf or less.
  10. As an alkaline water electrolyzer, The diaphragm for alkaline water electrolysis described in paragraph 1 or 2, and Positive poles and, cathode Equipped with, The alkaline water electrolysis cell, wherein the diaphragm for the alkaline water electrolysis is disposed between the anode and the cathode.
  11. A method of using a porous membrane comprising a polyolefin and having a peel strength of 2.0 N or more in the membrane thickness direction as a diaphragm for alkaline water electrolysis.
  12. In Paragraph 11, A method of use in which the above porous membrane comprises the above polyolefin as a main component.
  13. In Paragraph 11, A method of use in which the above porous membrane comprises 90 mass% or more of the above polyolefin.
  14. In Article 11 or Article 12, The above polyolefin is polyethylene with a viscosity average molecular weight of 900,000 or more, in a method of use.
  15. In Article 11 or Article 12, A method of use in which the peel strength in the membrane thickness direction of the above porous membrane is 3.0 N or more.
  16. In Article 11 or Article 12, A method of use in which the thickness of the above porous membrane is 25 μm or more and 500 μm or less.
  17. In Article 11 or Article 12, A method of use in which the porosity of the above porous membrane is 30% or more and 80% or less.
  18. In Article 11 or Article 12, A method of use in which the permeability of the above porous membrane is 10 seconds or more and 2000 seconds or less in 100 μm equivalent.
  19. In Article 11 or Article 12, A method of use in which the protrusion strength of the above porous membrane is 200 gf or more and 10,000 gf or less.

Description

Method of using diaphragms, alkaline water electrolysis cells, and porous membranes for alkaline water electrolysis The present disclosure relates to a diaphragm for alkaline water electrolysis, an alkaline water electrolysis cell, and a method of using a porous membrane. Recently, hydrogen produced using renewable energy is attracting attention as a clean energy source to address issues such as global warming caused by CO2 and the depletion of fossil fuel reserves. In the production of hydrogen using renewable energy, low costs comparable to those of conventional hydrogen production through the reforming of fossil fuels are required. Therefore, hydrogen production using renewable energy requires high energy efficiency and low-cost equipment that could not be achieved with conventional technology. One of the industrial methods for producing hydrogen is the electrolysis of water. This method has the advantage of producing high-purity hydrogen compared to hydrogen production methods involving the reforming of fossil fuels. In the electrolysis of water, it is common practice to use an aqueous solution to which an electrolyte, such as sodium hydroxide or potassium hydroxide, has been added to increase conductivity. Water is electrolyzed by applying a direct current to this electrolyte through a cathode and an anode. Among these, alkaline water electrolysis already has a track record in commercial plants because it can be implemented on a large scale and is cheaper compared to other electrolysis devices. Therefore, the development of large-scale hydrogen production facilities utilizing alkaline water electrolysis is anticipated. For example, several concepts have been proposed to produce hydrogen in large quantities by electrolyzing alkaline water using power generated from natural energy sources such as wind or solar power, and to transport and supply the hydrogen to consumption sites. An electrolytic cell for performing electrolysis (hereinafter referred to as "electrolysis") is divided into an anode chamber and a cathode chamber by a diaphragm, and oxygen gas is generated in the anode chamber and hydrogen gas is generated in the cathode chamber. The diaphragm requires gas barrier properties to prevent the mixing of these oxygen and hydrogen gases. Furthermore, in the electrolysis of water, the medium carrying electricity (electrons) is ions, and high ion permeability is required for the diaphragm to perform electrolysis efficiently. In this regard, a diaphragm having a porous structure (hereinafter referred to as a "porous membrane") has been proposed as a diaphragm equipped with gas barrier properties and ion permeability. In addition, in order to perform electrolysis efficiently, it is required to reduce the electrical resistance of the solution between the anode, cathode, and diaphragm, and it is considered desirable to have a structure in which a diaphragm is placed between the two electrodes (hereinafter referred to as a "zero-gap structure"). As a technology regarding such diaphragms, Patent Documents 1 and 2 disclose a diaphragm for alkaline water electrolysis, which is a porous membrane formed by a non-solvent organic phase separation method by incorporating zirconium oxide or magnesium oxide into polysulfone, an aromatic polymer resin. FIG. 1 is a side view illustrating the entire example of a bipolar electrolytic cell for alkaline water electrolysis according to the present embodiment. FIG. 2 is a side view illustrating an example of a zero-gap structure of a bipolar electrolytic cell for alkaline water electrolysis according to the present embodiment, with respect to the dashed square frame portion. FIG. 3 is a plan view illustrating an example of an electrode chamber portion of a bipolar electrolytic cell for alkaline water electrolysis according to the present embodiment. FIG. 4 is a diagram illustrating an overview of an alkaline water electrolysis device having an example of a bipolar electrolytic cell for alkaline water electrolysis according to the present embodiment. FIG. 5 is an explanatory diagram of a test specimen for measuring the peel strength in the film thickness direction of the porous membrane of the present embodiment. Hereinafter, embodiments of the present invention (hereinafter referred to as the present embodiments) will be described in detail. Furthermore, the present invention is not limited to the following embodiments and may be implemented with various modifications within the scope of its gist. The diaphragm for alkaline water electrolysis according to the present embodiment is characterized by comprising a porous membrane that includes polyolefin and has a peel strength in the membrane thickness direction of 2.0 N or more. The above-described diaphragm for alkaline water electrolysis comprises at least the porous membrane of the present embodiment described above and may further include other members such as a support. Among these, it is preferable that the above-descri