KR-102962852-B1 - WATER ELECTROLYISING SYSTEM COMPRISING ANION EXCHANGE MEMBRANE

Abstract

The present invention provides a water electrolysis system comprising an anion exchange membrane.

Inventors

• 최승목
• 박유세
• 양주찬
• 이주영
• 이지훈
• 정재훈
• 권채연
• 김글한
• 정재엽

Assignees

• 한국재료연구원

Dates

Publication Date

20260512

Application Date

20210924

Claims (10)

1. an anode comprising nickel foam and a catalyst layer; an anion exchange membrane; an electrolyte which is a basic solution containing chloride ions; and a cathode; comprising, The catalyst layer is located on the surface of the nickel foam, has a three-dimensional nanosheet structure, and contains Ni-doped FeOOH. The catalyst layer contains Fe to Ni in an atomic ratio of 1:0.1 to 1:1, and A water electrolysis system in which the Fe of the above Ni-doped FeOOH exists in a form in which oxidation states of 2+ and 3+ are mixed.
2. delete
3. In paragraph 1, A water electrolysis system in which the catalyst layer comprises α-FeOOH with a goethite structure.
4. In paragraph 1, The above-described water electrolysis system further comprises a porous transport layer on at least one of the side of the anode not adjacent to the anion exchange membrane; and the side of the cathode not adjacent to the anion exchange membrane.
5. In paragraph 4, A water electrolysis system in which one or more of the above anion exchange membrane, the above anode, the above cathode, and the above porous transport layer include a corrosion-resistant coating layer on their surface.
6. In paragraph 5, A water electrolysis system in which the corrosion-resistant coating layer comprises one or more of Ti, TiN, TaN, TiO2 , TaO2 , Au, and Pt.
7. In paragraph 1, A water electrolysis system in which the above electrolyte contains seawater.
8. In paragraph 1, The above-mentioned electrolyte is a water electrolysis system having a pH of 8 to 14.
9. In paragraph 1, The above cathode Pt, Ru, Ni, Co, Fe, or Mn metals; Metal oxides of Pt, Ru, Ni, Co, Fe, or Mn; An alloy comprising one or more of Pt, Ru, Ni, Co, Fe, and Mn; or A water electrolysis system comprising a hydrogen generation catalyst comprising a metal oxide comprising one or more of Pt, Ru, Ni, Co, Fe, and Mn.
10. In paragraph 1, A water electrolysis system having a driving voltage of 1.3 V to 2.5 V.

Description

Water electrolysis system comprising anion exchange membrane The present invention relates to a water electrolysis system comprising an anion exchange membrane. Specifically, it relates to a water electrolysis system comprising an anion exchange membrane that does not generate chlorine byproducts even when driven at high voltage. Hydrogen energy is considered one of the cleanest energy sources, and water electrolysis is an attractive approach to generating it. With the development of highly active electrocatalysts for water electrolysis, hydrogen energy has become a powerful energy source to replace fossil fuels. However, there is a serious obstacle that must be overcome to fully utilize hydrogen energy: the issue of water supply, a resource required for electrolysis. Generally, purified water is necessary to produce hydrogen energy through electrolysis technology. However, since the global use of ultrapure water for hydrogen production could lead to severe water distribution problems, it is realistically difficult to use purified water for all electrolysis processes. Meanwhile, seawater is one of the most abundant resources on Earth, and seawater electrolysis is a promising technology for hydrogen energy production and seawater desalination. However, when such seawater is applied to widely used alkaline water electrolysis, there are problems such as corrosion of the anode and cathode, the need for excessive pretreatment processes to use the seawater itself as a high-concentration alkaline electrolyte, and the inability to charge the generated hydrogen at high pressure. To address these problems, the application of seawater to polymer electrolyte membrane (PEM) water electrolysis systems has been considered. While high-pressure hydrogen production is possible using the PEM water electrolysis method, the chlorine generation reaction, a side reaction, is active at low voltages, which leads to severe corrosion of all components of the water electrolysis system, such as electrodes, catalysts, and membranes, resulting in poor durability. Additionally, the use of precious metals increases the cost of hydrogen production, making it undesirable in terms of cost. Therefore, there is a need for technology capable of producing high-pressure hydrogen with excellent durability while electrolyzing seawater at a lower cost. FIG. 1 is a conceptual diagram of a water electrolysis system according to one embodiment of the present invention. FIG. 2 is a schematic diagram of a water electrolysis system according to one embodiment of the present invention. Figure 3 shows a surface photograph of nickel foam (left) and the electrode prepared in Preparation Example 1 (right). Figure 4 is a surface SEM image of the electrode prepared in Preparation Example 1. Figure 5 is the XRD pattern of the electrode prepared in Preparation Example 1. Figure 6 shows the surface TEM image and SAED pattern of the electrode prepared in Preparation Example 1. Figures 7a and 7b are TEM images of the electrode surface prepared in Preparation Example 1 and mapping images of Fe, Ni, and O elements. Figure 8 is the EDS spectrum of the electrode surface prepared in Preparation Example 1. Figures 9a, 9b, and 9c are XPS spectra of Fe, Ni, and O elements in the catalyst layer of the electrode prepared in Preparation Example 1, respectively. Figure 10 is a side view of the electrode surface prepared in Preparation Example 1 and Preparation Example 2 with deionized water dropped on it. FIG. 11a is the polarization curve of the electrode prepared in Preparation Example 1 in electrolytes 1 to 3. FIG. 11b is a graph comparing the overpotential at a current density of 100 mA/ cm² of the electrode prepared in Preparation Example 1 in electrolytes 1 to 3 with and without 85% iR correction. FIG. 12 shows the resistance and conductivity of the electrode prepared in Preparation Example 1 in electrolytes 1 to 3. Figure 13 is the polarization curve of the electrodes prepared in Preparation Example 1 and Preparation Example 2 in a 3-electrode system using electrolyte 3. Figure 14 shows the Tafel slope calculated from the 85% iR corrected polarization curve of Figure 11a. Figure 15 shows the capacitance of the electrode prepared in Preparation Example 1 in electrolytes 1 to 3. Figure 16 is a graph showing the overpotential over time under constant current in electrolytes 1 to 3 of the electrode prepared in Preparation Example 1. FIG. 17 is the polarization curve of the water electrolysis system of Example 1, Example 2, Comparative Example 1, and Reference Example 1. FIGS. 18a and 18b are graphs showing the current density at 1.7 V cell and the energy efficiency at 500 mA/ cm² for the water electrolysis systems of Example 1, Example 2, Comparative Example 1, and Reference Example 1. FIG. 19 is a deconvolution graph of the overvoltage at 100 mA/ cm² or 500 mA/ cm² for the water electrolysis systems of Example 1 and Comparative Example 1. FIG. 20 is the EIS graph and HFR grap