Reversible fuel cell membrane electrode anode coating and method of making same
By employing a gradient structure in the anode coating of the membrane electrode of a reversible fuel cell, the EW value and distribution of ionomers were optimized, solving the problems of short catalyst lifetime and low catalyst utilization, and achieving highly efficient bifunctional catalytic performance and efficiency improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENZHEN CENT POWER TECH
- Filing Date
- 2024-05-30
- Publication Date
- 2026-08-04
AI Technical Summary
Existing alloy catalysts have short lifespans, and the performance of blended hydrogen production and power generation catalysts is reduced, resulting in low catalyst utilization and failing to meet the needs of large-scale energy systems.
A gradient structure anolyte coating was used. By optimizing the EW value, proportion and distribution of ionomers, a thin power generation catalyst coating and a hydrogen production catalyst coating were prepared on the proton exchange membrane using a stepwise spraying method, forming a gradient structure of catalyst and ionomer.
This improved catalyst utilization, enhanced the bifunctional catalytic performance of reversible fuel cells, increased the efficiency of hydrogen production and power generation, and achieved cost reduction and efficiency improvement.
Smart Images
Figure CN118460113B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of fuel cell technology, and particularly relates to a reversible fuel cell membrane electrode anode coating and its preparation method. Background Technology
[0002] The large-scale application of intermittent renewable energy power (such as wind power and solar power) in the future requires inexpensive, efficient, and flexible energy storage systems. Reversible fuel cells (URFCs), which combine water electrolysis for hydrogen production and hydrogen-oxygen fuel cell power generation, are promising new energy storage systems.
[0003] In reversible fuel cell (URFC) systems, the slow kinetics of ORR and OER at the membrane electrode assembly (MEA) result in excessively high reaction potentials and low system energy cycle efficiency. Mechanistically, Pt catalysts at the Cathode of the URFC can simultaneously possess ORR and HER functions. However, to enable the MEA to exhibit dual OER and HOR catalytic functions at the anode side, many researchers have synthesized various noble metal alloy catalysts. Through the multi-catalytic functions of these alloy catalysts, the anode has achieved simultaneous OER and HOR catalytic functions. Other researchers have directly co-blended hydrogen production catalysts and power generation catalysts, also achieving dual OER and HOR catalytic functions.
[0004] Currently, alloy catalysts are widely used in reversible fuel cells due to their high activity. However, alloy catalysts suffer from short lifespans, making them unsuitable for large-scale energy systems. Regarding the blending of hydrogen production catalysts and power generation catalysts, mechanistic analysis reveals inconsistencies in the EW value, side chain length, and proportion of ionomers in the coatings of hydrogen production and power generation catalysts. The choice of ionomers inevitably leads to a reduction in certain performance characteristics. Furthermore, hydrogen production catalysts are mostly Ir-based, while power generation catalysts are mostly Pt-based; their interactions with ionomers differ, and blending them results in uneven ionomer distribution, leading to reduced catalyst utilization. Summary of the Invention
[0005] This invention provides a reversible fuel cell membrane electrode anode coating and its preparation method, aiming to solve the problems of short lifespan of existing alloy catalysts, and performance degradation and reduced catalyst utilization in blended hydrogen production and power generation catalysts. The reversible fuel cell membrane electrode anode coating prepared by this invention is a gradient structure anode coating to improve the performance of the reversible membrane electrode, including: optimizing the EW value of ionomers; optimizing the proportion of ionomers; optimizing the distribution of ionomers; and improving catalyst utilization.
[0006] The technical solution of this invention is implemented as follows:
[0007] A method for preparing an anode coating for a reversible fuel cell membrane electrode includes the following steps:
[0008] S01: After first homogenization, 1-10 parts of the first catalyst, 60-90 parts of alcohol, 20-40 parts of water and 1-20 parts of the first ionomer are mixed to obtain a first catalyst dispersion.
[0009] S02: The first catalyst dispersion from step S01 is directly sprayed onto the proton exchange membrane and dried to obtain the first catalyst layer;
[0010] S03: After dispersing 1-10 parts of the second catalyst, 60-90 parts of alcohol, 20-40 parts of water and 1-20 parts of the second ionomer through a second homogenization process, a second catalyst dispersion is obtained.
[0011] S04: On the surface of the first catalyst layer in step S02, a second catalyst dispersion is sprayed and dried to form a second catalyst layer, thereby preparing a reversible fuel cell membrane electrode anode coating.
[0012] Furthermore, in step S01:
[0013] The first catalyst is preferably at least one of Pt / C, Pt black, or Ru-based catalyst.
[0014] The alcohol is at least one of ethanol, n-propanol, or isopropanol.
[0015] The first ionomer is preferably at least one of EW725, EW790 or EW825.
[0016] The preferred amounts of substances used in step S01 are: 2 parts of the first catalyst, 60 parts of alcohol, 30 parts of water and 8 parts of the first ionomer.
[0017] The first homogenization dispersion is preferably carried out in a homogenizer, with a homogenization linear velocity of 10–30 m / s and a homogenization time of 0.5–10 min. More preferably, the homogenization linear velocity is 30 m / s and the homogenization time is 10 min.
[0018] Furthermore, in step S03:
[0019] The second catalyst is preferably at least one of IrO2, Ir black, or Rh-based catalyst.
[0020] The alcohol is at least one of ethanol, n-propanol, or isopropanol.
[0021] The second ionomer is preferably at least one of EW975, EW1100, or EW1250. The EW value of the second ionomer is higher than that of the first ionomer.
[0022] In step S02: the thickness of the spray coating is 2 to 5 μm.
[0023] The preferred amounts of substances used in step S03 are: 2 parts of the second catalyst, 60 parts of alcohol, 34 parts of water, and 4 parts of the second ionomer.
[0024] The content of the second ionomer in the second catalyst dispersion is higher than the content of the first ionomer in the first catalyst dispersion.
[0025] The second homogenization dispersion is preferably carried out in a homogenizer, with a homogenization linear velocity of 10–30 m / s and a homogenization time of 0.5–10 min. More preferably, the homogenization linear velocity is 30 m / s and the homogenization time is 10 min.
[0026] In step S04, the thickness of the spray coating is 2–10 μm. More preferably, the thickness of the spray coating in step S02 is less than the thickness of the spray coating in step S04. A reversible fuel cell membrane electrode anode coating is obtained by the above-described preparation method.
[0027] The reversible fuel cell membrane electrode anode coating prepared in the above manner is applied in a reversible fuel cell system.
[0028] In the power generation process of reversible fuel cells, the anode catalyst coating requires a low EW value, short side chains, and a high proportion of ionomers. Furthermore, the effective reaction thickness (HOR) is very small, meaning that only a thin catalyst coating layer needs to be prepared on the proton exchange membrane to meet the HOR requirements. However, in water electrolysis for hydrogen production, the anode coating requires a high EW value, long side chains, and a low proportion of ionomers. Based on these different ionomer requirements, this patent proposes a stepwise spraying method. First, a thin power generation catalyst coating is prepared on the proton exchange membrane, and then a hydrogen production catalyst coating is sprayed on top, creating a catalyst gradient and ionomer gradient structure to improve the performance of the reversible fuel cell.
[0029] Compared with the prior art, the technical solution of the present invention has the following advantages:
[0030] The reversible fuel cell membrane electrode anode coating prepared by this invention can achieve catalytic function for both hydrogen production and power generation; and the performance of the reversible membrane electrode is improved by gradient spraying, optimizing the EW value, proportion and distribution of ionomers in the anode coating; in addition, the gradient structure in the anode coating can improve catalyst utilization and increase the efficiency of hydrogen production and power generation, achieving the effect of cost reduction and efficiency improvement. Attached Figure Description
[0031] Figure 1This is a schematic diagram of the structure of the reversible fuel cell membrane electrode anode coating prepared by the present invention and the reversible fuel cell membrane electrode anode coating prepared by the blending method.
[0032] Figure 2 The voltage and current density curves of the anode coatings prepared in Example 1 and Comparative Example 1 during the power generation process are shown in the figure.
[0033] Figure 3 The voltage-current density curves of the anode coatings prepared in Example 1 and Comparative Example 1 during the hydrogen production process are shown in the figure. Detailed Implementation
[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0035] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.
[0036] Currently, existing reversible fuel cell membrane electrode anode coatings mainly consist of alloy catalysts, blended hydrogen production catalysts, and power generation catalysts. Alloy catalysts suffer from short lifespans, while blended hydrogen production and power generation catalysts exhibit performance degradation and reduced catalyst utilization. To address these technical problems, this invention proposes a reversible fuel cell membrane electrode anode coating and its preparation method. The reversible fuel cell membrane electrode anode coating prepared by this invention is a gradient structure anode coating to improve the performance of the reversible membrane electrode, including: optimizing the EW value of ionomers; optimizing the proportion of ionomers; optimizing the distribution of ionomers; and improving catalyst utilization.
[0037] Example 1
[0038] A method for preparing an anode coating for a reversible fuel cell membrane electrode includes the following steps:
[0039] S01: Add 2 parts of Pt / C, 60 parts of isopropanol, 30 parts of water and 8 parts of EW 725 ionomer to a homogenizer, homogenize at a linear speed of 30 m / s for 10 min to obtain a Pt / C catalyst dispersion.
[0040] S02: The Pt / C catalyst dispersion from step S01 is directly sprayed onto a proton exchange membrane (perfluorosulfonic acid resin membrane) with a coating thickness of 2 μm. After drying, a Pt / C catalyst layer is obtained.
[0041] S03: Add 2 parts of IrO2, 60 parts of n-propanol, 34 parts of water and 4 parts of EW1100 ionomer to a homogenizer, homogenize at a linear speed of 30 m / s for 10 min to obtain an IrO2 catalyst dispersion.
[0042] S04: On the surface of the Pt / C catalyst layer in step S02, an IrO2 catalyst dispersion is sprayed on with a thickness of 5 μm. After drying, an IrO2 catalyst layer is formed, thereby preparing the anode coating of the reversible fuel cell membrane electrode.
[0043] Example 2
[0044] A method for preparing an anode coating for a reversible fuel cell membrane electrode includes the following steps:
[0045] S01: Add 2 parts of Pt black, 55 parts of n-propanol, 35 parts of water and 8 parts of EW790 ionomer to a homogenizer, homogenize at a linear speed of 30 m / s for 10 min to obtain a Pt black catalyst dispersion.
[0046] S02: The Pt black catalyst dispersion from step S01 is directly sprayed onto a proton exchange membrane (perfluorosulfonic acid resin membrane) with a coating thickness of 3 μm. After drying, a Pt black catalyst layer is obtained.
[0047] S03: Add 2 parts of Ir black, 65 parts of isopropanol, 29 parts of water and 4 parts of EW975 ionomer to a homogenizer, homogenize at a linear speed of 30 m / s for 10 min to obtain an Ir black catalyst dispersion.
[0048] S04: On the surface of the Pt black catalyst layer in step S02, Ir black catalyst dispersion is sprayed on with a coating thickness of 6 μm. After drying, Ir black catalyst layer is formed, thereby preparing the anode coating of the reversible fuel cell membrane electrode.
[0049] Example 3
[0050] A method for preparing an anode coating for a reversible fuel cell membrane electrode includes the following steps:
[0051] S01: Add 5 parts Ru black, 55 parts n-propanol, 30 parts water and 10 parts EW790 ionomer to a homogenizer, homogenize at a linear speed of 30 m / s for 10 min to obtain Ru black catalyst dispersion.
[0052] S02: The Ru black catalyst dispersion from step S01 is directly sprayed onto a proton exchange membrane (perfluorosulfonic acid resin membrane) with a coating thickness of 2 μm. After drying, a Ru black catalyst layer is obtained.
[0053] S03: Add 3 parts of Rh black, 65 parts of isopropanol, 20 parts of water and 6 parts of EW1100 ionomer to a homogenizer, homogenize at a linear speed of 30 m / s for 10 min to obtain Rh black catalyst dispersion.
[0054] S04: On the surface of the Ru black catalyst layer in step S02, an Rh black catalyst dispersion is sprayed on with a coating thickness of 5 μm. After drying, an Rh black catalyst layer is formed, thereby preparing the anode coating of the reversible fuel cell membrane electrode.
[0055] Comparative Example 1
[0056] A method for preparing an anode coating for a blended reversible fuel cell membrane electrode includes the following steps:
[0057] S01: Add 2 parts of Pt / C, 60 parts of isopropanol, 30 parts of water and 8 parts of EW 725 ionomer to a homogenizer, homogenize at a linear speed of 30 m / s for 10 min to obtain a Pt / C catalyst dispersion.
[0058] S02: Add 2 parts IrO2, 60 parts n-propanol, 34 parts water and 4 parts EW1100 ionomer to a homogenizer, homogenize at a linear speed of 30 m / s for 10 min to obtain an IrO2 catalyst dispersion.
[0059] S03: After blending the Pt / C catalyst dispersion from step S01 and the IrO2 catalyst dispersion from step S02, a blended catalyst dispersion is obtained.
[0060] S04: A blended catalyst dispersion is sprayed onto the surface of a proton exchange membrane (perfluorosulfonic acid resin membrane) with a coating thickness of 7 μm. After drying, a blended reversible fuel cell membrane electrode anode coating is obtained.
[0061] Schematic diagrams of the structures of the membrane electrode anode coatings prepared in Example 1 and Comparative Example 1 are shown below. Figure 1As shown, the reversible fuel cell membrane electrode anode coating prepared in Example 1 was prepared by a stepwise spraying method. First, a thin power generation catalyst coating was prepared on the proton exchange membrane, and then a hydrogen production catalyst coating was sprayed on. This prepared a catalyst gradient and ionomer gradient structure, thereby improving the performance of the reversible fuel cell.
[0062] The voltage and current density curves of the membrane electrode anode coatings prepared in Example 1 and Comparative Example 1 during the power generation process are shown in the figure below. Figure 2 As shown in the figure; the voltage-current density curves of the membrane electrode anode coatings prepared in Example 1 and Comparative Example 1 during the hydrogen production process are shown in the figure. Figure 3 As shown in the voltage-current density curve results, it can be seen that the performance of the reversible fuel cell membrane electrode anode coating (this patent) prepared in Example 1 is significantly better than the performance of the blended anode coating (blended) prepared in Comparative Example 1.
[0063] In the power generation process of reversible fuel cells, the anode catalyst coating requires a low EW value, short side chains, and a high proportion of ionomers. Furthermore, the effective reaction thickness (HOR) is very small, meaning that only a thin catalyst coating layer needs to be prepared on the proton exchange membrane to meet the HOR requirements. However, in water electrolysis for hydrogen production, the anode coating requires a high EW value, long side chains, and a low proportion of ionomers. Based on these different ionomer requirements, this patent proposes a stepwise spraying method. First, a thin power generation catalyst coating is prepared on the proton exchange membrane, and then a hydrogen production catalyst coating is sprayed on top, creating a catalyst gradient and ionomer gradient structure to improve the performance of the reversible fuel cell.
[0064] Compared with the prior art, the technical solution of the present invention has the following advantages:
[0065] The reversible fuel cell membrane electrode anode coating prepared by this invention can achieve catalytic function for both hydrogen production and power generation; and the performance of the reversible membrane electrode is improved by gradient spraying, optimizing the EW value, proportion and distribution of ionomers in the anode coating; in addition, the gradient structure in the anode coating can improve catalyst utilization and increase the efficiency of hydrogen production and power generation, achieving the effect of cost reduction and efficiency improvement.
[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for making a reversible fuel cell membrane electrode anode coating, characterized by: Includes the following steps: S01: After first homogenization, 1-10 parts of the first catalyst, 60-90 parts of alcohol, 20-40 parts of water and 8 parts of the first ionomer are mixed to obtain the first catalyst dispersion. S02: The first catalyst dispersion from step S01 is directly sprayed onto the proton exchange membrane and dried to obtain the first catalyst layer; S03: After dispersing 1-10 parts of the second catalyst, 60-90 parts of alcohol, 20-40 parts of water and 4 parts of the second ionomer through a second homogenization process, a second catalyst dispersion is obtained. S04: On the surface of the first catalyst layer in step S02, a second catalyst dispersion is sprayed and dried to form a second catalyst layer, thereby preparing a reversible fuel cell membrane electrode anode coating. The EW value of the second ionomer is higher than that of the first ionomer; The first catalyst is at least one of Pt / C, Pt black, or Ru-based catalyst; The second catalyst is at least one of IrO2, Ir black, or Rh-based catalyst; In step S02: the thickness of the spray coating is 2-5 μm; In step S04: the thickness of the spray coating is 2-10 μm; The thickness of the coating in step S02 is less than the thickness of the coating in step S04; The first ionomer is at least one of EW725, EW790 or EW825; The second ionomer is at least one of EW975, EW1100 or EW1250.
2. The method for preparing the anode coating of the reversible fuel cell membrane electrode according to claim 1, characterized in that: In step S01: the alcohol is at least one of ethanol, n-propanol, or isopropanol; In step S03: the alcohol is at least one of ethanol, n-propanol or isopropanol.
3. The method for preparing the anode coating of the reversible fuel cell membrane electrode according to claim 1, characterized in that: The first homogenization dispersion is carried out in a homogenizer, with a homogenization linear velocity of 10-30 m / s and a homogenization time of 0.5-10 min; The second homogenization dispersion is carried out in a homogenizer with a homogenization linear velocity of 10–30 m / s and a homogenization time of 0.5–10 min.
4. A reversible fuel cell membrane electrode anode coating is obtained by the preparation method described in any one of claims 1-3.