Reversible fuel cell and control method therefor, stack device

Abstract

This application provides a reversible fuel cell and its control method and stack device, belonging to the field of batteries. The reversible fuel cell includes an oxygen catalyst layer, an anion exchange membrane, and a hydrogen catalyst layer stacked sequentially along a first direction. The oxygen catalyst layer includes a first catalyst layer and a second catalyst layer, which are stacked sequentially along the first direction. Both the first and second catalyst layers include an oxygen evolution reaction catalyst and an oxygen reduction reaction catalyst. The mass ratio of the oxygen evolution reaction catalyst to the oxygen reduction reaction catalyst in the first catalyst layer is M, and the mass ratio of the oxygen evolution reaction catalyst to the oxygen reduction reaction catalyst in the second catalyst layer is N, where M < N. The specific gradient setting of the first and second catalyst layers in this application allows the ion transport network and the gas transport network to intertwine and coexist in a specific manner on the oxygen electrode side, ensuring rapid response and efficient operation when switching between different modes.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a reversible fuel cell and its control method and stack device. Background Technology

[0002] Hydrogen energy, as a clean and renewable secondary energy carrier, is one of the key pathways to achieving the "dual carbon" goal. Its efficient utilization depends on the coordinated development of energy conversion and storage technologies. The Unitized Regenerative Fuel Cell (URFC), an energy conversion and storage device integrating fuel cell (FC) power generation and water electrolysis (WE) hydrogen production, has attracted widespread attention. Compared to traditional solutions that separately configure fuel cell stacks and water electrolyzer stacks, URFCs can achieve a "power-hydrogen-power" cycle using a single device, significantly reducing system size, weight, and total cost. This makes it particularly suitable for space- and weight-sensitive applications such as renewable energy grid integration, distributed energy storage, aerospace, and drones.

[0003] Existing URFCs are mainly divided into PEM-URFCs based on proton exchange membranes (PEM) and AEM-URFCs based on anion exchange membranes (AEM). PEM-URFCs are heavily reliant on precious metal catalysts, resulting in high costs. AEM-URFCs, on the other hand, can utilize low-cost non-precious metal catalysts in an alkaline environment and offer high power density and fast start-up. During operation, the oxygen electrode in an AEM-URFC simultaneously handles the oxygen evolution reaction (OER) in electrolysis mode and the oxygen reduction reaction (ORR) in power generation mode. Current designs place ORR and OER catalyst layers on the oxygen electrode. In electrolysis mode, the ORR catalyst layer is inactive, and the oxidizing environment affects its activity. In fuel cell mode, the OER catalyst layer is inactive, and the reducing environment further degrades its activity. This results in low energy conversion efficiency and poor durability of AEM-URFCs. Summary of the Invention

[0004] This application provides a reversible fuel cell and its control method and stack device, aiming to solve the problems of low energy conversion efficiency and poor durability and stability of existing AEM-URFC.

[0005] In a first aspect, embodiments of this application provide a reversible fuel cell, comprising an oxygen catalyst layer, an anion exchange membrane, and a hydrogen catalyst layer sequentially stacked along a first direction; The oxygen catalytic layer includes a first catalytic layer and a second catalytic layer, and the first catalytic layer, the second catalytic layer and the anion exchange membrane are stacked sequentially along a first direction; both the first catalytic layer and the second catalytic layer include an oxygen evolution reaction catalyst and an oxygen reduction reaction catalyst, the mass ratio of the oxygen evolution reaction catalyst to the oxygen reduction reaction catalyst in the first catalytic layer is M, and the mass ratio of the oxygen evolution reaction catalyst to the oxygen reduction reaction catalyst in the second catalytic layer is N, where M < N.

[0006] This application configures the oxygen catalytic layer as including a first catalytic layer and a second catalytic layer, both of which include OER and ORR catalysts. In both the water electrolysis and fuel cell modes of the reversible fuel cell, both the first and second catalytic layers function, achieving full coverage of the reactive sites of the oxygen catalytic layer during reversible fuel cell operation and improving efficiency. Based on the fact that both the first and second catalytic layers can perform OER and ORR catalysis, the first catalytic layer, farther from the anion exchange membrane, primarily functions as an ORR catalyst, while the second catalytic layer, closer to the anion exchange membrane, primarily functions as an OER catalyst. In the water electrolysis mode, electrolyte is introduced to the oxygen catalytic layer side, where the OER reaction occurs, while the second catalytic layer, closer to the anion exchange membrane, primarily functions as an OER catalyst. OH- is generated on the hydrogen catalytic layer side. - The reaction can proceed simply by passing through an anion exchange membrane; OH - The transport path is shorter, the water electrolysis reaction has a faster response speed, and the high proportion of OER catalyst in the second catalyst layer can achieve OH... - Rapid and complete conversion; a small amount of OH passes through the second catalyst layer. -The reaction occurs under the influence of a smaller proportion of the OER catalyst in the first catalyst layer. In fuel cell mode, oxygen is introduced into the oxygen catalyst layer side, where the ORR reaction occurs. The first catalyst layer, located near the oxygen inlet, primarily functions as an ORR catalyst, with most of the oxygen reacting directly in this layer. This results in a shorter oxygen transport path and a faster electrochemical response in the fuel cell. Furthermore, the larger proportion of ORR catalyst in the first catalyst layer enables rapid and complete oxygen conversion and quickly consumes residual moisture, reducing flooding caused by excessive moisture. A small amount of oxygen passing through the first catalyst layer reacts under the influence of a smaller proportion of the ORR catalyst in the second catalyst layer. As can be seen, the layered gradient setting of the OER catalyst and ORR catalyst in the first and second catalyst layers of this application allows the ion transport network and gas transport network to intertwine and coexist in a specific manner on the oxygen catalyst layer side, reducing the mutual influence of different oxidation and reduction environments on the ORR catalyst and OER catalyst. At the same time, the necessary transport paths are pre-established and kept active when switching between different modes, thereby ensuring rapid response and high efficiency in different mode switching, while ensuring the adaptation of reaction sites to the reaction environment, taking into account the needs of both OER and ORR reactions, and further improving the reaction rate and conversion efficiency under different modes.

[0007] Optionally, the mass ratio of the oxygen evolution reaction catalyst to the oxygen reduction reaction catalyst in the first catalyst layer is 5~50:95~50; and / or, the mass ratio of the oxygen evolution reaction catalyst to the oxygen reduction reaction catalyst in the second catalyst layer is 95~50:5~50.

[0008] By rationally setting the mass ratio of OER catalyst and ORR catalyst in the first and second catalyst layers, this application not only ensures that the first catalyst layer mainly functions as ORR catalyst to fully realize the ORR reaction, and the second catalyst layer mainly functions as OER catalyst to fully realize the OER reaction, but also ensures the dual functionality of the first and second catalyst layers by using appropriate amounts of OER catalyst and ORR catalyst, thus achieving rapid response when switching between the two modes.

[0009] Optionally, the mass ratio of the oxygen evolution reaction catalyst to the oxygen reduction reaction catalyst in the first catalyst layer is 5~40:95~60; and / or, the mass ratio of the oxygen evolution reaction catalyst to the oxygen reduction reaction catalyst in the second catalyst layer is 95~60:5~40.

[0010] This application further optimizes the ratio of OER catalyst and ORR catalyst in the first and second catalyst layers. This not only better leverages the primary functions of the first and second catalyst layers but also makes the gradient structure formed by the first and second catalyst layers more conducive to the reaction of gas and OH. -This improves the transmission of energy, thereby enhancing the rapid conversion of reversible fuel cells when switching modes.

[0011] Optionally, the first catalyst layer further includes a first hydrophobic binder and a first anion exchange resin ionomer, wherein the mass ratio of the total mass of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst, the mass of the first hydrophobic binder, and the mass of the first anion exchange resin ionomer in the first catalyst layer is 18~22:1~5:1~5; and / or, the second catalyst layer further includes a second hydrophobic binder and a second anion exchange resin ionomer, wherein the mass ratio of the total mass of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst, the mass of the second hydrophobic binder, and the mass of the second anion exchange resin ionomer in the second catalyst layer is 18~22:1~5:1~5.

[0012] This application improves the mechanical properties of the first and second catalyst layers by incorporating a first hydrophobic binder in the first catalyst layer and a second hydrophobic binder in the second catalyst layer. Simultaneously, it imparts a certain degree of hydrophobicity to both catalyst layers, preventing the electrolyte or reaction-generated water from wetting the first and second catalyst layers and blocking the gas transport channels. The first and second anion exchange resin ionomers can respectively construct ion conduction networks in the first and second catalyst layers, allowing excess OH groups on the second catalyst layer side to pass through. - Transported to the first catalytic layer for reaction or causing OH to... - It can fully react on the first catalyst layer; by reasonably setting the mass ratio of catalyst, first hydrophobic binder and first anion exchange resin ionomer, an appropriate proportion of catalyst can ensure the smooth progress of OER and ORR reactions, while an appropriate amount of first hydrophobic binder and first anion exchange resin ionomer can provide a suitable environment for gas and OH-. - The transport of these substances provides favorable conditions, ensuring the smooth progress of different reactions. By rationally setting the mass ratio of catalyst, second hydrophobic binder, and second anion exchange resin ionomer, an appropriate proportion of catalyst can ensure the smooth progress of OER and ORR reactions. Simultaneously, an appropriate amount of second hydrophobic binder and second anion exchange resin ionomer can facilitate the transport of gases and OH-. - The transmission provides favorable conditions, ensuring the smooth progress of different reactions.

[0013] Optionally, the thickness of the first catalyst layer is 3 μm to 40 μm; and / or, the thickness of the second catalyst layer is 3 μm to 40 μm.

[0014] This application achieves the full conduct of the OER and ORR reactions by rationally setting the thickness of the first and second catalyst layers to accommodate suitable OER and ORR catalysts. Simultaneously, the appropriate thickness allows for the proper flow of gas, electrolyte, and OH-. -The appropriate transport path improves the reaction rate.

[0015] Optionally, the oxygen reduction reaction catalyst includes a support and a first metal element supported on the support, the first metal element including at least one of Ni, Fe, Co, Mn, Cu, Zn, Al, V, Cr, Mo, Pt, Ru, Pd, Au, Ag, Ir, Rh, and La; and / or, the oxygen evolution reaction catalyst is a metal-based catalyst containing a second metal element, the second metal element including at least one of Ni, Fe, Co, Mn, Cu, Zn, Al, V, Cr, Mo, Pt, Ru, Pd, Au, Ag, Ir, Rh, and La.

[0016] This application ensures the efficient execution of ORR and OER reactions by rationally setting the types of ORR and OER catalysts, while the variety of catalyst types can adapt to more scenarios.

[0017] Optionally, in the first catalyst layer, the oxygen reduction reaction catalyst is platinum metal / carbon, platinum alloy / carbon, transition metal-nitrogen-carbon, transition metal oxide, transition metal chalcogenide, or heteroatom-doped carbon material; the oxygen evolution reaction catalyst is iridium (Ir)-based catalyst, ruthenium (Ru)-based catalyst, transition metal (hydrogen) oxide, transition metal oxide, transition metal phosphide, transition metal sulfide, transition metal selenide, or heteroatom-doped carbon material; and / or, in the second catalyst layer, the oxygen reduction reaction catalyst is platinum metal / carbon, platinum alloy / carbon, transition metal-nitrogen-carbon, transition metal oxide, transition metal chalcogenide, or heteroatom-doped carbon material; the oxygen evolution reaction catalyst is iridium (Ir)-based catalyst, ruthenium (Ru)-based catalyst, transition metal hydroxide, transition metal oxide, transition metal phosphide, transition metal sulfide, transition metal selenide, or heteroatom-doped carbon material.

[0018] This application, through the rational selection of ORR and OER catalysts, can better realize the synergistic effect of ORR and OER catalysts, thereby improving the reaction efficiency and service life of reversible fuel cells.

[0019] Optionally, the hydrogen catalyst layer includes at least one of the following: a hydrogen evolution reaction (HER) bifunctional catalyst, a hydrogen oxidation reaction (HOR) catalyst, and a mixture of the HER catalyst and the HOR catalyst; and / or, the hydrogen catalyst layer further includes a third anion exchange resin ionomer and a third hydrophobic binder, wherein the ratio of the total mass of the HER catalyst and the HOR catalyst, the mass of the third hydrophobic binder, and the mass of the third anion exchange resin ionomer in the hydrogen catalyst layer is 18~22:1~5:1~5.

[0020] This application enables the hydrogen catalyst layer to have dual functionality by setting it to include at least one of HER, HOR bifunctional catalysts and a mixture of HER and HOR catalysts, thus better adapting to the switching of different modes in reversible fuel cells; by setting a third anion exchange resin ionomer and a third hydrophobic binder in the hydrogen catalyst layer, the smooth progress of HER and HOR reactions can be better realized.

[0021] Optionally, the reversible fuel cell further includes an oxygen gas diffusion layer and a hydrogen gas diffusion layer, wherein the oxygen gas diffusion layer is disposed on the side of the first catalyst layer opposite to the second catalyst layer; and the hydrogen gas diffusion layer is disposed on the side of the hydrogen catalyst layer opposite to the anion exchange membrane.

[0022] This application, by setting up an oxygen gas diffusion layer, not only provides sufficient electrolyte for the OER reaction and facilitates the smooth removal of generated oxygen, preventing oxygen accumulation, but also provides a sufficient oxygen transport channel for the ORR reaction. Similarly, by setting up a hydrogen gas diffusion layer, not only can the hydrogen generated in the HER reaction be smoothly removed, preventing hydrogen accumulation, but also a sufficient hydrogen transport channel can be provided for the HOR reaction, and the generated water can be smoothly removed.

[0023] Optionally, the porosity of the oxygen gas diffusion layer is 40% to 90%; and / or, the thickness of the oxygen gas diffusion layer is 0.1 mm to 0.6 mm; and / or, the oxygen gas diffusion layer is a hydrophobically modified oxygen gas diffusion layer; and / or, the porosity of the hydrogen gas diffusion layer is 40% to 90%; and / or, the thickness of the hydrogen gas diffusion layer is 0.1 mm to 0.6 mm; and / or, the hydrogen gas diffusion layer is a hydrophobically modified hydrogen gas diffusion layer.

[0024] This application achieves smooth operation of both the OER and ORR reactions by appropriately setting the porosity of the oxygen gas diffusion layer, providing sufficient electrolyte for the OER reaction and ample transport channels for the generated oxygen and the oxygen introduced into the ORR reaction; by appropriately setting the thickness of the oxygen gas diffusion layer, it ensures the smooth flow of gas and OH-. - The transport path of the electrolyte is suitable, thereby reducing mass transfer resistance; the oxygen gas diffusion layer is hydrophobically modified to prevent water flooding. By appropriately setting the porosity of the hydrogen gas diffusion layer, sufficient transport channels are provided for the hydrogen produced in the HER reaction and the hydrogen introduced into the HOR reaction, and the generated water is smoothly discharged, thus ensuring the smooth progress of the HER and HOR reactions. By appropriately setting the thickness of the hydrogen gas diffusion layer, the gas and OH... - The transport path is suitable, thereby reducing mass transfer resistance. Hydrophobic modification of the hydrogen gas diffusion layer prevents water flooding.

[0025] Optionally, the reversible fuel cell further includes a first bipolar plate and a second bipolar plate, wherein the first bipolar plate is disposed on the side of the oxygen gas diffusion layer opposite to the first catalyst layer; and the second bipolar plate is disposed on the side of the hydrogen gas diffusion layer opposite to the hydrogen catalyst layer.

[0026] This application, by setting a first bipolar plate and a second bipolar plate, not only enables the connection between the reversible fuel cell and the external circuit, providing conditions for the smooth operation of the reversible fuel cell; but also, in fuel cell mode, the first and second bipolar plates can evenly distribute the externally supplied gas to the gas diffusion layer, and the generated water is discharged in a timely manner; in water electrolysis mode, the first bipolar plate evenly distributes the externally supplied electrolyte to the oxygen gas diffusion layer, and the first and second bipolar plates can quickly collect the gas escaping from the gas diffusion layer.

[0027] Optionally, the first bipolar plate is at least one of a metal plate and a graphite plate; and / or, the second bipolar plate is at least one of a metal plate and a graphite plate.

[0028] This application achieves better connectivity between the first and second bipolar plates and the external circuit by rationally setting the materials of the first and second bipolar plates.

[0029] In a second aspect, this application provides a control method for the reversible fuel cell provided in the first aspect of this application. When the reversible fuel cell is in water electrolysis mode, the electrolyte is introduced from one side of the oxygen catalytic layer and discharged from the other side of the oxygen catalytic layer. When the reversible fuel cell is in fuel cell mode, oxygen is introduced from the oxygen catalyst layer side and hydrogen is introduced from the hydrogen catalyst layer side.

[0030] In this application, by circulating the electrolyte on the oxygen catalyst layer side during water electrolysis, the flooding problem of the hydrogen catalyst layer is avoided when switching to fuel cell mode, while simultaneously enabling rapid water electrolysis. By introducing oxygen from the oxygen catalyst layer side and hydrogen from the hydrogen catalyst layer side in fuel cell mode, the reaction in the fuel cell proceeds smoothly.

[0031] Thirdly, embodiments of this application provide a fuel cell stack device, including the reversible fuel cell provided in the first aspect of this application.

[0032] The fuel cell stack device of this application includes the reversible fuel cell provided in the first aspect of this application, thereby making the stack structure have a faster reaction speed, a faster response speed when switching between different modes, and a longer service life. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the reversible fuel cell provided in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the first bipolar plate and the second bipolar plate facing the oxygen electrode side provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the first bipolar plate and the second bipolar plate facing the hydrogen electrode side provided in the embodiments of this application; Figure 4 This is a schematic diagram illustrating the working principle of the reversible fuel cell in water electrolysis mode provided in the embodiments of this application; Figure 5 This is a schematic diagram illustrating the working principle of the reversible fuel cell in fuel cell mode provided in the embodiments of this application; Figure 6 This is a schematic diagram of the structure of the fuel cell stack device provided in the embodiments of this application.

[0035] Figure Labels 100. Reversible fuel cells; 10. First bipolar plate; 11. Hydrogen / water flow field; 111. Third inlet / outlet; 112. Fourth inlet / outlet; 113. Second drainage zone; 12. Oxygen / water flow field; 121. First inlet / outlet; 122. Second inlet / outlet; 123. First drainage zone; 20. Oxygen gas diffusion layer; 30. Oxygen catalytic layer; 31. First catalytic layer; 32. Second catalytic layer; 40. Anion exchange membrane; 50. Hydrogen catalytic layer; 60. Hydrogen gas diffusion layer; 70. Second bipolar plate; 80. Sealing assembly; 200. Fuel cell stack assembly. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] This application provides a reversible fuel cell 100 and its control method, as well as a fuel cell stack device 200. These are described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative and do not impose numerical requirements or establish an order. Various embodiments of the present invention may exist in a range format; it should be understood that the description in a range format is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0038] Reversible fuel cells based on anion exchange membranes can switch between electrolysis mode and fuel cell mode. Water is both a reactant in water electrolysis mode and a product in fuel cell mode. Water is transferred between the oxygen electrode and the hydrogen electrode. A reversible fuel cell includes an oxygen electrode, an anion exchange membrane, and a hydrogen electrode. In water electrolysis mode, the reversible fuel cell can provide water in time, while in fuel cell mode, it can drain water in time. Its working principle is as follows: (1) In water electrolysis mode (WE), oxygen evolution reaction (OER) occurs on the oxygen electrode side. The electrochemical reaction is 4OH - →O2 + 2H2O + 4e - The hydrogen evolution reaction (HER) occurs on the hydrogen electrode side, and the electrochemical reaction is 4H₂O + 4e⁻. - →2H₂ + 4OH⁻ - (2) In fuel cell mode (FC), the oxygen reduction reaction (ORR) occurs on the oxygen electrode side, and the electrochemical reaction is O2 + 2H2O + 4e. - →4OH - On the hydrogen electrode side, the hydrogen-oxygen evolution reaction (HOR) occurs, and the electrochemical reaction is 2H₂ + 4OH⁻. - →4H₂O + 4e - .

[0039] The technical solution of this application is as follows: Firstly, please refer to Figure 1 Embodiments of this application provide a reversible fuel cell 100, including a reversible fuel cell along a first direction ( Figure 1An oxygen catalyst layer 30, an anion exchange membrane 40, and a hydrogen catalyst layer 50 are sequentially stacked along the X-axis. The oxygen catalyst layer 30 includes a first catalyst layer 31 and a second catalyst layer 32, which are stacked sequentially along the first direction. Both the first catalyst layer 31 and the second catalyst layer 32 include an oxygen evolution reaction catalyst (OER catalyst) and an oxygen reduction reaction catalyst (ORR catalyst). The mass ratio of the OER catalyst to the ORR catalyst in the first catalyst layer 31 is M, and the mass ratio of the OER catalyst to the ORR catalyst in the second catalyst layer 32 is N, where M < N.

[0040] In this application, the water electrolysis reactor and the fuel cell are integrated into one unit, resulting in a compact structure. By configuring the oxygen catalyst layer 30 to include a first catalyst layer 31 and a second catalyst layer 32, and both the first catalyst layer 31 and the second catalyst layer 32 include OER catalyst and ORR catalyst, the first catalyst layer 31 and the second catalyst layer 32 can function in both the water electrolysis mode and the fuel cell mode of the reversible fuel cell 100. This achieves full coverage of the reactive sites of the oxygen catalyst layer 30 during the operation of the reversible fuel cell 100, thereby improving efficiency. Secondly, the first catalyst layer 31, the second catalyst layer 32, and the anion exchange membrane 40 are sequentially stacked along the first direction, and the mass ratio M of the OER catalyst to the ORR catalyst in the first catalyst layer 31 is lower than the mass ratio N of the OER catalyst to the ORR catalyst in the second catalyst layer 32. That is, based on the fact that both the first catalyst layer 31 and the second catalyst layer 32 can achieve OER catalysis and ORR catalysis, the first catalyst layer 31, which is farther away from the anion exchange membrane 40, mainly functions as ORR catalyst, while the second catalyst layer 32, which is closer to the anion exchange membrane 40, mainly functions as OER catalyst. With this arrangement, in water electrolysis mode, when an electrolyte (usually a 1M KOH solution) is introduced into the oxygen electrode side, the OH in the electrolyte on the oxygen electrode side... - Simultaneously, OER reactions occur in the first catalyst layer 31 and the second catalyst layer 32. The second catalyst layer 32, which is closer to the anion exchange membrane 40, mainly functions as an OER catalyst, while the OH- produced by the reaction on the hydrogen electrode side... - The reaction can proceed simply by passing through an anion exchange membrane 40°. - The transport path is relatively short, the water electrolysis reaction has a fast response speed, and the OER catalyst with a higher proportion in the second catalyst layer 32 can achieve OH - The rapid and complete conversion, and the water in the electrolyte and the water produced by the OER reaction, ensure sufficient wetting of the anion exchange membrane 40, thereby ensuring the interaction of water and OH groups. - The smooth transport of OH groups further increases the rate of the OER reaction. Simultaneously, a small amount of OH groups passes through the second catalyst layer 32. -The reaction occurs under the influence of a relatively small proportion of OER catalyst in the first catalyst layer 31. Specifically, through the stratified gradient of OER catalysts in the second catalyst layer 32 and the first catalyst layer 31, the OER catalysts in different regions function to their maximum extent, achieving a rapid, complete, and smooth OER reaction. Additionally, OH... - The transport path from the anion exchange membrane 40 to the first catalyst layer 31 is smoother, reducing interfacial impedance. In fuel cell mode, oxygen is introduced at the oxygen electrode side, where an ORR reaction occurs. The first catalyst layer 31, located near the oxygen inlet, primarily functions as an ORR catalyst, with most oxygen reacting directly within it. This shorter oxygen transport path results in a faster electrochemical reaction response in the fuel cell. Furthermore, the higher proportion of ORR catalyst in the first catalyst layer 31 enables rapid and complete oxygen conversion and quickly consumes residual moisture, reducing flooding caused by excessive moisture. Simultaneously, a small amount of oxygen passing through the first catalyst layer 31 reacts under the influence of the lower proportion of ORR catalyst in the second catalyst layer 32. This gradient of ORR catalyst between the first and second catalyst layers 31 maximizes the effectiveness of the ORR catalyst in different regions, ensuring a rapid, complete, and smooth ORR reaction. As can be seen, the layered gradient arrangement of the OER catalyst and ORR catalyst in the first catalyst layer 31 and the second catalyst layer 32 of this application allows the ion transport network and gas transport network to intertwine and coexist in a specific manner on the oxygen electrode side, reducing the mutual influence of the oxidation and reduction environments on the ORR catalyst and OER catalyst under different modes. Simultaneously, the necessary transport paths are pre-established and kept active during mode switching, ensuring rapid response and high operational efficiency in different mode switching, while also ensuring the adaptation of reaction sites to the reaction environment, balancing the needs of both OER and ORR reactions, and further improving the reaction rate and conversion efficiency under different modes. Furthermore, both the first catalyst layer 31 and the second catalyst layer 32 contain OER and ORR catalysts, reducing the physical differences at the interface between the first catalyst layer 31 and the second catalyst layer 32, thereby reducing the risk of delamination between the first catalyst layer 31 and the second catalyst layer 32 and improving their service life.

[0041] If the first catalyst layer 31 contains only ORR catalyst and the second catalyst layer 32 contains only OER catalyst, in different modes of the reversible fuel cell 100, one catalyst layer will always not participate in the reaction and become an inert layer, increasing resistance and mass transfer resistance, thereby affecting the reaction rate. At the same time, this inert layer may be destroyed by reactants or products in the reaction process. The composition and performance of the first catalyst layer 31 and the second catalyst layer 32 are quite different. With the switching of different modes of the reversible fuel cell 100, the delamination of the first catalyst layer 31 and the second catalyst layer 32 is easily aggravated.

[0042] Anion exchange membrane 40 is OH - The core of conduction. For example, the anion exchange membrane 40 includes one of a composite membrane and a homogeneous membrane.

[0043] In some embodiments, the mass ratio of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst in the first catalyst layer 31 is 5~50:95~50, for example, it can be 5:95, 10:90, 20:80, 40:60, 50:50, etc.

[0044] In this application, by setting the mass ratio of OER catalyst to ORR catalyst in the first catalyst layer 31 to 5~50:95~50, it is not only ensured that the first catalyst layer 31 mainly functions as ORR catalyst and fully realizes the ORR reaction, but also that the suitable OER catalyst can ensure the dual functionality of the first catalyst layer 31 and achieve a rapid response when switching between the two modes.

[0045] In some embodiments, the mass ratio of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst in the second catalyst layer 32 is 95~50:5~50, for example, it can be 95:5, 80:20, 60:40, 50:50, etc.

[0046] In this application, by setting the mass ratio of OER catalyst to ORR catalyst in the second catalyst layer 32 to 95~50:5~50, it is not only ensured that the second catalyst layer 32 mainly functions as OER catalyst and fully realizes the OER reaction, but also that the suitable ORR catalyst can ensure the dual functionality of the second catalyst layer 32 and achieve a rapid response when switching between the two modes.

[0047] In some embodiments, the mass ratio of the oxygen evolution reaction catalyst to the oxygen reduction reaction catalyst in the first catalyst layer 31 is 5~40:95~60; and / or, the mass ratio of the oxygen evolution reaction catalyst to the oxygen reduction reaction catalyst in the second catalyst layer 32 is 95~60:5~40.

[0048] In this application, by further optimizing the ratio of OER catalyst and ORR catalyst in the first catalyst layer 31 and the second catalyst layer 32, the main functions of the first catalyst layer 31 and the second catalyst layer 32 are better utilized, while the gradient structure formed by the first catalyst layer 31 and the second catalyst layer 32 is made more conducive to the reaction of gas and OH. - This improves the transmission of energy, thereby enhancing the rapid conversion of reversible fuel cells when switching modes.

[0049] In some embodiments, the first catalyst layer 31 further includes a first hydrophobic binder and a first anion exchange resin ionomer. In the first catalyst layer 31, the ratio of the total mass of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst, the mass of the first hydrophobic binder and the mass of the first anion exchange resin ionomer is 18~22:1~5:1~5.

[0050] In this application, by providing a first hydrophobic binder and a first anion exchange resin ionomer in the first catalyst layer 31, the first hydrophobic binder not only achieves a strong bond between the OER catalyst, ORR catalyst, and the first anion exchange resin ionomer in the first catalyst layer 31, improving the mechanical properties of the first catalyst layer 31, but also enables the first catalyst layer 31 to have a certain degree of hydrophobicity, thereby preventing the electrolyte or water generated in the reaction from wetting the first catalyst layer 31 and blocking the gas transport channels. The first anion exchange resin ionomer can build an ion conduction network in the first catalyst layer 31 and form hydrophilic ion channels on the catalyst surface, allowing excess OH groups on the second catalyst layer 32 side to pass through. - The mixture is transported to the first catalyst layer 31 for reaction. By rationally setting the mass ratio of the catalyst, the first hydrophobic binder, and the first anion exchange resin ionomer, an appropriate proportion of catalyst can ensure the smooth progress of the OER and ORR reactions. Simultaneously, an appropriate amount of the first hydrophobic binder and the first anion exchange resin ionomer can facilitate the reaction of gas and OH-. - The transmission provides favorable conditions, ensuring the smooth progress of different reactions.

[0051] Exemplarily, the first hydrophobic binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, and perfluoroethylene-propylene copolymer. The first anion exchange resin ionomer is a polymer containing a backbone and functional groups, wherein the backbone includes at least one of polysulfone, polyphenylene ether, polyarylpiperidine, polyarylquinine, polynorbornene, polystyrene, polybenzimidazole, styrene-butadiene block copolymer, and polyethylene, and the functional groups include at least one of quaternary ammonium, piperidinium, imidazolium, pyrrolidineium, and quaternary phosphorus.

[0052] In some embodiments, the second catalyst layer 32 further includes a second hydrophobic binder and a second anion exchange resin ionomer. In the second catalyst layer 32, the ratio of the total mass of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst, the mass of the second hydrophobic binder, and the mass of the second anion exchange resin ionomer is 18~22:1~5:1~5.

[0053] In this application, by providing a second hydrophobic binder and a second anion exchange resin ionomer in the second catalyst layer 32, the second hydrophobic binder not only improves the mechanical properties of the second catalyst layer 32 but also prevents the electrolyte or water generated during the reaction from wetting the second catalyst layer 32 and blocking the gas transport channels. The second anion exchange resin ionomer can build an ion conduction network in the second catalyst layer 32 and form hydrophilic ion channels on the catalyst surface, allowing OH... - The reaction can proceed fully on the first catalyst layer 31. By rationally setting the mass ratio of the catalyst, the second hydrophobic binder, and the second anion exchange resin ionomer, an appropriate proportion of catalyst can ensure the smooth progress of the OER and ORR reactions. Simultaneously, an appropriate amount of the second hydrophobic binder and the second anion exchange resin ionomer can facilitate the reaction of gas and OH-. - The transmission provides favorable conditions, ensuring the smooth progress of different reactions.

[0054] For example, the second hydrophobic binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, and perfluoroethylene-propylene copolymer. The second anion exchange resin ionomer is a polymer containing a main chain and functional groups, wherein the main chain includes at least one of polysulfone, polyphenylene ether, polyarylpiperidine, polyarylquinine, polynorbornene, polystyrene, polybenzimidazole, styrene-butadiene block copolymer, and polyethylene, and the functional groups include at least one of quaternary ammonium, piperidinium, imidazolium, pyrrolidineium, and quaternary phosphorus.

[0055] In some embodiments, the thickness of the first catalyst layer 31 is 3 μm to 40 μm; and / or, the thickness of the second catalyst layer 32 is 3 μm to 40 μm.

[0056] In this application, by reasonably setting the thickness of the first catalyst layer 31 and the second catalyst layer 32, the thickness of the first catalyst layer 31 and the second catalyst layer 32 is such that they can accommodate suitable OER catalyst and ORR catalyst, thereby achieving the full progress of the OER reaction and ORR reaction. At the same time, the suitable thickness allows for the mixing of gas, electrolyte, and OH-. - The appropriate transport path improves the reaction rate.

[0057] In some embodiments, the oxygen reduction reaction catalyst includes a support and a first metal element supported on the support, the first metal element including at least one selected from Ni, Fe, Co, Mn, Cu, Zn, Al, V, Cr, Mo, Pt, Ru, Pd, Au, Ag, Ir, Rh, and La; and / or, the oxygen evolution reaction catalyst is a metal-based catalyst containing a second metal element, the second metal element including at least one selected from Ni, Fe, Co, Mn, Cu, Zn, Al, V, Cr, Mo, Pt, Ru, Pd, Au, Ag, Ir, Rh, and La.

[0058] In this application, by rationally setting the types of ORR catalyst and OER catalyst, the high efficiency of ORR reaction and OER reaction is ensured, and multiple types of catalysts can be adapted to more scenarios.

[0059] For example, the ORR catalyst is supported by either a carbon material or a nitrogen-doped carbon material.

[0060] For example, the OER catalyst includes one of a metal alloy, a metal oxide (e.g., a perovskite oxide), or a metal hydroxide (e.g., a layered double hydroxide).

[0061] In some embodiments, in the first catalyst layer 31, the oxygen reduction reaction catalyst is platinum metal / carbon, platinum alloy / carbon, transition metal-nitrogen-carbon, transition metal oxide, transition metal chalcogenide, or heteroatom-doped carbon material; the oxygen evolution reaction catalyst is iridium (Ir)-based catalyst, ruthenium (Ru)-based catalyst, transition metal (hydrogen) oxide, transition metal oxide, transition metal phosphide, transition metal sulfide, transition metal selenide, or heteroatom-doped carbon material; and / or, in the second catalyst layer 32, the oxygen reduction reaction catalyst is platinum metal / carbon, platinum alloy / carbon, transition metal-nitrogen-carbon, transition metal oxide, transition metal chalcogenide, or heteroatom-doped carbon material; the oxygen evolution reaction catalyst is iridium (Ir)-based catalyst, ruthenium (Ru)-based catalyst, transition metal hydroxide, transition metal oxide, transition metal phosphide, transition metal sulfide, transition metal selenide, or heteroatom-doped carbon material.

[0062] In this application, by rationally selecting ORR catalyst and OER catalyst, the synergistic effect of ORR catalyst and OER catalyst can be better realized, thereby improving the reaction efficiency and service life of reversible fuel cell 100.

[0063] In some embodiments, the hydrogen catalyst layer 50 includes at least one of a bifunctional catalyst for hydrogen evolution reaction and hydrogen oxidation reaction, and a mixture of the hydrogen evolution reaction catalyst and the hydrogen oxidation reaction catalyst.

[0064] In this application, by setting the hydrogen catalyst layer 50 to include at least one of HER, HOR bifunctional catalysts and a mixture of HER and HOR catalysts, the hydrogen catalyst layer 50 is made bifunctional, which better adapts to the switching of different modes of the reversible fuel cell 100.

[0065] For example, the HER and HOR bifunctional catalyst includes at least one of Pt / C, platinum alloy catalyst, elemental metal (e.g., Ni, Mo, W, Mn, Co, Ir, Ru) and an alloy of the aforementioned elemental metals.

[0066] In some embodiments, the hydrogen catalyst layer 50 further includes a third anion exchange resin ionomer and a third hydrophobic binder. In the hydrogen catalyst layer 50, the ratio of the total mass of the hydrogen evolution reaction catalyst and the hydrogen oxidation reaction catalyst, the mass of the third hydrophobic binder and the mass of the third anion exchange resin ionomer is 18~22:1~5:1~5.

[0067] In this application, by providing a third anion exchange resin ionomer and a third hydrophobic binder in the hydrogen catalyst layer 50, the third anion exchange resin ionomer can build an ion conduction network in the hydrogen catalyst layer 50 to achieve OH - The smooth transport of hydrogen is ensured. The third hydrophobic binder improves the mechanical properties of the hydrogen catalyst layer 50 and prevents water flooding of the hydrogen electrode. By rationally setting the mass ratio of the catalyst, the third hydrophobic binder, and the third anion exchange resin ionomer, the smooth progress of the HER and HOR reactions can be better achieved.

[0068] For example, the third hydrophobic binder includes at least one of polytetrafluoroethylene, polyvinylidene fluoride, and perfluoroethylene-propylene copolymer. The third anion exchange resin ionomer is a polymer containing a main chain and functional groups, wherein the main chain includes at least one of polysulfone, polyphenylene ether, polyarylpiperidine, polyarylquinine, polynorbornene, polystyrene, polybenzimidazole, styrene-butadiene block copolymer, and polyethylene, and the functional groups include at least one of quaternary ammonium, piperidinium, imidazolium, pyrrolidineium, and quaternary phosphorus.

[0069] In some embodiments, please refer to Figure 1 The reversible fuel cell 100 also includes an oxygen gas diffusion layer 20 and a hydrogen gas diffusion layer 60. The oxygen gas diffusion layer 20 is disposed on the side of the first catalyst layer 31 away from the second catalyst layer 32; the hydrogen gas diffusion layer 60 is disposed on the side of the hydrogen catalyst layer 50 away from the anion exchange membrane 40.

[0070] In this application, by providing an oxygen gas diffusion layer 20 on the side of the first catalyst layer 31 opposite to the second catalyst layer 32, not only can sufficient electrolyte be provided for the OER reaction and oxygen be smoothly extracted to prevent oxygen accumulation, but also sufficient oxygen transport channels can be provided for the ORR reaction. Similarly, by providing a hydrogen gas diffusion layer 60 on the side of the hydrogen catalyst layer 50 opposite to the anion exchange membrane 40, not only can hydrogen generated by the HER reaction be smoothly extracted to prevent hydrogen accumulation, but also sufficient hydrogen transport channels can be provided for the HOR reaction and water generated can be smoothly extracted.

[0071] In some embodiments, the porosity of the oxygen gas diffusion layer 20 is 40% to 90%; and / or, the thickness of the oxygen gas diffusion layer 20 is 0.1 mm to 0.6 mm; and / or, the oxygen gas diffusion layer 20 is a hydrophobically modified oxygen gas diffusion layer 20.

[0072] In this application, by appropriately setting the porosity of the oxygen gas diffusion layer 20, sufficient electrolyte is provided for the OER reaction, and ample transport channels are provided for the generated oxygen and the oxygen introduced for the ORR reaction, thereby ensuring the smooth progress of both the OER and ORR reactions. By appropriately setting the thickness of the oxygen gas diffusion layer 20, the electrolyte, OH... - The gas transport path is suitable, thereby reducing mass transfer resistance. By modifying the oxygen gas diffusion layer 20 with hydrophobicity, the flooding of the oxygen gas diffusion layer 20 is prevented.

[0073] For example, the method of hydrophobically modifying the oxygen gas diffusion layer 20 includes: coating the oxygen gas diffusion layer 20 with a slurry containing a fourth hydrophobic binder, or immersing the oxygen gas diffusion layer 20 in a slurry containing a fourth hydrophobic binder, wherein the mass percentage of the fourth hydrophobic binder in the slurry is 5% to 40%. The fourth hydrophobic binder includes at least one selected from polytetrafluoroethylene, polyvinylidene fluoride, and perfluoroethylene propylene copolymer.

[0074] For example, the oxygen gas diffusion layer 20 is made of metal (e.g., titanium, stainless steel, nickel), and the type of oxygen gas diffusion layer 20 is at least one of fiber felt, powder felt, foam metal, woven mesh, stretched mesh, perforated mesh, non-woven fabric, woven cloth, and fiber paper.

[0075] In some embodiments, the porosity of the hydrogen gas diffusion layer 60 is 40% to 90%; and / or, the thickness of the hydrogen gas diffusion layer 60 is 0.1 mm to 0.6 mm; and / or, the hydrogen gas diffusion layer 60 is a hydrophobically modified hydrogen gas diffusion layer 60.

[0076] In this application, by appropriately setting the porosity of the hydrogen gas diffusion layer 60, sufficient transport channels are provided for the hydrogen gas generated in the HER reaction and the hydrogen gas introduced in the HOR reaction, thereby ensuring the smooth progress of both reactions. By appropriately setting the thickness of the hydrogen gas diffusion layer 60, the gas and OH... - The transport path is suitable, thereby reducing mass transfer resistance. By modifying the hydrogen gas diffusion layer 60 with hydrophobicity, the flooding of the hydrogen gas diffusion layer 60 is prevented.

[0077] For example, the method of hydrophobically modifying the hydrogen gas diffusion layer 60 includes: coating the hydrogen gas diffusion layer 60 with a fourth hydrophobic adhesive, or immersing the hydrogen gas diffusion layer 60 in a fourth hydrophobic adhesive, wherein the mass percentage of the fourth hydrophobic adhesive in the hydrogen gas diffusion layer 60 is 5% to 40%.

[0078] For example, the hydrogen gas diffusion layer 60 is made of a metal (e.g., titanium, stainless steel, nickel) and graphite, and the type of the hydrogen gas diffusion layer 60 is at least one of fiber felt, powder felt, foam metal, woven mesh, stretched mesh, perforated mesh, non-woven fabric, woven cloth, and fiber paper.

[0079] In some embodiments, please refer to Figure 1 The reversible fuel cell 100 also includes a first bipolar plate 10 and a second bipolar plate 70. The first bipolar plate 10 is disposed on the side of the oxygen gas diffusion layer 20 away from the first catalyst layer 31; the second bipolar plate 70 is disposed on the side of the hydrogen gas diffusion layer 60 away from the hydrogen catalyst layer 50.

[0080] In this application, by setting a first bipolar plate 10 on the side of the oxygen gas diffusion layer 20 away from the first catalyst layer 31, not only can the reversible fuel cell 100 be connected to the external circuit, providing conditions for the smooth operation of the reversible fuel cell 100; but also, in fuel cell mode, the first bipolar plate 10 can evenly distribute the externally supplied oxygen to the oxygen gas diffusion layer 20 and promptly discharge the generated water; in water electrolysis mode, the first bipolar plate 10 can quickly transfer the electrolyte to the oxygen gas diffusion layer 20 and discharge the oxygen escaping from the oxygen gas diffusion layer 20. By setting a second bipolar plate 70 on the side of the hydrogen gas diffusion layer 60 away from the hydrogen catalyst layer 50, not only can the reversible fuel cell 100 be connected to the external circuit, providing conditions for the smooth operation of the reversible fuel cell 100; but also, in fuel cell mode, the second bipolar plate 70 can evenly distribute the externally supplied hydrogen to the hydrogen gas diffusion layer 60; and in water electrolysis mode, the second bipolar plate 70 can quickly collect the hydrogen escaping from the hydrogen gas diffusion layer 60. The arrangement of the first bipolar plate 10 and the second bipolar plate 70 ensures an integrated structure of the plates and reduces the number of assembly parts.

[0081] In some embodiments, the first bipolar plate 10 is at least one of a metal plate and a graphite plate; and / or, the second bipolar plate 70 is at least one of a metal plate and a graphite plate.

[0082] In this application, by reasonably setting the materials of the first bipolar plate 10 and the second bipolar plate 70, the connection between the first bipolar plate 10 and the second bipolar plate 70 and the external circuit is better realized.

[0083] For example, the first bipolar plate 10 and the second bipolar plate 70 are highly conductive and corrosion-resistant metal plates, such as titanium plates, stainless steel plates, nickel-plated stainless steel plates, nickel-plated carbon steel, and pure nickel.

[0084] For example, please refer to Figure 2 and Figure 3 ( Figure 2 and Figure 3 plane and Figure 1(The direction of the X-axis is perpendicular to the center). Flow fields are provided on both sides of the first bipolar plate 10 and the second bipolar plate 70 along the first direction. Specifically, a hydrogen / water flow field 11 is provided on the side of the first bipolar plate 10 and the second bipolar plate 70 facing the hydrogen electrode, and an oxygen / water flow field 12 is provided on the side of the first bipolar plate 10 and the second bipolar plate 70 facing the oxygen electrode. Please refer to [link / reference]. Figure 2 , Figure 2 This is a schematic diagram of the structure of the first bipolar plate 10 and the second bipolar plate 70 facing the oxygen electrode. The oxygen / water flow field 12 includes a first inlet / outlet 121, a second inlet / outlet 122, and a first drainage region 123. The first inlet / outlet 121 and the second inlet / outlet 122 are used to introduce oxygen and electrolyte. It can be understood that when the first inlet / outlet 121 serves as the inlet for oxygen and electrolyte, the second inlet / outlet 122 serves as the outlet for reaction products. Please refer to [link / reference]. Figure 3 , Figure 3 The diagram shows the structure of the first bipolar plate 10 and the second bipolar plate 70 facing the hydrogen electrode. The hydrogen / water flow field 11 includes a third inlet / outlet 111, a fourth inlet / outlet 112, and a second drainage area 113. The third inlet / outlet 111 and the fourth inlet / outlet 112 are used to introduce hydrogen. It can be understood that when the third inlet / outlet 111 is used as the hydrogen inlet, the fourth inlet / outlet 112 is used as the reaction product outlet.

[0085] The flow field includes at least one of the following: lattice flow field, serpentine flow field, parallel flow field, interdigitated flow field, serpentine-parallel composite flow field, and meandering flow field. The diversion zone (i.e., the first diversion zone 123 and the second diversion zone 113) includes a flow channel (not shown in the figure) and a flow channel ridge (not shown in the figure). The cross-section of the flow channel is at least one of rectangular and trapezoidal. And / or, the width of the flow channel is 0.3 mm to 1.5 mm. And / or, the depth of the flow channel is 0.3 mm to 1.5 mm. And / or, the width of the flow channel ridge is 0.3 mm to 1.5 mm.

[0086] It is understood that the oxygen electrode includes a first bipolar plate 10, an oxygen gas diffusion layer 20, a first catalytic layer 31, and a second catalytic layer 32; the hydrogen electrolysis includes a hydrogen catalytic layer 50, a hydrogen gas diffusion layer 60, and a second bipolar plate 70.

[0087] Secondly, this application provides a control method for the reversible fuel cell 100 provided in the first aspect of this application. When the reversible fuel cell 100 is in water electrolysis mode, the electrolyte is introduced from the oxygen catalytic layer 30 (i.e., oxygen electrode) side and discharged from the oxygen catalytic layer 30 side, while the electrolyte is not introduced from the hydrogen catalytic layer 50 (i.e., hydrogen electrode) side. When the reversible fuel cell 100 is in fuel cell mode, oxygen is introduced from the oxygen catalyst layer 30 side and hydrogen is introduced from the hydrogen catalyst layer 50 side.

[0088] In this application, by circulating the electrolyte on the oxygen catalyst layer 30 (i.e., the oxygen electrode) side during water electrolysis mode, flooding of the hydrogen catalyst layer 50 (i.e., the hydrogen electrode) is avoided. No electrolyte flows through the hydrogen electrode side; instead, the electrolyte reaches the hydrogen electrode side through water permeation, ensuring the efficient transport of hydrogen generated on the hydrogen electrode side and preventing flooding on the hydrogen electrode side when switching to fuel cell mode. By introducing oxygen from the oxygen catalyst layer 30 side and hydrogen from the hydrogen catalyst layer 50 side in fuel cell mode, the reaction fuel cell can operate smoothly.

[0089] For example, please refer to Figure 4 When the water electrolysis mode is in operation, an electrolyte (usually a 1M KOH solution) is introduced into the first inlet 121 of the first bipolar plate 10 on the oxygen electrode side, and the oxygen generated on the oxygen electrode side is discharged from the second inlet 122. No electrolyte is introduced into the hydrogen electrode side; instead, the electrolyte reaches the hydrogen electrode side through water osmosis and reacts there. The generated hydrogen gas exits from the third inlet 111 and / or the fourth inlet 112 of the second bipolar plate 70, ensuring the efficient transfer of hydrogen generated on the hydrogen electrode side.

[0090] For example, please refer to Figure 5 When in fuel cell mode, the electrolyte is first discharged from the second inlet 122 of the first bipolar plate 10 on the oxygen electrode side, then oxygen is introduced into the first inlet 121 of the first bipolar plate 10 on the oxygen electrode side, and hydrogen is introduced into the fourth inlet 112 of the second bipolar plate 70 on the hydrogen electrode side.

[0091] Thirdly, this application provides a fuel cell stack device 200, including the reversible fuel cell 100 provided in the first aspect of this application.

[0092] In this application, the fuel cell stack device 200 includes the reversible fuel cell 100 provided in the first aspect of this application, thereby making the stack structure have a faster response speed, a faster response speed when switching between different modes, and a longer service life.

[0093] For example, the fuel cell stack 200 is formed by stacking multiple reversible fuel cells 100. It is understood that only a first bipolar plate 10 or a second bipolar plate 70 needs to be disposed between adjacent oxygen and hydrogen electrodes. See also... Figure 6Taking a stack of two reversible fuel cells 100 to form a stack device 200 as an example, the first inlets 121 on multiple first bipolar plates 10 (or second bipolar plates 70) are interconnected, and the second inlets 122 are interconnected, allowing oxygen and electrolyte to be simultaneously introduced into multiple first inlets 121 and multiple second inlets 122; the third inlets 111 are interconnected, and the fourth inlets 112 are interconnected, allowing hydrogen to be simultaneously introduced into multiple third inlets 111 and multiple fourth inlets 112. The products of each reversible fuel cell 100 are discharged from its corresponding outlet. It is understood that the oxygen and electrolyte inlets are not connected to the hydrogen inlet.

[0094] A sealing assembly 80 is provided on the first bipolar plate 10 and the second bipolar plate 70. The sealing assembly 80 includes one of a sealing ring, a sealing strip, and a sealing gasket.

[0095] The present application will be specifically described below through specific embodiments. These embodiments are only some embodiments of the present application and are not intended to limit the present application. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0096] Example 1 This embodiment provides a reversible fuel cell 100, including a first bipolar plate 10, an oxygen gas diffusion layer 20, a first catalyst layer 31, a second catalyst layer 32, an anion exchange membrane 40, a hydrogen catalyst layer 50, a hydrogen gas diffusion layer 60, and a second bipolar plate 70, which are sequentially stacked along a first direction.

[0097] Both the first bipolar plate 10 and the second bipolar plate 70 are nickel-plated stainless steel plates (316L) with a thickness of 1.5 mm. On the side of the first bipolar plate 10 and the second bipolar plate 70 facing the hydrogen electrode, a single-channel serpentine flow field with a depth of 0.5 mm and a width of 0.5 mm is etched. On the side facing the oxygen electrode, an interdigitated flow field with a depth of 0.8 mm and a width of 0.8 mm is etched. The ridge width of the flow fields is 0.8 mm in both cases. A sealing assembly 80 is provided on the first bipolar plate 10 and the second bipolar plate 70. The sealing assembly 80 uses a sealing ring with a thickness of 0.5 mm, which is embedded in the sealing groove of the first bipolar plate 10 and the second bipolar plate 70.

[0098] The oxygen gas diffusion layer 20 is a porous nickel felt with a porosity of 75% and a thickness of 0.4 mm. The oxygen gas diffusion layer 20 is hydrophobic by impregnation with PTFE emulsion, and the PTFE emulsion contains 20% PTFE by mass.

[0099] The hydrogen gas diffusion layer 60 is a carbon paper with a porosity of 75% and a thickness of 0.4 mm. The hydrogen gas diffusion layer 60 is hydrophobic by impregnation with PTFE emulsion, and the PTFE emulsion contains 20% PTFE by mass.

[0100] The anion exchange membrane 40 is an Alykmer W-75 with a thickness of 75 μm.

[0101] Preparation of the first catalyst layer 31: The OER catalyst NiFe layered double hydroxide (NiFe-LDH) and the ORR catalyst Pt / C (Pt content 40wt%) were mixed at a mass ratio of 20:80 to prepare the catalyst. The mixed catalyst was then combined with Alykmer I-250 ionomer and PTFE at a mass ratio of 20:2:2 to form a slurry. This slurry was coated onto the oxygen gas diffusion layer 20, controlling the total catalyst loading in the first catalyst layer 31 to be 2.5 mg / cm³. 2 The first catalyst layer 31 with a thickness of about 20 μm was obtained by drying at 80℃.

[0102] Preparation of the second catalyst layer 32: A catalyst was prepared by mixing NiFe layered double hydroxide (NiFe-LDH) and Pt / C (Pt content of 40wt%) at a mass ratio of 80:20. The mixed catalyst was then mixed with Alykmer I-250 ionomer and PTFE at a mass ratio of 20:2:2 to form a slurry. The slurry was coated on the first catalyst layer 31, and the total catalyst loading of the second catalyst layer 32 was controlled to be 2.5 mg / cm³. 2 The second catalyst layer 32 with a thickness of about 17 μm was obtained by drying at 80 °C.

[0103] Preparation of hydrogen catalytic layer 50: A slurry was prepared by mixing Pt / C catalyst (Pt content 40wt%), Alykmer-I-250 ionomer, and PTFE in a mass ratio of 20:2:2. The slurry was coated onto the hydrogen gas diffusion layer 60, and the Pt loading of Pt / C was controlled to be 0.5 mg / cm³. 2 The hydrogen catalyst layer 50 was obtained by drying at 80℃.

[0104] Example 2 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the first catalyst layer 31 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 10:90. The rest is the same as in Embodiment 1 and will not be described again here.

[0105] Example 3 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the first catalyst layer 31 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 5:95. The rest is the same as in Embodiment 1 and will not be described again here.

[0106] Example 4 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the first catalyst layer 31 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 40:60. The rest is the same as in Embodiment 1 and will not be described again here.

[0107] Example 5 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the first catalyst layer 31 is prepared by mixing NiFe-LDH and Pt / C in a mass ratio of 50:50. The rest is the same as in Embodiment 1 and will not be described again here.

[0108] Example 6 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the first catalyst layer 31 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 2:98. The rest is the same as in Embodiment 1 and will not be described again here.

[0109] Example 7 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the first catalyst layer 31 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 60:40. The rest is the same as in Embodiment 1 and will not be described again here.

[0110] Example 8 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the second catalyst layer 32 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 95:5. The rest is the same as in Embodiment 1 and will not be described again here.

[0111] Example 9 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the second catalyst layer 32 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 60:40. The rest is the same as in Embodiment 1 and will not be described again here.

[0112] Example 10 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the second catalyst layer 32 is prepared by mixing NiFe-LDH and Pt / C in a mass ratio of 50:50. The rest is the same as in Embodiment 1 and will not be described again here.

[0113] Example 11 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the second catalyst layer 32 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 98:2. The rest is the same as in Embodiment 1 and will not be described again here.

[0114] Example 12 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that the catalyst in the second catalyst layer 32 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 40:60. The rest is the same as in Embodiment 1 and will not be described again here.

[0115] Example 13 This embodiment provides a reversible fuel cell 100, which differs from Embodiment 1 only in that Pt / C is replaced with Fe-NC and NiFe-LDH is replaced with NiFeO. x Everything else is the same as in Example 1, and will not be repeated here.

[0116] Example 14 This embodiment provides a reversible fuel cell 100. Compared with Embodiment 1, the only difference is that Pt / C is replaced with Co-NC and NiFe-LDH is replaced with LaCoO3. The rest is the same as in Embodiment 1, and will not be described again here.

[0117] Comparative Example 1 This comparative example provides a reversible fuel cell 100. Compared with Example 1, the only difference is that the catalyst of the first catalyst layer 31 is only Pt / C, and the catalyst of the second catalyst layer 32 is only NiFe-LDH. The rest is the same as in Example 1, and will not be repeated here.

[0118] Comparative Example 2 This comparative example provides a reversible fuel cell 100. The only difference from Example 1 is that the oxygen catalyst layer 30 is a single-layer catalyst layer. The preparation of the single-layer catalyst layer is as follows: NiFe layered double hydroxide (NiFe-LDH) and Pt / C (Pt content 40wt%) are mixed at a mass ratio of 50:50 to obtain a catalyst. The mixed catalyst is then mixed with Alykmer I-250 ionomer and PTFE at a mass ratio of 20:2:2 to form a slurry. The slurry is coated onto the oxygen gas diffusion layer 20, and the total catalyst loading of the catalyst layer is controlled to be 5 mg / cm³. 2 The catalyst was dried at 80°C to obtain a single-layer catalyst layer with a thickness of approximately 35 μm. Other aspects remained the same as in Example 1 and will not be repeated here.

[0119] Comparative Example 3 This comparative example provides a reversible fuel cell 100. Compared with Example 1, the only difference is that the catalyst in the first catalyst layer 31 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 80:20, and the catalyst in the second catalyst layer 32 is prepared by mixing NiFe-LDH and Pt / C at a mass ratio of 20:80. The rest is the same as in Example 1, and will not be repeated here.

[0120] The reversible fuel cells 100 of Examples 1-14 and Comparative Examples 1-3 were assembled into a stack and their performance was tested. The test results are shown in Table 1.

[0121] The assembly of the fuel cell stack 200 includes: two sections: end plate, current collector, sealing material, hydrogen electrode (including hydrogen catalyst layer 50 and hydrogen gas diffusion layer 60), anion exchange membrane 40, oxygen electrode (including oxygen catalyst layer 30 and oxygen gas diffusion layer 20), bipolar plate (referring to the first bipolar plate 10 or the second bipolar plate 70), sealing material, hydrogen electrode, anion exchange membrane 40, oxygen electrode, current collector, and end plate, which are bolted together.

[0122] Test mode: constant current charge-discharge cycle, a complete cycle includes one 10-minute electrolysis mode and one 10-minute fuel cell mode.

[0123] Cyclic parameters: (1) Current density is -300mA / cm 2 (Electrolysis mode) and +300mA / cm² (fuel cell mode); (2) The duration of a single mode is 10 min.

[0124] Operating conditions: (1) Electrolysis mode (-300mA / cm²): Oxygen electrode: 1M KOH aqueous solution is introduced at a flow rate of 10mL / min; Hydrogen electrode: no solution is introduced. (2) Fuel cell mode (+300mA / cm²): Oxygen electrode: KOH aqueous solution is stopped, and the flow channel is purged with dry high-purity oxygen (>99.999%) for at least 30s to remove residual electrolyte. Then oxygen is continuously introduced at a flow rate of 200sccm; Hydrogen electrode: Humidified high-purity hydrogen (>99.999%) is introduced through a bubble bottle at 80°C at a flow rate of 200sccm.

[0125] Termination conditions: The test will continue until the battery's operating voltage in any mode decays to the preset cutoff condition. For example: (1) Electrolysis voltage > 2.0V (indicating that the reaction resistance is too high and the system efficiency is too low); (2) Discharge voltage < 0.5V (indicating that the power cannot be output effectively). Record the total number of cycles when the termination condition is reached as a key indicator for measuring its cycle life.

[0126] Table 1

[0127] As can be seen from the data in Examples 1-5 in Table 1, adjusting the mass ratio of OER catalyst and ORR catalyst in the first catalyst layer 31 within a certain range can regulate the performance of the first catalyst layer 31 and achieve better synergy between the first catalyst layer 31 and the second catalyst layer 32, thereby effectively regulating the conversion efficiency of the fuel cell stack 200 in charging mode (water electrolysis mode) and discharging mode (fuel cell mode) and improving the cycle life of the fuel cell stack 200. Specifically, the first catalyst layer 31 is close to the oxygen gas diffusion layer 20. (1) In the discharging mode, the first catalyst layer 31 is more likely to come into contact with oxygen and is less prone to water flooding. Adjusting the mass ratio of OER catalyst and ORR catalyst in the first catalyst layer 31 has a more significant effect on improving the discharge voltage, that is, it is more effective in improving the discharge efficiency. As the proportion of ORR catalyst in the first catalyst layer 31 increases, the discharge voltage of the fuel cell stack 200 increases, which means that the voltage output by the fuel cell stack 200 when generating electricity is higher, thereby improving the conversion efficiency. (2) In the charging mode, the presence of the second catalyst layer 32 provides favorable conditions for the water electrolysis mode, thereby making the change in the proportion of OER catalyst in the first catalyst layer 31 have a smaller impact on the electrolysis voltage. At the same time, the high catalytic activity of the appropriate amount of OER catalyst in the first catalyst layer 31 can reduce the impact of the oxidation environment on the ORR catalyst in the first catalyst layer 31 in the charging mode. Finally, under the effect of the appropriate proportion of OER catalyst and ORR catalyst in the first catalyst layer 31 and the synergy of the second catalyst layer 32, the performance of the fuel cell stack 200 is better. As can be seen from the data of Examples 6-7, when the mass ratio of OER catalyst to ORR catalyst in the first catalyst layer 31 is too large or too small, the performance of the fuel cell stack 200 is poor. This further illustrates that when the mass ratio of OER catalyst to ORR catalyst in the first catalyst layer 31 is 5-50:95-50, the OER catalyst and ORR catalyst can be fully utilized. At the same time, the synergy of the first catalyst layer 31 and the second catalyst layer 32 can reduce the impact of the oxidation environment on the ORR catalyst activity and reduce the impact of the reduction environment on the OER catalyst activity, thereby improving the performance of the fuel cell stack 200.

[0128] Data from Examples 8-10 show that adjusting the mass ratio of OER catalyst to ORR catalyst in the second catalyst layer 32 within a certain range can regulate the performance of the second catalyst layer 32 and achieve better synergy between the first catalyst layer 31 and the second catalyst layer 32. This effectively regulates the conversion efficiency of the fuel cell stack 200 in charging mode (water electrolysis mode) and discharging mode (fuel cell mode) and improves the cycle life of the fuel cell stack 200. Specifically, the second catalyst layer 32 is close to the anion exchange membrane 40, resulting in a lower contact resistance between the two. As the proportion of OER catalyst in the second catalyst layer 32 increases, the oxygen electrode can more efficiently convert OH- -When converted to water, the water electrolysis reaction has a fast response rate, and the charging voltage of the fuel cell stack 200 decreases, indicating that the charging voltage of the fuel cell stack 200 is reduced, and the water electrolysis efficiency is improved. As the proportion of ORR catalyst in the second catalyst layer 32 increases, the discharge voltage changes less. The high catalytic activity of an appropriate amount of ORR catalyst can reduce the impact of the reduction environment in the discharge mode on the OER catalyst in the second catalyst layer 32. Ultimately, the optimal performance of the fuel cell stack 200 is achieved through the combined effects of the appropriate proportion of OER and ORR catalysts in the second catalyst layer 32 and the synergy of the first catalyst layer 31. Data from Examples 11-12 show that when the mass ratio of OER catalyst to ORR catalyst in the second catalyst layer 32 is too large or too small, the performance of the fuel cell stack 200 is poor. This further illustrates that when the mass ratio of OER catalyst to ORR catalyst in the second catalyst layer 32 is 95-50:5-50, the OER catalyst and ORR catalyst can be fully utilized. At the same time, the synergy between the first catalyst layer 31 and the second catalyst layer 32 can reduce the impact of the oxidizing environment on the ORR catalyst activity and reduce the impact of the reducing environment on the OER catalyst activity, thereby improving the performance of the fuel cell stack 200.

[0129] Data from Examples 1, 13, and 14 show that when the ORR catalyst Pt / C in Example 1 is replaced with Fe-NC and Co-NC, and the OER catalyst NiFe-LDH is replaced with NiFeO... x When using LaCoO3, the fuel cell stack 200 still maintains high conversion efficiency and long cycle life. This strongly demonstrates that the gradient catalytic layer structure design of the present invention has broad compatibility and universality with different catalytic material systems.

[0130] As can be seen from the data in Comparative Example 1, when the catalyst of the first catalyst layer 31 is only Pt / C and the catalyst of the second catalyst layer 32 is only NiFe-LDH, the conversion efficiency and cycle number of the fuel cell stack 200 decrease significantly. This is mainly because in different modes of the fuel cell stack 200, there is always one catalyst layer that does not participate in the reaction and becomes an inert layer. This not only increases the resistance and mass transfer resistance, thus affecting the reaction rate, but the inert layer may also be destroyed by the reactants or products in the reaction process, further affecting the performance of the fuel cell stack 200.

[0131] As shown in Comparative Example 2, when the oxygen catalyst layer 30 is set as a single-layer catalyst layer containing both ORR and OER catalysts, the performance of the fuel cell stack 200 decreases significantly. This indicates that only by setting the oxygen catalyst layer 30 into a specific gradient structure can the mutual influence between the ORR and OER catalysts in the reversible process be reduced, and the mutual interference and poisoning caused by drastic environmental changes during reversible cycling be weakened. Furthermore, the ion transport network and gas transport network of the gradient-structured oxygen catalyst layer 30 are interwoven and coexist throughout the electrode. Regardless of mode switching, the necessary transport paths are pre-established and remain active, ensuring rapid response during mode switching and high operational efficiency.

[0132] As can be seen from the data of Comparative Example 3, when the gradient change of the first catalyst layer 31 and the second catalyst layer 32 is different from the gradient change of this application, the catalytic activity of the OER catalyst and ORR catalyst in the first catalyst layer 31 and the second catalyst layer 32 cannot be well utilized, and the synergistic effect of the first catalyst layer 31 and the second catalyst layer 32 will be affected, resulting in poor performance of the fuel cell stack device 200.

[0133] In summary, by setting the oxygen catalyst layer 30 to a specific gradient structure and rationally controlling the mass ratio of the OER catalyst and the ORR catalyst in the first catalyst layer 31 and the second catalyst layer 32, the present invention maximizes the role of the OER catalyst and the ORR catalyst and reduces the damage to the OER catalyst and the ORR catalyst during the reversible cycle, thereby obtaining a high-performance reversible fuel cell 100 and a stack device 200.

[0134] The reversible fuel cell 100 and its control method and stack device 200 provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A reversible fuel cell (100), characterized in that, It includes an oxygen catalyst layer (30), an anion exchange membrane (40) and a hydrogen catalyst layer (50) stacked sequentially along a first direction; The oxygen catalytic layer (30) includes a first catalytic layer (31) and a second catalytic layer (32), and the first catalytic layer (31), the second catalytic layer (32) and the anion exchange membrane (40) are stacked sequentially along the first direction; the first catalytic layer (31) and the second catalytic layer (32) each include an oxygen evolution reaction catalyst and an oxygen reduction reaction catalyst, the mass ratio of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst in the first catalytic layer (31) is M, and the mass ratio of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst in the second catalytic layer (32) is N, where M < N.

2. The reversible fuel cell (100) according to claim 1, characterized in that, The mass ratio of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst in the first catalyst layer (31) is 5~50:95~50; and / or, The mass ratio of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst in the second catalyst layer (32) is 95~50:5~50.

3. The reversible fuel cell (100) according to claim 2, characterized in that, The mass ratio of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst in the first catalyst layer (31) is 5~40:95~60; and / or, The mass ratio of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst in the second catalyst layer (32) is 95~60:5~40.

4. The reversible fuel cell (100) according to any one of claims 1 to 3, characterized in that, The first catalyst layer (31) further includes a first hydrophobic binder and a first anion exchange resin ionomer. In the first catalyst layer (31), the ratio of the total mass of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst, the mass of the first hydrophobic binder, and the mass of the first anion exchange resin ionomer is 18~22:1~5:1~5; and / or, The second catalyst layer (32) further includes a second hydrophobic binder and a second anion exchange resin ionomer. In the second catalyst layer (32), the ratio of the total mass of the oxygen evolution reaction catalyst and the oxygen reduction reaction catalyst, the mass of the second hydrophobic binder and the mass of the second anion exchange resin ionomer is 18~22:1~5:1~5.

5. The reversible fuel cell (100) according to any one of claims 1 to 4, characterized in that, The thickness of the first catalyst layer (31) is 3 μm to 40 μm; and / or, The thickness of the second catalyst layer (32) is 3μm~40μm.

6. The reversible fuel cell (100) according to any one of claims 1 to 5, characterized in that, The oxygen reduction catalyst comprises a support and a first metal element supported on the support, wherein the first metal element comprises at least one selected from Ni, Fe, Co, Mn, Cu, Zn, Al, V, Cr, Mo, Pt, Ru, Pd, Au, Ag, Ir, Rh, and La; and / or, The oxygen evolution reaction catalyst is a metal-based catalyst containing a second metal element, which includes at least one of Ni, Fe, Co, Mn, Cu, Zn, Al, V, Cr, Mo, Pt, Ru, Pd, Au, Ag, Ir, Rh, and La.

7. The reversible fuel cell (100) according to claim 6, characterized in that, In the first catalytic layer (31), the oxygen reduction reaction catalyst is platinum metal / carbon, platinum alloy / carbon, transition metal-nitrogen-carbon, transition metal oxide, transition metal chalcogenide, or heteroatom-doped carbon material; the oxygen evolution reaction catalyst is iridium-based catalyst, ruthenium-based catalyst, transition metal oxide, transition metal hydroxide, transition metal oxide, transition metal phosphide, transition metal sulfide, transition metal selenide, or heteroatom-doped carbon material; and / or, In the second catalytic layer (32), the oxygen reduction reaction catalyst is platinum metal / carbon, platinum alloy / carbon, transition metal-nitrogen-carbon, transition metal oxide, transition metal chalcogenide, heteroatom-doped carbon material, and the oxygen evolution reaction catalyst is iridium-based catalyst, ruthenium-based catalyst, transition metal hydroxide, transition metal oxide, transition metal phosphide, transition metal sulfide, transition metal selenide, heteroatom-doped carbon material.

8. The reversible fuel cell (100) according to any one of claims 1 to 7, characterized in that, The hydrogen catalyst layer (50) comprises at least one of the following: a bifunctional catalyst for hydrogen evolution reaction and hydrogen oxidation reaction, and a mixture of a hydrogen evolution reaction catalyst and a hydrogen oxidation reaction catalyst; and / or, The hydrogen catalyst layer (50) further includes a third anion exchange resin ionomer and a third hydrophobic binder. In the hydrogen catalyst layer (50), the ratio of the total mass of the hydrogen evolution reaction catalyst and the hydrogen oxidation reaction catalyst, the mass of the third hydrophobic binder and the mass of the third anion exchange resin ionomer is 18~22:1~5:1~5.

9. The reversible fuel cell (100) according to claim 8, characterized in that, The reversible fuel cell (100) further includes an oxygen gas diffusion layer (20) and a hydrogen gas diffusion layer (60). The oxygen gas diffusion layer (20) is disposed on the side of the first catalyst layer (31) away from the second catalyst layer (32), and the hydrogen gas diffusion layer (60) is disposed on the side of the hydrogen catalyst layer (50) away from the anion exchange membrane (40).

10. The reversible fuel cell (100) according to claim 9, characterized in that, The porosity of the oxygen gas diffusion layer (20) is 40%~90%; and / or, The thickness of the oxygen gas diffusion layer (20) is 0.1 mm to 0.6 mm; and / or, The oxygen gas diffusion layer (20) is a hydrophobically modified oxygen gas diffusion layer (20); and / or, The porosity of the hydrogen gas diffusion layer (60) is 40%~90%; and / or, The thickness of the hydrogen gas diffusion layer (60) is 0.1 mm to 0.6 mm; and / or, The hydrogen gas diffusion layer (60) is a hydrophobically modified hydrogen gas diffusion layer (60).

11. The reversible fuel cell (100) according to claim 9, characterized in that, The reversible fuel cell (100) further includes a first bipolar plate (10) and a second bipolar plate (70). The first bipolar plate (10) is disposed on the side of the oxygen gas diffusion layer (20) away from the first catalyst layer (31), and the second bipolar plate (70) is disposed on the side of the hydrogen gas diffusion layer (60) away from the hydrogen catalyst layer (50).

12. The reversible fuel cell (100) according to claim 11, characterized in that, The first bipolar plate (10) is at least one of a metal plate and a graphite plate; and / or, The second bipolar plate (70) is at least one of a metal plate and a graphite plate.

13. A control method for a reversible fuel cell (100) according to any one of claims 1 to 12, characterized in that, When the reversible fuel cell (100) is in water electrolysis mode, the electrolyte is introduced from one side of the oxygen catalyst layer (30) and discharged from the other side of the oxygen catalyst layer (30); When the reversible fuel cell (100) is in fuel cell mode, oxygen is introduced from the oxygen catalyst layer (30) side and hydrogen is introduced from the hydrogen catalyst layer (50) side.

14. A fuel cell stack device (200), characterized in that, Including the reversible fuel cell (100) according to any one of claims 1 to 12.

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