Reversible hydrogen electrochemical cell

Abstract

The application provides a reversible hydrogen electrochemical cell. The reversible hydrogen electrochemical cell comprises a hydrogen electrochemical assembly and a packaging structure, wherein the hydrogen electrochemical assembly comprises: oppositely arranged anode substrate and cathode substrate, both of which are porous materials; an anode catalyst layer arranged on the surface of the anode substrate close to the cathode substrate; a cathode catalyst layer arranged on the surface of the cathode substrate close to the anode substrate; an alkaline composite electrolyte arranged between the anode catalyst layer and the cathode catalyst layer and having a porous structure; and the packaging structure has at least one sealing opening, and a sealing member is used for sealing the sealing opening. The reversible hydrogen electrochemical cell can realize efficient conversion between electric energy and chemical energy, can avoid rapid loss of electrodes and electrolytes at high temperature, can realize conversion between electric energy and chemical energy in a single device, and has the advantages of more compact overall structure and lower cost compared with a split type electrolytic cell and a fuel cell.

Description

Technical Field

[0001] The invention belongs to the field of electrochemistry, and in particular relates to a reversible hydrogen electrochemical cell. Background Art

[0002] With the continuous growth of the global population and the continued expansion of industrialization, human society's use of traditional fossil energy has increased significantly, resulting in a series of climate problems such as greenhouse gas emissions. The large-scale utilization of renewable energy sources such as wind, photovoltaic, and hydropower is crucial for the long-term stable and sustainable development of my country's social economy and the construction of an ecological civilization. However, the electricity generated by these sources is naturally highly temporally volatile and spatially dependent, necessitating the efficient conversion of unstable electrical energy into stable chemical energy for storage to meet subsequent utilization needs.

[0003] Clean energy carriers such as green hydrogen, green ammonia, green alcohol and green hydrocarbons are believed to have the potential to replace traditional fossil fuels, enabling power units such as fuel cells, gas turbines and internal combustion engines to achieve near-zero emissions. Among them, carbon-based clean energy made from carbon dioxide and green hydrogen as raw materials is expected to replace traditional fuels without causing a huge impact on the traditional power unit market, and effectively promote the smooth realization of the "dual carbon" goals.

[0004] Therefore, it is urgent to develop a corresponding high-efficiency electrochemical conversion device for the production and utilization of green hydrogen, a key energy carrier and green chemical raw material. Summary of the Invention

[0005] The present invention aims to at least partially address one of the technical problems in the related art. To this end, one object of the present invention is to provide a reversible hydrogen electrochemical cell that can achieve efficient conversion between electrical energy and chemical energy, avoid rapid loss of electrodes and electrolytes at high temperatures, or achieve electrical and chemical energy conversion in a single device.

[0006] In one aspect of the present invention, the present invention proposes a reversible hydrogen electrochemical cell. According to an embodiment of the present invention, the reversible hydrogen electrochemical cell includes a hydrogen electrochemical component and a packaging structure for packaging the hydrogen electrochemical component, wherein the hydrogen electrochemical component includes: an anode substrate and a cathode substrate arranged relatively to each other, and the anode substrate and the cathode substrate are both porous materials; an anode catalyst layer, the anode catalyst layer is arranged on the surface of the anode substrate close to the cathode substrate; a cathode catalyst layer, the cathode catalyst layer is arranged on the surface of the cathode substrate close to the anode substrate; an alkaline composite electrolyte, the alkaline composite electrolyte is arranged between the anode catalyst layer and the cathode catalyst layer, and the alkaline composite electrolyte is a porous structure; the packaging structure has at least one sealing port, a sealing member is provided in the sealing port, and the sealing member is used to seal the sealing port. Thus, the above-mentioned reversible hydrogen electrochemical cell can achieve efficient conversion between electrical energy and chemical energy, can avoid rapid loss of electrodes and electrolytes at high temperatures, can achieve conversion of electrical energy and chemical energy in a single device, and has the advantages of a more compact overall structure and lower cost compared to split electrolytic cells and fuel cells.

[0007] According to an embodiment of the present invention, the alkaline composite electrolyte includes a porous skeleton and a metal compound, the metal compound includes at least one of a metal hydroxide and a metal oxide, and the metal element of the metal compound includes at least one of lithium, sodium, potassium, calcium, barium, strontium, and cesium.

[0008] According to an embodiment of the present invention, in the alkaline composite electrolyte, the porous skeleton and the metal compound are mixed into one, or the metal compound is attached to the pore surfaces of the porous skeleton.

[0009] According to an embodiment of the present invention, the material of the porous skeleton includes at least one of polytetrafluoroethylene, polyetheretherketone, polybenzimidazole, polyphenylene sulfide, polyimide, zirconium oxide, nickel oxide, potassium titanate, strontium titanate, and zirconium titanate.

[0010] According to an embodiment of the present invention, the materials of the cathode substrate and the anode substrate independently include at least one of foamed nickel, foamed platinum, foamed palladium, foamed stainless steel, titanium felt, platinum felt, palladium felt, Raney nickel and carbon paper.

[0011] According to an embodiment of the present invention, the cathode catalyst layer and the anode catalyst layer independently include at least one of a metal element, an alloy of the metal, an oxide of the metal, a sulfide of the metal and / or a hydroxide of the metal, wherein the metal includes at least one of nickel, palladium, platinum, iridium, ruthenium, gold, silver, copper and iron.

[0012] According to an embodiment of the present application, the packaging structure comprises a metal flow field plate and / or a graphite flow field plate, wherein the metal in the metal flow field plate comprises at least one of nickel, palladium, platinum, iridium, ruthenium, gold, silver, copper and iron.

[0013] According to an embodiment of the present application, the seal is at least one of a polytetrafluoroethylene seal, a perfluoroelastomer seal and a dense ceramic seal.

[0014] According to an embodiment of the present application, the preparation process of the alkaline composite electrolyte comprises: mixing the porous framework and the metal compound uniformly, and sintering to obtain the alkaline composite electrolyte; or, the preparation process of the alkaline composite electrolyte comprises: placing the porous framework in a molten metal compound melt or in a metal compound aqueous solution to infiltrate, so that the metal compound is adsorbed on the pore surface of the porous framework; room temperature cooling and solidification to obtain the alkaline composite electrolyte.

[0015] According to an embodiment of the present application, the cathode substrate has a fuel gas flow channel, and the anode substrate has an oxidizing gas flow channel.

[0016] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the accompanying drawings, wherein:

[0018] Figure 1 is a schematic diagram of the overall structure of a reversible hydrogen electrochemical cell in an embodiment of the present application.

[0019] Reference signs: 1, cathode substrate; 2, cathode catalyst layer; 3, alkaline composite electrolyte; 4, anode catalyst layer; 5, anode substrate; 6, packaging structure; 7, seal. DETAILED DESCRIPTION

[0020] The embodiments of the present application are described in detail below, which are intended to explain the present application and cannot be understood as a limitation of the present application.

[0021] In one aspect of the present application, the present application proposes a reversible hydrogen electrochemical cell. According to an embodiment of the present application, with reference to Figure 1The reversible hydrogen electrochemical cell comprises a hydrogen electrochemical assembly and a packaging structure 6 for packaging the hydrogen electrochemical assembly, wherein the hydrogen electrochemical assembly comprises: oppositely arranged anode substrate 5 and cathode substrate 1, both of which are porous materials; anode catalyst layer 4 arranged on the surface of the anode substrate 5 close to the cathode substrate 1; cathode catalyst layer 2 arranged on the surface of the cathode substrate 1 close to the anode substrate 5; alkaline composite electrolyte 3 arranged between the anode catalyst layer 4 and the cathode catalyst layer 2, and the alkaline composite electrolyte 3 is a porous structure; the packaging structure 6 has at least one sealing port, and a sealing element 7 is arranged in the sealing port, and the sealing element 7 is used for sealing the sealing port. Therefore, in the reversible hydrogen electrochemical cell, the alkaline composite electrolyte 3 is a porous structure, the anode substrate 5 and the cathode substrate 1 are both porous materials, that is, the alkaline composite electrolyte, the anode substrate and the cathode substrate all have a porous structure, the porous structure can realize the flow of gas and ions, so that the reversible hydrogen electrochemical cell of the application can realize the efficient conversion between electrical energy and chemical energy, can avoid the rapid loss of electrodes and electrolyte at high temperature, and can realize the conversion of electrical energy and chemical energy in a single device. Compared with the split type electrolytic cell and fuel cell, the overall structure is more compact and the cost is more low.

[0022] According to some embodiments of the application, the cathode substrate 1 has a fuel gas flow channel, and the anode substrate 5 has an oxidation gas flow channel. The fuel gas flow channel can be filled with hydrogen, ammonia and the like, so that the reversible hydrogen electrochemical cell can carry out electrochemical reaction on the cathode side under fuel cell working condition; the oxidation gas flow channel can be filled with oxygen, air and the like, so that the reversible hydrogen electrochemical cell can carry out electrochemical reaction on the anode side under fuel cell working condition.

[0023] According to the embodiments of the application, the working process of the reversible hydrogen electrochemical cell includes electrolysis working condition and battery working condition, as follows:

[0024] In the electrolysis working condition of the reversible hydrogen electrochemical cell, water vapor is introduced into the anode and cathode of the reversible hydrogen electrochemical cell, and a voltage is applied to the reversible hydrogen electrochemical cell. Water vapor reacts on the cathode, 2 water molecules combine with 2 electrons to produce 1 hydrogen molecule and 2 hydroxyl anions, and the half reaction is as follows:

[0025] 2H2O+2e - →H2+2OH - ;

[0026] On the anode, 4 hydroxyl anions release 4 electrons and produce 2 water molecules and 1 oxygen molecule, and the half reaction is as follows:

[0027] 4OH - →4e - +O2+2H2O

[0028] In the process of switching from electrolysis mode to fuel cell mode, water vapor is cut off, hydrogen gas is introduced into the cathode side of the reversible hydrogen electrochemical cell, oxygen gas is introduced into the anode side of the reversible hydrogen electrochemical cell, the power supply is disconnected and switched to the load.

[0029] In the fuel cell mode, hydrogen gas is introduced into the cathode side of the reversible hydrogen electrochemical cell, oxygen gas is introduced into the anode side of the reversible hydrogen electrochemical cell, and an external load is applied to the reversible hydrogen electrochemical cell at this time. The amount of hydrogen and oxygen introduced is determined according to the power generation capacity.

[0030] At the cathode, hydrogen gas reacts, with each hydrogen molecule combining with two hydroxyl anions to produce two water molecules and two electrons, with the half-reaction as follows:

[0031] H2+2OH - →2H2O+2e -

[0032] At the anode, oxygen gas reacts, with each oxygen molecule absorbing four electrons and producing four hydroxyl anions, with the half-reaction as follows:

[0033] 4e - +O2+2H2O→4OH -

[0034] In the process of switching from fuel cell mode to electrolysis mode, hydrogen and oxygen are cut off, water vapor is introduced into the anode and cathode of the reversible hydrogen electrochemical cell, and the load is disconnected and switched to the power supply.

[0035] According to some embodiments of the present application, the alkaline composite electrolyte includes a porous framework and a metal compound, the metal compound includes at least one of a metal hydroxide and a metal oxide, and the metal element in the metal compound includes an alkali metal containing at least one of lithium, sodium, potassium, calcium, barium, strontium, and cesium. The porous framework provides a good porous structure for the alkaline composite electrolyte, thereby providing a larger contact area. The metal compound is an alkali metal, which enables the alkaline composite electrolyte to have good performance. The alkaline composite electrolyte serves to separate the anode and cathode and transfer hydroxyl ions in the reversible hydrogen electrochemical cell, and also catalyzes the chemical reaction of the battery, thereby improving the reaction rate and efficiency.

[0036] Among them, the existence mode between the porous skeleton and the metal compound in the alkaline composite electrolyte can include the following two: In some embodiments, the porous skeleton and the metal compound are mixed into one, that is, the metal compound is doped in the porous skeleton. In the preparation process, the preparation process of the alkaline composite electrolyte of this structure includes: mixing the porous skeleton and the metal compound evenly, and sintering to obtain an alkaline composite electrolyte of an integrated structure. In other embodiments of the present invention, the metal compound is attached to the pore surface of the porous skeleton. In the preparation process, the preparation process of the alkaline composite electrolyte of this structure includes: placing the porous skeleton in a molten metal compound melt or in a metal compound aqueous solution to be immersed, so that the metal compound is adsorbed on the pore surface of the porous skeleton; cooling and solidifying at room temperature to obtain an alkaline composite electrolyte. The alkaline composite electrolyte of the above structure has good structural stability, and can still maintain structural stability during the long-term use of the battery, while allowing the alkaline composite electrolyte to achieve a better use effect.

[0037] In some embodiments of the present invention, the porous framework comprises at least one of an organic material such as polytetrafluoroethylene, polyetheretherketone, polybenzimidazole, polyphenylene sulfide, and polyimide, and a ceramic material such as zirconium oxide, nickel oxide, potassium titanate, strontium titanate, and zirconium titanate. As a result, the alkaline composite electrolyte with the porous framework of the aforementioned materials has excellent stability, is not easily corroded during long-term battery use, and can provide a well-formed porous structure, thereby facilitating the conversion of electrical energy into chemical energy in a single device.

[0038] According to some embodiments of the present invention, the alkaline composite electrolyte with the aforementioned structure and material can effectively protect the reversible hydrogen electrochemical cell based on the alkaline composite electrolyte of the present invention at temperatures between 170°C and 400°C for electrochemical synthesis of hydrogen, oxygen, and other products, as well as the electrochemical conversion of hydrogen, oxygen, and other fuels with combustion aids for generating various types of DC and AC power. Specifically, under the action of an electric field, the directional migration of hydroxide anions in molten metal hydroxide at temperatures between 170°C and 400°C enables ion transport, and electrochemical reactions occur at the cathode and anode under the action of the electric potential, achieving water electrolysis and hydrogen-oxygen combination reactions. In molten metal hydroxide at temperatures between 170°C and 400°C, hydroxide anions migrate from the cathode to the anode under the action of the electric field. Temperatures below 170°C reduce the conductivity of the alkaline composite electrolyte and may cause local solidification of the alkaline composite electrolyte, affecting the gas barrier performance of the battery. Temperatures above 400°C may damage the seal and increase electrode attenuation, potentially leading to rapid battery failure in a strong alkaline environment.

[0039] According to some embodiments of the present invention, the materials of the cathode substrate and the anode substrate independently include at least one of foamed nickel, foamed platinum, foamed palladium, foamed stainless steel, titanium felt, platinum felt, palladium felt, Raney nickel, and carbon paper. Thus, the cathode substrate and the anode substrate made of the above materials can provide good gas flow channels for the cathode substrate and the anode substrate, respectively, and the above materials have good alkali resistance and are not prone to corrosion during the use of the battery. In some specific embodiments, the cathode substrate and the anode substrate can respectively use nickel-based or titanium-based alloy plates with flow channels that are stamped or milled. Thus, the passage of gas and liquid flow is ensured.

[0040] According to some embodiments of the present invention, the cathode catalyst layer and the anode catalyst layer each independently include at least one of a single metal, a metal alloy, a metal oxide, a metal sulfide, and / or a metal hydroxide, wherein the metal includes at least one of nickel, palladium, platinum, iridium, ruthenium, gold, silver, copper, and iron. Thus, catalysts of the aforementioned materials can effectively promote the reaction and improve battery efficiency.

[0041] In some embodiments of the present invention, the method for preparing the catalyst layer may be: by using electrodeposition or hydrothermal synthesis in a catalyst precursor solution to make the catalyst adhere to the surface of the cathode substrate and / or anode substrate, thereby forming a catalyst layer; in other embodiments of the present invention, the method for preparing the catalyst layer may be: preparing the catalyst alloy material into an independent or porous catalytic layer attached to the surface of the cathode substrate and / or anode substrate by casting or solid powder additive manufacturing technology or impregnation slurry method or vapor deposition.

[0042] According to some embodiments of the present invention, the packaging structure includes a metal flow field plate and / or a graphite flow field plate, wherein the metal in the metal flow field plate includes at least one of nickel, palladium, platinum, iridium, ruthenium, gold, silver, copper and iron. As a result, the packaging structure of the above materials has good sealing performance and is not easy to react with the solution inside the battery, thereby improving the overall safety of the battery. In some embodiments, the packaging structure can be obtained by metal milling or metal / graphite additive manufacturing or stamping. In some embodiments of the present invention, the packaging structure is provided with a gas flow channel, and the gas enters the cathode substrate and the anode substrate from both sides of the packaging structure close to the cathode substrate and the anode substrate to generate an electrochemical reaction.

[0043] According to some embodiments of the present invention, the sealing member is at least one of a polytetrafluoroethylene sealing sheet, a perfluoroether rubber sealing sheet, and a dense ceramic sealing sheet. Therefore, the sealing member made of the above materials has a good sealing effect. In some embodiments of the present invention, the sealing member can be formed by stamping and shearing. According to one embodiment of the present invention, the sealing member does not have an air intake capability and is a component that seals between the two sides of the packaging structure to ensure that no gas leakage occurs.

[0044] The present invention is described below with reference to specific examples. It should be noted that these examples are merely illustrative and do not limit the present invention in any way.

[0045] Example

[0046] Example 1

[0047] A set of clamps are used to sequentially clamp and assemble a cathode substrate with a cathode catalyst layer attached thereto, an alkaline composite electrolyte, an anode catalyst layer with an anode substrate attached thereto, a packaging component, and a seal to obtain a reversible hydrogen electrochemical cell, wherein the clamps are made of nickel-containing stainless steel or titanium alloy with a nickel, gold, or silver coating on the surface; the cathode substrate and the anode substrate are both made of foamed nickel; the cathode catalyst layer and the anode catalyst layer are both made of palladium; the alkaline composite electrolyte is made of a porous zirconium oxide skeleton, and barium hydroxide is attached to the surface of the porous skeleton after melting; and the packaging component and the seal are both made of polytetrafluoroethylene.

[0048] The resulting reversible hydrogen electrochemical cell is heated to 170°C to 250°C and an operating pressure of 0.1MPa-10MPa. Saturated water vapor is introduced into the cathode and anode substrates at the operating pressure and electricity is applied to achieve electrolysis. After a period of electrolysis, the water vapor injection is stopped, hydrogen is introduced into the cathode substrate side, and oxygen is introduced into the anode substrate side. The power supply is disconnected and switched to the load to achieve fuel cell power generation. During the switch from battery operation to electrolysis operation, the hydrogen and oxygen supply is stopped, and water vapor is introduced into the anode and cathode of the device. The load is disconnected and switched to the power supply.

[0049] The performance of the battery in Example 1 can be verified by electrochemical impedance spectroscopy and volt-ampere characteristic tests using an electrochemical workstation. The test results show that when producing and using pure hydrogen and pure oxygen, the ohmic impedance at 170°C to 250°C is no more than 0.1Ω·cm in the electrolysis mode. 2 , 1000mA·cm -2 The electrolysis voltage is below 1.8V; in fuel cell mode, its ohmic impedance at 170℃~250℃ is not greater than 0.1Ω·cm 2 , 1000mA·cm -2 The power generation voltage is above 0.64 V. This shows that the reversible hydrogen electrochemical cell in Example 1 has good electrolysis mode and fuel cell mode, which means that the reversible hydrogen electrochemical cell of the present invention has good working performance and can effectively realize the conversion of electrical energy and chemical energy in a single device.

[0050] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0051] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A reversible hydrogen electrochemical cell, characterized in that The invention comprises a hydrogen electrochemical component and a packaging structure for packaging the hydrogen electrochemical component, wherein: The hydrogen electrochemical component comprises: An anode substrate and a cathode substrate are arranged opposite to each other, and both the anode substrate and the cathode substrate are made of porous materials; an anode catalyst layer, the anode catalyst layer being disposed on a surface of the anode substrate close to the cathode substrate; a cathode catalyst layer, the cathode catalyst layer being disposed on a surface of the cathode substrate close to the anode substrate; an alkaline composite electrolyte, wherein the alkaline composite electrolyte is disposed between the anode catalyst layer and the cathode catalyst layer, and the alkaline composite electrolyte has a porous structure; The packaging structure has at least one sealing opening, in which a sealing member is provided, and the sealing member is used to seal the sealing opening.

2. The reversible hydrogen electrochemical cell according to claim 1, characterized in that The alkaline composite electrolyte includes a porous skeleton and a metal compound, the metal compound includes at least one of a metal hydroxide and a metal oxide, and the metal element of the metal compound includes at least one of lithium, sodium, potassium, calcium, barium, strontium, and cesium.

3. The reversible hydrogen electrochemical cell according to claim 2, characterized in that In the alkaline composite electrolyte, the porous skeleton and the metal compound are mixed into one, or the metal compound is attached to the pore surfaces of the porous skeleton.

4. The reversible hydrogen electrochemical cell according to claim 2, characterized in that The material of the porous skeleton includes at least one of polytetrafluoroethylene, polyetheretherketone, polybenzimidazole, polyphenylene sulfide, polyimide, zirconium oxide, nickel oxide, potassium titanate, strontium titanate, and zirconium titanate.

5. The reversible hydrogen electrochemical cell according to claim 1, characterized in that The materials of the cathode substrate and the anode substrate independently include at least one of foamed nickel, foamed platinum, foamed palladium, foamed stainless steel, titanium felt, platinum felt, palladium felt, Raney nickel and carbon paper.

6. The reversible hydrogen electrochemical cell according to claim 1, characterized in that The cathode catalyst layer and the anode catalyst layer independently include at least one of a metal element, an alloy of the metal, an oxide of the metal, a sulfide of the metal and / or a hydroxide of the metal, wherein the metal includes at least one of nickel, palladium, platinum, iridium, ruthenium, gold, silver, copper and iron.

7. The reversible hydrogen electrochemical cell according to claim 1, characterized in that The packaging structure includes a metal flow field plate and / or a graphite flow field plate, wherein the metal in the metal flow field plate includes at least one of nickel, palladium, platinum, iridium, ruthenium, gold, silver, copper and iron.

8. The reversible hydrogen electrochemical cell according to claim 1, characterized in that The sealing element is at least one of a polytetrafluoroethylene sealing sheet, a perfluoroether rubber sealing sheet and a dense ceramic sealing sheet.

9. The reversible hydrogen electrochemical cell according to claim 3, characterized in that The preparation process of the alkaline composite electrolyte comprises: uniformly mixing the porous skeleton and the metal compound, and sintering to obtain the alkaline composite electrolyte; Alternatively, the preparation process of the alkaline composite electrolyte includes: placing the porous skeleton in a molten metal compound solution or infiltrating it in a metal compound aqueous solution so that the metal compound is adsorbed on the pore surface of the porous skeleton; cooling and solidifying at room temperature to obtain the alkaline composite electrolyte.

10. The reversible hydrogen electrochemical cell according to claim 1, characterized in that The cathode substrate has a fuel gas flow channel, and the anode substrate has an oxidizing gas flow channel.

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