Reversible hydrogen electrochemical cell

Abstract

Reversible hydrogen electrochemical cells are presented. The reversible hydrogen electrochemical cell comprises a hydrogen electrochemical assembly and a packaging structure, the hydrogen electrochemical assembly comprises an anode substrate and a cathode substrate which are oppositely arranged, and the anode substrate and the cathode substrate are both made of porous materials; the anode catalyst layer is arranged on the surface, close to the cathode substrate, of the anode substrate; the cathode catalyst layer is arranged on the surface, close to the anode substrate, of the cathode substrate; the alkaline composite electrolyte is arranged between the anode catalyst layer and the cathode catalyst layer and is of a porous structure; the packaging structure is provided with at least one sealing opening, and the sealing piece 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 electrolyte 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 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 continuous expansion of industrialization, human society has significantly increased its use of traditional fossil energy, resulting in a series of climate problems such as greenhouse gas emissions. The large-scale use of renewable energy such as wind power, photovoltaic power and hydropower is crucial to the long-term stable and sustainable development of my country's social economy and the construction of ecological civilization, but the electricity generated by them naturally has strong temporal volatility and spatial dependence. It is necessary to efficiently convert 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 devices 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 device 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 solve at least one of the technical problems in the related art to a certain extent. 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, can avoid rapid loss of electrodes and electrolytes at high temperatures, or can achieve conversion between electrical energy and chemical energy 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, 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 arranged in the sealing port, and the sealing member is used to seal the sealing port. As a result, the above-mentioned reversible hydrogen electrochemical cell can realize the efficient conversion between electrical energy and chemical energy, can avoid the rapid loss of electrodes and electrolytes at high temperatures, can realize the conversion of electrical energy and chemical energy in a single device, and has the advantages of more compact overall structure and lower cost compared with 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 as one, or the metal compound is attached to the pore surfaces in 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 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.

[0013] According to an embodiment of the present invention, the sealing element is at least one of a polytetrafluoroethylene sealing sheet, a perfluoroether rubber sealing sheet and a dense ceramic sealing sheet.

[0014] According to an embodiment of the present invention, the preparation process of the alkaline composite electrolyte includes: uniformly mixing the porous skeleton and the metal compound, and sintering to obtain the alkaline composite electrolyte; or, 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.

[0015] According to an embodiment of the present invention, 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 invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0018] Figure 1 Schematic diagram of the overall structure of the reversible hydrogen electrochemical cell in an embodiment of the present invention.

[0019] Figure numerals: 1 cathode substrate; 2 cathode catalyst layer; 3 alkaline composite electrolyte; 4 anode catalyst layer; 5 anode substrate; 6 packaging structure; 7 sealing member. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below, which are intended to explain the present invention but should not be construed as limiting the present invention.

[0021] In one aspect of the present invention, the present invention provides a reversible hydrogen electrochemical cell. According to an embodiment of the present invention, referring to Figure 1The reversible hydrogen electrochemical cell comprises a hydrogen electrochemical component and a packaging structure 6 for packaging the hydrogen electrochemical component, wherein the hydrogen electrochemical component comprises: an anode substrate 5 and a cathode substrate 1 arranged opposite to each other, both of which are porous materials; an anode catalyst layer 4, the anode catalyst layer 4 is arranged on the surface of the anode substrate 5 close to the cathode substrate 1; a cathode catalyst layer 2, the cathode catalyst layer 2 is arranged on the surface of the cathode substrate 1 close to the anode substrate 5; an alkaline composite electrolyte 3, the alkaline composite electrolyte 3 is 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, a sealing member 7 is arranged in the sealing port, and the sealing member 7 is used to seal the sealing port. Therefore, in the above-mentioned reversible hydrogen electrochemical cell, the alkaline composite electrolyte 3 is a porous structure, and 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 pore structure, and the porous structure can realize the circulation of gas and ions. In this way, the reversible hydrogen electrochemical cell of the present invention can realize the efficient conversion between electrical energy and chemical energy, can avoid the rapid loss of electrodes and electrolytes at high temperatures, can realize the 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.

[0022] According to some embodiments of the present invention, 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 fed with hydrogen, ammonia, etc., so as to reversibly react the cathode side of the hydrogen electrochemical cell under the working condition of the fuel cell; the oxidation gas flow channel can be fed with oxygen, air, etc., so as to reversibly react the anode side of the hydrogen electrochemical cell under the working condition of the fuel cell.

[0023] According to an embodiment of the present invention, the working process of the reversible hydrogen electrochemical cell includes an electrolysis condition and a battery condition, which are specifically as follows:

[0024] Under the electrolysis condition of the reversible hydrogen electrochemical cell: water vapor is introduced into the anode and cathode of the reversible hydrogen electrochemical cell, and voltage is applied to the reversible hydrogen electrochemical cell. Water vapor reacts at the cathode, and every two water molecules combine with two electrons to produce one hydrogen molecule and two hydroxyl anions. The half reaction is as follows:

[0025] 2H2O+2e - →H2+2OH - ;

[0026] Water vapor reacts at the anode, and every 4 hydroxyl anions release 4 electrons and produce 2 water molecules and 1 oxygen molecule. The half reaction is as follows:

[0027] 4OH - →4e - +O2+2H2O

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

[0029] The reversible hydrogen electrochemical cell is under fuel cell operating conditions: hydrogen is introduced into the cathode side of the reversible hydrogen electrochemical cell, and oxygen is introduced into the anode side of the reversible hydrogen electrochemical cell. At this time, the reversible hydrogen electrochemical cell is loaded, and the amount of hydrogen and oxygen introduced is determined according to the power generation.

[0030] Hydrogen reacts at the cathode, and each hydrogen molecule combines with two hydroxyl anions to produce two water molecules and two electrons. The half-reaction is as follows:

[0031] H2+2OH - →2H2O+2e -

[0032] Oxygen reacts at the anode, with each oxygen molecule absorbing 4 electrons with 2 water molecules and producing 4 hydroxyl anions. The half-reaction is as follows:

[0033] 4e - +O2+2H2O→4OH -

[0034] During the switch from dye cell operation to electrolysis operation, 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 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 in the metal compound includes an alkali metal containing at least one of lithium, sodium, potassium, calcium, barium, strontium, and cesium. The porous skeleton provides a good porous structure for the alkaline composite electrolyte, thereby making it have a large contact area, and the metal compound is an alkali metal, so that the alkaline composite electrolyte has good performance, and the alkaline composite electrolyte plays the role of isolating the cathode and anode and transferring hydroxide 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 may include the following two: In some embodiments, the porous skeleton and the metal compound are mixed as 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: the porous skeleton and the metal compound are mixed evenly, and sintered to obtain an alkaline composite electrolyte of an integrated structure. In some 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 infiltrate, 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 exert a better use effect.

[0037] In some embodiments of the present invention, the material of the porous skeleton includes at least one of organic materials such as polytetrafluoroethylene, polyetheretherketone, polybenzimidazole, polyphenylene sulfide, polyimide, and ceramic materials such as zirconium oxide, nickel oxide, potassium titanate, strontium titanate, and zirconium titanate. As a result, the alkaline composite electrolyte of the porous skeleton of the above materials has better stability, is not easily corroded during long-term use of the battery, and can provide a good porous structure, which helps to achieve the technical effect of converting electrical energy into chemical energy in a single device.

[0038] According to some embodiments of the present invention, the alkaline composite electrolyte of the above structure and material can effectively protect the reversible hydrogen electrochemical cell based on the alkaline composite electrolyte of the present invention between 170 and 400 ° C for the electrochemical synthesis of hydrogen, oxygen and other products and the electrochemical conversion of hydrogen, oxygen and other fuels and combustion aids for generating various types of DC and AC power. Specifically: the directional movement of hydroxide anions in molten metal hydroxides at 170 ° C to 400 ° C under the action of the electric field can realize ion transport, and electrochemical reactions occur at the cathode and anode under the action of the electric potential to realize the electrolysis of water and the combination of hydrogen and oxygen. In molten metal hydroxides at 170 ° C to 400 ° C, hydroxide anions move from the cathode to the anode under the action of the electric field. Among them, if the temperature is lower than 170 ° C, the conductivity of the alkaline composite electrolyte will be reduced, and the alkaline composite electrolyte may be partially solidified, affecting the gas barrier performance of the battery; if the temperature is higher than 400 ° C, the seal may be damaged, and the electrode attenuation is enhanced, which may cause the battery to be rapidly damaged 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 easy to be corroded during the use of the battery. In some specific embodiments, the cathode substrate and the anode substrate can respectively use stamping or milling nickel-based or titanium-based alloy plates with flow channels. Thus, the passage of gas and liquid flow is guaranteed.

[0040] According to some embodiments of the present invention, the cathode catalyst layer and the anode catalyst layer independently include at least one of a metal element, 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, the catalyst of the above materials can effectively promote the reaction and improve the 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 the 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 catalyst layer attached to the surface of the cathode substrate and / or the 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, 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 seal is at least one of a polytetrafluoroethylene sealing sheet, a perfluoroether rubber sealing sheet and a dense ceramic sealing sheet. Therefore, the sealing effect of the seal of the above materials is good. In some embodiments of the present invention, the seal can be obtained by stamping and shearing. According to one embodiment of the present invention, the seal does not have the ability to intake air, and it 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 embodiments. It should be noted that these embodiments 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 clamp and assemble the cathode substrate and the cathode catalyst layer attached thereto, the alkaline composite electrolyte, the anode catalyst layer and the anode substrate attached thereto, the packaging component and the seal in sequence to obtain a reversible hydrogen electrochemical cell, wherein the clamp is 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 zirconium oxide porous skeleton, and barium hydroxide is attached to the surface of the porous skeleton after melting; the packaging component and the seal are both made of polytetrafluoroethylene.

[0048] The obtained reversible hydrogen electrochemical cell is heated to 170℃~250℃, with a working pressure of 0.1MPa-10MPa, and saturated water vapor is introduced into the cathode substrate and the anode substrate under the working pressure and powered on to realize electrolysis. After a period of electrolysis, the water vapor injection is stopped, hydrogen is introduced into the cathode substrate side, oxygen is introduced into the anode substrate side, the power supply is disconnected and switched to the load, and fuel cell power generation is realized. In the process of switching from the battery operating condition to the electrolysis operating condition, the introduction of hydrogen and oxygen 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 working performance of the battery in Example 1 can be verified by using an electrochemical workstation to perform electrochemical impedance spectroscopy and volt-ampere characteristic tests. The test results show that when producing and using pure hydrogen and pure oxygen, in the electrolysis mode, its ohmic impedance at 170°C to 250°C is not greater than 0.1Ω·cm 2 , 1000mA·cm -2 The electrolysis voltage is below 1.8V; in the 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. It can be seen 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 description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0051] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary 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, a sealing member is arranged in the sealing opening, 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 together, or the metal compound is attached to the pore surfaces in 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 in a metal compound aqueous solution for immersion, 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 oxidant gas flow channel.

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