Integrated gas-liquid thermal management structure and electrolytic cell for all-gas-phase co2 reduction

Abstract

The application relates to the technical field of electro-catalysis, and particularly relates to an integrated gas-liquid heat management structure and an electrolytic cell for full-gas-phase CO2 reduction. The integrated gas-liquid heat management structure comprises a plurality of structural units, each of the structural units comprises, in sequence, an anode assembly, a solid-state electrolyte separator and a cathode assembly, the solid-state electrolyte separator is provided with a plurality of through holes on a peripheral side, and the through holes are used for discharging regenerated gas and liquid in the operation process of the electrolytic cell; a plurality of metal bipolar plates are arranged between two adjacent structural units, the anode side and the cathode side of the metal bipolar plate are respectively attached to the anode assembly and the cathode assembly in the adjacent structural units, and the metal bipolar plate is provided with a plurality of cooling flow channels for discharging heat generated in the operation process of the electrolytic cell. The integrated gas-liquid heat management structure integrates the cooling flow channels and the gas-liquid management structure in the membrane electrode structure, constructs a highly integrated and collaborative management platform, and can realize precise gas-liquid heat management.

Description

Technical Field

[0001] This invention relates to the field of electrocatalysis technology, specifically to an integrated gas-liquid thermal management structure and electrolytic cell for the reduction of CO2 in the entire gas phase. Background Technology

[0002] Electrochemical CO2 reduction reaction (CO2RR) is an important green technology for converting CO2 into high-value-added chemicals. Membrane electrode electrolyzers (MEEs) employing all-gas-phase feed (CO2 at the cathode, H2 at the anode) can avoid problems such as salting out associated with liquid electrolytes, making them a current research hotspot. These electrolyzers typically utilize a composite MEE structure consisting of an anode catalyst layer, a proton exchange membrane, a solid electrolyte layer, an anion exchange membrane, and a cathode catalyst layer. However, this battery faces severe challenges in gas-liquid thermal management during operation. Overpotentials in the electrode reactions and ohmic impedance during ion migration generate Joule heating, leading to self-heating of the battery. If this heat cannot be dissipated in time, the cell operating temperature will rise significantly, accelerating the evaporation of critical moisture, causing the solid electrolyte layer and ion exchange membrane to dry out, resulting in a sharp decrease in ionic conductivity, a surge in cell voltage, and even membrane perforation failure, ultimately affecting the electrolyzer performance. Furthermore, uneven temperature distribution can also lead to localized reaction rate differences, affecting product selectivity and battery life. Building upon the challenges of thermal management, the cathode carbon dioxide reduction reaction produces liquid and gaseous products that are difficult to remove effectively in the gaseous environment, easily accumulating and clogging reactive sites, thus reducing efficiency. Simultaneously, the anodic hydroxide reaction requires maintaining a proper moisture balance to prevent the proton exchange membrane from drying out. Therefore, the coordinated management of the gas, liquid, and heat transfer processes becomes a key challenge.

[0003] Existing technologies largely rely on external cooling plates or heat sinks, treating gas path management, liquid discharge, and thermal management as independent issues. This results in complex systems, slow response times, a lack of holistic solutions, and difficulty in precise temperature control. Furthermore, existing gas-liquid thermal management schemes designed by borrowing cooling methods from traditional electrolyzers or fuel cells have significant shortcomings. For example, external cooling and fragmented gas-liquid management schemes typically suffer from high thermal resistance, low heat dissipation efficiency, large size, and difficulty in coordinated control. Passive thermal management and simplified gas-liquid management schemes have limited and uncontrollable cooling and gas-liquid management capabilities, making it difficult to meet the requirements of all-gas phase CO2RR electrolyzers with high requirements for hydrothermal balance. Therefore, a highly efficient and compact thermal management scheme is urgently needed to address these problems. Summary of the Invention

[0004] The purpose of this invention is to provide an integrated gas-liquid thermal management structure for all-gas phase CO2 reduction. By integrating thermal management and gas-liquid management structures inside the membrane electrode structure, precise gas-liquid thermal management is achieved, solving the problems of complex structure and slow response of existing management systems.

[0005] The present invention also provides an electrolytic cell that does not require additional cooling plates and external gas-liquid management units, and can achieve higher power output within a limited space.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an integrated gas-liquid thermal management structure for all-gas-phase CO2 reduction, comprising: Multiple structural units, each of which includes an anode assembly, a solid electrolyte separator, and a cathode assembly arranged in sequence. The solid electrolyte separator has multiple through holes on its periphery for discharging the gas and liquid regenerated during the operation of the electrolytic cell. Multiple metal bipolar plates are provided, each of which is disposed between two adjacent structural units. The anode side and cathode side of the metal bipolar plate are respectively attached to the anode assembly and the cathode assembly in the adjacent structural unit. Multiple cooling channels are provided inside the metal bipolar plate, and the multiple cooling channels penetrate the metal bipolar plate along the width or length direction of the metal bipolar plate to discharge the heat generated during the operation of the electrolytic cell.

[0007] Furthermore, the solid electrolyte separator includes a separator frame and a solid electrolyte filling layer made of solid electrolyte particles. The separator frame is sleeved on the periphery of the solid electrolyte filling layer, and the separator frame is provided with a through hole that penetrates the separator frame along the width or length direction.

[0008] Furthermore, the particle size of the solid electrolyte particles is any value between 50μm and 500μm, and the porosity of the solid electrolyte filling layer is any value between 30% and 70%, in order to maintain ideal gas-liquid balance and stabilize the cell voltage.

[0009] Furthermore, the anode assembly sequentially includes an anode gas diffusion layer, an anode catalyst layer, and a cation exchange membrane, wherein the cation exchange membrane is bonded to the solid electrolyte separator; The cathode assembly comprises, in sequence, an anion exchange membrane, a cathode catalyst layer, and a cathode gas diffusion layer, wherein the anion exchange membrane is bonded to the solid electrolyte separator.

[0010] Furthermore, grooves are provided on the anode side and cathode side of the metal bipolar plate, so that a reaction gas flow channel is formed between the anode side of the metal bipolar plate and the anode gas diffusion layer attached thereto, and between the cathode side of the metal bipolar plate and the cathode gas diffusion layer attached thereto.

[0011] Furthermore, the depth of the trench gradually increases along the flow direction of the reactant gas to enhance the mass transfer effect.

[0012] Furthermore, the grooves on the metal bipolar plate are aligned or staggered with the cooling channels inside them.

[0013] Furthermore, the shape of the cooling channel includes any one or more of the following: straight parallel channel, serpentine channel, and cross channel.

[0014] This application also provides an electrolytic cell, which includes two end plate assemblies and the aforementioned integrated gas-liquid thermal management structure. The integrated gas-liquid thermal management structure is disposed between the two end plate assemblies. Each end plate assembly includes an end plate and a conductive plate disposed on the inner side of the end plate. An air inlet and an air outlet are provided on the end plate.

[0015] Furthermore, the metal bipolar plate is also provided between the end plate assembly and the structural unit.

[0016] The beneficial effects of this invention are as follows: The integrated gas-liquid thermal management structure provided in this application integrates the cooling channel with the gas-liquid management structure within its membrane electrode structure, constructing a highly integrated and collaborative management platform to achieve precise gas-liquid thermal management. Specifically, in terms of gas-liquid management, the transport paths of gaseous reactants and liquid products are controlled through the porous structure and through-holes on the solid electrolyte separator, effectively discharging gaseous and liquid products and preventing membrane drying. In terms of thermal management, by integrating the cooling channel within the metal bipolar plate structure, it is directly and tightly coupled to the reaction zone, utilizing the efficient heat exchange effect to rapidly remove the large amount of heat generated during the reaction. This precise gas-liquid thermal management method significantly improves the stability and operating efficiency of the electrolyzer, contributing to its long-term stable operation.

[0017] Through its integrated structural design, this integrated gas-liquid thermal management structure responds more rapidly to the heat of reaction, thereby facilitating precise temperature control and preventing performance degradation due to temperature fluctuations. Simultaneously, by regulating the characteristics and perforations of the pore structure on the solid electrolyte separator, gas diffusion, liquid product discharge, and moisture retention are optimized. This fundamentally avoids the problems of membrane electrode drying or flooding, ensuring long-term stable operation of the electrolyzer and significantly improving the reliability and service life of the equipment.

[0018] By integrating cooling channels within the metal bipolar plate structure, efficient thermal management can be achieved while maintaining good hydration of the ion exchange membrane, ensuring smooth ion conduction and significantly improving the electrochemical performance of the electrolytic cell. The controllable pore structure and perforations on the solid electrolyte separator can also create an optimal local microenvironment for the reaction, promoting reaction progress while helping to reduce cell pressure and energy loss. Furthermore, by controlling the pore structure and perforations on the solid electrolyte separator, the selectivity of the target product can potentially be improved, enhancing the economic efficiency of the reaction.

[0019] The electrolytic cell provided in this application eliminates the need for a separate cooling plate and external gas-liquid management unit, significantly reducing its overall volume and weight. This results in a substantial increase in both volumetric and gravimetric power density, enabling higher power output within a limited space. Furthermore, the pore structure of the solid electrolyte separator can be flexibly designed and adjusted to meet the specific gas-liquid environment requirements of different CO2 reduction systems, giving the electrolytic cell excellent adaptability to meet the needs of various application scenarios. Moreover, the integrated structure allows for the collaborative design of the microstructures of the cooling channels, gas channels, and solid electrolyte separator. This collaborative design enables the synergistic enhancement of mass transfer, heat transfer, and reaction microenvironment control. It solves the problem of mutual constraints among management units in existing discrete solutions, allowing the entire system to operate more efficiently and improving the overall performance of the reaction.

[0020] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of an integrated gas-liquid thermal management structure according to an embodiment of the present invention; Figure 2 This is a physical image of a metal bipolar plate according to an embodiment of the present invention; Figure 3 This is a three-dimensional structural schematic diagram of a partition frame according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an electrolytic cell according to an embodiment of the present invention; Figure 5 This is a gas chromatogram of the gas discharged from the cathode outlet as shown in Embodiment 1 of the present invention. Figure label: 10. Structural Unit; 1. Anode Assembly; 11. Anode Gas Diffusion Layer; 12. Anode Catalyst Layer; 13. Cation Exchange Membrane; 2. Cathode Assembly; 21. Cathode Gas Diffusion Layer; 22. Cathode Catalyst Layer; 23. Anion Exchange Membrane; 3. Solid Electrolyte Separator; 31. Separator Frame; 32. Solid Electrolyte Filling Layer; 33. Through Hole; 4. Metal Bipolar Plate; 41. Cooling Channel; 42. Groove; 5. End Plate Assembly; 51. End Plate; 52. Conductive Plate; 53. Air Inlet; 54. Air Outlet. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] Please see Figure 1This application discloses an integrated gas-liquid thermal management structure for all-gas phase CO2 reduction, comprising multiple structural units 10 and multiple metal bipolar plates 4, according to a preferred embodiment. Each structural unit 10 includes an anode assembly 1, a solid electrolyte separator 3, and a cathode assembly 2 arranged sequentially. The solid electrolyte separator 3 has multiple through holes 33 on its periphery, which are used to promptly discharge regenerated gas and liquid during electrolysis, ensuring the stability of the internal environment of the electrolysis cell. Each metal bipolar plate 4 is disposed between two adjacent structural units 10, with its anode and cathode sides respectively in contact with the anode assembly 1 and cathode assembly 2 in the adjacent structural unit 10 to ensure effective current conduction. Multiple cooling channels 41 are provided within the metal bipolar plate 4, such as... Figure 2 As shown, these cooling channels 41 all penetrate the metal bipolar plate 4 along its width or length. During the operation of the electrolytic cell, the cooling channels 41 serve as heat transfer channels, providing a stable flow path for the cooling medium. As the cooling medium circulates within the channels, it efficiently exchanges heat with the heat generated inside the electrolytic cell, rapidly carrying away the heat and preventing heat accumulation inside the cell. This effectively maintains a stable temperature within the electrolytic cell, ensuring the electrolytic reaction proceeds efficiently under suitable temperature conditions. In this embodiment, thermal management and gas-liquid management are deeply integrated with the membrane electrode structure. In terms of thermal management, the cooling channel 41 is integrated into the bipolar plate structure to achieve microscopic tight coupling with the reaction zone, making thermal management more efficient and the structure more compact. In terms of gas-liquid management, a solid electrolyte separator 3 is set between the cathode assembly 2 and the anode assembly 1. By setting through holes 33 on the periphery of the solid electrolyte separator 3 and combining it with the pore structure in the central region of the solid electrolyte separator 3, the transport path and balance of gaseous reactants and liquid products are actively regulated, while the regenerated gas and liquid are effectively discharged, providing more precise gas-liquid environment control for the all-gas phase CO2 reduction reaction.

[0027] In one embodiment, the solid electrolyte separator 3 includes a separator frame 31 and a solid electrolyte filling layer 32 filled with solid electrolyte particles. The solid electrolyte filling layer 32, as the core functional part of the solid electrolyte separator 3, allows for flexible adjustment of the particle size, filling density, and distribution of its solid electrolyte particles according to actual needs. By controlling these parameters, a pore network with specific size and distribution characteristics can be formed within the solid electrolyte filling layer 32, thereby creating and maintaining the most suitable gas-liquid microenvironment for different all-gas phase CO2 reduction reaction systems. Simultaneously, this customizable pore network design allows the formed pore network to be specifically designed according to the characteristics of the gas to be reduced; for example, when using larger-diameter solid electrolyte particles, the larger pores facilitate rapid gas and liquid transport, helping to improve reaction efficiency; when using smaller-diameter solid electrolyte particles, the smaller pores can better retain moisture while facilitating the export of liquid products, providing a suitable humidity environment for the reaction. The separator frame 31 is fitted around the periphery of the solid electrolyte filling layer 32, providing stable mechanical support and structural constraints for the entire solid electrolyte separator 3. like Figure 3 As shown, the partition frame 31 is provided with through holes 33 extending through the partition frame along its width or length, providing a flow channel for the gas and liquid generated during the operation of the electrolytic cell, effectively promoting the discharge of gas and liquid generated in the solid electrolyte filling layer 32. In this embodiment or other embodiments, the particle size of the solid electrolyte particles is preferably any value between 50μm and 500μm to adapt to the different requirements of gas phase diffusion and liquid product discharge for different carbon dioxide reduction product systems. Simultaneously, when the particle size of the solid electrolyte particles is within this range, the porosity of the solid electrolyte filling layer 32 can be controlled to stably maintain it within the range of 30%-70%. Under this porosity condition, the gas-liquid balance inside the electrolytic cell can be effectively maintained, providing a stable and suitable reaction environment for the carbon dioxide reduction reaction, thereby ensuring that the cell voltage remains stable and ensuring the reliability and efficiency of the entire electrolysis process. Regarding the material selection of the solid electrolyte particles, DOWEX 50W×8 hydrogen-type resin can be used, or other ion exchange resins or solid acid materials with proton conductivity can be selected. It is important to clarify that different materials differ in key characteristics such as exchange capacity, particle size, and stability, and these characteristics directly affect ion conduction efficiency and carbon dioxide regeneration rate. Therefore, in practical applications, appropriate solid electrolyte particle materials should be selected based on specific usage requirements and a comprehensive consideration of various factors to ensure optimal system performance.

[0028] In one embodiment, the anode assembly 1 sequentially includes an anode gas diffusion layer 11, an anode catalyst layer 12, and a cation exchange membrane 13 (i.e., a proton exchange membrane). The cation exchange membrane 13 is tightly adhered to one side surface of the solid electrolyte separator 3, ensuring the continuity and stability of the ion transport path. The cathode assembly 2 sequentially includes an anion exchange membrane 23, a cathode catalyst layer 22, and a cathode gas diffusion layer 21; the anion exchange membrane 23 is tightly adhered to the other side surface of the solid electrolyte separator 3, thereby constructing a complete and efficient electrochemical structure, providing a structural basis for the smooth progress of the electrolysis reaction. In this embodiment and other embodiments, the cathode gas diffusion layer 21 and the anode gas diffusion layer 11 can be made of carbon paper, carbon cloth, or foamed metal materials, such as nickel foam or copper foam. These materials typically have higher porosity and mechanical strength, which facilitates gas transport and diffusion. In addition to Nafion series membranes, other perfluorosulfonic acid membranes can be used for cation exchange membrane 13; in addition to Sustainion series membranes, other polymer membranes or porous membranes with cationic functional groups can be used for anion exchange membrane 23. The cathode silver catalyst can be copper-based, bismuth-based, or zinc-based, or other metal or molecular catalysts with carbon dioxide reduction activity. Using copper-based catalysts promotes the formation of multi-carbon products, while using bismuth-based catalysts promotes the formation of formic acid. Provided the purity of the hydrogen supply is ensured, low-platinum or non-platinum catalysts can be used for the anode platinum-based catalyst to reduce costs.

[0029] In one embodiment, grooves 42 are provided on both the anode and cathode sides of the metal bipolar plate 4. When the anode side of the metal bipolar plate 4 is in close contact with the anode gas diffusion layer 11 and the cathode side is in close contact with the cathode gas diffusion layer 21, reaction gas channels with specific configurations can be formed between the anode side and the anode gas diffusion layer 11, and between the cathode side and the cathode gas diffusion layer 21, respectively. This channel design helps to achieve efficient transport and uniform distribution of the reaction gas in the electrode region, thereby improving the efficiency and stability of the electrochemical reaction. In this embodiment or other embodiments, the depth of the grooves 42 gradually increases along the flow direction of the reaction gas. This design can optimize the flow state of the reaction gas in the channel, effectively enhance the mass transfer effect between the film layers, and thus improve the overall efficiency and performance stability of the electrochemical reaction. In some embodiments, grooves are provided on the sides of the anolyte gas diffusion layer 11 and the cathode gas diffusion layer 21 that are in contact with the anode and cathode sides of the metal bipolar plate 4, corresponding to the trench 42, so that reaction gas channels are formed between the anode side and the anolyte gas diffusion layer 11, and between the cathode side and the cathode gas diffusion layer 21, respectively. The metal bipolar plate 4 can be made of stainless steel, or surface-modified metal materials such as titanium plates or aluminum alloys, to obtain better corrosion resistance or lightweight effect. Graphite plates or composite carbon plates can also be used instead of metal bipolar plates 4 to give them excellent conductivity and chemical stability. The cooling medium can be natural air cooling, ethylene glycol aqueous solution, etc. Natural air cooling achieves heat dissipation by natural air convection, without the need for additional complex cooling equipment; ethylene glycol aqueous solution, due to its good low-temperature fluidity and thermal conductivity, can still maintain a stable cooling effect under low-temperature conditions. For scenarios with extremely high electrical safety requirements and where the risk of short circuits due to leakage must be completely avoided, insulating oil is a more suitable choice. Its excellent insulation properties can effectively isolate live components and prevent short circuit accidents. Since different cooling media differ in key characteristics such as heat capacity, viscosity, and insulation performance, these characteristics affect the system's heat dissipation efficiency and overall safety. Therefore, appropriate selection must be made based on the actual application scenario.

[0030] In one embodiment, the grooves 42 on the anode and cathode sides of the metal bipolar plate 4 are parallel and aligned with or staggered with the internal cooling channels 41. For example, the cooling channels 41 inside the metal bipolar plate 4 penetrate the metal bipolar plate 4 along its width and adopt a straight-through parallel channel design. In this case, the grooves 42 on the anode and / or cathode sides of the metal bipolar plate 4 are also designed as straight-through channels and precisely aligned with the cooling channels 41. From a structural and manufacturing perspective, the metal bipolar plate 4 exhibits a high degree of regularity, which allows for the use of relatively conventional and mature processes during manufacturing, greatly simplifying the processing flow and reducing the requirements for processing equipment and technology. Therefore, it has a significant advantage in manufacturing costs, effectively controlling production costs and making it suitable for large-scale industrial production. However, from the perspective of fluid dynamics and heat transfer performance, this layout has certain limitations. Because both cooling channels 41 and grooves 42 are straight-through and aligned, the flow of the cooling medium within the channels is relatively stable with weak turbulence, which limits heat dissipation efficiency. Therefore, this distribution pattern is more suitable for operating conditions with medium to low heat loads, where its heat dissipation capacity meets system requirements while fully leveraging its advantages of regular structure and low cost. Alternatively, as... Figure 2As shown, the cooling channel 41 inside the metal bipolar plate 4 is still a straight-through parallel channel. However, the grooves 42 on the anode and cathode sides of the metal bipolar plate 4 are non-straight-through parallel channels, and the extension direction of the grooves 42 intersects with the extension direction of the cooling channel 41. The interspersed grooves 42 and cooling channels 41 can significantly change the flow state of the cooling medium inside the channel, forming a turbulence effect, making the heat transfer between the cooling medium and the wall of the metal bipolar plate 4 more complete and efficient, and improving the heat dissipation efficiency. Therefore, this distribution mode is particularly suitable for harsh operating conditions with high current density and high heat load, and can meet the strict heat dissipation requirements of the system under high load. However, this complex structure places higher demands on the processing accuracy, which will increase the processing difficulty and cycle, resulting in a corresponding increase in manufacturing cost. In practical applications, it is necessary to comprehensively consider factors such as specific operating conditions and cost requirements to select the most suitable distribution mode. In this embodiment and other embodiments, the shape of the cooling channel 41 includes any one or more of straight-through parallel channels, serpentine channels, and intersecting channels. The shape of the trench 42 can also adopt a straight-through parallel flow channel, a serpentine flow channel, or a cross-shaped flow channel. Furthermore, when designing the heat dissipation method in conjunction with the shape of the cooling channel 41 to meet heat dissipation requirements, several options are available. Among them, the natural cooling combined with a straight-through flow channel scheme and the forced cooling combined with a high-disturbance flow channel scheme are more common. In the natural cooling combined with a straight-through flow channel scheme, the cooling channel 41 adopts a low-flow-resistance straight-through parallel flow channel design. Its internal channels are straight and parallel, providing an extremely smooth path for the flow of the cooling medium. Simultaneously, this scheme does not actively pump coolant into the cooling channel 41, but fully utilizes the natural convection of air within the channel and the thermal conductivity of the plates to exchange heat with the external environment. This scheme completely eliminates external auxiliary systems such as circulating pumps, significantly simplifying the overall system structure and improving system reliability; it also significantly reduces system operating costs, achieving zero-power heat dissipation, making it highly attractive for applications that are sensitive to energy consumption and cost. However, during high power density operation, a significant amount of heat is generated. Natural cooling may not be able to dissipate this heat in time, leading to excessively high plate temperatures and impacting system performance and lifespan. In the forced cooling combined with a high-disturbance flow channel scheme, the cooling channel 41 is designed with a serpentine or cross-shaped structure, exhibiting high-disturbance characteristics. The serpentine channel, through continuous bends and turns, causes the cooling medium to constantly change direction and velocity during flow; the cross-shaped channel, with multiple intersecting channels, increases the flow path and mixing degree of the cooling medium; both significantly improve the heat transfer coefficient between the cooling medium and the plate wall, increasing the heat transfer area and thus improving heat dissipation efficiency. Simultaneously, this scheme actively pumps cooling gas or liquid into the flow channel to enhance the heat dissipation effect.Therefore, this solution is highly suitable for high-heat-load conditions, effectively and quickly removing large amounts of heat from the inside of the plates, ensuring stable system operation in high-temperature environments. Furthermore, by precisely controlling parameters such as the flow rate, temperature, and pressure of the cooling medium, accurate control of the operating temperature can be achieved, meeting the needs of applications with extremely stringent temperature requirements.

[0031] This application also provides an electrolytic cell, such as Figure 4 As shown, the electrolytic cell includes two end plate assemblies 5 and the aforementioned integrated gas-liquid thermal management structure. The integrated gas-liquid thermal management structure is disposed between the two end plate assemblies 5. Each end plate assembly 5 includes an end plate 51 and a conductive plate 52 attached to the end plate 51. The end plate 51 has an inlet 53 and an outlet 54. In this embodiment and other embodiments, a metal bipolar plate 4 is also disposed between the end plate assembly 5 and the structural unit 10. In some embodiments, in addition to welding, the fixed connection between the components can also be achieved by bonding with an adhesive that meets the requirements of sealing and insulation. The adhesive material can be selected from elastomer materials such as polytetrafluoroethylene, silicone rubber, and EPDM rubber to meet the requirements of temperature resistance and chemical resistance.

[0032] The electrolytic cell operates as follows: During the operation of the electrolytic cell, CO2 gas flows through the cathode channel, while H2 flows through the anode channel, diffusing to the cathode gas diffusion layer 21 and the anode gas diffusion layer 11, respectively. Electrochemical reactions occur under the action of the catalysts in the cathode catalyst layer 22 and the anode catalyst layer 12, namely, the carbon dioxide reduction reaction and the hydrogenation reaction. These two reactions inevitably generate heat while releasing electrical energy. Furthermore, as the reactions proceed, various products are produced on the cathode side, including liquid products (such as water and formic acid) and gaseous products (such as carbon monoxide).

[0033] During the ongoing electrolysis reaction, the cooling medium flows within the cooling channel 41, exchanging heat with the interior of the electrolytic cell and directly removing the heat generated by the reaction. By precisely controlling the flow rate and temperature of the cooling medium, the operating temperature of the electrolytic cell can be stably maintained within the optimal range, such as 25°C. A suitable temperature ensures that the ion exchange membrane and the solid electrolyte are in a well-hydrated state, maintaining their high ionic conductivity, thereby guaranteeing efficient ion transport across the membrane electrode and improving the efficiency of the electrolysis reaction. Simultaneously, effective temperature control can prevent excessive evaporation of water due to excessively high temperatures, which could disrupt the gas-liquid balance inside the electrolytic cell, affecting the stability of the reaction and the quality of the products.

[0034] During the ongoing electrolysis reaction, the porous structure on the solid electrolyte separator 3 allows for the mutual transfer and balance of liquids generated in the cathode assembly 2 and anode assembly 1 on both sides of the solid electrolyte separator 3, preventing flooding. The through-hole 33 allows for the timely discharge of regenerated gas and some liquid, ensuring a dynamic balance of the gas-liquid environment inside the electrolytic cell. This maintains necessary hydration and prevents the cation exchange membrane 13 or anion exchange membrane 23 from drying out. This customized gas-liquid transport path design can be optimized according to different reaction requirements and product characteristics, improving the efficiency and accuracy of gas-liquid transport.

[0035] This electrolyzer employs an integrated structural design to achieve microscopic tight coupling between the reaction zone, gas-liquid management zone, and cooling zone. The solid electrolyte separator 3, through its porous structure and through-holes 33, provides a specific transport path for gas-liquid exchange, ensuring the smooth discharge of reaction products while maintaining gas-liquid balance within the electrolyzer. The metal bipolar plate 4 integrates cooling channels 41, and by precisely controlling the flow rate and temperature of the cooling medium, it provides a stable temperature base for the electrolyzer, guaranteeing the performance of the ion exchange membrane and the solid electrolyte. The synergistic operation of these two components integrates gas diffusion, liquid product removal, moisture retention, and heat removal into a unified whole, significantly improving the performance and stability of the electrolyzer and providing technical support for the efficient conversion and utilization of CO2.

[0036] Example 1 An electrolytic cell includes two end plate assemblies 5 and an integrated gas-liquid thermal management structure disposed between the two end plate assemblies 5. The integrated gas-liquid thermal management structure includes two structural units 10 and metal bipolar plates 4. The effective active area of ​​each structural unit 10 is 25 cm². 2 Each structural unit 10 includes, in sequence, an anode gas diffusion layer 11, an anode catalyst layer, a proton exchange membrane (Nafion® 115), a solid electrolyte separator 3, an anion exchange membrane 23 (Sustainion® X37-50 Grade T), a cathode catalyst layer, and a cathode gas diffusion layer 21. The solid electrolyte layer in the solid electrolyte separator 3 is filled with DOWEX 50W×8 hydrogen-type cation exchange resin particles with a particle size range of 100-150 micrometers. Multiple through-holes 33 are provided on the sides of the separator frame 31 along its length, and the through-holes 33 penetrate the separator frame 31 along its width. The porosity of the solid electrolyte layer is 35%. The cathode catalyst layer is loaded with metallic silver (Ag) catalyst via physical vapor deposition at a loading of 1.0 mg / cm³. 2 The anode catalyst layer is supported on a platinum-supported carbon catalyst (Pt / C, Pt weight percentage is 60%), with a loading of 1.0 mg / cm³. 2A metal bipolar plate 4 is provided between two adjacent structural units 10 and between structural unit 10 and end plate assembly 5, and a cooling channel 41 is provided inside the metal bipolar plate 4, and the cooling channel 41 is designed as a straight-through parallel channel.

[0037] Dry hydrogen gas is introduced into the anode at a flow rate of 200 sccm, while dry carbon dioxide gas is introduced into the cathode at a flow rate of 200 sccm. The controlled current is 2.5 A (i.e., a current density of 100 mA / cm²). 2 Operating in constant current mode, the electrolytic cell voltage stabilizes at approximately 3.5V. Under these conditions, the gas-liquid management function of the solid electrolyte separator 3 and the integrated thermal management of the metal bipolar plate 4 work synergistically: the through-holes 33 on the solid electrolyte separator 3 provide rapid diffusion channels for the gaseous and liquid products generated at the cathode, preventing gas and liquid accumulation; the cooling medium circulates in the cooling channels 41 inside the metal bipolar plate 4, rapidly removing the heat generated by the reaction through heat exchange, precisely maintaining the reaction interface temperature at 25±2℃, maintaining the stability of the reaction system, and effectively suppressing excessive water evaporation. Simultaneously, the hydrophilic nature of the solid electrolyte particle surface helps maintain the necessary hydration level at key interfaces such as the anion exchange membrane 23 or proton exchange membrane. Combined with the aforementioned gas-liquid management and thermal management functions, this prevents "flooding" or "membrane drying," providing comprehensive protection for the stable operation of the electrolytic cell.

[0038] To further verify the performance of the electrolytic cell, gas chromatography analysis was performed on the gas discharged from the cathode outlet. The analysis results are as follows: Figure 5 As shown.

[0039] Depend on Figure 5 It is known that the Faraday efficiency of the target product, carbon monoxide (CO), exceeds 95%. Faraday efficiency is a crucial indicator of the selectivity of an electrolytic reaction. Such a high Faraday efficiency demonstrates that the electrolyzer exhibits extremely high selectivity and efficiency in reducing carbon dioxide to carbon monoxide, effectively converting most of the input electrical energy into the chemical energy of the target product. Furthermore, the electrolyzer can operate stably for over 200 hours under these conditions, exhibiting excellent long-term operational stability. This fully demonstrates that the method employed in this application—achieving adjustable gas-liquid management through the solid electrolyte separator 3 and integrating thermal management through cooling channels 41 within the metal bipolar plate 4—can synergistically ensure the long-term stable operation of the all-gas-phase carbon dioxide reduction electrolyzer under high performance, providing a reliable and effective solution for the efficient conversion and utilization of carbon dioxide.

[0040] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0041] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An integrated gas-liquid thermal management structure for all-gas-phase CO2 reduction, characterized in that, include: Multiple structural units, each of which includes an anode assembly, a solid electrolyte separator, and a cathode assembly arranged in sequence. The solid electrolyte separator has multiple through holes on its periphery for discharging the gas and liquid regenerated during the operation of the electrolytic cell. Multiple metal bipolar plates are provided, each of which is disposed between two adjacent structural units. The anode side and cathode side of the metal bipolar plate are respectively attached to the anode assembly and the cathode assembly in the adjacent structural unit. Multiple cooling channels are provided inside the metal bipolar plate, and the multiple cooling channels penetrate the metal bipolar plate along the width or length direction of the metal bipolar plate to discharge the heat generated during the operation of the electrolytic cell.

2. The integrated gas-liquid thermal management structure as described in claim 1, characterized in that, The solid electrolyte separator includes a separator frame and a solid electrolyte filling layer made of solid electrolyte particles. The separator frame is sleeved on the periphery of the solid electrolyte filling layer, and the separator frame is provided with a through hole that penetrates the separator frame along the width or length direction.

3. The integrated gas-liquid thermal management structure as described in claim 2, characterized in that, The particle size of the solid electrolyte particles is any value between 50μm and 500μm, and the porosity of the solid electrolyte filling layer is any value between 30% and 70% in order to maintain ideal gas-liquid balance and stabilize the cell voltage.

4. The integrated gas-liquid thermal management structure as described in claim 1, characterized in that, The anode assembly sequentially includes an anode gas diffusion layer, an anode catalyst layer, and a cation exchange membrane, wherein the cation exchange membrane is bonded to the solid electrolyte separator; The cathode assembly comprises, in sequence, an anion exchange membrane, a cathode catalyst layer, and a cathode gas diffusion layer, wherein the anion exchange membrane is bonded to the solid electrolyte separator.

5. The integrated gas-liquid thermal management structure as described in claim 4, characterized in that, Grooves are provided on the anode and cathode sides of the metal bipolar plate, so that a reaction gas flow channel is formed between the anode side of the metal bipolar plate and the anode gas diffusion layer attached thereto, and between the cathode side of the metal bipolar plate and the cathode gas diffusion layer attached thereto.

6. The integrated gas-liquid thermal management structure as described in claim 5, characterized in that, The depth of the trench gradually increases along the flow direction of the reactant gas to enhance the mass transfer effect.

7. The integrated gas-liquid thermal management structure as described in claim 5, characterized in that, The grooves on the metal bipolar plate are aligned or staggered with the cooling channels inside them.

8. The integrated gas-liquid thermal management structure as described in claim 5, characterized in that, The shape of the cooling channel includes any one or more of the following: straight parallel channel, serpentine channel, and cross channel.

9. An electrolytic cell, characterized in that, The device includes two end plate assemblies and an integrated gas-liquid thermal management structure as described in any one of claims 1-8. The integrated gas-liquid thermal management structure is disposed between the two end plate assemblies. Each end plate assembly includes an end plate and a conductive plate disposed on the inner side of the end plate. An air inlet and an air outlet are provided on the end plate.

10. The electrolytic cell as described in claim 9, characterized in that, The metal bipolar plate is disposed between the end plate assembly and the structural unit.

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