Membrane electrode stack for electroreduction of carbon dioxide

Abstract

The invention belongs to the technical field of membrane electrode stacks, and discloses a membrane electrode stack for carbon dioxide electroreduction, the membrane electrode stack comprises a group of main body polar plates and N groups of expanded polar plates, the main body polar plates comprise a polar plate A, a polar plate D and a polar plate E, and the expanded polar plates comprise a polar plate B and a polar plate C; the internal arrangement mode is A-(B-C) N-D-E, and N is a natural number; the first flow channel of each main body pole plate or expanded pole plate is arranged opposite to the second flow channel of the adjacent main body pole plate or expanded pole plate; the first runner is used for flowing through a first material and realizing series control of the first material in the main body pole plate and the expansion pole plate; and the second runner is used for flowing through a second material and realizing independent control of the second material in the main body pole plate and the expansion pole plate. According to the invention, the conversion efficiency of carbon dioxide can be improved, the reaction conditions can be adjusted according to specific chemical reaction requirements, and accurate control of product selectivity is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of membrane electrode stacks, and specifically, it relates to a membrane electrode stack for carbon dioxide electroreduction. Background Art

[0002] Using clean and renewable energy to replace traditional fossil fuels can reduce carbon emissions at the source. However, it is still necessary to develop efficient carbon capture, utilization, and storage (CCUS) technologies to neutralize existing carbon emissions. In CCUS technology, carbon dioxide electroreduction technology is a potential chemical utilization method. This technology can convert carbon dioxide into high-value chemicals such as carbon monoxide, formic acid, and ethylene at room temperature and atmospheric pressure.

[0003] Among the numerous reactors in this technical field, membrane electrode reactors have attracted much attention due to their low mass transfer resistance and ohmic impedance. Currently, the area of membrane electrode reactors at the laboratory scale is often small, and their throughput is far from the industrial scale. Therefore, it is necessary to scale up the membrane electrode reactor. Specifically, it is necessary to increase the reaction area of the membrane electrode reactor to improve the carbon dioxide throughput.

[0004] However, during the scaling-up process of traditional membrane electrode reactors, problems such as increased energy consumption and decreased throughput are faced. How to reduce the excessive energy consumption and improve the energy consumption output ratio during the scaling-up process has become a key issue for membrane electrode reactors in industrial applications. And an efficient membrane electrode reactor structure design will effectively solve this problem. Summary of the Invention

[0005] The present invention aims to solve the related technical problems of the existing membrane electrode reactor structure design, and provides a membrane electrode stack for carbon dioxide electroreduction, which couples two different electrochemical flow fields, realizes the series feeding control of one side of the material and the separate feeding control of the other side of the material within the same membrane electrode stack, and applies it to the carbon dioxide electroreduction reaction.

[0006] To solve the above technical problems, the present invention is realized through the following technical solutions:

[0007] The present invention provides a membrane electrode stack for carbon dioxide electroreduction, including a group of main plates and N groups of extended plates, where N is a natural number; a group of the main plates includes plate A, plate D, and plate E, and a group of the extended plates includes plate B and plate C; a first flow channel is arranged on one side surface of plate A, first flow channels and second flow channels are respectively arranged on both side surfaces of plate B, plate C, and plate D, and a second flow channel is arranged on one side surface of plate E;

[0008] The internal arrangement of a group of main plates and N groups (where N is a natural number) of extended plates is A-(B-C)N -D-E, and the first flow channels of each main plate or extended plate are arranged opposite to the second flow channels of the adjacent main plate or extended plate;

[0009] The first flow channel is used for flowing the first material and realizing the series control of the first material in the main plate and the extended plate, and the second flow channel is used for flowing the second material and realizing the independent control of the second material in the main plate and the extended plate.

[0010] Further, a first material inlet A is arranged outside the plate A, and the first material inlet A is communicated with the starting end of the first flow channel of the plate A; a first material outlet A is arranged on the side surface where the first flow channel of the plate A is located, and the first material outlet A is communicated with the ending end of the first flow channel of the plate A;

[0011] A first material perforation D is arranged on the side surface where the second flow channel of the plate D is located; when N = 0, the first material perforation D is arranged opposite to the first material outlet A of the plate A; when N≥1, the first material perforation D is arranged opposite to the first material outlet C of the plate C; a first material inlet D is arranged on the side surface where the first flow channel of the plate D is located, and the first material inlet D is communicated with the first material perforation D to realize the in-plate shuttle of the first material in the plate D5; a first material outlet D, a second material inlet D and a second material outlet D are arranged outside the plate D, the first material outlet D is communicated with the ending end of the first flow channel, and the starting end of the first flow channel is communicated with the first material inlet D; the second material inlet D and the second material outlet D are respectively communicated with the starting end and the ending end of the second flow channel of the plate D;

[0012] A second material inlet E and a second material outlet E are arranged outside the plate E, and the second material inlet E and the second material outlet E are respectively communicated with the starting end and the ending end of the second flow channel of the plate E.

[0013] Further, a first material perforation B is arranged on the side surface where the second flow channel of the plate B is located; when N = 1, the first material perforation B is arranged opposite to the first material outlet A of the plate A; when N>1, the first material perforation B is arranged opposite to the first material outlet C of the plate C; a first material inlet B and a first material outlet B are arranged on the side surface where the first flow channel of the plate B is located, the first material inlet B is respectively communicated with the first material perforation B and the starting end of the first flow channel of the plate B, and the first material outlet B is communicated with the ending end of the first flow channel of the plate B; a second material inlet B and a second material outlet B are arranged outside the plate B, and the second material inlet B and the second material outlet B are respectively communicated with the starting end and the ending end of the second flow channel of the plate B;

[0014] The plate C is provided with a first material perforation C on the side where its second flow channel is located, and the first material perforation C is arranged opposite to the first material outlet B of the plate B; the plate C is provided with a first material inlet C and a first material outlet C on the side where its first flow channel is located, the first material inlet C is respectively communicated with the first material perforation C and the starting end of the first flow channel of the plate C, and the first material outlet C is communicated with the end of the first flow channel of the plate C; a second material inlet C and a second material outlet C are arranged outside the plate C, and the second material inlet C and the second material outlet C are respectively communicated with the starting end and the end of the second flow channel of the plate C.

[0015] Preferably, the first material perforation B and the first material inlet B are correspondingly arranged on the two opposite sides of the plate B; the first material perforation C and the first material inlet C are correspondingly arranged on the two opposite sides of the plate C.

[0016] Further, the first flow channel and the second flow channel are respectively selected from one of a single serpentine flow channel, a multi-channel serpentine flow channel, a parallel flow channel, a staggered flow channel, and a pin flow channel.

[0017] Further, the second material inlet and the second material outlet of the same plate can be located on the same side or on both sides.

[0018] Preferably, for the cathode CO2 electroreduction coupled with the anodic electrolysis of water, the first material is CO2 and the second material is an electrolyte; the first flow channel is preferably a serpentine flow channel; the second flow channel is preferably a parallel flow channel.

[0019] Optionally, positioning holes are respectively arranged at the four corners of the main plate and the extended plate, and the positioning holes are used for connecting the main plate and the extended plate.

[0020] Optionally, a membrane electrode assembly is arranged between adjacent two layers of plates, and the plates include a main plate and an extended plate; the membrane electrode assembly includes a cathode, a cathode gasket, a membrane, an anode gasket, and an anode stacked in sequence; positioning holes are respectively arranged at the four corners of the cathode gasket and the anode gasket, and the cathode gasket and the anode gasket are provided with gasket perforations for aligning with the first material perforations of each plate.

[0021] Optionally, a first end plate and a second end plate are respectively arranged on the side of the plate A where the first flow channel is not arranged and on the side of the plate E where the second flow channel is not arranged; an end plate insulating gasket and a current collector plate are sequentially arranged between the first end plate and the plate A and between the second end plate and the plate E.

[0022] The beneficial effects of the present invention are:

[0023] The membrane electrode stack for carbon dioxide electroreduction of the present invention can allow carbon dioxide to pass through each layer of membrane electrode in series inside the stack, so that a higher single-pass conversion rate of the raw material carbon dioxide can be easily achieved. This structure also allows independent control of the anolyte flow in different layers, thereby reducing the increase in local resistance caused by the coalescence of oxygen bubbles generated by the anodic oxygen evolution reaction inside the flow channel and improving the energy efficiency of the system. In addition, the independent liquid-phase flow field design also provides the possibility for realizing multi-stage tandem reactions, which is particularly important in chemical synthesis. In multi-stage tandem reactions, different reaction steps may require different pH environments, and the raw materials are required to be in the reaction system all the time. Therefore, the stack structure of the present invention can independently adjust the pH of each reaction unit to adapt to the optimal reaction conditions of different steps, realizing efficient conversion of reactants and precise control of product selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the material flow field of the membrane electrode stack of the present invention;

[0025] Figure 2 It is a schematic diagram of the double-sided structure of plate A in the membrane electrode stack;

[0026] Figure 3 It is a schematic diagram of the double-sided structure of plate B in the membrane electrode stack;

[0027] Figure 4 It is a schematic diagram of the double-sided structure of plate C in the membrane electrode stack;

[0028] Figure 5 It is a schematic diagram of the double-sided structure of plate D in the membrane electrode stack;

[0029] Figure 6 It is a schematic diagram of the double-sided structure of plate E in the membrane electrode stack;

[0030] Figure 7 It is a schematic diagram of the structure of the membrane electrode stack in Example 1;

[0031] Figure 8 It is a schematic diagram of the structure of the membrane electrode stack in Example 2;

[0032] Figure 9 It is a schematic diagram of the structure of the membrane electrode assembly with gaskets;

[0033] Figure 10 It is a comparison chart of the product Faraday efficiency and energy efficiency between the membrane electrode stack in Example 1 and the membrane electrode single cell with the same total area;

[0034] Figure 11 It is a comparison chart of the energy consumption output ratio between the membrane electrode stack in Example 1 and the membrane electrode single cell with the same total area;

[0035] Figure 12 It is a comparison chart of the Faraday efficiency and energy efficiency of the membrane electrode stack and the membrane electrode single cell with the same total area in Example 2;

[0036] Figure 13 It is a comparison chart of the energy consumption output ratio of the membrane electrode stack and the membrane electrode single cell with the same total area in Example 2.

[0037] In the above figures: 1: the first end plate; 2: the end plate insulating gasket; 3: the current collector plate; 4: the plate A; 4-1: the first material inlet A; 4-2: the first material outlet A; 5: the plate B; 5-1: the second material inlet B; 5-2: the second material outlet B; 5-3: the first material perforation B; 5-4: the first material inlet B; 5-5: the first material outlet B; 6: the plate C; 6-1: the second material inlet C; 6-2: the second material outlet C; 6-3: the first material perforation C; 6-4: the first material inlet C; 6-5: the first material outlet C; 7: the plate D; 7-1: the second material inlet D; 7-2: the second material outlet D; 7-3: the first material perforation D; 7-4: the first material inlet D; 7-5: the first material outlet D; 8: the plate E; 8-1: the second material inlet E; 8-2: the second material outlet E; 9: the membrane electrode assembly; 9-1: the cathode, 9-2: the cathode gasket, 9-3: the membrane, 9-4: the anode gasket, 9-5: the anode; 9-6: the gasket perforation; 10: the second end plate; 11: the positioning hole; 12 - the heating and temperature measuring hole. Specific embodiments

[0038] To further understand the content, features and effects of the present invention, the following examples are cited and described in detail with the accompanying drawings as follows:

[0039] Figure 1 It shows a schematic diagram of the internal material flow field of the stack of the present invention, including a set of main plates and N sets of extended plates, and different numbers of extended plates can be configured according to the requirements of the total reaction area.

[0040] A set of main plates are the plate A4, the plate D7, and the plate E8 arranged in parallel in sequence. Materials realize different material control methods within the same stack through the main plates. Two materials flow through two flow channels on the plates respectively. Without special instructions, the flow channel through which the first material flows is called the first flow channel, and the materials other than the first material are collectively called the second materials, and the flow channel through which the second materials flow is called the second flow channel. The first flow channel and the second flow channel can respectively select a single serpentine flow channel, a multi-channel serpentine flow channel, a parallel flow channel, a staggered flow channel, a needle-like flow channel, etc. according to different reaction systems.

[0041] The flow channel arrangement of the main plates:

[0042] One side of the electrode plate A4 is provided with a first flow channel; both sides of the electrode plate D7 are respectively provided with a first flow channel and a second flow channel, and the second flow channel of the electrode plate D7 and the first flow channel of the electrode plate A4 are arranged opposite to each other; one side of the electrode plate E8 is provided with a second flow channel, and the second flow channel of the electrode plate E8 and the first flow channel of the electrode plate D7 are arranged opposite to each other. For the convenience of description, the four surfaces other than the two surfaces provided with the flow channels are all called the outer sides. A first material inlet A4-1 is provided on the outer side of the electrode plate A4, a first material inlet D7-4, a second material inlet D7-1 and a second material outlet D7-2 are provided on the outer side of the electrode plate D7, and a second material inlet and a second material outlet are provided on the outer side of the electrode plate E8.

[0043] The first flow channel realizes the series control of the first material:

[0044] As Figure 2 shown, the first material inlet A4-1 on the outer side of the electrode plate A4 communicates with the starting end of the first flow channel of the electrode plate A4. The first material can be introduced from the first material inlet on the outer side of the electrode plate A4 into the starting end of the first flow channel of the electrode plate A4, flow along the first flow channel of the electrode plate A4 and reach the end of the first flow channel of the electrode plate A4, and flow out from the first material outlet A4-2.

[0045] Among them, the first material outlet A4-2 is opened on the side surface where the first flow channel of the electrode plate A4 is located, and is located between the end of the first flow channel and the outer side of the electrode plate A4.

[0046] As Figure 3 shown, the electrode plate D7 is provided with a first material perforation D7-3 on the side surface where its second flow channel is located. The first material perforation D7-3 is arranged opposite to the first material outlet A4-2 of the electrode plate A4 and is communicated with the first material inlet D7-4 of the electrode plate D7, realizing the shuttle of the first material inside the electrode plate D5, reaching the starting end of the first flow channel of the electrode plate D7. The first material flows along the first flow channel of the electrode plate D7 to the end of the first flow channel. The end of the first flow channel of the electrode plate D7 is communicated with the second material outlet 7-2D. The first material finally flows out from the second material outlet 7-2D on the outer side of the electrode plate D7, realizing the series connection of the first material.

[0047] Among them, the first material inlet D 7-4 is opened on the side surface where the first flow channel of the electrode plate D7 is located, and is located between the starting end of the first flow channel and the outer side. Preferably, the first material perforation D7-3 and the first material inlet D 7-4 are correspondingly arranged on the two side surfaces of the electrode plate D7.

[0048] The second flow channel realizes the independent control of the second material:

[0049] As Figure 3As shown, the second material inlet of the main body plate is in through connection with the start end of the second flow channel, and the second material outlet is in through connection with the end of the second flow channel. Therefore, the second material is introduced into the start end of the second flow channel of the plate D7 through the second material inlet D7-1 outside the plate D7, flows through the flow channel to the end of the second flow channel, and finally flows out from the second material outlet D7-2 outside the plate D7. Similarly, as Figure 4 shown, the plate E8 with the second material inlet E8-1, the second material outlet E8-2 and the second flow channel can also achieve the control of the entry and exit of the second material. Since the second flow channel of the plate D7 is not connected to the second flow channel of the plate E8, the second material is independently controlled.

[0050] Flow channel arrangement of the extended plates:

[0051] A group of extended plates includes the plate B5 and the plate C6. The first flow channel and the second flow channel are respectively arranged on both side surfaces of the plate B5 and the plate C6. The internal arrangement mode of a group of main body plates and N groups (where N is a natural number) of extended plates is A-(B-C) N -D-E, and the first flow channel of each main body plate or extended plate is arranged opposite to the second flow channel of its adjacent main body plate or extended plate.

[0052] As Figure 5 shown, the second material inlet B5-1 and the second material outlet B5-2 are arranged outside the plate B5 to achieve the independent control of the second material. The plate B5 is provided with a first material perforation B5-3 on the side surface where its second flow channel is located. The first material perforation B5-3 has the same position as the first material perforation D7-3 of the plate D7, and both are arranged opposite to the first material outlet A4-2 of the plate A4. The plate B5 is provided with a first material inlet B5-4 and a first material outlet B5-5 on the side surface where its first flow channel is located. Among them, the first material inlet B5-4 is respectively communicated with the first material perforation B5-3 and the start end of the first flow channel of the plate B5, and the first material outlet B5-5 is connected with the end of the first flow channel of the plate B5. Thus, the first material shuttles inside the plate B5, reaches the first material inlet B5-4 of the plate B5 through the first material inlet B5-4, and flows along its first flow channel to the first material outlet B5-5 and flows out, realizing the series connection of the first material.

[0053] Among them, the first material inlet B5-4 is located between the start end of the first flow channel and the outside, and the first material outlet B5-5 is located between the end of the first flow channel and the outside. Preferably, the first material perforation B5-3 and the first material inlet B5-4 are correspondingly arranged on both side surfaces of the plate B5. In some embodiments, the first material inlet B5-4 and the first material outlet B5-5 are arranged diagonally with respect to the first flow channel.

[0054] As Figure 6As shown in the figure, a second material inlet C6-1 and a second material outlet C6-2 are provided on the outer side of the electrode plate C6 to achieve independent control of the second material. The electrode plate C6 is provided with a first material perforation C6-3 on the side where its second flow channel is located, and the first material perforation C6-3 is arranged opposite to the first material outlet B5-5 of the electrode plate B5. The electrode plate C6 is provided with a first material inlet C6-4 and a first material outlet C6-5 on the side where its first flow channel is located. Among them, the first material inlet C6-4 is respectively communicated with the first material perforation C6-3 and the starting end of the first flow channel of the electrode plate C6, and the first material outlet C6-5 is connected to the end of the first flow channel of the electrode plate C6. Thus, the first material shuttles inside the electrode plate C6, reaches the first material inlet C6-4 of the electrode plate C6 through the first material inlet C6-4, and flows along its first flow channel to the first material outlet C6-5 and flows out, realizing the series connection of the first material.

[0055] Among them, the first material inlet C6-4 is located between the starting end of the first flow channel and the outside, and the first material outlet C6-5 is located between the end of the first flow channel and the outside. Preferably, the first material inlet C6-4 and the first material outlet C6-5 are correspondingly arranged on the two side faces of the electrode plate C6. In some embodiments, the first material inlet C6-4 and the first material outlet C6-5 are arranged diagonally with respect to the first flow channel.

[0056] It can be seen that the addition of the extended electrode plate does not change the control modes of the first material and the second material. For the series-connected first material, it still reaches the starting end of the next electrode plate flow channel through the in-plate shuttle mode at the end of the previous electrode plate flow channel, and for the same coordinate system, the starting and ending ends of the flow channels of the first material on the electrode plates B and C are opposite.

[0057] The starting end and the ending end of the first flow channel are respectively the starting and ending positions of the first material flowing in the first flow channel. The starting end and the ending end of the second flow channel are respectively the starting and ending positions of the second material flowing in the second flow channel.

[0058] Generally, the second material inlet and the second material outlet of the same electrode plate can be located on the same side or on both sides.

[0059] Usually, the first material inlet, the first material outlet, the second material inlet, and the second material outlet of each electrode plate can be set as threaded holes for connecting external pipelines.

[0060] In addition, the membrane electrode stack of the present invention is used for cathode CO2 electroreduction coupled with anode electrolysis of water. Preferably, the first material is CO2 and the second material is electrolyte; the first flow channel is preferably a serpentine flow channel; the second flow channel is preferably a parallel flow channel.

[0061] Such as Figure 7 and Figure 8As shown, when performing electrochemical tests on the stack using this structure, it is also necessary to cut the membrane electrode assembly 9 and gaskets of appropriate sizes according to the stack size and flow channel size for isolating the anode and cathode electrochemical reactions and for sealing. The membrane electrode assembly 9 is located between adjacent two layers of plate electrodes. For a stack with an A-(B-C) N -D-E structure, (2 + 2N) groups of membrane electrode assemblies 9 need to be prepared.

[0062] As Figure 9 shown, the membrane electrode assembly 9 includes a cathode 9-1, a cathode gasket 9-2, a membrane 9-3, an anode gasket 9-4, and an anode 9-5 stacked in sequence. The size of the central square hole of the cathode gasket 9-2 is the same as that of the cathode 9-1; the size of the membrane 9-3 is slightly larger than that of the cathode 9-1 and the anode 9-2; the size of the central square hole of the anode gasket 9-4 is the same as that of the cathode 9-1; the size of the anode 9-5 is slightly larger than that of the cathode 9-1. Both the cathode gasket 9-2 and the anode gasket 9-4 are provided with a gasket through-hole 9-6 and four positioning holes 11. The four positioning holes 11 are respectively located at the four corners and are left with a certain distance from the edge. The gasket through-hole 9-6 is used to align with the first material through-holes of each plate electrode to achieve the series control of the first material. It should be noted during assembly that the gasket through-holes 9-6 of the cathode gasket 9-2 and the anode gasket 9-4 need to be aligned. During all assembly processes, the positioning holes 11 need to be aligned, and no additional description will be given hereafter.

[0063] On the side of the plate electrode A4 where the first flow channel is not provided and the side of the plate electrode E8 where the second flow channel is not provided, it is preferable to add a first end plate 1 and a second end plate 10 for uniformly distributing the current and for fixing the stack. Between the first end plate 1 and the plate electrode A4 and between the second end plate 10 and the plate electrode E8, end plate insulating gaskets 2 and current collector plates 3 are sequentially provided. The materials of each plate electrode, the first end plate 1, the second end plate 10, and the current collector plate 3 can preferably be TC4 titanium alloy, gold-plated copper, or stainless steel, and the materials of the end plate insulating gasket 2 and the gaskets of the membrane electrode assembly 9 can preferably be polytetrafluoroethylene.

[0064] Example 1: As Figure 7 shown, for a 4×25 cm 2 Assembly and testing of the membrane electrode stack

[0065] In this example, the arrangement of the plate electrodes of the membrane electrode stack is ABCDE, and the area of the cathode 9-1 is 25 cm 2; and four groups of membrane electrode assemblies 9 with gaskets are prepared. For each plate, except for the two side surfaces of the flow channels and the two side surfaces of the material inlet and outlet, two heating and temperature measuring holes 12 are provided on one of the remaining two side surfaces. For the convenience of description, the side surface where the heating and temperature measuring holes 12 are located is collectively referred to as the upper side, and the plane where the material inlet and outlet threaded holes are located is called the left and right side. Four positioning holes 11 are respectively provided at the four corners of each plate. In addition, the stack also includes a first end plate 1, a second end plate 10, two end plate insulating gaskets 2, and two current collector plates 3, all of which are provided with four positioning holes 11, and the sizes of the positioning holes 11 are the same. The sizes of the first end plate 1 and the second end plate 10 are both larger than those of the plates, and sixteen fixing holes are evenly distributed near the edges of the first end plate 1 and the second end plate 10. Among them, the fixing holes on the first end plate 1 are circular through holes, and the fixing holes on the second end plate 10 are regular hexagonal counterbores.

[0066] In this embodiment, the first flow channels on the plate A4, plate B5, plate C6, and plate D7 are three-channel serpentine flow channels, and the second flow channels on the plate B5, plate C6, plate D7, and plate E8 are parallel flow channels.

[0067] For the plate A4, a first material inlet A4-1 with a threaded hole is provided on the right side, and a first material outlet A4-2 is provided between the end of the first flow channel of the plate A4 and the upper left positioning hole 11. The end of the first flow channel is communicated with the first material outlet A4-2 through a flow channel groove.

[0068] For the plate B5, a second material inlet B5-1 with a threaded hole is provided on the left side, a second material outlet B5-2 with a threaded hole is provided on the right side, a first material inlet B5-4 and a first material outlet B5-5 are provided between the starting and ending ends of the first flow channel on the upper left and lower right positioning holes 11, and a first material through hole B5-3 is provided on the side of the second flow channel and is communicated with the first material inlet B5-4.

[0069] For the plate C6, a second material inlet C6-1 with a threaded hole is provided on the left side, a second material outlet C6-2 with a threaded hole is provided on the right side, a first material inlet C6-4 and a first material outlet C6-5 are provided between the starting and ending ends of the first flow channel on the lower right and upper left positioning holes 11, and a first material through hole C6-3 is provided on the side of the second flow channel and is communicated with the first material inlet C6-4.

[0070] For the plate D7, a second material inlet D7-1 with a threaded hole is provided on the left side, a first material outlet D7-5 with a threaded hole and a second material outlet D7-2 with a threaded hole are provided on the right side, a first material inlet D7-4 is provided between the starting end of the first flow channel and the upper left positioning hole 11, and a first material through hole D7-3 is provided on the side of the second flow channel and is communicated with the first material inlet D7-4.

[0071] For the electrode plate E8, a second material inlet E8-1 with a threaded hole is provided on the left side, and a second material outlet E8-2 with a threaded hole is provided on the right side.

[0072] During assembly, the first end plate 1, the end plate insulating gasket 2, and the current collector plate 3 are placed flat on the table in sequence from bottom to top.

[0073] Place the electrode plate A4 with the non-flow channel side facing down and lay it flat on the current collector plate 3. After laying it flat, it is divided into four sides: front, back, left, and right from a top-down view. The heating and temperature measuring hole 12 faces forward, and the first material inlet A4-1 faces right. Place the first group of membrane electrode assemblies 9 with gaskets with the cathode 9-1 side facing down and lay it flat on the first flow channel side of the electrode plate A4. Align the gasket perforation 9-6 with the first material outlet A4-2 on the electrode plate A4. Thus, the first layer of membrane electrode assembly is completed.

[0074] Place the electrode plate B5 with the second flow channel side facing down and lay it flat on the first layer of membrane electrode. Align the first material perforation hole B5-3 with the gasket perforation 9-6 of the upper layer of membrane electrode, and the second material outlet B5-2 faces right. Place the second group of membrane electrode assemblies 9 with gaskets with the cathode 9-1 side facing down and lay it flat on the first flow channel side of the electrode plate B5. Align the gasket perforation 9-6 with the first material outlet B5-5 on the electrode plate B5. Thus, the second layer of membrane electrode assembly is completed.

[0075] Place the electrode plate C6 with the second flow channel side facing down and lay it flat on the second layer of membrane electrode. Align the first material perforation C6-3 with the gasket perforation 9-6 of the upper layer of membrane electrode, and the second material outlet C6-2 faces right. Place the third group of membrane electrode assemblies 9 with gaskets with the cathode 9-1 side facing down and lay it flat on the first flow channel side of the electrode plate C6. Align the gasket perforation 9-6 with the first material outlet C6-5 on the electrode plate C6. Thus, the third layer of membrane electrode assembly is completed.

[0076] Place the electrode plate D7 with the second flow channel side facing down and lay it flat on the third layer of membrane electrode. Align the first material perforation D7-3 with the gasket perforation 9-6 of the upper layer of membrane electrode, and the second material outlet D7-2 faces right. Place the fourth group of membrane electrode assemblies 9 with gaskets with the cathode 9-1 side facing down and lay it flat on the first flow channel of the electrode plate D7. Note that the gasket perforation 9-6 on the fourth group of membrane electrode assemblies 9 with gaskets should not coincide with the first material outlet D7-4 on the electrode plate D7. Thus, the fourth layer of membrane electrode assembly is completed.

[0077] Place the electrode plate E with the non-flow channel side facing up and lay it flat on the fourth layer of membrane electrode. The second material outlet threaded hole E8-2 faces right.

[0078] Place the additional current collector plate 3, end plate insulating gasket 2, and the second end plate 10 flat on the electrode plate E in sequence from bottom to top. Note that the side with the regular hexagonal counterbore of the second end plate 10 is placed facing up. Insert the hexagonal nuts and bolts into the corresponding positions on the end plates and tighten the bolts. Thus, the assembly of the 4×25 cm 2 membrane electrode stack is completed.

[0079] The 4×25 cm of this embodiment 2 The CO2 electroreduction performance test of the membrane electrode stack is as follows:

[0080] For the 4×25 cm in Example 1 2 membrane electrode stack used for the CO2 electroreduction performance test, the composition of the membrane electrode assembly 9 with gaskets is as follows: The cathode 9-1 selects SIGRACET 38BC carbon paper loaded with Ag / C catalyst; the cathode gasket 9-2 selects a polytetrafluoroethylene gasket; the membrane 9-3 selects an anion exchange membrane Fumasep FAA-3-50; the anode gasket 9-4 selects a fluororubber gasket; the anode 9-5 selects a Ti mesh loaded with IrO2.

[0081] Connect the threaded hole on the side of the assembled 4×25 cm 2 membrane electrode stack to the inverted cone joint with corresponding threads. Pass CO2 with different flow rates into the first material inlet threaded hole A4-1. The CO2 flows through the three-channel serpentine flow path in the electrode plates ABCD in the order of "first material inlet A4-1 → first material outlet A4-2 → first material perforation B5-3 → first material inlet B5-4 → first material outlet B5-5 → first material perforation C6-3 → first material inlet C6-4 → first material outlet C6-5 → first material perforation D7-3 → first material inlet D7-4 → first material outlet D7-5" in and out of the 4×25 cm 2 membrane electrode stack. Pass Cs2CO3 electrolyte into the second material inlets B5-1, C6-1, D7-1, and E8-1 respectively. The flow rate of the electrolyte is 30 mL / min for all, and the concentration of the electrolyte is 0.05 mol / L for all. The four streams of electrolyte flow through the parallel flow paths in the electrode plates B, C, D, and E in the order of "second material inlet B5-1 → second material outlet B5-2; second material inlet C6-1 → second material outlet C6-2; second material inlet D7-1 → second material outlet D7-2; second material inlet E8-1 → second material outlet E8-2" in and out of the 4×25 cm 2 membrane electrode stack. Connect the current collector plate 3 on the side of the electrode plate A close to the first end plate to the negative pole of the power supply, and connect the current collector plate 3 on the side of the electrode plate E close to the second end plate to the positive pole of the power supply. Use a constant current source to set the total current to 1.25 A.

[0082] The layered membrane electrode reactor with a cathode area of 100 cm 2 was also tested. Its cathode flow channel is a three-channel serpentine flow channel, and the anode flow channel is a parallel flow channel. The flow channel depth and the width of the flow channel ridge groove are both the same as those of the 4×25 cm 2 membrane electrode stack. The cathode uses SIGRACET 38BC carbon paper loaded with Ag / C catalyst; the cathode gasket uses a polytetrafluoroethylene gasket; the membrane uses an anion exchange membrane Fumasep FAA-3-50; the anode gasket uses a fluororubber gasket; the anode uses a Ti mesh loaded with IrO2. CO2 was introduced into the 100 cm 2 layered membrane electrode reactor at the same flow rate, and 0.05 mol / L Cs2CO3 electrolyte was introduced into the 100 cm 2 layered membrane electrode reactor at a flow rate of 120 mL / min. The total current was set to 5 A (the current density was 50 mA / cm 2 ).

[0083] 4×25 cm 2 The test results of the membrane electrode stack and the 100 cm 2 layered membrane electrode reactor are as Figures 10 to 11 shown. It can be seen from the results that the stack of the present invention has a higher Faraday efficiency (FE CO) and energy efficiency (EE) of the main product CO and a higher CO energy consumption output ratio (m 2 ·kWh 3 ·kWh -1 ) than the 100 cm

[0084] layered membrane electrode reactor. Figure 8 Example 2: As 2 shown, the assembly and testing of the 4×4 cm

[0085] membrane electrode stack 2 The main difference between the membrane electrode stack used in Example 2 and that in Example 1 is that the cathode 9-1 area is 4 cm

[0086] . In Example 2, the first flow channels on the plate A4, plate B5, plate C6, and plate D7 are single serpentine flow channels. In addition, there are only nine fixed holes on the first end plate 1 and the second end plate 10 of the membrane electrode stack in this example, and they are all circular through holes. 2 The assembled 4×4 cm 2 membrane electrode stack was tested for CO2 electroreduction performance, and the layered membrane electrode reactor with a cathode area of 16 cm 2 was tested under the current density condition of 200 mA / cm 2The cathode flow channel of the layered membrane electrode reactor is a single serpentine flow channel, and the anode flow channel is a parallel flow channel. The flow channel depth and the width of the flow channel ridge groove are both 4×4 cm 2 The membrane electrode stack is consistent. All other test conditions are kept the same.

[0087] 4×4 cm 2 The membrane electrode stack and the 16 cm 2 The test results of the layered membrane electrode reactor are as follows Figures 12 to 13 shown. It can be seen from the results that the stack of the present invention has a higher Faraday efficiency (FE CO) and energy efficiency (EE) of the main product CO and a higher CO energy consumption output ratio (m 2 ·kWh 3 ·kWh -1 ) than that of the 16 cm

[0088] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many specific transformations in form without departing from the spirit of the invention and the scope protected by the claims. All of these fall within the protection scope of the present invention.

Claims

1. A membrane electrode stack for carbon dioxide electroreduction, characterized in that: It includes a group of main plates and N groups of extended plates, where N is a natural number; one group of the main plates includes plates A, D and E, and one group of the extended plates includes plates B and C; a first flow channel is arranged on one side of the plate A, a first flow channel and a second flow channel are arranged on both sides of the plates B, C and D, and a second flow channel is arranged on one side of the plate E; The internal arrangement of a set of main plates and N sets (where N is a natural number) of extended plates is A-(BC) N -DE, and the first flow channel of each main plate or extended plate is arranged opposite to the second flow channel of the adjacent main plate or extended plate; The first flow channel is used to flow through the first material and realize the series control of the first material in the main plate and the extended plate, and the second flow channel is used to flow through the second material and realize the independent control of the second material in the main plate and the extended plate.

2. A membrane electrode stack for carbon dioxide electroreduction according to claim 1, characterized in that: The outer side of the electrode plate A is provided with a first material inlet A, and the first material inlet A is connected with the starting end of the first flow channel of the electrode plate A; the side where the first flow channel of the electrode plate A is located is provided with a first material outlet A, and the first material outlet A is connected with the end of the first flow channel of the electrode plate A; The electrode D is provided with a first material through-hole D on the side where the second flow channel is located; when N=0, the first material through-hole D is arranged opposite to the first material outlet A of the electrode A; when N≥1, the first material through-hole D is arranged opposite to the first material outlet C of the electrode C; the electrode D is provided with a first material inlet D on the side where the first flow channel is located, and the first material inlet D is connected with the first material through-hole D, so that the first material can shuttle inside the electrode D5; the outer side of the electrode D is provided with a first material outlet D, a second material inlet D and a second material outlet D, the first material outlet D is connected with the end of the first flow channel, and the beginning of the first flow channel is connected with the first material inlet D; the second material inlet D and the second material outlet D are respectively connected with the beginning and the end of the second flow channel of the electrode D; A second material inlet E and a second material outlet E are provided on the outer side of the electrode plate E. The second material inlet E and the second material outlet E are connected to the starting end and the end of the second flow channel of the electrode plate E respectively.

3. A membrane electrode stack for carbon dioxide electroreduction according to claim 1, characterized in that: The electrode B is provided with a first material through-hole B on the side where the second flow channel is located; when N=1, the first material through-hole B is arranged opposite to the first material outlet A of the electrode A; when N>1, the first material through-hole B is arranged opposite to the first material outlet C of the electrode C; the electrode B is provided with a first material inlet B and a first material outlet B on the side where the first flow channel is located, the first material inlet B is connected to the first material through-hole B and the starting end of the first flow channel of the electrode B respectively, and the first material outlet B is connected to the end of the first flow channel of the electrode B; the outer side of the electrode B is provided with a second material inlet B and a second material outlet B, the second material inlet B and the second material outlet B are connected to the starting end and the end of the second flow channel of the electrode B respectively; The pole plate C is provided with a first material through-hole C on the side where the second flow channel is located, and the first material through-hole C is arranged opposite to the first material outlet B of the pole plate B; the pole plate C is provided with a first material inlet C and a first material outlet C on the side where the first flow channel is located, the first material inlet C is communicated with the first material through-hole C and the starting end of the first flow channel of the pole plate C respectively, and the first material outlet C is communicated with the end of the first flow channel of the pole plate C; the outer side of the pole plate C is provided with a second material inlet C and a second material outlet C, and the second material inlet C and the second material outlet C are respectively communicated with the starting end and the end of the second flow channel of the pole plate C.

4. A membrane electrode stack for carbon dioxide electroreduction according to claim 3, characterized in that: The first material through hole B and the first material inlet B are correspondingly arranged on the two sides of the electrode plate B; the first material through hole C and the first material inlet C are correspondingly arranged on the two sides of the electrode plate C.

5. A membrane electrode stack for carbon dioxide electroreduction according to any one of claims 1 to 3, characterized in that: The first flow channel and the second flow channel are respectively selected from one of a single serpentine flow channel, a multi-channel serpentine flow channel, a parallel flow channel, a staggered flow channel, and a needle-shaped flow channel.

6. A membrane electrode stack for carbon dioxide electroreduction according to any one of claims 1 to 3, characterized in that: The second material inlet and the second material outlet of the same electrode plate may be located on the same side or on both sides.

7. A membrane electrode stack for carbon dioxide electroreduction according to any one of claims 1 to 3, characterized in that: For cathode CO2 electroreduction coupled to anode water electrolysis, the first material is CO2, and the second material is electrolyte; the first flow channel is preferably a serpentine flow channel; and the second flow channel is preferably a parallel flow channel.

8. A membrane electrode stack for carbon dioxide electroreduction according to any one of claims 1 to 3, characterized in that: Positioning holes are respectively arranged at the four corners of the main pole plate and the extended pole plate, and the positioning holes are used for connecting the main pole plate and the extended pole plate.

9. A membrane electrode stack for carbon dioxide electroreduction according to any one of claims 1 to 3, characterized in that: A membrane electrode assembly is arranged between two adjacent layers of electrode plates, and the electrode plates include a main electrode plate and an extended electrode plate; the membrane electrode assembly includes a cathode, a cathode gasket, a membrane, an anode gasket, and an anode stacked in sequence; positioning holes are respectively arranged at the four corners of the cathode gasket and the anode gasket, and the cathode gasket and the anode gasket are provided with gasket perforations for aligning with the first material perforations of each electrode plate.

10. A membrane electrode stack for carbon dioxide electroreduction according to any one of claims 1 to 3, characterized in that: A first end plate and a second end plate are respectively provided on the side of the electrode plate A where the first flow channel is not provided and on the side of the electrode plate E where the second flow channel is not provided; an end plate insulating gasket and a current collecting plate are sequentially provided between the first end plate and the electrode plate A and between the second end plate and the electrode plate E.

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