CN114395773B - Carbon dioxide electrolysis cell and carbon dioxide electrolysis stack device - Google Patents

Abstract

The invention relates to the technical field of carbon dioxide electrolysis, in particular to a carbon dioxide electrolysis cell and a carbon dioxide electrolysis stack device. The carbon dioxide electrolysis cell includes: a first pole plate; a cathode electrode disposed on one side of the first pole plate, and the cathode electrode and the first pole plate form a carbon dioxide gas chamber; a liquid flow plate disposed on a side of the cathode electrode away from the first pole plate, and the liquid flow plate is provided with a hole for catholyte to pass through; a diaphragm is disposed on a side of the liquid flow plate away from the cathode electrode, and a catholyte chamber is formed between the diaphragm and the cathode electrode; an anode electrode is disposed on the diaphragm and away from the liquid flow plate and a second pole plate disposed on a side of the anode electrode away from the diaphragm, an anolyte chamber is formed between the second pole plate and the diaphragm.

Description

Carbon dioxide electrolysis cell and carbon dioxide electrolysis stack device

technical field

The invention relates to the technical field of carbon dioxide electrolysis, in particular to a carbon dioxide electrolysis cell and a carbon dioxide electrolysis stack device.

Background technique

With the development of efficient carbon dioxide emission reduction technology in my country is imperative, among many technologies, carbon dioxide electrolysis is generally considered to have broad prospects, using cheap renewable electricity, can efficiently convert carbon dioxide into formic acid, ethanol and other high value-added chemicals. However, most of the research on electrolysis of carbon dioxide is still in the laboratory research stage, the total reaction current is less than 0.1A, and the total electrolysis power is less than 0.5W; only a few large-scale carbon dioxide electrolysis devices are based on the research of a single electrolytic cell, the overall power is still limited (<20W), and most of them adopt the two-chamber membrane electrode configuration based on anion membrane. This two-chamber electrolytic cell configuration only includes a cathode gas chamber and an anolyte chamber. The anion membrane is in direct contact with the cathode electrode. The operational stability of the device mainly depends on the life of the anion membrane under strong alkaline conditions. Limited by the current low performance of the anion membrane, the running time of carbon dioxide electrolysis cells in this configuration is generally less than 50 hours. Therefore, there is still a lack of carbon dioxide electrolysis cells and carbon dioxide electrolysis stack devices that can maintain a running time of more than 200 hours and an electrolysis power of more than 1kW, which severely limits the industrial application of carbon dioxide electrolysis.

Contents of the invention

Based on this, the present invention provides a carbon dioxide electrolysis cell and a carbon dioxide electrolysis stack device capable of long-term stable operation, low energy consumption and higher electrolysis efficiency.

One aspect of the present invention provides a carbon dioxide electrolytic cell, comprising:

first plate;

The cathode electrode is arranged on one side of the first pole plate, and the cathode electrode and the first pole plate form a carbon dioxide gas chamber;

A liquid flow plate is located on the side of the cathode electrode away from the first plate, and the liquid flow plate is provided with holes for catholyte to pass through;

a diaphragm, arranged on the side of the liquid flow plate away from the cathode electrode, forming a catholyte chamber between the diaphragm and the cathode electrode;

an anode electrode located on the side of the diaphragm facing away from the flow plate; and

The second pole plate is arranged on the side of the anode electrode away from the diaphragm, and an anolyte chamber is formed between the second pole plate and the diaphragm;

Wherein, a surface of the first pole plate facing the cathode electrode is provided with a first groove, a surface of the second pole plate facing the anode electrode is provided with a second groove, and the plurality of first grooves and/or the second grooves extend to form a flow channel, and the flow channel is a multi-channel flow channel.

In one embodiment, the flow channel is a multi-channel serpentine flow channel, the number of channels is 3-8, the width of a single channel is 0.5 mm-5 mm, and the depth is 0.1 mm-3 mm.

In one embodiment, the anode electrode is a porous material formed by an anode catalyst or is composed of a porous substrate and a catalyst layer formed by an anode catalyst disposed on the surface of the porous substrate.

In one embodiment, the cathode electrode is a porous gas diffusion electrode, comprising a laminated gas diffusion layer and a cathode catalyst layer, the gas diffusion layer is disposed toward the side of the first plate, and the cathode catalyst layer is disposed toward the side of the liquid flow plate.

In one of the embodiments, the gas diffusion layer includes at least one gas diffusion sublayer, and the cathode catalyst layer includes at least one cathode catalyst sublayer.

In one embodiment, the membrane is an anion exchange membrane or a cation exchange membrane.

In one embodiment, the materials of the first pole plate and the second pole plate are conductive materials independently selected from one or more of aluminum, titanium, stainless steel and graphite, and/or, the material of the liquid flow plate is insulating resin.

In one of the embodiments, the carbon dioxide electrolytic cell further includes a flow-limiting channel, and the flow-limiting channel includes a pipeline for transmitting the anolyte from the outside to the second plate, a pipeline for transmitting the gas from the outside to the first plate, and a pipeline for transmitting the catholyte to the liquid flow plate from the outside, and the length of each pipeline is 5 cm to 50 cm. .

Still another aspect of the present invention provides a carbon dioxide electrolytic cell stack device, comprising a plurality of carbon dioxide electrolytic cells stacked in series, wherein at least one carbon dioxide electrolytic cell is the carbon dioxide electrolytic cell.

In one embodiment, each of the carbon dioxide electrolytic cells is the carbon dioxide electrolytic cell described in any one of claims 1-7.

In one of the embodiments, there are at least two adjacent carbon dioxide electrolytic cells, wherein the first plate of one of the carbon dioxide electrolytic cells is shared with the second plate of the other carbon dioxide electrolytic cell, and one surface of the shared plate is provided with the first groove, and the other surface is provided with the second groove.

Compared with the prior art, the present invention at least includes the following beneficial effects:

The carbon dioxide electrolytic cell provided by the present invention, on the one hand, introduces a catholyte chamber on the cathode side on the basis of the two-chamber configuration, so that the carbon dioxide electrolyzer forms a three-chamber structure of a carbon dioxide gas chamber, a catholyte chamber, and an anolyte chamber. Stable operation, thereby significantly improving the operating life of the electrolytic cell; on the other hand, by setting grooves on the first pole plate, the second pole plate and the liquid flow plate to form a multi-channel flow channel, the fluid resistance pressure drop in the flow channel and the resistance pressure drop in the flow-limiting channel are regulated through the multi-channel flow channel, thereby increasing the mass transfer rate and reducing energy consumption.

Based on the carbon dioxide electrolysis cell provided by the present invention, a plurality of electrolysis cells can be connected in series to form a carbon dioxide electrolysis stack device, which efficiently enlarges the area of the reaction electrodes, even the total electrode area can be enlarged to ^0.3m2 or more, and the electrolysis power can reach more than 1kW, realizing a reaction scale close to industrial grade and stable running time.

Description of drawings

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the specific embodiments or prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative work.

Fig. 1 is a schematic diagram of a carbon dioxide electrolysis cell of an embodiment;

Fig. 2 is a schematic structural view of a first pole plate in an embodiment;

3 is a schematic structural view of a cathode electrode in an embodiment;

Fig. 4a is a schematic plan view of a liquid flow plate according to an embodiment;

Fig. 4b is a schematic cross-sectional structure diagram of a liquid flow plate in an embodiment;

5 is a schematic structural view of a second pole plate in an embodiment;

Fig. 6 is a schematic structural diagram of a carbon dioxide electrolysis stack device in an embodiment;

Fig. 7 is a schematic structural diagram of a carbon dioxide electrolysis stack device in another embodiment

Explanation of reference signs:

100. Carbon dioxide electrolysis cell;

110, the first pole plate; 120, the cathode electrode; 121, the gas diffusion layer; 122, the cathode catalyst layer; 130, the flow plate; 140, the diaphragm; 150, the anode electrode; 160, the second pole plate;

200, fixed plate;

300. Screwed fasteners;

L1, anolyte distribution pipe;

M1, anolyte converging pipe;

L2, catholyte distribution pipe;

M2, anolyte converging pipe;

L3, gas distribution pipe;

M3, gas converging pipe.

Detailed ways

Reference will now be made in detail to embodiments of the invention, one or more examples of which are described below. Each example is provided by way of explanation, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment can be used on another embodiment to yield a still further embodiment.

Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the invention are disclosed in or are apparent from the following detailed description. It is to be understood by those of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended to limit the broader aspects of the invention.

Except as shown in the working examples or otherwise indicated, all numbers used in the specification and claims expressing amounts of ingredients, physicochemical properties, etc. are understood to be adjusted in all cases by the term "about". For example, therefore, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and appended claims are approximations that can be appropriately altered by those skilled in the art to obtain the desired properties sought to obtain using the teachings disclosed herein. The use of numerical ranges by endpoints includes all numbers within that range and any range within that range, eg, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, and so on.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to FIG. 1 , an embodiment of the present invention provides a carbon dioxide electrolysis cell 100 , including a first pole plate 110 , a cathode electrode 120 , a liquid flow plate 130 , a diaphragm 140 , an anode electrode 150 and a second pole plate 160 .

A surface of the first plate 110 facing the cathode electrode 120 is provided with a first groove a. Please refer to FIG. 2 , the first groove a extends to form a flow channel with a plurality of channels. The flow channel may be a serpentine flow channel, a parallel flow channel or an intersecting comb flow channel. In the specific example shown in FIG. 2 , the flow channel is a serpentine flow channel.

In some preferred embodiments, the flow channel is a multi-channel serpentine flow channel, the number of channels is 3-8, the width of a single channel is 0.5 mm-5 mm, and the depth is 0.1 mm-3 mm. The channel design can control the ratio of the fluid resistance pressure drop in the flow channel to the resistance pressure drop in the flow-limiting channel between 10 and 100, control the operating pressure of the fluid in a better range, further increase the mass transfer rate, reduce energy consumption, and improve the electrolysis efficiency of the electrolytic cell.

The material of the first pole plate 110 can be independently selected from chemically stable conductive materials (such as metal aluminum, titanium, stainless steel, or graphite, etc.), so that the first pole plate 110 can be used as a current collector. In some embodiments, the first electrode plate 110 is further provided with a current collecting joint, through which the current collecting joint communicates with an external circuit.

The cathode electrode 120 is disposed on one side of the first pole plate 110, and the cathode electrode 120 and the first pole plate 110 form a carbon dioxide gas chamber through which the carbon dioxide gas can circulate. A gas inlet (not shown) and a gas outlet (not shown) are connected to the first plate 110 , and carbon dioxide gas or gas containing carbon dioxide is introduced and discharged by a flow controller not shown through the gas inlet and gas outlet. Carbon dioxide gas or a gas containing carbon dioxide flows through the carbon dioxide gas chamber so as to be in contact with the cathode electrode 120 .

What takes place at the cathode electrode 120 is the reduction reaction of carbon dioxide (CO ₂ ), which generates carbon-containing compounds such as formic acid (HCOOH), carbon monoxide (CO), methane (CH ₄ ), acetic acid (CH ₃ COOH), ethylene (C ₂ H ₄ ), methanol (CH ₃ OH), ethanol (C ₂ H ₅ OH), and n-propanol (C ₃ H ₇ OH).

Referring to FIG. 3 , in some embodiments, the cathode electrode 120 has a gas diffusion layer 121 and a cathode catalyst layer 122 disposed on the gas diffusion layer 121 . As shown in FIG. 3 , the gas diffusion layer 121 is disposed on the side of the carbon dioxide gas flow path, that is, on the side facing the first electrode plate 110 in the carbon dioxide electrolytic cell. The cathode catalyst layer 122 is arranged on the side of the cathode solution flow path, that is, on the side facing the liquid flow plate 130 in the carbon dioxide electrolytic cell. The cathode catalyst layer 122 preferably has catalyst nanoparticles and catalyst nanostructures. The gas diffusion layer 111 is made of, for example, porous carbon substrates such as carbon paper and carbon cloth, metal mesh, metal foam, porous film and other materials.

In the cathode catalyst layer 122, the catholyte, ions are supplied and discharged from the catholyte chamber, and in the gas diffusion layer 121, the _CO2 gas is supplied from the carbon dioxide gas chamber. The gas diffusion layer 121 is a hydrophobic and breathable porous structure, so as to ensure that CO ₂ gas can pass through the gas diffusion layer 121 to reach the cathode catalyst layer 122 . The reduction reaction of _CO2 occurs near the boundary between the gas diffusion layer 121 and the cathode catalyst layer 122, and the gas phase products are mainly discharged from the carbon dioxide gas chamber, and the liquid phase products are mainly discharged from the catholyte chamber.

The cathode catalyst layer 122 is preferably made of a catalytic material (cathode catalytic material), which can reduce carbon dioxide to generate a specific carbon-containing compound, and has a lower overpotential and a higher selectivity. Such materials include one or more of carbon materials, transition metal materials, composite materials of carbon and transition metals, composite materials of carbon and transition metal oxides, alloys of noble metals and transition metals, and composite materials of noble metals and transition metal oxides, wherein the transition metals can be selected from one or more of copper, tin, bismuth, lead, indium, cadmium, zinc, and nickel, and the noble metals can be selected from one or more of gold, silver, and platinum group metals. The preparation method of the above-mentioned composite material can be selected from one or more of electrodeposition, physical mixing, hydrothermal method, pyrolysis method, ball milling method and vapor deposition method. In the composite material, the mass percentage content of transition metal or transition metal oxide can be 30%-100%, and the mass percentage content of noble metal or carbon is not more than 70%. Various shapes such as a plate shape, a grid shape, a wire shape, a particle shape, a porous shape, a film shape, and an island shape can be applied to the cathode catalyst layer 122 .

The liquid flow plate 130 is disposed on a side of the cathode electrode 120 away from the first electrode plate 110 . Please refer to FIG. 4a and FIG. 4b , the liquid flow plate 130 is provided with a hollow channel c for the catholyte to pass through. A plurality of channels c are extended to form a flow channel. Similarly, the flow channel can also be a serpentine flow channel, a parallel flow channel or an intersecting comb flow channel, preferably a multi-channel serpentine flow channel, the number of channels is 3 to 8, the width of a single channel is 0.5 mm to 5 mm, and the depth is 0.1 mm to 10 mm. By setting such a multi-channel serpentine flow channel on the liquid flow plate, the operating pressure of the fluid can be further reduced, the mass transfer rate can be increased, energy consumption can be reduced, and the electrolysis efficiency of the electrolytic cell can be improved. It should be noted that the width of the channel c is the width of a single channel, and the depth of the channel c is the depth of a single channel. In some embodiments, the channel c of the liquid flow plate 130 is further provided with a plurality of connecting ribs d, the connecting ribs d are arranged between the two panels forming the channel c to enhance the mechanical strength of the flow channel, and the thickness of the connecting ribs d is 0.1 mm to 8 mm.

The material of the fluid flow plate 130 can be independently selected from chemically stable insulating materials, preferably insulating resin materials with high chemical stability and high mechanical strength, such as polyether ether ketone (PEEK), chlorinated polyvinyl chloride, ABS plastic, and the like. .

The diaphragm 140 is disposed on a side of the liquid flow plate 130 away from the cathode electrode 120 . A catholyte chamber through which the catholyte can flow is formed between the separator 140 and the cathode electrode 120 . The catholyte chamber is disposed between the cathode electrode 120 and the membrane 140 such that the catholyte is in contact with the cathode electrode 120 and the membrane 140 . A catholyte inlet (not shown) and a catholyte outlet (not shown) are connected to the liquid flow plate 130 , and the catholyte is introduced and discharged by a pump (not shown) through these catholyte inlets and catholyte outlets. The catholyte flows through the catholyte channel (catholyte chamber) in contact with the cathode electrode 120 and the separator 140 .

The separator 140 is constituted by, for example, an ion exchange membrane capable of moving ions between the anode electrode 150 and the cathode electrode 120 and capable of separating the anode and cathode of the electrolytic cell. As the ion exchange membrane, for example, cation exchange membranes such as Nafion and Flemion, and anion exchange membranes such as Neosepta and Selemion can be used. Preferably, the membrane 140 is composed of a cation exchange membrane. However, a glass filter, a porous polymer membrane, a porous insulating material, or the like may be used for the separator 140 as long as it is a material capable of moving ions between the anode electrode 150 and the cathode electrode 120 other than the ion exchange membrane.

The anode electrode 150 is disposed on the side of the diaphragm 140 away from the liquid flow plate 130 . The anode electrode 150 can oxidize water (H ₂ O) to generate oxygen and hydrogen ions, or can oxidize hydroxide ions (OH ⁻ ) to generate water and oxygen, and is preferably mainly composed of a catalytic material (anode catalytic material) that can reduce the overvoltage of such a reaction. Examples of such catalytic materials include metals such as platinum (Pt), palladium (Pd), nickel (Ni), alloys containing these metals, intermetallic compounds, manganese oxide (Mn-O), iridium oxide (Ir-O), nickel oxide (Ni-O), cobalt oxide (Co-O), iron oxide (Fe-O), tin oxide (Sn-O), indium oxide (In-O), ruthenium oxide (Ru-O), lithium oxide (Li-O), lanthanum oxide (La-O), and the like. Elementary metal oxides, Ni-Co-O, Ni-Fe-O, La-Co-O, Ni-La-O, Sr-Fe-O and other ternary metal oxides, Pb-Ru-Ir-O, La-Sr-Co-O and other quaternary metal oxides, Ru complexes, Fe complexes and other metal complexes.

In addition, the anode electrode 150 also has a structure capable of moving the anolyte and ions between the diaphragm and the anolyte chamber, such as mesh material, punched material, porous body, metal fiber sintered body and other substrates with a porous structure. The base material can be made of metal materials such as titanium (Ti), nickel (Ni), iron (Fe), alloys containing at least one of these metals (such as stainless steel), or the above-mentioned anode catalyst materials. When an oxide is used as the anode catalyst material, it is preferable to form a catalyst layer by adhering or laminating the anode catalyst material on the surface of the substrate made of the above-mentioned metal material. In terms of enhancing the oxidation reaction, the anode catalyst material preferably has nanoparticles, nanostructures, nanowires, and the like. The nanostructure is a structure in which nanoscale irregularities are formed on the surface of the catalytic material.

The second electrode plate 160 is disposed on a side of the anode electrode 150 away from the separator 140 . An anolyte chamber through which the anolyte can flow is formed between the second plate 160 and the diaphragm 140 . The anolyte chamber is used to supply the anolyte to the anode electrode 150, and the second plate is provided with an anolyte inlet (not shown) and an anolyte outlet (not shown), through which the anolyte inlet and the anolyte outlet, the anolyte is introduced and discharged by a pump not shown. The anolyte is circulated within the anolyte chamber in contact with the second plate 160 .

Referring to FIG. 5 , a surface of the second plate 160 facing the anode electrode 150 is provided with a second groove b. The second groove b extends to form a flow channel with multiple channels. The flow channel formed by the second groove b can also be a serpentine flow channel, a parallel flow channel or an intersecting comb-shaped flow channel. FIG. 5 shows a serpentine flow channel.

The material of the second pole plate 160 can be independently selected from chemically stable conductive materials (such as metal aluminum, titanium, stainless steel, or graphite, etc.), so as to ensure that the second pole plate 160 can be used as a current collector. In some embodiments, the second electrode plate 160 is further provided with a current collecting joint, which communicates with the external circuit through the current collecting joint.

The anolyte and catholyte of the carbon dioxide electrolytic cell of the present invention are preferably solutions containing at least water (H ₂ O). Carbon dioxide (CO ₂ ) is supplied from the CO ₂ gas chamber, so the catholyte may or may not contain carbon dioxide (CO ₂ ). The anolyte and catholyte can be the same solution or different solutions. Examples of the H ₂ O-containing solution used as the anolyte and the catholyte include an aqueous solution containing an arbitrary electrolyte. Examples of aqueous solutions containing electrolytes include hydroxide ions (OH ^- ), hydrogen ions (H ⁺ ), potassium ions (K ⁺ ), sodium ions (Na ⁺ ), lithium ions (Li ⁺ ), cesium ions (Cs ⁺ ), chloride ions (Cl ^- ), bromide ions (Br ^- ), iodide ions (I ^- ), nitrate ions (NO ₃ ^- ), sulfate ions (SO ₄ ^2- ), and formate ions (HCOO ^- ). , an aqueous solution of at least one ion of phosphate ion (PO _{4 3− ), borate ion (BO 3 3−} ⁾ , and bicarbonate ion (HCO ³ ₋ ⁾ . In order to reduce the resistance of the solution, it is preferable to use a solution obtained by dissolving an electrolyte such as potassium hydroxide, sodium hydroxide, and potassium bicarbonate at a high concentration as the anolyte and catholyte.

The catholyte may also be composed of salts of cations such as imidazolium ions and pyridinium ions and anions such as BF ₄ ^- , PF ₆ ^-, and ionic liquids that are liquid in a wide temperature range or aqueous solutions thereof may be used. Examples of other catholytes include amine solutions such as ethanolamine, imidazole, and pyridine, or aqueous solutions thereof. The amine may be any of primary, secondary and tertiary amines.

In some embodiments, the carbon dioxide electrolysis cell further includes a flow-limiting channel (not shown in the figure). The flow-restricting channel includes a pipeline that transmits the anolyte from the outside to the second plate 160, a pipeline that transmits the gas from the outside to the first plate 120, and a pipeline that transmits the catholyte from the outside to the liquid flow plate 130, and the length of each section of pipeline is 5 cm to 50 cm.

Further, the present invention also provides a carbon dioxide electrolysis cell stack device, including a plurality of carbon dioxide electrolysis cells, the plurality of carbon dioxide electrolysis cells are stacked in series, wherein at least one carbon dioxide electrolysis cell is the carbon dioxide electrolysis cell 100 of any of the above-mentioned embodiments.

Please refer to FIG. 6 , in some embodiments, in the carbon dioxide electrolysis cell stack device, each carbon dioxide electrolysis cell is the above-mentioned carbon dioxide electrolysis cell 100 . Two adjacent carbon dioxide electrolytic cells 100, wherein the first pole plate 110 of one carbon dioxide electrolytic cell 100 and the second pole plate 160 of another carbon dioxide electrolytic cell 100 are shared, and one surface of the shared pole plate is provided with the first groove a, and the other surface is provided with the second groove b.

In order to ensure good sealing performance of the carbon dioxide electrolysis cell stack device, in some embodiments, positioning holes are provided on the first pole plate 110 , the liquid flow plate 130 and the second pole plate 160 . Preferably, the number of fixing holes on each plate is four, and more preferably, the fixing holes are evenly distributed around the plate. The positioning holes on the first pole plate 110 , the liquid flow plate 130 and the second pole plate 160 are in one-to-one correspondence.

Further, in some embodiments, the carbon dioxide electrolysis cell stack device is also provided with a fixing assembly, including two fixing plates 200 and a plurality of screw fasteners 300 . Considering multiple carbon dioxide electrolytic cells stacked in series as a whole, as a device to be fixed, two fixing plates are respectively arranged on opposite sides of the device to be fixed, and fixing holes are provided on the fixing plate 200 . Preferably, the number of fixing holes on the fixing plate is 8, and more preferably, the fixing holes are evenly distributed around the fixing plate. The fixing holes on the two fixing plates are in one-to-one correspondence.

In some preferred embodiments, the threaded fastener 300 is a spring screw fastener including a screw, a nut and a coil spring. The use of spring screw fasteners to realize the sealing of the carbon dioxide electrolytic stack can solve the problem of thermal expansion and cold contraction of the carbon dioxide electrolytic stack when it is operated at different temperatures, avoiding damage to the device, and improving the operating stability and life of the device.

In order to further ensure the sealing performance of the carbon dioxide electrolysis cell stack, in some embodiments, a sealing assembly is also provided between the first pole plate 110 and the liquid flow plate 130, and/or between the second pole plate 160 and the liquid flow plate 130, and/or between the liquid flow plate 130 and the diaphragm 140.

In some embodiments, the sealing assembly includes a sealing ring and a gasket, the sealing ring is disposed on the outer periphery of the required sealing component, and the gasket is disposed between the sealing ring and the required sealing component.

Further, please refer to Fig. 7, the carbon dioxide electrolysis stack device of the present invention also includes:

a power supply (not shown in the figure) that causes current to flow between the anode and cathode sections of each electrolysis cell of the carbon dioxide electrolysis stack;

a solution system for controlling the flow of solution in the device; and

Gas system for controlling the flow of gas in the unit.

The power source is not limited to a general commercial power source, battery, etc., and may be a power source that supplies electric power generated by renewable energy such as solar cells or wind power generation.

The solution system includes a first solution system connected to the anolyte chamber with a pressure control part, an anolyte distribution pipe L1, a flow control part (pump), an anolyte converging pipe M1; and

The second solution system connected to the catholyte chamber has a pressure control part, a catholyte distribution pipe L2, a flow control part (pump), and an anolyte converging pipe M2.

The gas system includes a pressure control part connected to the carbon dioxide gas chamber, a temperature regulation part, a gas distribution pipe L3, a flow control part (flow controller), and a gas converging pipe M3.

The solution flow rate and pressure of the anolyte and catholyte are controlled by the solution system. The solution flow rate of the anolyte and catholyte was controlled at about 100 mL/min, and the pressure was controlled at 1 bar to 5 bar. The carbon dioxide electrolysis cell device provided by the present invention controls the ratio of the fluid resistance pressure drop in the flow channel to the resistance pressure drop in the flow-limiting channel between 10 and 100. If it is higher than 10, it can ensure the uniform distribution of the fluid in each electrolytic cell, and if it is lower than 100, it can reduce the power consumption of the pump and improve the energy efficiency.

In the carbon dioxide electrolysis stack device, the flow-limiting channels include the pipeline from the anolyte distribution pipe L1 to the second pole plate 160, the pipeline from the gas distribution pipe L31 to the first pole plate 110, and the pipeline from the catholyte distribution pipe L2 to the liquid flow plate 130.

The gas flow rate, pressure and temperature are controlled by the gas system. The gas flow rate is controlled at 100-500 sccm (single electrolytic cell). If it is lower than 100 sccm, it cannot provide enough CO ₂ to participate in the reaction; if it is higher than 500 sccm, the energy efficiency of the reaction will be significantly reduced. The gas pressure is controlled at slightly higher than normal pressure. The gas temperature is controlled at 0°C to 100°C.

The following are specific examples. The present invention is intended to be further described in detail to help those skilled in the art and researchers to further understand the present invention, and relevant technical conditions and the like do not constitute any limitation to the present invention. Any form of modification made within the scope of the claims of the present invention is within the protection scope of the claims of the present invention.

Example 1

Connect and assemble the carbon dioxide electrolysis cell shown in Fig. 7 with the solution system and the gas system to form an electrolytic stack device, and test the electrolysis performance of carbon dioxide. The carbon dioxide electrolysis cell stack contains a total of 30 electrolytic cells, in which the gas diffusion electrode (Sigracet 39BC) loaded with tin dioxide is used as the cathode electrode, the iridium dioxide-loaded titanium foam (0.8mm thick, pore diameter 50 microns) is used as the anode electrode, DuPont’s Nafion 211 is used as the ion exchange membrane, and potassium bicarbonate solution (concentration: 1mol/L) is used as the electrolyte. The pole plate is made of titanium, and the flow plate is made of chlorinated polyvinyl chloride resin. The flow channel formed by the grooves on the plate and the liquid flow plate is a serpentine flow channel (as shown in the figure).

In this electrolysis device, a first solution system including a pressure control unit (not shown in the figure), an anolyte distribution pipe L1, a flow control unit (pump) and an anolyte collection pipe M1 is connected to the anolyte flow path.

A second solution system including a pressure control unit (not shown in the figure), a catholyte distribution pipe L2, a flow control unit (not shown in the figure) and an anolyte collecting pipe M2 is connected to the catholyte flow path.

A pressure control unit (not shown in the figure), a temperature adjustment unit (not shown in the figure), a gas distribution pipe L3, a flow control unit (not shown in the figure) and a gas converging pipe M3 are connected to the carbon dioxide gas flow path.

After the humidified carbon dioxide raw gas passes through the gas distribution pipe L3, it is equally divided into 30 airflows with the same flow rate, which flow into the serpentine flow channels on the cathode side of the bipolar plates of 30 single electrolytic cells, and then pass through the gas diffusion electrode and reach the surface of the cathode catalyst. After rapid electron transfer, it is reduced to formate, and unreacted carbon dioxide flows out of the bipolar plates. The generated formate enters the liquid flow plate, flows out with the electrolyte through the flow channel, converges in the electrolyte converging pipe, and then flows out of the stack, where the subsequent product separation process can be carried out. The gas flow rate in the cathode plate is controlled at 500 sccm (single electrolytic cell) by the flow controller, the gas pressure is controlled at slightly higher than normal pressure by the back pressure controller, and the gas temperature is controlled at 0°C to 100°C.

The anolyte flows through the anolyte distribution pipe L1, is divided into 30 branches with the same flow rate, and then flows into the serpentine flow channel on the anode side of the bipolar plate of 30 single electrolytic cells, and then reaches the surface of the anode catalyst through the pores of the foam electrode (anode electrode). The electrolyte is oxidized on the surface of the catalyst to generate oxygen, and the generated bubbles flow out of the plate along with the flowing electrolyte, converge in the liquid converging pipe and flow out of the stack, and the generated oxygen can be recirculated and flow into the electrolysis device to participate in the reaction. A peristaltic pump is used to transport the anolyte and the flow rate of the single electrolytic cell is controlled at about 100mL/min, and the liquid pressure is controlled at 1 bar to 5 bar through a back pressure controller.

In the above electrolysis device, the ratio of the fluid resistance pressure drop in the serpentine channel to the resistance pressure drop in the flow-limiting channel is controlled at about 100.

In the above carbon dioxide electrolysis cell stack device, under the condition that the total current is 10A (the current density is 100mA/cm ² ), the total voltage of the electrolysis cell stack is 102.7V. The corresponding total power is 1027W, and it remains between 1020W and 1030W during the 300-hour running time. The energy efficiency reaches 53%, showing excellent performance.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, which are convenient for a specific and detailed understanding of the technical solution of the present invention, but should not be construed as limiting the protection scope of the invention patent. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. It should be understood that technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided by the present invention are within the protection scope of the appended claims of the present invention. Therefore, the protection scope of the patent for the present invention shall be determined by the content of the appended claims, and the description and drawings may be used to explain the content of the claims.

Claims (7)

1. A carbon dioxide electrolysis cell stack device, characterized in that at least two adjacent carbon dioxide electrolysis cells are arranged in series in a stacked manner for converting carbon dioxide into a liquid product;

the carbon dioxide electrolytic cell includes:

a first plate;

the cathode electrode is arranged on one side of the first polar plate, and the cathode electrode and the first polar plate form a carbon dioxide gas chamber;

the liquid flow plate is arranged on one side of the cathode electrode, which is far away from the first polar plate, and is provided with a pore canal for the passage of the catholyte;

a diaphragm arranged on one side of the liquid flow plate, which is far away from the cathode electrode, and a catholyte chamber is formed between the diaphragm and the cathode electrode;

an anode electrode arranged on one side of the diaphragm, which is away from the flow plate; and

The second polar plate is arranged on one side of the anode electrode, which is far away from the diaphragm, and an anolyte chamber is formed between the second polar plate and the diaphragm;

the first electrode plate is provided with a first groove towards one surface of the cathode electrode, the second electrode plate is provided with a second groove towards one surface of the anode electrode, the first groove and/or the second groove extend to form a flow channel, the flow channel is a multichannel snake-shaped flow channel, the number of the channels is 3-8, the width of a single channel is 0.5 mm-5 mm, and the depth is 0.1 mm-3 mm; the first polar plate and the second polar plate are made of conductive materials;

wherein a first polar plate of one carbon dioxide electrolytic cell and a second polar plate of the other carbon dioxide electrolytic cell are shared, one surface of the shared polar plate is provided with the first groove, and the other surface is provided with the second groove;

the carbon dioxide electrolysis cell stack device further comprises:

a power supply that causes an electric current to flow between an anode portion and a cathode portion of each of the carbon dioxide cells of the carbon dioxide electrolysis cell stack device;

a solution system for controlling the flow of solution in the device;

a gas system for controlling the flow of gas in the apparatus; and

a flow restricting passage;

the solution system comprises a 1 st solution system which is connected with the anolyte chamber and provided with a pressure control part, an anolyte distributing pipe L1, a flow control part and an anolyte converging pipe M1; and

a 2 nd solution system which is connected with the catholyte chamber and provided with a pressure control part, a catholyte distributing pipe L2, a flow control part and a catholyte converging pipe M2;

the gas system comprises a pressure control part, a temperature adjusting part, a gas distribution pipe L3, a flow control part and a gas converging pipe M3 which are connected with the carbon dioxide gas chamber;

the flow limiting channel comprises a pipeline from the anolyte distributing pipe L1 to the second polar plate, a pipeline from the gas distributing pipe L3 to the first polar plate and a pipeline from the catholyte distributing pipe L2 to the liquid flow plate, and the length of each pipeline is 5 cm-50 cm;

controlling the solution flow rate and the solution pressure of the anolyte and the catholyte through the solution system, wherein the ratio of the fluid resistance pressure drop in the flow channel to the resistance pressure drop in the flow-limiting channel is controlled between 10 and 100 by the carbon dioxide electrolysis galvanic pile device;

and controlling the flow rate, pressure and temperature of the gas through the gas system, wherein the flow rate of the gas of each carbon dioxide electrolytic cell is controlled to be 100-500 sccm.

2. The carbon dioxide electrowinning cell device in accordance with claim 1, wherein said anode electrode is a porous material formed with an anode catalyst.

3. The carbon dioxide electrowinning cell device as recited in claim 1, wherein the anode electrode is formed from a porous substrate and an anode catalyst layer disposed on a surface of the porous substrate.

4. The carbon dioxide electrowinning cell device in accordance with claim 1, wherein the cathode electrode comprises a gas diffusion layer and a cathode catalyst layer stacked, the gas diffusion layer being disposed toward the first plate side, the cathode catalyst layer being disposed toward the flow plate side.

5. The carbon dioxide electrolysis cell stack device according to claim 1, wherein the membrane is an anion exchange membrane or a cation exchange membrane.

6. The carbon dioxide electrowinning cell device as recited in any one of claims 1-5, wherein the first and second electrode plates are each independently selected from one or more of aluminum, titanium, stainless steel and graphite.

7. The carbon dioxide electrowinning cell device as claimed in any one of claims 1 to 5, wherein the material of the flow plate is insulating resin.