Bipolar membrane cells for carbon dioxide capture

Abstract

In one aspect, a bipolar membrane battery comprises a separation layer disposed between an anode half-cell and a cathode half-cell, the anode half-cell having a proton exchange membrane and an anode, the proton exchange membrane being disposed between the anode and the separation layer, the cathode half-cell having an anion exchange membrane and a cathode, the anion exchange membrane being disposed between the cathode and the separation layer, and the bipolar membrane battery further comprising an external circuit connecting the anode and the cathode.

Description

[Technical field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. Provisional Application No. 63 / 272,093, filed October 26, 2021, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] As carbon dioxide (CO2) emissions are increasing globally and causing significant climate change, it is essential to accelerate efforts to reduce CO2 levels to pre-industrial levels. One way to achieve this goal is the development of market-viable CO2 mitigation solutions. However, many carbon-neutral or carbon-negative conversion technologies require concentrated CO2 feedstocks rather than the trace amounts (~400 ppm) of CO2 that can be obtained directly from air. In this context, many direct air (CO2) capture technologies have been developed, such as liquid- or solid-based sorbent systems, fuel cell- or dialysis-based electrochemical systems, and redox (oxidation-reduction) flow battery systems. For example, state-of-the-art liquid sorbent technologies for CO2 capture and separation are essentially realized by a direct capture step by exposing an amine-based organic solution with high CO2 solubility to a large surface area air-liquid interface, followed by a CO2 separation step by temperature swing desorption. Similarly, solid sorbent technologies are realized by pressure swing adsorption (PSA) systems that selectively capture CO2 in an adsorption step and separate CO2 in a desorption step. Nevertheless, these adsorbent technologies require high energy inputs due to high temperature or pressure swing operation.

[0003] Therefore, improved technologies for capturing CO2 are desirable. Summary of the Invention

[0004] Disclosed herein is a bipolar membrane battery for carbon dioxide capture.

[0005] In one aspect, a bipolar membrane battery comprises a separation layer disposed between an anode half-cell and a cathode half-cell, the anode half-cell having a proton exchange membrane and an anode, the proton exchange membrane being disposed between the anode and the separation layer, the cathode half-cell having an anion exchange membrane and a cathode, the anion exchange membrane being disposed between the cathode and the separation layer, and the bipolar membrane battery further comprising an external circuit connecting the anode and the cathode.

[0006] In addition to or in the alternative to one or more features described herein, the cathode half-cell in the bipolar membrane cell according to further embodiments may further comprise a cathode side chamber and a carbon dioxide source stream in fluid communication with the cathode side chamber to supply carbon dioxide to the cathode side chamber.

[0007] In addition to or in place of one or more features described herein, the cathode half-cell of the bipolar membrane cell according to further embodiments may further comprise a cathode chamber and a carbon dioxide depleted stream in fluid communication with the cathode chamber for being withdrawn from the cathode chamber.

[0008] In addition to or in place of one or more of the features described herein, the anode half-cell in the bipolar membrane cell according to further embodiments may further comprise an anode side chamber and a hydrogen-rich stream in fluid communication with the anode side chamber for delivery therefrom.

[0009] In addition to or in the alternative to one or more features described herein, the separator, the anode half-cell, and the cathode half-cell in a bipolar membrane battery according to further embodiments may have a planar configuration facing each other.

[0010] In addition to or in the alternative to one or more features described herein, in a bipolar membrane battery according to a further embodiment, the anode half-cell and the cathode half-cell may be concentrically arranged to form a tubular bipolar membrane battery, and the separation layer may be concentrically arranged between the anode half-cell and the cathode half-cell.

[0011] In addition to or in the alternative to one or more of the features described herein, in further embodiment bipolar membrane batteries, the anode half-cell may be disposed within a tube formed by the cathode half-cell, or the cathode half-cell may be disposed within a tube formed by the anode half-cell.

[0012] In addition to or in the alternative to one or more features described herein, in further embodiment bipolar membrane batteries, both the hydrogen-rich stream and the carbon dioxide source stream may be in fluid communication with a proximal end of the tubular bipolar membrane battery, and a carbon dioxide product stream may be in fluid communication with a distal end of the tubular bipolar membrane battery.

[0013] In addition to or in the alternative to one or more features described herein, in a bipolar membrane battery according to a further embodiment, both the carbon dioxide product stream and the carbon dioxide source stream may be in fluid communication with a proximal end of the tubular bipolar membrane battery, and the hydrogen-rich stream may be in fluid communication with a distal end of the tubular bipolar membrane battery.

[0014] In addition to or in the alternative to one or more of the features described herein, bipolar membrane batteries according to further embodiments may include the anode comprising platinum and the cathode comprising at least one non-platinum group metal.

[0015] In addition to or in the alternative to one or more features described herein, in a bipolar membrane battery according to further embodiments, the separation layer may comprise porous carbon and the thickness of the separation layer may be from 0.25 micrometers to 5 millimeters, or from 1 micrometer to 1 millimeter.

[0016] In addition to or in the alternative to one or more of the features described herein, in a bipolar membrane battery according to a further embodiment, the separation layer may comprise porous carbon, the porous carbon having microporous bodies with pore sizes of less than 2 nanometers, mesoporous bodies with pore sizes of 2 nanometers to 50 nanometers, and porous bodies having pore sizes of 0.0001 cm 3 / g or more 0.1cm 3 / g or less total pore volume and 2m 2 / g or more 500m 2 / g or less, 100m 2 / g or more 2000m 2 / g or less, or 500m 2 / g or more 1000m 2 / g or less BET surface area and 10 -2 and an electrical conductivity of 0.1 S / cm or more.

[0017] In addition to or as an alternative to one or more of the features described herein, bipolar membrane cells according to further embodiments may include a hydrogen withdrawal stream in fluid communication with the anode chamber.

[0018] In another aspect, a device comprises the bipolar membrane battery described above.

[0019] In another aspect, there is provided an apparatus comprising a bipolar membrane battery as claimed in any one of claims 1 to 5, wherein a water electrolysis device is in fluid communication with an inlet of the bipolar membrane battery via a hydrogen rich stream, and wherein a CO electrolysis device is in fluid communication with an outlet of the bipolar membrane battery via a carbon dioxide product stream.

[0020] In yet another aspect, a method for purifying a carbon dioxide product stream includes the steps of: directing a carbon dioxide source stream containing carbon dioxide to a cathode chamber having a cathode half-cell having an anion exchange membrane and a cathode, the cathode being disposed on a side of the anion exchange membrane adjacent to the cathode chamber; withdrawing a carbon dioxide depleted stream from the cathode chamber; reacting the carbon dioxide with water at the cathode to form carbonate ions and bicarbonate ions; directing the carbonate ions and the bicarbonate ions through the anion exchange membrane to a separation layer; and reacting the carbon dioxide with water at the cathode to form carbonate ions and bicarbonate ions through a proton exchange membrane. conducting a hydrogen-rich stream comprising hydrogen to an anode chamber comprising an anode half-cell having an anode and an anode disposed on a side of the proton exchange membrane adjacent to the anode chamber; reacting the hydrogen to form protons and electrons at the anode and conducting the protons through the proton exchange membrane to the separation layer; reacting the protons, carbonate ions, and bicarbonate ions in the separation layer to form carbon dioxide and water; and withdrawing a carbon dioxide product stream comprising the carbon dioxide and the water from the separation layer.

[0021] In addition to or as an alternative to one or more features described herein, further embodiments of the method may further comprise directing at least a portion of the carbon dioxide product stream to at least one of a separation unit, a storage unit, and a direct feed to a CO2 electrolysis cell.

[0022] In addition to or in the alternative to one or more features described herein, in further embodiments of the method, the carbon dioxide source stream may include at least one of air and off-gas from an industrial process.

[0023] In addition to or in the alternative to one or more features described herein, in a further embodiment of the method, the carbon dioxide source stream may have a volume percentage of carbon dioxide of 50% or less, based on a total volume of the carbon dioxide source stream on a dry basis.

[0024] In addition to or in the alternative to one or more features described herein, in further embodiments of the method, the hydrogen-rich stream may have a volume percentage of hydrogen of between 90% and 100%, or between 95% and 99%, based on a total volume of the hydrogen-rich stream on a dry basis.

[0025] In addition to or in the alternative to one or more features described herein, in a further embodiment of the method, the carbon dioxide product stream may have a volume percentage of carbon dioxide, based on the total volume of the carbon dioxide product stream, of greater than or equal to 90% and less than or equal to 100%.

[0026] In addition to or as an alternative to one or more of the features described herein, further embodiments of the bipolar membrane battery are contemplated.

[0027] The above-disclosed and other features are illustrated in the following figures, detailed description, and claims. [Brief description of the drawings]

[0028] The following figures depict exemplary embodiments provided for purposes of illustration of the present disclosure. These figures are for illustrative purposes only and devices manufactured according to the present disclosure are not limited to the materials, conditions, or process parameters described herein.

[0029] [Figure 1] FIG. 1 illustrates an embodiment of a bipolar membrane battery. [Diagram 2] FIG. 1 illustrates one embodiment of a bipolar membrane battery having a planar configuration. [Diagram 3]FIG. 1 illustrates an embodiment of a bipolar membrane battery having a tubular configuration. [Figure 4] FIG. 1 is a diagram of a support system (balance of plant) comprising a bipolar membrane battery 10 in fluid communication with a CO2RENEW processing device 300. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] According to the present invention, a bipolar membrane cell has been developed that can concentrate CO2 from a gas mixture (e.g., directly from air or from industrial exhaust gas) by a single-step electrochemical capture separation process. The bipolar membrane cell comprises an anode half-cell membrane of a proton exchange membrane fuel cell (PEMFC) and a cathode half-cell membrane of an anion exchange membrane fuel cell (AEMFC). A separation layer, which may have mixed ionic conductivity, is disposed between the anode half-cell membrane and the cathode half-cell membrane. The separation layer may function as a CO2 formation and separation region.

[0031] Bipolar membrane fuel cells have several advantages over other systems, such as the ability to concentrate CO2 via a single-step electrochemical capture and separation process directly from air or from industrial exhaust gases, and the ability to operate beneficially at low temperatures (e.g., below 100°C). Additionally, the reaction used in bipolar membrane fuel cells to capture (capture) carbon dioxide may rely on the oxygen reduction reaction (ORR). The oxygen reduction reaction (ORR) produces hydroxide ions (OH), which have a faster equilibrium rate, in association with CO2 present at the air cathode of an anion exchange membrane fuel cell (AEMFC). - Specifically, the primary cathodic oxygen reduction reaction (ORR) converts oxygen from the air into hydroxide ions (OH - This allows CO2 in the air to be easily captured and converted into carbonate ions (CO3 2- ) or bicarbonate ion (HCO3 -Another unique advantage of these fuel cell-based CO2 capture systems is the co-generation of electricity from renewable hydrogen (fuel). Moreover, the CO2 separated from the bipolar membrane cell along with the water can be further utilized as a direct feedstock for electrochemical CO2 electrolysis, for example using SKYRE's CO2RENEW™ technology, to produce carbon-neutral organic liquids, syngas, or high energy density fuels.

[0032] Further advantages of the bipolar membrane battery of the present invention include one or more of the following: The system may be an all-solid-state electrochemical device with no liquid electrolyte or moving parts. CO2 capture (capture) and separation may be performed in a single device. The bipolar membrane battery can be used for either direct air capture of CO2 or capture of CO2 from flue gases, etc. High current density (500 mA / cm 2 When operated at current densities greater than 1000 kV, CO2 capture and power generation can be done simultaneously. When integrated with renewable energy sources (e.g., solar energy, wind energy, etc.), depleted H2 can be regenerated using water electrolysis. Bipolar membrane batteries can be resistant to chemical pollutants (e.g., CO, NOx, H2S, etc.). Bipolar membrane batteries can be ideal for continuous CO2 scrubbing applications in closed-loop life support or closed-loop controlled environments, such as submarines.

[0033] For example, if a bipolar membrane fuel cell is used as a CO2 scrubber in a closed loop environment, the following closed loop system can be envisioned.

[0034] FIG. 1 shows a bipolar membrane cell 10 in a forward bias configuration. FIG. 1 shows that a separation layer 40 is disposed between an anode half-cell 20 and a cathode half-cell 60. The anode half-cell 20 may be a p-type proton-conducting proton exchange membrane-based anode half-cell membrane. The anode half-cell 20 comprises a proton exchange membrane 22 and an anode 24. The proton exchange membrane 22 may be disposed between the anode 24 and the separation layer 40. The anode 24 may be disposed on the proton exchange membrane 22 so as to be in direct physical contact with the proton exchange membrane 22 without the presence of an intervening layer. The anode-side current collector 26 may be disposed on the surface of the anode 24 opposite the proton exchange membrane 22. The anode-side current collector 26 may be in direct physical contact with the anode 24 without the presence of an intervening layer.

[0035] The cathode half-cell 60 is a cathode that converts n-type hydroxide ions (OH - ) conductive anion exchange membrane-based cathode half-cell membrane. The cathode half-cell 60 comprises an anion exchange membrane 62 and a cathode 64. The anion exchange membrane 62 may be disposed between the cathode 64 and the separation layer 40. The cathode 64 may be disposed on the anion exchange membrane 62 such that the cathode 64 is in direct physical contact with the anion exchange membrane 62 without the presence of an intervening layer. A cathode-side current collector 66 may be disposed on the surface of the cathode 64 opposite the anion exchange membrane 62. The cathode-side current collector 66 may be in direct physical contact with the cathode 64 without the presence of an intervening layer.

[0036] In the anode half-cell 20, a hydrogen oxidation reaction occurs, converting hydrogen to protons (H + ) and electrons (e - ) [ka] Electrons can be conducted from the anode 24 to the cathode 64 via an external circuit 90. Protons can be conducted through the proton exchange membrane 22 to the separation layer 40 depending on the polarity of the applied voltage.

[0037] The oxygen reduction reaction takes place in the cathode half-cell 60. The oxygen reduction reaction uses electrons from the hydrogen oxidation reaction. The electrons are converted to hydroxide ions (OH - ) at the cathode 64 . [ka] Carbon dioxide present at cathode 64 may react with water, hydroxide ions produced from reaction (2) above, or oxygen according to any of the following reactions (3)-(6). [ka] [ka] [ka] [ka] The rate of capture of carbon dioxide is generally determined by the above reactions (4) and (5), which occur at a faster rate than the above reactions (3) and (6). The hydroxide ions produced from reaction (2) and the carbonate ions (CO3 2- ), and the bicarbonate ion (HCO3 - ), water can be conducted to the separation layer 40 through the anion exchange membrane 62 .

[0038] Carbonate ion (CO3 2- ) and bicarbonate ion (HCO3 - ) is transported through the anion exchange membrane 62 to form hydroxide ions (OH - ) can react with the protons transported through the proton exchange membrane 22 according to the following acid-base reactions (7)-(9). [ka] [ka] [ka] The carbonic acid (H2CO3) produced by reaction (7) above is then used to generate carbon dioxide by reaction (3) or bicarbonate ions (HCO3) transported through the anion exchange membrane 62 or generated by reaction (8). - ) can be used to produce carbon dioxide by reaction (4). The carbon dioxide and water present in separation layer 40 can then be removed from separation layer 40.

[0039] Considering the reactions in the two half-cells of the system, at the anode alone and at the cathode alone, the redox potential (E°) of the entire cell is 0.4 volts (at a potential E 還元 to 0 volts potential E 酸化 This potential is lower than the standard theoretical redox potential (E°=1.23V) of a hydrogen fuel cell system, but due to the possibility of depletion layer formation, a residual potential difference can be maintained at the bipolar interface. However, the acid-base (H + / OH - For example, enthalpic heat losses of up to -57 kilojoules per mole (kJ / mol) can occur associated with the neutralization reaction, which contributes up to 25% of the Gibbs free energy (ΔG = -237 kJ / mol) of a standard hydrogen fuel cell. Additionally, resistive losses due to the ionic and electronic resistance of the carbon layer and overpotentials associated with the electrode reactions can also contribute to fuel cell efficiency losses.

[0040] Alternatively, when the oxygen evolution reaction (OER), as shown in reaction (10) below, occurs in the anode half-cell 20 to generate the protons necessary for conduction through the proton exchange membrane (PEM), the bipolar membrane operates as an oxygen-concentrating electrolyzer with a theoretical across-cell potential condition of −0.83 V. The entire bipolar membrane cell functions as a combined device that captures and separates both oxygen and CO2 directly from air. [ka]

[0041] FIG. 2 illustrates an apparatus including a planar bipolar membrane cell 110 having a planar configuration. In this specification, the term "planar" simply refers to the planes of the anode half-cell 20 and the cathode half-cell 60 being substantially parallel to each other (e.g., inclined within 0° (parallel) to 5° from each other, or inclined within 0° to 2° from each other). It should be noted that the anode half-cell 20 and the cathode half-cell 60 are not limited to a parallel relationship to each other, and other configurations can be easily envisioned. FIG. 2 illustrates that a hydrogen-rich stream 30 can be fluidly connected to the anode chamber 120 of the planar bipolar membrane cell 110. Although not shown, a water vapor stream can be added to the anode chamber 120 of the planar bipolar membrane cell 110. The water vapor stream may be combined with the hydrogen-rich stream 30 before being introduced into the planar bipolar membrane cell 110, or may be added to the anode chamber 120 of the planar bipolar membrane cell 110 separately from the hydrogen-rich stream 30. The anode chamber 120 may be a closed chamber into which only the hydrogen-rich stream 30 and any water vapor stream flow, as indicated by the closed end 32. Conversely, a hydrogen withdrawal stream may be fluidly connected to the anode chamber 120 to withdraw the spent stream from the anode chamber 120.

[0042] A carbon dioxide source stream 50 may be fluidly connected to the cathode chamber 160 of the planar bipolar membrane battery 110. The carbon dioxide source stream 50 may comprise at least one of a direct air stream or an exhaust gas stream. A water vapor stream may be added to the cathode chamber 160 of the planar bipolar membrane battery 110. The water vapor stream may be combined with the carbon dioxide source stream 50 before being introduced into the planar bipolar membrane battery 110, or may be added to the cathode chamber 160 of the planar bipolar membrane battery 110 independently of the carbon dioxide source stream 50. A carbon dioxide depleted stream 52 may be fluidly connected to the cathode chamber 160. In this case, the carbon dioxide depleted stream 52 is configured to be withdrawn from the bipolar membrane battery 110.

[0043] A carbon dioxide product stream 70 may be fluidly connected to the separation layer 40 to remove the carbon dioxide product from the planar bipolar membrane battery 110. The separation layer 40 may be contained within a closed chamber such that only one carbon dioxide product stream 70 is in fluid communication with the closed chamber, as shown by a blocked end 72. Conversely, more than one carbon dioxide product stream 70 may be fluidly connected to the separation layer 40 to remove the carbon dioxide product from the planar bipolar membrane battery 110. The carbon dioxide product streams may be directed to a phase separator for further separation.

[0044] FIG. 3 illustrates a bipolar membrane battery having a tubular configuration, i.e., a tubular bipolar membrane battery 210. In the tubular bipolar membrane battery 210, the anode half-cell 20 and the cathode half-cell 60 form a concentric tube. In FIG. 3, the image on the left is a cross section along the length of the tube, and the image on the right is a cross section along line AA through the radial plane of the tube. FIG. 3 illustrates that a hydrogen-rich stream 30 can be fluidly connected to the anode chamber 220 of the tubular bipolar membrane battery 210. In the illustrated example, the hydrogen-rich stream 30 enters the tubular bipolar membrane battery 210 at a proximal end 214 to create a parallel flow of the hydrogen-rich stream 30 and the carbon dioxide source stream 50. However, conversely, the hydrogen-rich stream 30 may enter the tubular bipolar membrane battery 210 at a distal end 216 to create a counterflow relative to the flow of the carbon dioxide source stream 50.

[0045] The anode side chamber 220 forms the center of the tubular bipolar membrane cell 210, and the anode half-cell 20 forms a tube around the center. The anode half-cell 20 may include an anode side current collector 26 on the inner surface of the anode half-cell 20. The anode side current collector 26 is located on the surface adjacent to the center (i.e., the anode side chamber 220). The anode side current collector 26 may be porous. Although not shown, a water vapor stream may be added to the anode side chamber 220. The water vapor stream may be combined with the hydrogen-rich stream 30 before being introduced into the tubular bipolar membrane cell 210, or may be added to the anode side chamber 220 of the tubular bipolar membrane cell 210 independently of the hydrogen-rich stream 30. The anode side chamber 220 may be a closed chamber that only contains the hydrogen-rich stream 30 and any water vapor stream, as shown by the closed chamber end 232. Conversely, the hydrogen draw stream may be fluidly connected to the anode chamber 220 to withdraw the spent stream from the anode chamber 220, for example through an opening in the chamber end 232. A phase separator may be disposed at the outlet of the tubular bipolar membrane cell 210 to separate the carbon dioxide from the water in the carbon dioxide product stream 70.

[0046] The carbon dioxide source stream 50 may be fluidly connected to the cathode chamber 260 of the tubular bipolar membrane cell 210 at the proximal end 214. FIG. 3 shows that the cathode half-cell 60 does not extend to the outer wall surface 212 of the tube. However, examples are envisioned in which the cathode half-cell 60 extends to the outer wall surface 212, in which case the carbon dioxide depleted stream 52 may be collected from the surface S. A water vapor stream may be added to the cathode chamber 260 of the tubular bipolar membrane cell 210. The water vapor stream may be combined with the carbon dioxide source stream 50 before being introduced into the tubular bipolar membrane cell 210, or may be added to the cathode chamber 260 of the tubular bipolar membrane cell 210 independently of the carbon dioxide source stream 50. The carbon dioxide depleted stream 52 may be fluidly connected to the cathode side chamber 260 such that the carbon dioxide depleted stream 52 may be withdrawn from the tubular bipolar membrane cell 210 .

[0047] The carbon dioxide product stream 70 may be fluidly connected to the separation layer 40 to allow for removal of carbon dioxide product from the tubular bipolar membrane battery 210. In the illustrated example, the carbon dioxide product stream 70 is configured to exit the tube at the distal end 216 to provide for co-flow of the carbon dioxide product stream 70 with the carbon dioxide source stream 50. However, alternatively, or in addition, the carbon dioxide product stream 70 may be configured to exit the tubular bipolar membrane battery 210 at the proximal end 214 to provide for counter- or bi-directional flow relative to the flow of the carbon dioxide source stream 50.

[0048] The separation layer 40 may be contained within a closed chamber such that only one carbon dioxide product stream 70 is in fluid communication with the closed chamber, as indicated by closed product chamber end 272. Conversely, more than one carbon dioxide product stream 70 may be in fluid communication with the separation layer 40 to allow for removal of carbon dioxide product from the tubular bipolar membrane cell 210.

[0049] 3, the anode half-cell 20 is configured as the innermost layer relative to the cathode half-cell 60 in the tubular bipolar membrane cell, but it should be noted that their relative arrangement within the tube may be reversed such that the cathode half-cell 60 is inside the anode half-cell 20. Similarly, the anode half-cell 20 and cathode half-cell 60 may be configured in multiple concentric layers.

[0050] The bipolar membrane battery may also include flow field structures (not shown) that may be positioned on either side of each electrode structure. The flow field structures may provide space for the flow of fluids in contact with each membrane electrode assembly (MEA).

[0051] The system may also include a controller (not shown) configured to communicate (e.g., via electronic signals) with at least one layer of each half-cell, at least one stream, a power source, or a process control component (e.g., a pump, a mass flow controller, a heat exchanger, a pressure control valve, or a fluid control valve, etc.). Additionally, an analytical device may be configured to quantify the concentration of carbon dioxide in the carbon dioxide product stream 70. The controller may adjust one or more parameters during use to optimize the separation of carbon dioxide.

[0052] The carbon dioxide source stream 50 may include air or off-gas from an industrial process. The carbon dioxide source stream 50 may have a volume percent of carbon dioxide up to 50% based on the total volume of the stream on a dry basis (i.e., without any water vapor that may be present), or may have a volume percent of carbon dioxide between 0.001% and 30%. The carbon dioxide source stream 50 may have a volume percent of oxygen between 10% and 15% based on the total volume of the stream on a dry basis. The carbon dioxide source stream 50 may have a volume percent of inert gas (e.g., nitrogen, argon, helium, etc.) between 10% and 70% based on the total volume of the stream. The carbon dioxide source stream 50 may include air, and the bipolar membrane battery may operate at low throughput (e.g., 50 milliamps per square centimeter (50 mA / cm)). 2 The carbon dioxide source stream 50 may include exhaust gas, and the bipolar membrane battery may have a high throughput (e.g., 50 mA / cm 2 The current density may be higher than 100 .mu.m.

[0053] The hydrogen-rich stream 30 may have a volume percent of hydrogen of 90% to 100% or 95% to 99% based on the total volume of the hydrogen-rich stream 30 on a dry basis. The carbon dioxide product stream 70 may have a volume percent of carbon dioxide of 90% to 100% based on the total volume of the carbon dioxide product stream 70. The carbon dioxide product stream 70 may have a volume percent of water of 95% to 99% based on the total volume of the carbon dioxide product stream 70. Diffusion of reactant gases from both the cathode half-cell membrane and the anode half-cell membrane may affect the aforementioned concentration ranges of the carbon dioxide product stream 70. Alternatively, when the bipolar device is operated at elevated pressures, for example in the range of 10 to 50 atmospheres, the composition of the carbon dioxide product stream 70 may change due to permeation.

[0054] The carbon dioxide product stream 70 may be fluidly connected to a fuel cell for further upconversion to carbon-neutral hydrocarbons or fuels using the CO2RENEW™ process. The carbon dioxide product stream 70 may be fluidly connected to be fed directly to a CO2 electrolysis cell. The carbon dioxide product stream 70 may be separated, for example using a phase separator, to form a carbon dioxide rich stream and a water stream. The carbon dioxide product stream 70 may be compressed to a high pressure gas or condensed to a liquid. The carbon dioxide product stream 70 may be directed to a storage vessel.

[0055] FIG. 4 illustrates an overall support system (balance of plant (BOP)) with a bipolar membrane battery 10 in fluid communication with a CO2RENEW processor 300. In the example of FIG. 4, the carbon dioxide product stream 70 may be fluidly connected to the cathode of a proton exchange membrane (PEM)-based CO2 electrolyzer for further upconversion to a carbon-neutral hydrocarbon stream 302 using a CO2RENEW processor commercially available from SKYRE. The carbon-neutral hydrocarbon stream 302 may be stored in a storage tank 304, if desired. A water electrolyzer 310 may electrolyze water into hydrogen forming a hydrogen-rich stream 30 and oxygen forming an oxygen stream 312. The hydrogen-rich stream 30 may be fluidly connected to the bipolar membrane battery 10 at the anode. A carbon dioxide source stream 50 may be fluidly connected to the bipolar membrane battery 10. A carbon dioxide-depleted stream 52 may be combined with the oxygen stream 312.

[0056] The method of purifying a carbon dioxide stream may include directing a carbon dioxide source stream 50 containing carbon dioxide to a cathode chamber 160, 260 containing a cathode half-cell 60. The cathode half-cell 60 may include an anion exchange membrane 62 and a cathode 64, the cathode 64 being located on the side of the anion exchange membrane 62 adjacent to the cathode chamber 160, 260. A carbon dioxide depleted stream 52 may be withdrawn from the cathode chamber 160, 260. The carbon dioxide may react with water at the cathode 64 to form carbonate ions and bicarbonate ions. The carbonate ions and bicarbonate ions may be directed through the anion exchange membrane 62 to the separation layer 40. A hydrogen rich stream 30 may be directed to an anode chamber 120, 220. The anode chamber 120, 220 may include a proton exchange membrane 22 and an anode current collector 26. The anode current collector 26 may be disposed on the side of the proton exchange membrane 22 adjacent the anode chamber 120, 220. Hydrogen may react at the anode 24 to form protons and electrons, and the protons may be conducted through the proton exchange membrane 22 to the separation layer 40. The protons, carbonate ions, and bicarbonate ions may react in the separation layer 40 to form carbon dioxide and water. A carbon dioxide product stream 70 comprising carbon dioxide and water may be removed from the separation layer 40. At least a portion of the carbon dioxide product stream 70 may be conducted to at least one of a separation unit, a storage unit, and another electrochemical cell.

[0057] The separation layer 40 may comprise porous carbon, which may include at least one of graphene (e.g., doped graphene or functionalized graphene), graphene oxide (e.g., reduced graphene oxide), graphene fluoride, graphite, expanded graphite (e.g., graphene spacing of 0.4 nanometers or greater), activated carbon, carbon black, carbon nanotubes, carbon fibers, graphite fibers, carbonized polymer fibers, or chemically treated coke.

[0058] The porous carbon may have at least one of a microporous body having a pore size of less than 2 nanometers and a mesoporous body having a pore size of 2 to 50 nanometers. The ratio of the microporous body to the mesoporous body may be 20:80 to 50:50 in volume percent. The porous carbon may have a total pore volume of 0.0001 to 0.1 cubic centimeters per gram. The porous carbon may have a total pore volume of 2 to 500 square meters (2 to 500 m) per gram. 2 / g) or 100 to 2000m 2 / g or 500~1000m 2 The carbon may have a BET surface area of ​​100 / g. The specific surface area (SSA) and pore volume of the carbon may be measured using single-point or multipoint nitrogen physisorption techniques. The specific surface area (SSA) may be calculated based on nitrogen physisorbed at a single-point partial pressure of 0.3 (approximate value for BET monolayer coverage). The pore volume may be estimated based on the volume of liquid nitrogen condensed at a nitrogen partial pressure of 0.99-1. The electrical conductivity of the porous carbon may be 10 -2 The electrical conductivity of carbon materials can be measured using a four-probe measurement after sandwiching them between two thin copper layers.

[0059] The thickness x of the isolation layer 40 should be thin so that resistive losses are minimized. For example, the thickness x may be between 0.25 micrometers and 5 millimeters, or may be between 1 micrometer and 1 millimeter.

[0060] The porous carbon layer absorbs acidic cations (H + ) and alkaline anion (OH - , CO3 2- , HCO3 -) may have a mixed ion conductivity of both. For example, the porous carbon layer may include an electrocharged coating layer. The electrocharged coating layer may be a solid electrolyte layer. The electrocharged coating layer may be formed by mixing at least one of a proton conducting ionomer or an alkali ion conducting ionomer and coating the mixture on the porous carbon. The coating mixture may include 5 to 10 weight percent of the proton conducting ionomer or 1 to 20 weight percent of the alkali ion conducting ionomer, based on the total weight of the coating mixture.

[0061] The separation layer may include porous carbon and a fluoropolymer (e.g., polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF)). The fluoropolymer may increase the hydrophobicity of the separation layer. The fluoropolymer may be negatively charged, for example, sulfonated tetrafluoroethylene. The separation layer may be formed by mixing the carbon and the fluoropolymer and heating in an inert atmosphere at a temperature of 200 to 600°C, or at a temperature of 300 to 350°C.

[0062] The electrodes (anode 24 and / or cathode 64) may be in direct physical contact with the respective exchange membranes 22, 62 and may cover 90-100% of the surface area of ​​the exchange membranes 22, 62, respectively. Each electrode independently comprises a catalyst layer. The catalyst layer of the anode 24 may dissociate hydrogen into protons and electrons. The catalyst layer of the cathode 64 may promote an oxygen reduction reaction, which produces hydroxide ions that are subsequently converted to bicarbonate ions, which may subsequently be produced upon reaction of the hydroxide ions with CO2 present in the reactant feed at the cathode. The catalyst layer of the cathode may include at least one of platinum, palladium, rhodium, carbon, gold, tantalum, tungsten, ruthenium, iridium, osmium, nickel, manganese, iron, cobalt, tungsten, or silver. The catalyst layer of the anode 24 may include platinum, or a composite or alloy formed of platinum group metals. The catalyst layer of the cathode 64 may include at least one of aluminum, nickel, or platinum. The catalyst layer of the cathode 64 may include a metal other than the platinum group (e.g., a MNx-based catalyst based on a transition metal). The catalyst layer of the cathode 64 may include at least one of rhodium, carbon, gold, tantalum, tungsten, ruthenium, iridium, osmium, or silver. Each catalyst may independently include a binder catalyst. The binder may include at least one of a fluoropolymer or particulate carbon. Each catalyst and any binder may be deposited directly on the surface of the proton exchange membrane. Each catalyst may independently be disposed on the gas diffusion layer, either disposed throughout the gas diffusion layer or disposed on a surface of the gas diffusion layer that contacts the proton exchange membrane. The gas diffusion layer may be porous. The gas diffusion layer may be a mesh. The gas diffusion layer may include a graphite material. The gas diffusion layer may include a plurality of fibers, such as carbon fibers. The gas diffusion layer may be electrically conductive.

[0063] The catalyst loading in the cathode 64 is minimal (e.g., 1 milligram per square centimeter (1 mg / cm 2The reduction in the amount of catalyst in the cathode 64 can be achieved by reducing the amount of excess hydroxide ions (OH - ) and helps limit the formation of hydroxide ions (OH - ) is led directly through the anion exchange membrane 62, and H + The effective surface area of ​​the cathode 64 is preferably between 200 and 1000 m per gram to enhance the interaction of the catalyst with the CO2 gas and improve the overall CO2 capture efficiency. 2 / g).

[0064] The proton exchange membrane may include an ionomeric polymer electrolyte (such as, for example, a hydrocarbon-based resin and a fluorocarbon-based resin) having a certain amount of ionic groups on the hydrophobic backbone or on pendant groups off the hydrophobic backbone. The hydrocarbon-based ion exchange resin may include at least one of a phenolic resin or a polystyrene. The hydrocarbon-based ion exchange resin may be sulfonated, for example, a sulfonated polymer (xylylene oxide). The hydrocarbon-based ion exchange resin may include a proton-conducting molecule (for example, at least one of a fullerene molecule, a carbon fiber, or a carbon nanotube). The proton-conducting molecule may include a proton dissociating group (for example, at least one of a sulfate group (-OSOH), a phosphate ester group (-OPO(OH)2), a carboxyl group (-COOH), a sulfone group (-SO3H), a phenylene group (-CH4), or a hydroxyl group (-OH)). The proton conducting molecule may form the proton exchange membrane alone or may be present in a mixture with a binder polymer (e.g., at least one of a fluoropolymer (e.g., polyfluoroethylene or polyvinylidene fluoride) or polyvinyl alcohol). Because oxygen is not present in significant amounts in the proton exchange membrane, oxidation is of less concern, and the proton exchange membrane may include a hydrocarbon-based ion exchange resin.

[0065] The fluorocarbon-based ion exchange resin may include a hydrate of at least one of tetrafluoroethylene-perfluorosulfonylethoxyvinyl ether or tetrafluoroethylene-hydroxide (perfluorovinyl ether) copolymer. The fluorocarbon-based ion exchange resin may have at least one of sulfonic acid, carboxylic acid, or phosphoric acid functional groups. The fluorocarbon-based ion exchange resin may be a sulfonated fluoropolymer (e.g., lithium salt of perfluoroethylene sulfonic acid, etc.). An example of a fluorocarbon-based ion exchange resin is Nafion™, available from DuPont. The proton exchange membrane itself may act as a barrier, allowing the transport of protons across its thickness from the anode 24 (feed side) to the separation layer 40 (exhaust side) while excluding other components present in the hydrogen-rich stream. Proton exchange membranes generally only conduct protons when they are hydrated. Maximum electrical performance of an electrochemical device may be achieved when the membrane is fully in acid form. In other words, hydrogen ions can coordinate a large amount of water around the sulfonic acid groups, so that the sulfonic acid groups in the proton exchange membrane are completely protonated.

[0066] The thickness of the proton exchange membrane 22 may be 25 to 550 micrometers, 75 to 550 micrometers, or 100 to 300 micrometers.

[0067] The anion exchange membrane 62 may be selectively permeable to carbonate anions. The anion exchange membrane 62 may be formed from any material that allows carbonate anions to diffuse through it. For example, the anion exchange membrane 62 may include at least one of a polyolefin, tetrafluoroethylene (TFE), fluorinated ethylene propylene / tetrafluoroethylene (FEP / TFE), polystyrene divinylbenzene (PS-DVB) on nylon, PS-DVB on polytetrafluoroethylene (PTFE), or PS-DVB on polyvinyl chloride. Suitable membranes are available, for example, from Versogen (particularly PiperIon and Orion AMX membranes), Ionics Incorporated (Watertown, Massachusetts) (particularly AR-204 and AR-708 membranes), Pall RAI (Hauppauge, NY) (particularly R1030 and R4030 membranes), Tokuyama Soda (Tokyo, Japan) (particularly AMH membranes), Asahi Glass America, Inc. (New York, NY) (particularly AAV and AMP membranes), and Tosoh Corporation (Tokyo, Japan) (particularly Tosflex membranes).

[0068] The thickness of the anion exchange membrane 62 may be 25 to 550 micrometers, or 75 to 550 micrometers.

[0069] The following non-limiting aspects of the present disclosure may be combined with one or more of the other listed aspects.

[0070] [Aspect 1] 1. A bipolar membrane battery comprising an anode half-cell and a cathode half-cell, the anode half-cell having a proton exchange membrane and an anode, the proton exchange membrane being disposed between the anode and the separation layer, the cathode half-cell having an anion exchange membrane and a cathode, the anion exchange membrane being disposed between the cathode and the separation layer, and an external circuit connecting the anode and the cathode.

[0071] [Aspect 2] The cathode half-cell may further comprise a cathode chamber and a carbon dioxide source stream in fluid communication with the cathode chamber to supply carbon dioxide to the cathode chamber.

[0072] [Aspect 3] The cathode half-cell may further comprise a cathode chamber and a carbon dioxide depleted stream in fluid communication with the cathode chamber for being withdrawn from the cathode chamber.

[0073] [Aspect 4] The anode half-cell may further comprise an anode chamber and a hydrogen-rich stream in fluid communication with the anode chamber for exiting the anode chamber.

[0074] [Aspect 5] The separation layer, the anode half-cell, and the cathode half-cell may have a planar configuration facing each other.

[0075] [Aspect 6] The anode half-cell and the cathode half-cell may be concentrically arranged to form a tubular bipolar membrane cell, and the separator layer may be concentrically arranged between the anode half-cell and the cathode half-cell. The anode half-cell may be disposed within a tube formed by the cathode half-cells. The cathode half-cell may be disposed within a tube formed by the anode half-cells. Both the hydrogen-rich stream and the carbon dioxide source stream may be in fluid communication with a proximal end of the tubular bipolar membrane cell, and a carbon dioxide product stream may be in fluid communication with a distal end of the tubular bipolar membrane cell. Both the carbon dioxide product stream and the carbon dioxide source stream may be in fluid communication with a proximal end of the tubular bipolar membrane cell, and the hydrogen-rich stream may be in fluid communication with a distal end of the tubular bipolar membrane cell.

[0076] [Aspect 7] The anode may comprise platinum and the cathode may comprise at least one non-platinum group metal.

[0077] [Aspect 8] The separation layer may include porous carbon. The porous carbon may comprise a microporous body having a pore size of less than 2 nanometers. The porous carbon may comprise a mesoporous body having a pore size of 2 nanometers or more and 50 nanometers or less. The total pore volume of the porous carbon may be 0.0001 to 0.1 cubic centimeters per gram. The BET surface area of ​​the porous carbon may be 2 to 500 m. 2 / g, 100-2000m 2 / g or 500~1000m 2 The electrical conductivity of the porous carbon may be 10 -2 It may be S / cm or more.

[0078] [Aspect 9] The thickness of the separation layer may be 0.25 micrometers or more and 5 millimeters or less, or may be 1 micrometer or more and 1 millimeter or less.

[0079] [Aspect 10] The bipolar membrane cell may further comprise a hydrogen withdrawal stream in fluid communication with the anode chamber.

[0080] [Aspect 11] A method for purifying a carbon dioxide product stream includes the steps of: directing a carbon dioxide source stream containing carbon dioxide to a cathode chamber having a cathode half-cell having an anion exchange membrane and a cathode, the cathode being disposed on a side of the anion exchange membrane adjacent to the cathode chamber; withdrawing a carbon dioxide depleted stream from the cathode chamber; reacting the carbon dioxide with water at the cathode to form carbonate ions and bicarbonate ions; directing the carbonate ions and bicarbonate ions through the anion exchange membrane to a separation layer; and directing the carbonate ions and bicarbonate ions through a separation layer having a proton exchange membrane and an anode. conducting a hydrogen-rich stream comprising hydrogen to an anode chamber comprising an anode half-cell having a proton exchange membrane disposed adjacent to the anode chamber, the anode being disposed on a side of the proton exchange membrane adjacent to the anode chamber; reacting the hydrogen to form protons and electrons at the anode and conducting the protons through the proton exchange membrane to the separation layer; reacting the protons, carbonate ions, and bicarbonate ions in the separation layer to form carbon dioxide and water; and withdrawing a carbon dioxide product stream comprising the carbon dioxide and the water from the separation layer.

[0081] [Aspect 12] The method may further comprise directing at least a portion of the carbon dioxide product stream to at least one of a separation unit, a storage unit, and a direct feed to a CO2 electrolysis cell.

[0082] [Aspect 13] The carbon dioxide source stream may include at least one of air and off-gas from an industrial process.

[0083] [Aspect 14] The carbon dioxide source stream may have a volume percent of carbon dioxide less than or equal to 50% based on the total volume of the carbon dioxide source stream on a dry basis.

[0084] [Aspect 15] The hydrogen-rich stream may have a volume percentage of hydrogen of from 90% to 100%, or from 95% to 99%, based on the total volume of the hydrogen-rich stream on a dry basis.

[0085] [Aspect 16] The carbon dioxide product stream may have a volume percentage of carbon dioxide, based on the total volume of the carbon dioxide product stream, of greater than or equal to 90% and less than or equal to 100%.

[0086] [Aspect 17] The carbon dioxide product stream may be directed to at least one of a separation unit, a storage unit, and a CO2 electrolyzer.

[0087] An apparatus may comprise the bipolar membrane battery, and optionally further comprise a water electrolysis device in fluid communication with an inlet of the bipolar membrane battery via a hydrogen rich stream, and optionally further comprise a CO2 electrolysis device in fluid communication with an outlet of the bipolar membrane battery via a carbon dioxide product stream.

[0088] The compositions, methods, and articles may comprise, consist of, or consist essentially of any suitable materials, steps, or ingredients disclosed herein. The compositions, methods, and articles may additionally or alternatively be configured to be devoid of, or substantially free of, any material (or type), step, or ingredient that is not necessary to achieve the function or purpose of the compositions, methods, and articles.

[0089] Countable nouns used herein are intended to include both the singular and the plural, unless the context clearly dictates otherwise. For example, the term "an element" is equivalent to "at least one element," unless the context clearly dictates otherwise. The term "combination" includes blends, mixtures, alloys, reaction products, and the like. Additionally, the term "at least one" is intended to include each listed element individually, combinations of two or more listed elements, and combinations of at least one listed element with a similar element not specified.

[0090] The term "or" means "and / or" unless otherwise clearly indicated by context. Throughout this specification, references to "one aspect," "another aspect," "some aspects," etc., mean that a particular element (e.g., a feature, structure, step, or characteristic) described in connection with that aspect is included in at least one aspect described herein and may or may not be present in other aspects. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various aspects.

[0091] When an element, such as a layer, film, region, or substrate, is referred to as being "on" another element, the element may be directly on the other element, or there may be intervening elements present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0092] Unless otherwise specified herein, all test specifications are the latest specifications in effect as of the filing date of this application or, if priority is claimed, as of the filing date of the earliest priority application in which the test specifications are listed.

[0093] The endpoints (thresholds) of ranges stated for the same component or property are intended to be inclusive, independently combinable, and inclusive of all intermediate points and ranges. For example, a range stated as "up to 25 vol.%, or 5-20 vol.%" is intended to include the endpoints (upper and lower limits) and all intermediate values ​​(e.g., 10-23 vol.%) of the range "5-25 vol.%."

[0094] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0095] All cited patents, patent applications, and other references are incorporated herein by reference in their entirety, except that if a term in this application contradicts or conflicts with a term in an incorporated reference, the term in this application shall control over the conflicting term in the incorporated reference.

[0096] While particular embodiments have been described above, alternatives, modifications, variations, improvements, and substantial equivalents may occur to applicant or other persons skilled in the art that may not be presently foreseen or foreseeable, and therefore, the appended claims as filed and as amended are intended to embrace all such alternatives, modifications, variations, improvements, and substantial equivalents.

Claims

1. a separator layer disposed between the anode half-cell and the cathode half-cell; the anode half-cell includes a proton exchange membrane and an anode; the proton exchange membrane is disposed between the anode and the separation layer; the cathode half-cell comprises an anion exchange membrane and a cathode; the anion exchange membrane is disposed between the cathode and the separation layer; The bipolar membrane battery further comprises an external circuit connecting the anode and the cathode.

2. 10. The bipolar membrane battery of claim 1, wherein the cathode half-cell further comprises a cathode chamber and a carbon dioxide source stream in fluid communication with the cathode chamber to supply carbon dioxide to the cathode chamber.

3. 3. The bipolar membrane battery of claim 2, wherein the cathode half-cell further comprises a carbon dioxide-depleted stream in fluid communication with the cathode chamber for being withdrawn from the cathode chamber.

4. 4. The bipolar membrane battery of claim 3, wherein the anode half-cell further comprises an anode chamber and a hydrogen-rich stream in fluid communication with the anode chamber for delivery therefrom.

5. 5. The bipolar membrane battery of claim 4, wherein the separator, the anode half-cell, and the cathode half-cell have a planar configuration facing each other.

6. the anode half-cell and the cathode half-cell are concentrically arranged to form a tubular bipolar membrane cell; 6. The bipolar membrane battery of claim 5, wherein the separator layer is concentrically disposed between the anode half-cell and the cathode half-cell.

7. 7. The bipolar membrane battery of claim 6, wherein the anode half-cell is disposed within a tube formed by the cathode half-cell, or the cathode half-cell is disposed within a tube formed by the anode half-cell.

8. both the hydrogen-rich stream and the carbon dioxide source stream are in fluid communication with a proximal end of the tubular bipolar membrane battery; 8. The bipolar membrane battery of claim 7, wherein a carbon dioxide product stream is in fluid communication with a distal end of the tubular bipolar membrane battery.

9. both the carbon dioxide product stream and the carbon dioxide source stream are in fluid communication with a proximal end of the tubular bipolar membrane cell; 8. The bipolar membrane battery of claim 7, wherein the hydrogen-rich stream is in fluid communication with a distal end of the tubular bipolar membrane battery.

10. the anode comprises platinum; 10. The bipolar membrane battery of claim 1, wherein the cathode comprises at least one non-platinum group metal.

11. the separation layer comprises porous carbon, or the thickness of the separation layer is 0.25 micrometers to 5 millimeters, or 1 micrometer to 1 millimeter; or 10. The bipolar membrane battery of claim 1, further comprising a hydrogen withdrawal stream in fluid communication with the anode-side chamber.

12. the separation layer comprises porous carbon; The porous carbon is a microporous body having a pore size of less than 2 nanometers; a mesoporous material having a pore diameter of 2 nanometers or more and 50 nanometers or less; 0.0001 cm ３ / g or more 0.1cm ３ / g or less total pore volume; 2 m ２ / g or more 500m ２ / g or less, 100m ２ / g or more 2000m ２ / g or less, or 500m ２ / g or more 1000m ２ / g or less BET surface area; 10 －２ and an electrical conductivity of 100 S / cm or more.

13. The bipolar membrane battery according to claim 1; a water electrolysis device in fluid communication with the inlet of the bipolar membrane cell via a hydrogen-rich stream; a CO 2 product stream in fluid communication with an outlet of the bipolar membrane battery; ２ an electrolysis device.

14. 1. A method for purifying a carbon dioxide product stream, comprising: directing a carbon dioxide source stream containing carbon dioxide to a cathode chamber comprising a cathode half-cell having an anion exchange membrane and a cathode, the cathode being disposed on a side of the anion exchange membrane adjacent to the cathode chamber; withdrawing a carbon dioxide-depleted stream from the cathode chamber; reacting the carbon dioxide with water at the cathode to form carbonate ions and bicarbonate ions; directing the carbonate ions and the bicarbonate ions through the anion exchange membrane to a separation layer; directing a hydrogen-rich stream containing hydrogen to an anode chamber comprising an anode half-cell having a proton exchange membrane and an anode, the anode being disposed on a side of the proton exchange membrane adjacent to the anode chamber; reacting the hydrogen to form protons and electrons at the anode and directing the protons through the proton exchange membrane to the separation layer; reacting the protons, the carbonate ions, and the bicarbonate ions in the separation layer to form carbon dioxide and water; removing a carbon dioxide product stream from the separation layer, the carbon dioxide product stream comprising the carbon dioxide and the water; A method for providing the above.

15. Separation unit, storage unit, and CO ２ and a direct feed to an electrolysis cell; The carbon dioxide source stream comprises at least one of air and off-gas from an industrial process, and optionally the carbon dioxide source stream has a volume percent of carbon dioxide of 50% or less based on the total volume of the carbon dioxide source stream on a dry basis; and optionally the hydrogen-rich stream has a volume percent of hydrogen of 90% or more and 100% or less, or 95% or more and 99% or less, based on the total volume of the hydrogen-rich stream on a dry basis; and optionally 15. The method of claim 14, wherein the carbon dioxide product stream has a volume percent of carbon dioxide of at least 90% and at most 100%, based on the total volume of the carbon dioxide product stream.

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