Gas deposition cell with alkali metal ion-based charge compensation

Abstract

The present invention relates to an electrochemical gas separation cell (10) for separating a gaseous Lewis acid, in particular carbon dioxide, which comprises an adsorption electrode (20) with at least one electrochemically active material (21) for the reversible electrochemical adsorption of the Lewis acid, a counter electrode (30), and a separator (40) arranged between the adsorption electrode (20) and the counter electrode (30). In order to provide a new type of gas separation cell, in particular one which can be used for electrochemical (potential) swing adsorption or electro(chemical) swing adsorption (ESA), the counter electrode (30) is an alkali metal electrode and / or the cell (10) comprises at least one alkali metal ion-conducting solid electrolyte (LiFE / NaFE). Furthermore, the invention relates to such a gas separation system and an operating method therefor.

Description

[0001] The present invention relates to an electrochemical gas separation cell for separating a gaseous Lewis acid, in particular carbon dioxide, from a fluid mixture containing the Lewis acid, a gas separation system and an operating method therefor. State of the art

[0002] Carbon dioxide is an electrophilic electron pair acceptor and is therefore a Lewis acid.

[0003] The separation of carbon dioxide from process gas streams or atmospheric air is also called carbon capture.

[0004] In the scientific publication Energy Enviren. Sci., 2019, 12, 3530, Hatton et al. describe a gas separation cell for carbon dioxide capture that can be operated using electrochemical (potential) swing adsorption or electro(chemical) swing adsorption (ESA). The gas separation cell features an adsorption electrode based on polyanthraquinone-functionalized carbon nanotubes (PAQ-CNT) and a counter electrode based on polyvinyl ferrocene-functionalized carbon nanotubes (PVFc-CNT). Carbon dioxide is bound to the adsorption electrode by reacting with electrons. The necessary electrical charge equalization takes place via the counter electrode based on polyvinyl ferrocene-functionalized carbon nanotubes, which supplies electrons from the ferrocene.Charge equalization between the adsorption electrode and the counter electrode occurs via the ion mobility of an ionic liquid impregnated into both electrodes. A separator in the form of a porous membrane made of an insulating material impregnated with ionic liquid is arranged between the electrodes. This separator, on the one hand, interrupts the electron conduction between the two electrode compartments and, at the same time, connects the two electrode compartments in an ion-conducting manner via diffusion of the ionic liquid through its pores.

[0005] The document US 2022 / 0339579 A1 describes a process for the electrochemical deposition of a gaseous Lewis acid from a fluid mixture containing the Lewis acid. Disclosure of the invention

[0006] The present invention relates to an electrochemical gas deposition cell for the, in particular electrochemical, deposition of a gaseous Lewis acid, in particular carbon dioxide, from a fluid mixture, in particular a gas mixture, containing the Lewis acid.

[0007] A Lewis acid can be understood in particular as an electrophilic electron pair acceptor, i.e. a compound to which an electron pair of an electron pair donor can be attached, for example in which the compound has an empty orbital that is energetically accessible to the electron pair of the electron pair donor.

[0008] The gas separation cell comprises an adsorption electrode with at least one electrochemically active material for the reversible electrochemical adsorption of the Lewis acid, for example carbon dioxide, a counter electrode and a separator arranged between the adsorption electrode and the counter electrode.

[0009] In particular, the counter electrode is an alkali metal electrode, for example a lithium electrode or a sodium electrode, and / or the cell comprises at least one alkali metal ion-conducting, for example lithium ion-conducting or sodium ion-conducting, solid electrolyte.

[0010] Thus, an alkali metal ion-based, for example lithium ion-based or sodium ion-based, charge balance or charge balance based on alkali metal ions, in particular lithium ions or sodium ions, can advantageously be achieved between the adsorption electrode and the counter electrode and charges between the adsorption electrode and the counter electrode can be balanced or can be balanced, in particular substantially, for example mainly, optionally exclusively, by alkali metal ions, for example lithium ions or sodium ions.

[0011] This advantageously provides a novel gas deposition cell. Furthermore, it allows the use of different counter electrodes and / or electrolytes, thereby achieving advantages over counter electrodes conventionally used in such gas deposition cells, for example, counter electrodes based on ferrocene-functionalized carbon nanotubes, and / or liquid electrolytes, such as ionic liquids.

[0012] By using an alkali metal electrode, for example a lithium electrode or a sodium electrode, in particular which alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na +), which can be reversibly electrochemically provided (and in particular also reabsorbed), as a counter electrode, can advantageously replace a comparatively cost-intensive ferrocene-based electrode conventionally used as a counter electrode in such gas deposition cells. Furthermore, the electrochemical efficiency and / or service life of the cell can be advantageously increased by using an alkali metal electrode, for example, a lithium electrode or a sodium electrode.

[0013] By using an alkali metal ion-conducting solid electrolyte, for example, a lithium ion-conducting or sodium ion-conducting solid electrolyte, the function of an ionic liquid conventionally used in such gas deposition cells can advantageously be assumed. Due to its solid (and thus immobile) nature, a solid electrolyte can offer several advantages over liquid electrolytes and ionic liquids: Firstly, the alkali metal ion-conducting solid electrolyte, for example, a lithium ion-conducting or sodium ion-conducting solid electrolyte, can simplify cell design, for example, by eliminating the need for liquid encapsulation, and / or avoid liquid-related disadvantages, such as a loss of cell function due to liquid loss, for example, in the event of liquid leakage due to mechanical damage and / or liquid discharge by a gas stream.On the other hand, alkali metal ion-conducting solid electrolytes, such as lithium ion-conducting or sodium ion-conducting, can increase the robustness of the cell, for example, against mechanical damage and / or quality deviations. Furthermore, alkali metal ion-conducting solid electrolytes, such as lithium ion-conducting or sodium ion-conducting, can be more cost-effective than conventionally very expensive ionic liquids.

[0014] The gas separation cell can be used particularly advantageously for the separation of carbon dioxide (carbon capture) and / or for electrochemical (potential) swing adsorption, in particular potential swing adsorption, or electro(chemical) swing adsorption (ESA).

[0015] Overall, a new type of gas separation cell for separating a gaseous Lewis acid, in particular carbon dioxide, from a fluid mixture containing the Lewis acid, in particular a gas mixture, can be provided in a simple and cost-effective manner, in particular which can be used, for example, for the separation of carbon dioxide (carbon capture) and / or for electrochemical (potential) swing adsorption (ESA; English: Electro(chemical) Swing Adsorption) and in particular can have an increased efficiency and / or an increased service life.

[0016] In one embodiment, the counter electrode can be an alkali metal intercalation material electrode or a metallic alkali metal electrode. An alkali metal intercalation material electrode can advantageously be particularly cost-effective. A metallic alkali metal electrode can advantageously further increase efficiency.

[0017] The counter electrode may in particular comprise at least one electrochemically active material, for example in the form of a metallic alkali metal, for example in the form of lithium metal or sodium metal, or in the form of an alkali metal-containing intercalation material, for example in the form of lithiated graphite.

[0018] In a further embodiment, the at least one alkali metal ion-conducting solid electrolyte comprises or is at least one, in particular alkali metal ion-conducting, polyethylene oxide (PEO) and / or at least one, in particular alkali metal ion-conducting, fluorinated, in particular perfluorinated, sulfonate ionomer. Thus, the alkali metal ion-conducting solid electrolyte can be realized in a simple and cost-effective manner—particularly compared to very expensive ionic liquids.

[0019] In another embodiment, the counter electrode is a lithium electrode and / or the cell comprises at least one lithium-ion-conducting solid electrolyte. This advantageously optimizes lithium-ion-based charge balance between the adsorption electrode and the counter electrode. Furthermore, numerous suitable, cost-effective, and series-producible lithium electrodes and lithium-ion-conducting solid electrolytes are available.

[0020] In a specific embodiment of this embodiment, the counter electrode is a lithium intercalation material electrode, in particular based on a lithiated carbon material, for example, lithiated graphite, or a lithium metal electrode. Thus, the counter electrode can advantageously be realized in a simple and—compared to cost-intensive ferrocene-based electrodes—cost-effective manner.

[0021] Within the scope of a further specific embodiment of this embodiment, the at least one lithium-ion-conducting solid electrolyte comprises or is at least one, in particular lithium-ion-conducting, polyethylene oxide and / or at least one, in particular lithium-ion-conducting, fluorinated, in particular perfluorinated, sulfonate ionomer. Using lithium-ion-conducting polyethylene oxides and lithium-ion-conducting fluorinated, in particular perfluorinated, sulfonate ionomers, the solid electrolyte can advantageously be realized in a simple and—compared to very expensive ionic liquids—cost-effective manner.

[0022] In another embodiment, the counter electrode is a sodium electrode and / or the cell comprises at least one sodium ion-conducting solid electrolyte. This advantageously optimizes sodium ion-based charge balance between the adsorption electrode and the counter electrode.

[0023] In a specific embodiment of this type, the counter electrode is a sodium metal electrode or a sodium intercalation material electrode, in particular based on a sodium-containing carbon material, for example, sodium-containing graphite. Thus, the counter electrode can advantageously be realized in a simple and—compared to cost-intensive ferrocene-based electrodes—cost-effective manner.

[0024] Within the scope of a further specific embodiment of this embodiment, the at least one sodium-ion-conducting solid electrolyte comprises or is at least one, in particular sodium-ion-conducting, polyethylene oxide and / or at least one, in particular sodium-ion-conducting, fluorinated, in particular perfluorinated, sulfonate ionomer. Using sodium-ion-conducting polyethylene oxides and sodium-ion-conducting, fluorinated, in particular perfluorinated, sulfonate ionomers, the solid electrolyte can advantageously be realized in a simple and—compared to very expensive ionic liquids—cost-effective manner.

[0025] Within the scope of a further embodiment, the adsorption electrode and / or the separator and / or the counterelectrode comprises at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte. In particular, the adsorption electrode and / or the separator and / or the counterelectrode can comprise at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, polyethylene oxide and / or at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, fluorinated, in particular perfluorinated, sulfonate ionomer. In principle, the alkali metal ion-conducting solid electrolyte can advantageously be used in just one of these components, in two of these components, or in all of these components.

[0026] Within the scope of one embodiment of this embodiment, the counterelectrode comprises at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte. In particular, the counterelectrode can comprise at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, polyethylene oxide and / or at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, fluorinated, in particular perfluorinated, sulfonate ionomer. In this way, charge equalization can be improved by the counterelectrode. The counterelectrode can in particular be designed such that the at least one electrochemically active material of the counterelectrode and the at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte of the counterelectrode form a dense body.For example, the at least one electrochemically active material of the counter electrode can be coated and / or encapsulated with the at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte.

[0027] Within the scope of another additional or alternative embodiment of this embodiment, the adsorption electrode comprises at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte. In particular, the counterelectrode can comprise at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, polyethylene oxide and / or at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, fluorinated, in particular perfluorinated, sulfonate ionomer. Thus, charge balance can be improved by the adsorption electrode.The adsorption electrode can in particular be designed such that the at least one electrochemically active material of the adsorption electrode, the at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte of the adsorption electrode and the fluid mixture, in particular gas mixture, or the Lewis acid to be separated, for example carbon dioxide, form three-phase boundaries.

[0028] Within the scope of a further additional or alternative embodiment of this embodiment, the separator comprises at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte. In particular, the separator can comprise at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, polyethylene oxide and / or at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, fluorinated, in particular perfluorinated, sulfonate ionomer. Thus, charge balancing can be improved by the separator.

[0029] Within the scope of a specific embodiment of this embodiment, the adsorption electrode, the separator, and the counterelectrode comprise at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte. In particular, the adsorption electrode, the separator, and the counterelectrode can comprise at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, polyethylene oxide and / or at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, fluorinated, in particular perfluorinated, sulfonate ionomer. This allows charge balance to be optimized throughout the entire cell.

[0030] The separator can, in particular, be alkali metal ion conductive, for example, lithium ion conductive or sodium ion conductive, and electrically insulating. Thus, the separator can electrically separate the adsorption electrode from the counter electrode and, at the same time, connect the adsorption electrode and the counter electrode in an alkali metal ion conductive manner, for example, lithium ion conductive or sodium ion conductive, through its alkali metal ion conductive properties, for example, lithium ion conductive or sodium ion conductive.

[0031] In another embodiment, the separator is designed to be gas-tight and / or liquid-tight. This allows the separator to spatially separate the adsorption electrode from the counter electrode.

[0032] In a further embodiment, the separator is formed from at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte. For example, the separator can be formed from at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, polyethylene oxide and / or from at least one, in particular alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, fluorinated, in particular perfluorinated, sulfonate ionomer. This can be particularly advantageous.

[0033] Within the scope of a further embodiment, the at least one electrochemically active material of the adsorption electrode is capable of binding and / or adsorbing the Lewis acid, for example carbon dioxide, in at least one reduced state and releasing it again into an oxidized state by oxidation. Charges formed during the binding and / or adsorption of the Lewis acid can be formed in particular by alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na + ), can be compensated. This has proven particularly advantageous.

[0034] In a further embodiment, the at least one electrochemically active material of the adsorption electrode comprises or is at least one quinone-functionalized carbon material. For example, the at least one electrochemically active material of the adsorption electrode can comprise or be at least one para-quinone-functionalized carbon material and / or at least one ortho-quinone-functionalized carbon material. The quinone can, in particular, be a polyquinone and / or polymerized and / or polymer-bound.For example, the at least one electrochemically active material of the adsorption electrode may comprise or be at least one poly- and / or -para-quinone-functionalized carbon material, in particular at least one poly- and / or -para-anthraquinone-functionalized carbon material, for example at least one polyanthraquinone-functionalized carbon material, for example polyanthraquinone-functionalized carbon nanotubes (PAQ-CNT).

[0035] The adsorption electrode can, in particular, be porous. In particular, the adsorption electrode can be open-pored. In particular, the adsorption electrode can have a porosity sufficiently high for gas transport.

[0036] In a further embodiment, the Lewis acid, in particular a gaseous one, is carbon dioxide (CO2), carbonyl sulfide (COS), a sulfur oxide, such as sulfur dioxide (SO2) or sulfur trioxide (SO3), a sulfuric acid ester, for example with the general chemical formula R2SO4, for example dimethyl sulfate, a nitrogen oxide, such as nitrogen dioxide (NO2) or nitrogen trioxide (NO3), a phosphoric acid ester, for example with the general chemical formula: R3PO4, for example trimethyl phosphate, a sulfide, for example with the general chemical formula R2S, a carboxylic acid ester, for example with the general chemical formula: RCOOR', such as methyl formate or methyl acrylate, an aldehyde, for example with the general chemical formula: RCHO, such as formaldehyde or acrolein, a ketone, for example with the general chemical formula: R'2CO, such as acetone, an isocyanate, for example with the general chemical formula: R'NCO,such as methyl isocyanate, an isothiocyanate, for example with the general chemical formula: R'NCS, a borane, for example with the general chemical formula: BR''3, such as trimethylborane, or a borate, for example with the general chemical formula: R''3BO3, such as trimethylborate, or a combination thereof. R, in particular each R independently of one another, can represent a hydrogen atom, an alkyl group, in particular having 1 to 12 carbon atoms, a cycloalkyl group, in particular having 3 to 12 carbon atoms, a heterocycloalkyl group, in particular having 1 to 12 carbon atoms, an aryl group, in particular having 6 to 20 carbon atoms, or a heteroaryl group, in particular having 1 to 12 carbon atoms. R', in particular each R' independently of one another, can represent an alkyl group, in particular having 1 to 12 carbon atoms, a cycloalkyl group, in particular having 3 to 12 carbon atoms, a heterocycloalkyl group,in particular having 1 to 12 carbon atoms, an aryl group, in particular having 6 to 20 carbon atoms, or a heteroaryl group, in particular having 1 to 12 carbon atoms. R'', in particular each R'' independently of one another, can represent a hydrogen atom, a halogen atom, an alkyl group, in particular having 1 to 12 carbon atoms, a cycloalkyl group, in particular having 3 to 12 carbon atoms, a heterocycloalkyl group, in particular having 1 to 12 carbon atoms, an aryl group, in particular having 6 to 20 carbon atoms, or a heteroaryl group, in particular having 1 to 12 carbon atoms.

[0037] Within the scope of one embodiment of this embodiment, the Lewis acid, in particular gaseous, is carbon dioxide (CO2), carbonyl sulfide (COS), sulfur dioxide (SO2), sulfur trioxide (SO3), nitrogen dioxide (NO2) or nitrogen trioxide (NO3) or a combination thereof.

[0038] In a preferred embodiment of this method, the Lewis acid, particularly in gaseous form, is carbon dioxide (CO2). The gas separation cell can be used particularly advantageously for carbon capture.

[0039] Within the scope of a further embodiment, the gas separation cell is designed for the separation of carbon dioxide and / or the adsorption electrode is designed for the reversible electrochemical adsorption of carbon dioxide and / or the at least one electrochemically active material of the adsorption electrode is capable of binding and / or adsorbing carbon dioxide in at least one reduced state and releasing it again by oxidation into an oxidized state, in particular wherein charges formed during the binding and / or adsorption of carbon dioxide are converted into alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na +), and / or the at least one electrochemically active material of the adsorption electrode has alkali metal carboxylate groups, in particular lithium carboxylate groups or sodium carboxylate groups, in at least one reduced, carbon dioxide-binding state.

[0040] The alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte and / or the alkali metal carboxylate groups, in particular lithium carboxylate groups or sodium carboxylate groups, formed in the reduced state of the electrochemically active material of the adsorption electrode can be detected, for example, by chemical analysis methods.

[0041] With regard to further technical features and advantages of the gas separation cell according to the invention, reference is hereby explicitly made to the explanations in connection with the gas separation system according to the invention and the operating method according to the invention as well as to the figure and the figure description.

[0042] A further subject of the invention is an electrochemical gas separation system for the, in particular electrochemical, separation of a gaseous Lewis acid, in particular carbon dioxide, from a fluid mixture containing the Lewis acid, in particular a gas mixture, which comprises gas separation cells according to the invention, for example a plurality of gas separation cells according to the invention.

[0043] With regard to further technical features and advantages of the gas separation system according to the invention, reference is hereby explicitly made to the explanations in connection with the gas separation cell according to the invention and the operating method according to the invention as well as to the figure and the figure description.

[0044] Furthermore, the invention relates to a method for operating a gas separation cell according to the invention and / or a gas separation system according to the invention for the, in particular electrochemical, separation of a gaseous Lewis acid, in particular carbon dioxide, from a fluid mixture containing the Lewis acid, in particular a gas mixture.

[0045] In the process, the gas separation cell or cells are operated in particular by means of electrochemical (potential) swing adsorption, in particular potential swing adsorption, or electro(chemical) swing adsorption (ESA).

[0046] Within the scope of one embodiment, in an adsorption operation of the gas separation cell, the fluid mixture containing the Lewis acid, in particular a gas mixture, is passed over and / or through the adsorption electrode and a potential (or a voltage) is set between the adsorption electrode and the counter electrode of the cell in such a way that the at least one electrochemically active material of the adsorption electrode is reduced by absorbing electrons, by binding and / or adsorbing the Lewis acid and by forming, in particular negative, charges, and the, in particular negative, charges are reduced by alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na + ), be compensated.

[0047] The gas separation cell can, for example, be operated in adsorption mode up to a certain saturation, for example up to a complete saturation, of the at least one electrochemically active material of the adsorption electrode with the Lewis acid.

[0048] After reaching the certain saturation of the at least one electrochemically active material of the adsorption electrode with the Lewis acid, the gas separation cell can then be switched to and / or operated in a gas release mode.

[0049] Within the scope of a further embodiment, in a / the gas release operation of the gas separation cell, the potential set between the adsorption electrode and the counter electrode of the cell (or the voltage applied between the adsorption electrode and the counter electrode of the cell) is reversed, in particular compared to the adsorption operation, wherein the at least one electrochemically active material of the adsorption electrode releases electrons, releases gaseous Lewis acid, in particular neutralizes charge, and releases alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na + ), oxidized and the released alkali metal ions, especially lithium ions (Li + ) or sodium ions (Na +), through which at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte and / or are conducted to the counter electrode and / or are taken up by the counter electrode in a reduced metallic form.

[0050] The released gaseous Lewis acid, in particular carbon dioxide, can in particular be separated or removed.

[0051] The gas separation cell can, for example, be switched from the Lewis acid to the gas release mode and / or operated therein up to a certain degree of desorption, for example up to complete desorption, of the at least one electrochemically active material of the adsorption electrode.

[0052] After reaching the specific degree of desorption of the at least one electrochemically active material of the adsorption electrode, the gas separation cell can be switched back to adsorption mode and / or operated in it.

[0053] If a voltage is applied during adsorption operation, any electrical energy consumed can advantageously be recovered during gas release operation. In the case of lithium, gas adsorption can even be exothermic, or energy can be extracted from gas absorption and / or a voltage can be removed during adsorption operation.

[0054] The operating process can be carried out in cycles, in particular, with each cycle comprising at least one adsorption phase and one gas release phase. The Lewis acid can be separated, in particular, by repeatedly running through these cycles.

[0055] With regard to further technical features and advantages of the operating method according to the invention, reference is hereby explicitly made to the explanations in connection with the gas separation cell according to the invention and the gas separation system according to the invention as well as to the figure and the figure description. drawing

[0056] Further advantages and advantageous embodiments of the invention are illustrated by the drawings and explained in the following description. It should be noted that the drawings are for descriptive purposes only and are not intended to limit the invention in any way. It shows Fig. 1 a schematic cross-section through an embodiment of an electrochemical vapor deposition cell according to the invention.

[0057] Fig. 1 shows that the gas separation cell 10 for separating a gaseous Lewis acid, for example carbon dioxide, from a fluid mixture containing the Lewis acid, in particular a gas mixture, in the embodiment shown therein comprises an adsorption electrode 20 with an electrochemically active material 21 for the reversible electrochemical adsorption of the Lewis acid, for example carbon dioxide, a counter electrode 30 and a separator 40 arranged between the adsorption electrode 20 and the counter electrode 30. The Li + / N / a + -Double arrow in Fig. 1 illustrates that the cell 10 thereby has an alkali ion-based, in particular lithium ion-based or sodium ion-based, charge balance Li + / N / a +between the adsorption electrode 20 and the counter electrode 30. For this purpose, in the cell 10 shown, the counter electrode 30 is an alkali metal electrode, in particular a lithium electrode or a sodium electrode, and the adsorption electrode 20, the counter electrode 30 and the separator 40 each comprise an alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte 22,LiFE / NaFE; 32,LiFE / NaFE; 40,LiFE / NaFE.

[0058] The alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte 22,LiFE / NaFE;32,LiFE / NaFE;40,LiFE / NaFE of the adsorption electrode 20, the counter electrode 30 and the separator 40 can in particular comprise or be a polyethylene oxide and / or a fluorinated, in particular perfluorinated, sulfonate ionomer.

[0059] The counter electrode 30 may in particular be an alkali metal intercalation material electrode or a metallic alkali metal electrode. Fig. 1 illustrates that the counter electrode 30 comprises in particular at least one electrochemically active material 31, for example in the form of a metallic alkali metal, for example in the form of lithium metal or sodium metal, or in the form of an alkali metal-containing intercalation material, for example in the form of lithiated graphite.

[0060] Fig. 1 indicates that the counterelectrode 30 can be designed in particular such that the at least one electrochemically active material 31 of the counterelectrode 30 and the at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte 32, LiFE / NaFE of the counterelectrode 30 form a dense body. For example, the at least one electrochemically active material 31 of the counterelectrode 30 can be coated and / or encapsulated with the at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte 32, LiFE / NaFE.

[0061] In addition, Fig. 1 indicates that the adsorption electrode 20 can be designed in particular such that the at least one electrochemically active material 21 of the adsorption electrode 20, the alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte 21, LiFE / NaFE of the adsorption electrode 20 and the fluid mixture, in particular the gas mixture, or the Lewis acid to be separated, for example carbon dioxide, form three-phase boundaries in free areas and / or spaces of the adsorption electrode 20 (not explicitly shown).

[0062] The separator 40 can be formed in particular from the alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte 40, LiFE / NaFE, in particular gas-tight and / or liquid-tight.

[0063] The electrochemically active material 21 of the adsorption electrode 20 can, in particular, be capable of binding and / or adsorbing the Lewis acid, in particular carbon dioxide, in at least one reduced state and releasing it again into an oxidized state by oxidation. Charges formed during the binding and / or adsorption of the Lewis acid can be replaced by alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na + ). For example, the electrochemically active material 21 of the adsorption electrode 20 may comprise or be a quinone-functionalized, in particular poly- and / or para-anthraquinone-functionalized, carbon material, for example polyanthraquinone-functionalized carbon nanotubes (PAQ-CNT).

[0064] The Fig.The gas adsorption cell 10 shown in Figure 1 can be operated by means of electrochemical (potential) alternating adsorption, for example in two, in particular alternating, phases, namely in an adsorption mode and in a gas release mode.

[0065] During adsorption operation, the Lewis acid, for example carbon dioxide, for example in the form of a fluid mixture, in particular a gas mixture, with a high carbon dioxide content, can be passed in particular over and / or through the adsorption electrode 20, wherein - for example by a voltage source or - in particular in the case of lithium - by a voltage collector 50 - a potential is set between the adsorption electrode 20 and the counter electrode 30 of the cell 10 such that the at least one electrochemically active material 21 of the adsorption electrode 20 is reduced by absorbing electrons, by binding and / or adsorbing the Lewis acid and by forming charges, in particular negative ones, and the charges, in particular negative ones, are replaced by the at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte 22, LiFE / NaFE;32,LiFE / NaFE;40,LiFE / NaFE conducted alkali metal ions, in particular lithium ions (Li; + ) or sodium ions (Na + ), be compensated.

[0066] In a cell 10 with lithium ion-based charge compensation, in adsorption operation for adsorbing the Lewis acid carbon dioxide (CO2), in particular at the adsorption electrode 20, the partial reaction A + 2 CO2 + 2 Li + + 2 e - → A(-COO - Li + )2, where A stands for quinone, for example anthraquinone, for example polyanthraquinone (PAQ), of the electrochemically active material 21 of the adsorption electrode 20, and at the counter electrode 30 the partial reaction: 2 Li→2 Li + +2e - expire.

[0067] In a cell 10 with sodium ion-based charge compensation, in adsorption operation for adsorbing the Lewis acid carbon dioxide (CO2), in particular at the adsorption electrode 20, the partial reaction A + 2 CO2 + 2 Na + + 2 e - → A(-COO - N / a + )2, where A stands for anthraquinone, for example polyanthraquinone (PAQ), of the electrochemically active material 21 of the adsorption electrode 20, and at the counter electrode 30 the partial reaction 2 Na→2 Na + + 2 e - expire.

[0068] In this case, the electrochemically active material 21(A) of the adsorption electrode 20 can, in particular, absorb electrons (e - ), with binding and / or adsorption of the Lewis acid carbon dioxide (CO2) and with formation of negative charges, especially in the form of carboxylate groups, (-COO -) and the negative charges, especially of the carboxylate groups, (-COO - ) by alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na + ), forming alkali metal carboxylate groups, especially lithium carboxylate groups (-COO - Li + ) or sodium carboxylate groups (-COO - N / a + ), can be compensated. Thus, the electrochemically active material 21 of the adsorption electrode 20 in the reduced, carbon dioxide-binding state can form alkali metal carboxylate groups, in particular lithium carboxylate groups (-COO - Li + ) or sodium carboxylate groups (-COO - N / a +). In adsorption operation, the Lewis acid carbon dioxide (CO2) can thus be adsorbed from the fluid mixture, in particular gas mixture, passed over and / or through the adsorption electrode 20, and its carbon dioxide content can thereby be reduced, so that the fluid mixture, in particular gas mixture, after flowing over and / or through the adsorption electrode 20, can have a reduced carbon dioxide content or can possibly even be substantially carbon dioxide-free.

[0069] In gas release mode, the potential set at the adsorption electrode 20 and the counter electrode 30 of the cell 10 can be reversed, particularly compared to adsorption mode. This also reverses the reaction direction.

[0070] In a cell 10 with lithium ion-based charge compensation, in gas release mode, the partial reaction can be carried out with the release of the gaseous Lewis acid carbon dioxide (CO2), particularly at the adsorption electrode 20 A(-COO - Li + )2 → A + 2 CO2 + 2 Li + + 2 e - , where A stands for quinone, for example anthraquinone, for example polyanthraquinone (PAQ), of the electrochemically active material 21 of the adsorption electrode 20, and at the counter electrode 30 the partial reaction 2 Li + + 2 e - → 2 Li expire.

[0071] In a cell 10 with lithium ion-based charge compensation, in gas release mode, the partial reaction can be carried out with the release of the gaseous Lewis acid carbon dioxide (CO2), particularly at the adsorption electrode 20 A(-COO - N / a + )2 → A + 2 CO2 + 2 Na + + 2 e - , where A stands for quinone, for example anthraquinone, for example polyanthraquinone (PAQ), of the electrochemically active material 21 of the adsorption electrode 20, and at the counter electrode 30 the partial reaction 2 Na + + 2 e - → 2 Na expire.

[0072] The electrochemically active material 21 of the adsorption electrode 20 can release electrons (e - ), in particular which migrate via the circuit to the counter electrode 30, releasing the gaseous Lewis acid carbon dioxide (CO2), and releasing alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na + ), are oxidized and the released alkali metal ions, especially lithium ions (Li + ) or sodium ions (Na +), through the alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte 22,LiFE / NaFE; 32,LiFE / NaFE; 40,LiFE / NaFE and / or to the counter electrode 30 and / or absorbed by the counter electrode 30 in a reduced metallic form. Concentrated gaseous Lewis acid can be released in the form of concentrated gaseous carbon dioxide (CO2), which can then be separated.

[0073] In this case, an adsorption phase and a gas release phase can, in particular, jointly form a cycle. The separation of the Lewis acid, especially carbon dioxide, can be achieved, for example, by repeatedly running through these cycles. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2022 / 0339579 A1

[0005]

Claims

[1] Electrochemical gas separation cell (10) for separating a gaseous Lewis acid, in particular carbon dioxide, from a fluid mixture containing the Lewis acid, in particular a gas mixture, comprising - an adsorption electrode (20) with at least one electrochemically active material (21) for the reversible electrochemical adsorption of the Lewis acid, in particular carbon dioxide, - a counter electrode (30) and - a separator (40) arranged between the adsorption electrode (20) and the counter electrode (30), wherein the counter electrode (30) is an alkali metal electrode and / or wherein the cell (10) comprises at least one alkali metal ion-conducting solid electrolyte (LiFE / NaFE). [2] The gas deposition cell (10) of claim 1, wherein the counter electrode (30) is an alkali metal intercalation material electrode or a metallic alkali metal electrode. [3] Gas deposition cell (10) according to claim 1 or 2, wherein the at least one alkali metal ion-conducting solid electrolyte (LiFE / NaFE) comprises at least one polyethylene oxide and / or at least one fluorinated, in particular perfluorinated, sulfonate ionomer. [4] Gas deposition cell (10) according to one of claims 1 to 3, wherein the counter electrode (30) is a lithium electrode and / or wherein the cell (10) comprises at least one lithium ion conductive solid electrolyte (LiFE). [5] Gas separation cell (10) according to claim 4, wherein the counter electrode (30) is a lithium intercalation material electrode, in particular based on a lithiated carbon material, in particular lithiated graphite, or a lithium metal electrode, and / or wherein the at least one lithium ion-conducting solid electrolyte (LiFE) comprises at least one polyethylene oxide and / or at least one fluorinated, in particular perfluorinated, sulfonate ionomer. [6] Gas deposition cell (10) according to one of claims 1 to 3, wherein the counter electrode (30) is a sodium electrode, and / or wherein the cell (10) comprises at least one sodium ion-conducting solid electrolyte (NaFE). [7] Gas separation cell (10) according to claim 6, wherein the counter electrode (30) is a sodium metal electrode or a sodium intercalation material electrode, in particular based on a sodium-containing carbon material, and / or wherein the at least one sodium ion-conducting solid electrolyte (NaFE) comprises at least one polyethylene oxide and / or at least one fluorinated, in particular perfluorinated, sulfonate ionomer. [8] Gas deposition cell (10) according to one of claims 1 to 7, wherein the adsorption electrode (20) and / or the separator (40) and / or the counter electrode (30) comprises at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte (LiFE / NaFE), in particular at least one polyethylene oxide and / or at least one fluorinated, in particular perfluorinated, sulfonate ionomer. [9] Gas separation cell (10) according to one of claims 1 to 8, wherein the separator (40) is formed from at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte (LiFE / NaFE), in particular from at least one polyethylene oxide and / or from at least one fluorinated, in particular perfluorinated, sulfonate ionomer, and / or wherein the separator (40) is gas-tight and / or liquid-tight. [10] Gas deposition cell (10) according to one of claims 1 to 9, wherein the at least one electrochemically active material (21) of the adsorption electrode (20) is capable of binding and / or adsorbing the Lewis acid, in particular carbon dioxide, in at least one reduced state and of releasing it again by oxidation into an oxidized state, wherein charges formed during the binding and / or adsorption of the Lewis acid are replaced by alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na + ), can be compensated. [11] Gas deposition cell (10) according to one of claims 1 to 10, wherein the at least one electrochemically active material (21) of the adsorption electrode (20) comprises or is at least one quinone-functionalized carbon material. [12] Gas deposition cell (10) according to one of claims 1 to 11, wherein the Lewis acid is carbon dioxide, carbonyl sulfide, sulfur dioxide, sulfur trioxide, a sulfuric acid ester, nitrogen dioxide, nitrogen trioxide, a phosphoric acid ester, a sulfide, a carboxylic acid ester, an aldehyde, a ketone, an isocyanate, an isothiocyanate, a borane or a borate or a combination thereof, in particular wherein the Lewis acid is carbon dioxide. [13] Gas separation cell (10) according to one of claims 1 to 12, wherein the gas separation cell (10) is designed to separate carbon dioxide, and / or wherein the adsorption electrode (20) is designed for the reversible electrochemical adsorption of carbon dioxide, and / or wherein the at least one electrochemically active material (21) of the adsorption electrode (20) is capable of binding and / or adsorbing carbon dioxide in at least one reduced state and releasing it again by oxidation into an oxidized state, wherein charges formed during the binding and / or adsorption of carbon dioxide are replaced by alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na + ), are offsettable, and / or wherein the at least one electrochemically active material (21) of the adsorption electrode (20) has alkali metal carboxylate groups, in particular lithium carboxylate groups or sodium carboxylate groups, in at least one reduced, carbon dioxide-binding state. [14] Electrochemical gas deposition system for separating a gaseous Lewis acid, in particular carbon dioxide, from a fluid mixture containing the Lewis acid, in particular a gas mixture, comprising electrochemical gas deposition cells (10) according to one of claims 1 to 13. [15] Method for operating a gas separation cell (10) according to one of claims 1 to 13 and / or a gas separation system according to claim 14 for separating a gaseous Lewis acid, in particular carbon dioxide, from a fluid mixture containing the Lewis acid, in particular a gas mixture, in which the gas separation cell (10) or the gas separation cells are operated by means of electrochemical alternating adsorption, in particular potential alternating adsorption, wherein, in an adsorption operation of the gas separation cell (10), the fluid mixture containing the Lewis acid, in particular a gas mixture, is passed over and / or through the adsorption electrode (20) and a potential is set between the adsorption electrode (20) and the counter electrode (30) of the cell in such a way that the at least one electrochemically active material (21) of the adsorption electrode (20) is reduced by absorbing electrons, by binding and / or adsorbing the Lewis acid and by forming, in particular negative, charges, and the charges are reduced by alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na + ), be offset, and / or wherein in a gas release operation of the gas separation cell (10) the potential set between the adsorption electrode (20) and the counter electrode (30) of the cell (10) is reversed, in particular compared to the adsorption operation, wherein the at least one electrochemically active material (21) of the adsorption electrode (20) releases electrons, releases gaseous Lewis acid, in particular carbon dioxide, and releases alkali metal ions, in particular lithium ions (Li + ) or sodium ions (Na + ), oxidized and the released alkali metal ions, especially lithium ions (Li + ) or sodium ions (Na +), through which at least one alkali metal ion-conducting, in particular lithium ion-conducting or sodium ion-conducting, solid electrolyte (LiFE / NaFE), and / or are conducted to the counter electrode (30) and / or are taken up by the counter electrode (30) in a reduced metallic form, in particular wherein the released gaseous Lewis acid, in particular carbon dioxide, is separated or precipitated.

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