Switchable electrode arrangement

Abstract

The present invention relates to an electrode arrangement (10) for an electrochemical cell, the electrode arrangement having at least a first electrode (14) and a second electrode (16), the first electrode (14) and the second electrode (16) being operable with the same polarity, the first electrode (14) being arranged in a first electrode chamber (18) and the second electrode (16) being arranged in a second electrode chamber (20) which is separated from the first electrode chamber (18) by a separator (22), and the first electrode (14) and the second electrode (16) being independently operable such that the first electrode (14) can be operated in contact with a first fluid and the second electrode (16) can be operated in contact with a second fluid different from the first fluid, and the first electrode (14) being configured for a first reaction and the second electrode (16) being configured for a second reaction different from the first reaction.

Description

[0001] Switchable electrode arrangement

[0002] The present invention relates to an electrode arrangement. The present invention further relates to an electrolysis arrangement comprising such an electrode arrangement.

[0003] The transition from fossil fuels to renewable energy resources will bring significant fluctuations in future energy supply, as solar and wind power generation varies. Furthermore, electrochemical processes will play a crucial role in the future, replacing centralized, fossil-based chemical synthesis through electrification.

[0004] To effectively respond to fluctuations in electricity prices, one approach is to modify the electrochemical reaction, for example, on the anode side. During periods of low electricity prices, an example reaction at the anode involves the oxidation of water to oxygen (oxygen evolution reaction - OER) with a standard potential of 1.23 V and sluggish kinetics. In contrast, during periods of high electricity prices, hydrogen can be oxidized (hydrogen oxidation reaction - HOR) with a standard potential of 0 V and faster kinetics. However, such a switchover requires the electrochemical cell to be switched off and subsequently purged with an inert gas, such as nitrogen, to prevent the formation of the explosive oxyhydrogen mixture.

[0005] This leads to financial losses due to the complete shutdown during the rinsing process.

[0006] EP 3 428 319 A relates to an electrochemical water electrolysis system with a membrane-electrode arrangement, comprising: at least one electrolysis section comprising a first anode and a first cathode separated from each other by the first membrane. The anode is designed for the oxidation of the water and the first cathode is designed for the reduction of the protons, the first anode being designed to receive water from the main inlet. Also included is at least one separation section located downstream of the electrolysis section, comprising a second anode and a second cathode separated from each other by the membrane, the second anode being designed to carry out the oxidation of the hydrogen obtained, and the electrolysis section and the second cathode being suitable for carrying out the reduction of the protons.

[0007] EP 0 333 281 A1 describes a membrane electrolysis device for producing hydrogen, chlorine, and alkali hydroxide from an alkali chloride solution, comprising a semipermeable membrane with cation exchange properties between each anode and cathode, wherein the membrane electrolysis device incorporates components from a diaphragm electrolysis device. This device is characterized in that the anodes of the membrane electrolysis device have a frame in which one to three anodes from a diaphragm electrolysis device are mounted, each anode having electrochemically active anode surfaces with a grid structure and a current conductor arranged between the anode surfaces, and the current conductor being connected to the frame.

[0008] DE 10 2014 010 359 Al concerns a hydrogen production plant that operates using electrolysis powered by electricity drawn from the grid. To achieve greater flexibility and improved integration of the plant into the overall energy landscape, the plant has at least two electrolysis units whose electrical supply can be switched on and off independently.

[0009] CN 104674293 A discloses a polarity-reversible electrolysis circuit for the electrolysis of a saline solution to produce sodium hypochlorite. The electrolysis circuit comprises a transformer unit, a first rectifier circuit unit, a second rectifier circuit unit, a first driver circuit unit, a second driver circuit unit, a first overcurrent protection circuit unit, a second overcurrent protection circuit unit, a first group of transistors, a second group of transistors, a first current sensing circuit unit, a second current sensing circuit unit, an electrolysis electrode, a single-chip microcomputer control and protection circuit unit, and a power module. It allows any group of transistors to operate or for the two groups of transistors to be switched alternately to operate.

[0010] WO 2017 / 174563 Al relates to an oxygen-consuming electrode for use in chi-or alkaline electrolysis, which can either generate hydrogen or consume oxygen as required, based on a silver-based catalyst and an additional electrocatalyst based on ruthenium and / or iridium. This document also relates to an electrolysis apparatus consisting thereof.

[0011] However, the state of the art described above still offers potential for improvement, particularly with regard to the flexible adaptation of an electrolysis process.

[0012] It is therefore an object of the present invention to provide a measure by which at least one disadvantage of the prior art is at least partially overcome. In particular, it is an object of the present invention to provide a solution by means of which the flexibility of an electrolysis process or an electrolysis arrangement can be improved.

[0013] The problem is solved according to the invention by an electrode arrangement having the features of claim 1. The problem is further solved by an electrolysis arrangement having the features of claim 7, as well as by use with the features of claim 12 or by use with the features of claim 13. Preferred embodiments of the invention are disclosed in the dependent claims, in the description and in the figures, wherein further features described or shown in the dependent claims or in the description or the figures may, individually or in any combination, constitute an object of the invention unless the context clearly indicates otherwise.

[0014] The present invention relates to an electrode arrangement for an electrochemical cell, wherein the electrode arrangement comprises at least a first electrode and a second electrode, wherein the first electrode and the second electrode can be operated in the same polarity, wherein the first electrode is arranged in a first electrode chamber and wherein the second electrode is arranged in a second electrode chamber separated from the first electrode chamber by a separator, wherein the first electrode and the second electrode can be operated separately such that the first electrode can be operated in contact with a first fluid and the second electrode can be operated in contact with a second fluid different from the first fluid, and wherein the first electrode is configured for a first reaction and wherein the second electrode is configured for a second reaction different from the first reaction.

[0015] Such an electrode arrangement can offer significant advantages over prior art solutions. In particular, such an electrode arrangement can be a component of an electrochemical cell for an electrolysis setup, which can be suitable for carrying out a wide variety of electrochemical reactions, as described in greater detail below.

[0016] The electrode arrangement comprises at least a first electrode and a second electrode, wherein the first electrode and the second electrode can be operated in the same polarity. In the context of the present invention, polarity refers in particular to their electrical polarity during use, such that, for example, two cathodes have the same polarity and one cathode and one anode have different polarities or a polarity complementary to the other electrode. Accordingly, polarity in the context of the present invention refers in particular to the ability to carry out a reduction or oxidation.

[0017] Accordingly, when operating the electrode arrangement, at least two electrodes can be operated in the same polarity, which can occur simultaneously, but need not; rather, switching between them is also possible, as described below. Furthermore, at least one electrode is provided, in a manner readily apparent to a person skilled in the art, which can be operated in the complementary polarity. For example, the at least two electrodes of the same polarity can be operated as an anode or as a cathode.

[0018] Regarding the two electrodes that can be operated in the same polarity, it is further provided that the first electrode is arranged in a first electrode chamber and that the second electrode is arranged in a second electrode chamber, separated from the first electrode chamber by a separator. Accordingly, it is provided that the at least two electrodes of the same polarity are not intended for the same reaction under the same conditions, but that the at least two electrodes of the same polarity can be operated differently, for example with different charge transfer rates, or used for different reactions.

[0019] Furthermore, a separator within the meaning of the present invention is, in principle and in accordance with the prior art, to be understood as an ion-conducting separating layer that can retain, in particular, at least one substance, such as hydrogen (H2) or oxygen (O2). Examples include a cation exchange membrane, anion exchange membrane, bipolar membrane, or porous separating layers, such as a hydrogen separator marketed under the brand name Zirfon®.

[0020] The first and second electrodes of the same polarity can be operated separately such that the first electrode can be operated in contact with a first fluid and the second electrode in contact with a second fluid different from the first. Accordingly, the conditions for operating the at least two different electrodes of the same polarity can differ significantly.

[0021] Furthermore, according to the invention, the first electrode of the electrodes of the same polarity is provided for a first reaction, and the second electrode of the electrodes of the same polarity is configured for a second reaction different from the first. This can be achieved, for example, by having different electrode designs, such as different structures, different materials, or being fundamentally adapted to different reactions. Alternatively, this can also be achieved by having the same electrode design, but allowing them to be brought into contact with different media to promote different reactions. The electrode arrangement according to the invention thus makes it possible to generate highly dynamic electrochemical cells by means of tunable and switchable anodes and / or cathodes, in which the reaction on the anode side and / or cathode side can be modified.

[0022] In state-of-the-art solutions, such a switchover requires shutting down the electrochemical cell and subsequently purging it with an inert gas, such as nitrogen, to avoid negatively impacting the subsequent reaction. Depending on the reaction, an explosive mixture of hydrogen and oxygen could otherwise form, which must obviously be prevented. This purging step is time-consuming and therefore costly, as the cell must be completely shut down for the process. Accordingly, purging steps should be kept to a minimum. Furthermore, the purging step requires additional fittings and piping for the gas supply, resulting in significantly increased equipment costs.

[0023] These disadvantages can be easily circumvented according to the invention, since different electrodes can simply be used in different electrode chambers for different reactions. This eliminates the need for a rinsing step, saving resources, time, and money, and making the electrode arrangement significantly more adaptable.

[0024] Furthermore, in the current state of the art there is no way to control the reactions on the electrode surface in a defined manner, so that the respective reaction usually takes place either at 100% or at 0%.

[0025] In contrast, the electrode arrangement described here discloses an electrochemical cell having two anodes and / or cathodes that can be operated both dependently and independently. Implementations of dependent or independent operation of electrodes of the same polarity include, in particular, shared or separate electrical contacting of the electrodes. In dependent operation configurations, electrodes of the same polarity are electrically connected. In these configurations, switching between the reactions at the electrodes of the same polarity can be achieved by changing the fluid or mass flow, for example, by switching a hydrogen supply on or off. In independent operation configurations, electrodes of the same polarity are electrically connected separately. In these configurations, switching between the reactions at the electrodes of the same polarity can be achieved by changing the fluid or mass flow, for example, by switching a hydrogen supply on or off.The reaction rates can be controlled by switching the current or voltage supply to the electrodes on or off, or by changing it.

[0026] For example, an oxygen evolution reaction (OER) can take place at one of the anodes, and a hydrogen oxidation reaction (HÖR) at the other. In dependent operation, switching from one anode to the other is seamless. In independent operation, both anodes can then be operated simultaneously with different current inputs.

[0027] This example demonstrates that, according to the invention, complex modifications for switching between the corresponding reactions at an electrode can be completely avoided. This allows the corresponding changeover to be implemented more easily and with less effort and cost.

[0028] In principle, the aforementioned method can be implemented on both the anode and cathode sides. The two electrodes of the same polarity are separated by a separator, which prevents the formation of an explosive gas mixture and thus eliminates the need for a purge step. This allows the two electrodes, for example, anodes, operating simultaneously at different inputs, to be matched. All of this enables extremely flexible adaptation of the reaction to be carried out based on energy fluctuations and process adjustments.

[0029] Preferably, a first fluid supply can be provided to selectively supply the first electrode with a first fluid flow, and a second fluid supply can be provided to selectively supply the second electrode with a second fluid flow that differs from the first. In this configuration, in particular, it is possible to quickly and easily switch between electrodes of the same polarity and thus, by actively using different reaction media located in the immediate vicinity of the electrodes, to initiate or promote different reactions.

[0030] The fluid feeds can be completely separate and, for example, coupled to or supplied by different fluid sources. Accordingly, in this configuration, the reaction to be carried out with the electrode can be selected by choosing the fluid contacting the electrode.

[0031] However, it is also possible that the different fluid feeds only affect the different fluid sources, but that the fluids from the fluid sources are at least partially routed through the same line, meaning, for example, that a valve can be switched in one line to couple the different fluid feeds to the electrode chambers. It may also be preferred that the first electrode and the second electrode can be electrically connected and controlled separately. In particular, it may be preferred that the first electrode can be connected to a first voltage source or a first current source, and that the second electrode can be connected to a second voltage source or a second current source.However, it is equally possible that only one current source or only one voltage source is provided for both electrodes, whereby this can be selectively connected to the first or the second electrode of the same polarity, for example by means of a corresponding circuit.

[0032] In this configuration, it is possible for only one electrode to be supplied with current or voltage at a time, or for both electrodes to be supplied accordingly. In other words, it becomes possible for the current flow to be divided between both electrodes, or for only one of the two electrodes to be active. Accordingly, in this configuration, the selection of the active electrode, and thus the reaction to be carried out, can be achieved through an electrical circuit.

[0033] When both electrodes are operated simultaneously, two voltage or current sources are required. With complete switching, the electrodes could also be operated with a single voltage or current source, which is switched between the electrodes by a suitable circuit / control unit. Furthermore, it is also possible to use one voltage or current source for both electrodes and control the reaction by choosing the type of fluid flowing over the electrodes. In this case, depending on the availability of the reactant, e.g., iron (FE), either the first or the second electrode can be active. The higher the reactant concentration, e.g., the iron concentration, the more active the first electrode is (due to its more favorable potential and kinetics) compared to the second electrode when using a single voltage / current source.Thus, both electrodes can be supplied with current or voltage, and the reaction is controlled by the appropriate supply of the reactant. It is also preferred that at least two anodes are provided as the first and second electrodes. Alternatively or additionally, at least two cathodes can be provided as the first and second electrodes. The specific configuration can be chosen depending on the reaction to be carried out, specifically regarding the anode and cathode configuration and how the reaction is to be adapted.

[0034] Furthermore, it can be advantageous for the anodes, or possibly also the cathodes, to be separated from each other by a fluid-tight and ion-conducting membrane. This also enables effective separation of the different electrode chambers, preventing contamination by the reaction media.

[0035] It may also be preferred that at least the first or the second electrode or the first and second electrodes contact a separator or ion-conducting separating layer, for example by resting on or being connected to it.

[0036] In principle, due to the preferably different design of the electrodes of the same polarity, it can be advantageous that switching is possible both with regard to the material flow and with regard to the electrical connection, i.e. with regard to the current and / or voltage source.

[0037] The fact that the membrane between the anodes or cathodes of the same polarity is ion-conducting is also advantageous with regard to functionality, as is described in greater detail below.

[0038] Regarding further technical features and advantages of the electrode arrangement, reference is made to the description of the electrolysis arrangement, its use, the figures, and the description of the figures. An electrolysis arrangement is further described, comprising a first electrode arrangement configured as an anode arrangement with at least one electrode and a second electrode arrangement configured as a cathode arrangement with at least one electrode, wherein at least one voltage source or current source is provided, which is connected to the first electrode arrangement and to the second electrode arrangement, characterized in that at least one of the first electrode arrangement and the second electrode arrangement is configured as described above.

[0039] Accordingly, an electrolysis arrangement is described which has the previously described electrode arrangement. The electrode arrangement can be, for example, a cathode arrangement or an anode arrangement, or it can have both.

[0040] In other words, an electrolysis arrangement comprises at least one half-cell formed from a previously described electrode arrangement. In an exemplary operation of at least one previously described electrode arrangement, whose first and second electrodes are operated in the same polarity, at least one further electrode is provided which can be operated in the complementary polarity. Such an electrolysis arrangement comprises at least three electrode combs for at least three electrodes, separated by at least two separators or ion-permeable membranes. When the exemplary electrolysis arrangement is in operation, the at least three electrodes can be operated for at least three different reactions.In certain embodiments, different reactions can occur at electrodes operated with the same polarity, or electrodes of the same polarity can be operated differently, for example, with different charge transfer rates, while the reaction at the electrode of complementary polarity can be kept constant during operation. Furthermore, at least one voltage source or current source is provided, through which a corresponding voltage can be applied to the electrodes to generate a current flow. In principle, it is possible for only one voltage source or current source to supply all electrodes. Alternatively, different electrodes of the same polarity can be supplied by different current sources or voltage sources to completely switch the supply, as described above in greater detail.

[0041] In principle, the electrolysis setup described here allows for the advantages described with regard to the electrode arrangement. In summary, it is thus possible to easily change the electrolysis reaction to be carried out, or to adapt the electrolysis setup to different reactions, without complex modifications or elaborate rinsing steps.

[0042] In one embodiment, it may be advantageous for the electrolysis arrangement to have two current sources or two voltage sources, wherein in a first switching state a first current source or a first voltage source can be connected to a first electrode of the first electrode arrangement and in a second switching state a second current source or second voltage source can be connected to a second electrode of the first electrode arrangement, or wherein in a first switching state a first current source or a first voltage source can be connected to a first electrode of the second electrode arrangement and in a second switching state a second current source or second voltage source can be connected to a second electrode of the second electrode arrangement, and wherein the first switching state or the second switching state can be selected selectively.In this configuration, it is possible for the different electrodes of the same polarity to be supplied by different voltage or current sources. This allows for a particularly simple switching of the electrodes of the same polarity by simply changing the active current or voltage source, thus enabling the desired reaction to be controlled. This allows for effective influence on the reaction to be carried out, again without complex modifications or time-consuming rinsing steps.

[0043] Alternatively, the electrolysis arrangement may be provided to have a current source or a voltage source, wherein in a first switching state the current source or the voltage source can be connected to a first electrode of the first electrode arrangement and in a second switching state the current source or the voltage source can be connected to a second electrode of the first electrode arrangement, or wherein in a first switching state the current source or the voltage source can be connected to a first electrode of the second electrode arrangement and in a second switching state the current source or the voltage source can be connected to a second electrode of the second electrode arrangement, and wherein the first switching state or the second switching state can be selected selectively.

[0044] In this embodiment, the reaction to be carried out, as described above, can also be effected by an electrical circuit, although only one voltage source or one current source is required. The current source or the voltage source can then be connected to the desired electrode. As in the previously described embodiment, the electrode with the complementary polarity can either be permanently connected to the current source or the voltage source, or it can be selectively switched depending on whether one or more electrodes of the same polarity are present. For example, if both electrodes of the same polarity are operated simultaneously, two current sources or two voltage sources are required. With a complete switching operation, the electrodes of the same polarity could also be operated with a single source that is switched between the electrodes by a suitable circuit / control unit.

[0045] Alternatively or additionally, it may be provided that a first fluid supply is provided for supplying a first fluid to a first electrode of the first electrode arrangement and a second fluid supply is provided for supplying a second fluid, different from the first fluid, to a second electrode of the first electrode arrangement, or that a first fluid supply is provided for supplying a first fluid to a first electrode of the second electrode arrangement and a second fluid supply is provided for supplying a second fluid, different from the first fluid, to a second electrode of the second electrode arrangement.

[0046] In this embodiment, the reaction to be carried out can be selected by controlling, for example, the fluid flowing to the respective electrode of the same polarity. As described above, switching can thus be controlled by selecting the fluid, which, as also described above, can be very advantageous. Similarly, it is also possible to use a voltage or current source for both electrodes and control the reaction by choosing the fluid type. In this case, depending on the availability of the reactant, for example, iron (FE), the first electrode can be active. The higher the reactant concentration, i.e., the iron concentration, the more active the first electrode is (due to the more favorable potential and kinetics) compared to the second electrode when using a voltage-current source. An exemplary embodiment could be configured as follows.For example, an inner fluid-filled chamber can be located between an outer anode and an outer cathode. This chamber has at least one further inner electrode and is bounded by at least one ion-conducting separator, for example, one that is in contact with or adjacent to at least one ion-conducting separator. In a first operating state, current flow between the outer anode and the outer cathode through the chamber is possible either by the chamber containing an ionically conductive material or by at least two different electrochemical reactions with opposite polarities taking place at the inner and electrically connected electrodes of the chamber. In the latter variant, the electrode arrangement can represent a series connection of at least two electrochemical cells.In a second operating state, at least one inner electrode can form at least one electrochemical cell with the outer anode and / or the outer cathode.

[0047] In such an exemplary embodiment, in particular three electrode chambers for three electrodes, for example outer anode, outer cathode and inner electrode, are provided, separated by at least two ion-conducting separators.

[0048] An electrode that is bounded by at least one ion-conducting separator, for example, one that is in contact with or adjacent to at least one ion-conducting separator, is also referred to as a "zero-gap" electrode or membrane electrode assembly (MEA).

[0049] It may be further preferred that a chamber through which a reactant flows, and which is bounded by two electrodes, at least one of which is the first or the second electrode, be provided with an electrically conductive element connecting the electrodes bounding the chamber and through which a fluid flows. For example, this electrically conductive element can be designed as a foam-like, grid-like, or fabric-like structure and can primarily serve to reduce electrical resistance. This allows the formation of an electrochemical cell, which can further improve the versatility of the electrode arrangement.

[0050] Regarding further technical features and advantages of the electrolysis arrangement, reference is made to the description of the electrode arrangement, the use, the figures and the description of the figures.

[0051] The use of at least one of an electrode arrangement and an electrolysis arrangement as described above for selectively carrying out a reduction of carbon dioxide, a chlor-alkali electrolysis or a hydrochloric acid electrolysis is further described.

[0052] In particular, as described in relation to the electrode arrangement, it is provided that the at least two electrodes of the same polarity are not used for the same reaction under the same conditions, but that the at least two electrodes of the same polarity are operated differently, for example with different charge transfer rates, or can be used for different reactions.

[0053] During carbon dioxide reduction, carbon dioxide reduction occurs at the cathode, while at the anode, switching is possible between hydrogen oxidation (HÖR) and oxygen generation (OER). For chi-alkali electrolysis or hydrochloric acid electrolysis, the previously described electrode arrangement can be used on the cathode side, allowing switching between hydrogen evolution (HER) or oxygen reduction (ORR), and chlorine evolution (CER) can occur at the anode.

[0054] Accordingly, the use of at least one electrode arrangement and one electrolysis arrangement as described above for the selectable execution of at least one electrolysis reaction is further described, wherein the selectable execution of at least one electrolysis reaction is controlled by the selectable execution of one anode reaction or two parallel anode reactions or one cathode reaction or two parallel cathode reactions, in particular wherein the at least one anode reaction is selected from an oxygen evolution reaction (OER) and a hydrogen oxidation reaction (HÖR) and the cathode reaction is selected from a hydrogen evolution reaction (HER) and an oxygen reduction reaction (ORR).

[0055] The term "two parallel anode reactions" or "two parallel cathode reactions" means, in particular, that the two reactions occur in parallel or simultaneously at the anodes or cathodes. This is especially advantageous for carrying out an electrically controlled electrolysis reaction and allows for mixed operation of both anodes or both cathodes, enabling the electrolysis cell to be operated with a variable electrical power input.

[0056] The invention is explained below by way of example with reference to the accompanying drawings, wherein the features shown below can represent an aspect of the invention both individually and in combination, and wherein the invention is not limited to the following drawing, the following description and the following embodiment.

[0057] They show:

[0058] Fig. 1 shows a schematic representation of one embodiment of an electrode arrangement;

[0059] Fig. 2 shows a schematic representation of a further embodiment of an electrode arrangement;

[0060] Fig. 3 shows a schematic representation of a further embodiment of an electrode arrangement; Fig. 4 shows a schematic representation of a further embodiment of an electrode arrangement;

[0061] Fig. 5 shows a schematic representation of one configuration of an electrolysis arrangement;

[0062] Fig. 6 shows a schematic representation of a further embodiment of an electrolysis arrangement; and

[0063] Fig. 7 shows a schematic representation of a further embodiment of an electrolysis arrangement;

[0064] Fig. 8 shows a schematic representation of the design of an electrode arrangement with counter electrode shown in Fig. 2;

[0065] Fig. 9 shows a schematic representation of the design of an electrode arrangement with counter electrode shown in Fig. 3;

[0066] Fig. 10 is a schematic representation of the embodiment of an electrode arrangement with counter electrode shown in Fig. 4.

[0067] Fig. 11 shows the electrical power consumption over time for several switching operations between HOR operation (low power consumption) and OER operation (high power consumption) for an exemplary embodiment of a use;

[0068] Fig. 12 shows ten switching operations between HOR operation with low electrical power consumption and OER operation with high power consumption for an exemplary embodiment of a use;

[0069] Fig. 13 shows the stability of the system over 120 switching operations and 4 hours of operating time for the exemplary embodiment of a use shown in Fig. 12;

[0070] Fig. 14 shows the variable electrical power consumption of two anodes for an exemplary embodiment of a use.

[0071] Figure 1 schematically shows an electrode arrangement 10 according to an embodiment of the present invention. The electrode arrangement 10 is, in particular, part of an electrolysis arrangement 12 and can be used, for example, for selectively carrying out a reduction of carbon dioxide, a chlor-alkali electrolysis, or a hydrochloric acid electrolysis.

[0072] The described electrode arrangement 10 comprises at least a first electrode 14 and a second electrode 16, wherein the first electrode 14 and the second electrode 16 can be operated with the same polarity, and wherein the first electrode 14 is arranged in a first electrode chamber 18, and wherein the second electrode 16 is arranged in a second electrode chamber 20, which is separated from the first electrode chamber 18 by a separator 22. The first electrode 14 and the second electrode 16 can be operated separately such that the first electrode 14 can be in contact with a first fluid and the second electrode 16 can be in contact with a second fluid different from the first fluid. Furthermore, the first electrode 14 is configured for a first reaction, and the second electrode 16 is configured for a second reaction different from the first reaction.

[0073] Figure 1 shows in more detail an electrode arrangement 10, which comprises two anode combs as electrode chambers 18, 20 and two anodes as first electrode 14 and second electrode 16, which are separated by an ion-conducting membrane as separator 22. The cathode side of the electrochemical cell comprising the electrode arrangement 10 is not shown.

[0074] A more detailed illustration shows a base plate 24 on which a sealing layer 26 and a sheet 28, made of titanium, for example, are placed, with a milled meandering flow channel 30. The meandering flow channel 30, together with a carbon paper 32, which can also be referred to as a gas diffusion layer (GDL), forms a porous, electrically conductive layer with carbon particles and carbon fibers. This layer then forms the first electrode chamber 18, designed as an anode chamber, through which hydrogen (H2) can flow. The meandering flow channel 30 thus serves as an electrically conductive layer (current collector) in contact with the carbon paper 32, which represents a porous medium for gas diffusion to the catalyst layer 14.On the carbon paper 32 lies an ion exchange membrane 34 coated with catalyst particles (platinum-coated carbon particles), such as, for example, a cation exchange membrane made of Nafion. The catalyst particles on the ion exchange membrane 34 are the active part of the first electrode 14 for a hydrogen oxidation reaction (HÖR). The particles are electrically contacted via the carbon paper 32 and the milled titanium sheet 28.

[0075] Following the first electrode 14, which serves as the anode, a flow frame 36 for a liquid electrolyte is provided in the embodiment shown in Figure 1. For example, a conductive aqueous solution, such as water together with a salt, acid, base, or similar substance, such as sulfuric acid, can be used as the electrolyte. A flowable structure, such as a plastic mesh 38, is located within the flow frame of the fluid guide 36. A sealing layer 40 is situated on this structure. This sealing layer can comprise a sealing material made of a thermoplastic elastomer, such as EPDM or PP, which has been hot-pressed into a titanium mesh.

[0076] The titanium mesh has a tab that protrudes laterally from the sealing layer 40, allowing for electrical contact between the mesh and the fabric. A carbon paper 42, coated with catalyst particles, such as iridium dioxide-coated carbon particles, lies on top of the titanium mesh. These catalyst particles form the active region of the second electrode 16, which serves as the anode and is designed for an oxygen evolution reaction (OER). The flow frame, the titanium mesh, and the carbon paper 42 together form the second electrode chamber 20, which can be filled with liquid electrolyte. The gaseous oxygen generated is transported out of the anode chamber by the electrolyte flow.

[0077] The second electrode chamber 20 is separated from the cathode chamber (not shown here) by a second ion exchange membrane, for example again formed from a cation exchange membrane made of Nafion. All layers are pressed against each other between two stainless steel base plates 24, of which only one is shown.

[0078] Also shown are the flow of hydrogen, arrow 46, and aqueous anolyte, arrow 48. Furthermore, the current flow is to be shown, where flow 50 represents the current flow in a hydrogen oxidation reaction, HÖR, and flow 52 represents the flow in an oxygen evolution reaction, OER.

[0079] The two anodes of the same polarity, i.e., the first electrode 14 and the second electrode 16, can be connected and controlled separately. Accordingly, they are connected to two different current sources 54, 56, which can also be voltage sources, and can be controlled independently of each other by specifying two currents or two voltages, as shown, for example, in Figures 5 to 7. This allows the type of reaction carried out, in particular the hydrogen oxidation reaction (HOR) or the oxygen evolution reaction (OER), to be selectively switched and adjusted.Accordingly, the electrolysis arrangement 12 is provided to have two current sources 54, 56 or two voltage sources, wherein in a first switching state a first current source 54 or a first voltage source can be connected to a first electrode 14 of the first electrode arrangement 10 and in a second switching state a second current source 56 or second voltage source can be connected to a second electrode 16 of the first electrode arrangement 10, or wherein in a first switching state a first current source 54 or a first voltage source can be connected to a first electrode 14 of the second electrode arrangement 10 and in a second switching state a second current source 56 or second voltage source can be connected to a second electrode 16 of the second electrode arrangement 10, and wherein the first switching state or the second switching state can be selected selectively.

[0080] In principle, it would also be possible for both anodes to be connected to a common current source 54, 56 or voltage source, and for the type of reaction, such as hydrogen oxidation reaction (HOR) or oxygen evolution reaction (OER), to change, for example, by switching the gas flow in the first anode chamber from reactive hydrogen to non-reactive nitrogen. Furthermore, it may be possible to adjust the activity of the electrodes via a common current or voltage source by changing the composition of the flowing gas, for example, by changing the hydrogen content relative to nitrogen, for instance, to 20 vol% H₂ and 80 vol% N₂, etc.

[0081] Accordingly, it is provided that a first fluid supply is provided to selectively supply the first electrode 14 with a first fluid flow and that a second fluid supply is provided to selectively supply the second electrode 16 with a second fluid flow that differs from the first fluid flow.Furthermore, in this embodiment, the electrolysis arrangement 12 may be provided to have a current source 54, 56 or a voltage source, wherein in a first switching state the current source 54, 56 or the voltage source can be connected to a first electrode 14 of the first electrode arrangement 10 and in a second switching state the current source 54, 56 or the voltage source can be connected to a second electrode 16 of the first electrode arrangement 10, or wherein in a first switching state the current source 54, 56 or the voltage source can be connected to a first electrode 14 of the second electrode arrangement 10 and in a second switching state the current source 54, 56 or the voltage source can be connected to a second electrode 16 of the second electrode arrangement 10, and wherein the first switching state or the second switching state can be selected selectively.

[0082] As soon as insufficient hydrogen is available in the first anode chamber, the hydrogen oxidation reaction (HOR) can no longer take place at the first anode. The external power source 54, 56 therefore increases the voltage to maintain a constant current, thereby activating the second electrode 16, which also serves as an anode, with an oxygen evolution reaction (OER). The ion exchange membrane 34, or the ion-conducting separating layer, is sufficiently impermeable to hydrogen and oxygen between the two anode chambers, i.e., between the first electrode chamber 18 and the second electrode chamber 20, and thus separates the hydrogen in the first electrode chamber 18 from the oxygen produced in the second electrode chamber 20.The ion exchange membrane 34 thus reliably prevents an explosive mixture of hydrogen and oxygen from forming in one of the two electrode combs 18, 20 in the example described above.

[0083] Figure 2 shows an electrode configuration for an adjustable oxygen evolution reaction (OER) which follows the reaction equation below: 0.5 H₂O 0.5 O₂ + 2 H₂ + +

[0084] 2 e“ , and a hydrogen oxidation, HÖR, which follows the following reaction equation: H2-> 2 H +-I- 2 e”, shown. The first electrode 14, configured as an anode for hydrogen oxidation, is shown, adjacent to which a channel 58 for hydrogen is arranged; this channel can be formed, for example, as a channel milled into a plate. Furthermore, the second electrode 16, also configured as an anode, for an oxygen evolution reaction is shown, separated by a separator from a cathode side 60, which can be configured as desired. More precisely, the cathode side 60 comprises an electrode or cathode and a possible fluid flow, which can be gaseous or liquid, for supplying reactants to the cathode. Between the first electrode 14 and the second electrode 16, a channel 64 for a fluid flow, for example, for supplying an electrolyte or a gaseous substance flow, is arranged. The channel 64 can be configured in any way as a lattice-like structure through which the electrolyte flows.The grid can be made of a conductive material and contact the adjacent electrode(s). The grid structure can also increase the contact pressure of the layers. In principle, it may be preferable to achieve a gapless arrangement in any embodiment. Furthermore, the fluid-tight, ion-conducting membrane or the ion exchange membrane 34 is provided between at least one anode, i.e., at least between the first electrode 14 or the second electrode 16, and the electrolyte. In this embodiment, the gas-consuming reaction can take place externally.

[0085] Figures 3 and 4 show further electrode configurations in which the gas-consuming reaction takes place inside. In these configurations, the electrolyte solution between electrodes 14 and 16 can be bypassed.

[0086] Figure 3 again shows an electrode configuration for an adjustable oxygen evolution reaction (OER) and a hydrogen oxidation reaction (HÖR). A first electrode 14, configured as an anode for oxygen evolution, is shown, adjacent to which a channel 64 is arranged. A second electrode 16, also configured as an anode, is shown, separated by a separator 62 from a cathode side 60, which can be configured as desired. The second electrode 16 is configured for hydrogen oxidation. A channel 58 for guiding hydrogen is arranged between the first electrode 14 and the second electrode 16, running adjacent to the second electrode 16. Furthermore, the fluid-tight, ion-conducting membrane, or ion-exchange membrane 34, is provided between at least one anode, i.e., at least between the first electrode 14 or the second electrode 16, and the hydrogen flow.Furthermore, an optional electrode 63 is shown, which is described in greater detail below with reference to Figure 6 and Figure 7.

[0087] Figure 4 shows an electrode configuration for a hydrogen evolution reaction (HER) which follows the reaction equation below: 2 H + + 2 e" -> H2, and an oxygen reduction reaction (ORR), which follows the reaction equation: 0.5 O2 + 2 H ++ 2 e“ -> 0.5 H2O, shown. A first electrode 14, configured as a cathode for water evolution, is shown, adjacent to which, separated by a separator 62, an anode side 66 is located. The anode side 66 comprises an electrode or anode and a possible fluid flow, which can be gaseous or liquid, for supplying reactants to the anode. A second electrode 16, also configured as a cathode, is provided, adjacent to which a channel 68 is provided for supplying oxygen, for example, to supply oxygen to the second electrode 16. Furthermore, a channel 64 is provided adjacent to the first electrode 14 and the second electrode 16, through which the electrolyte can be supplied to the cathodes. Depending on the desired function, hydrogen can also be supplied through this channel.

[0088] Figure 5 shows the electrode configuration from Figure 1, in particular a switching operation between a state in which the hydrogen oxidation reaction is active (see Figure 5a) and a state in which the oxygen evolution reaction is active (Figure 5b), wherein the anodes are connected to each other and also to the cathode. Thus, an embodiment with a current source is shown.

[0089] The hydrogen oxidation reaction is activated when hydrogen (H₂) flows through chamber 58 downstream of the outer anode (see Fig. 5a). The hydrogen oxidation reaction requires a significantly lower voltage than the oxygen evolution reaction; therefore, the voltage drops at the same current. The oxygen evolution reaction cannot occur at low voltage, and the inner anode is inactive. The oxygen evolution reaction is activated when an inert gas, such as nitrogen (N₂), flows through chamber 58 downstream of the outer anode (see Fig. 5b). Without a sufficient supply of hydrogen, the outer electrode 14 is almost inactive, and the hydrogen oxidation reaction cannot take place. This can be achieved by switching the flow of the gases and also by connecting the power source 54 to the respective electrode of the same polarity, in this case, the anodes.This is shown in Figure 5, wherein in Figure 5a) an electrical connection is made between the first electrode 14, designed as an anode, and the power source 54 to carry out the hydrogen oxidation reaction, and wherein in Figure 5b) an electrical connection is made between the second electrode 16, designed as an anode, to carry out the oxygen evolution reaction.

[0090] Figure 6 again shows the electrode configuration from Figure 1, with the oxygen evolution reaction being active in Figure 6a) and the hydrogen oxidation reaction being active in Figure 6b). Switching between the active reactions is possible by simply switching the power sources 54, 56, since this configuration includes two power sources 54, 56. Thus, in Figure 6a), the first power source 54 is active, whereas in Figure 6b), the second power source is active, so that the anode suitable for the respective reaction is active in each case. This is possible without switching the fluid flow. The anodes are advantageously electrically separated or electrically insulated from each other. While the electrolyte can be conductive, it has a comparatively high electrical resistance, which reduces the efficiency of the hydrogen oxidation reaction.The electrolyte should therefore be as conductive as possible and the distance between the two anodes should be as small as possible.

[0091] Furthermore, an electrolyte gap 70 is shown. This is formed by the liquid flow in the channel 64 and the second electrode 16 and is ionically conductive. Accordingly, an electrolyte with the highest possible conductivity should be selected, and the electrolyte gap 70, and in particular the channel 64, should be as thin as possible. However, even with a highly conductive electrolyte, the electrical resistance is comparatively high. The voltage drops across the resistance, resulting in a loss of electrical energy as heat.

[0092] Figure 7 again shows the electrode configuration similar to that of Figure 1, with the hydrogen oxidation reaction being active in Figure 7a) and the oxygen evolution reaction being active in Figure 6b). A difference from the embodiment shown in Figure 1 and Figure 6 is that in Figure 7, the hydrogen is guided in chamber 55 inside the electrode arrangement, and the channel 64 is located on the outside. Switching between the active reactions is again possible by simply switching the power sources 54, 56, since this embodiment has two power sources 54, 56. Thus, in Figure 7a), the first power source 54 is active, whereas in Figure 7b), the second power source 56 is active, so that the anode suitable for the respective reaction is active in each case. The anodes are advantageously electrically separated or electrically insulated from each other.

[0093] Figure 7 shows an example of a cathode reaction with two switchable or adjustable anode reactions. Figure 7 further shows that the chamber 55, which can serve as a HOR chamber or an HER chamber depending on the operating conditions, is permeable to a fluid, such as hydrogen, but provides electrical conductivity. For example, the chamber 55 can form a grid-like or mesh-like structure made of an electrically conductive material, such as a metal. This allows the second electrode 16, which functions as the HER and HOR electrodes, and the optional electrode 63 to be electrically connected, resulting in a significantly lower electrical resistance than with ionic conduction through an electrolyte, such as the electrolyte gap 70 shown in Figure 6.An advantageous feature is a planar electrical connection of the electrodes through a conductive structure between them, such as a metal grid, metal mesh, metal foam, etc. The HER and HÖR electrodes on the sides of chamber 55, i.e., the second electrode 16 and the optional electrode 63, are required as a link for the conversion of ionic to electrical charge transport via electrochemical reactions, i.e., HER / HOR. HER and HÖR are very efficient electrochemical reactions; with suitable electrodes (e.g., platinum-based), the reactions occur even at very low voltages, approximately near OV. Chamber 55, with the HER + electrical conduction + HÖR connection, can therefore achieve a lower voltage drop than with ionic conduction through an electrolyte gap. Since the electrical resistance is negligible, chamber 56 does not need to be particularly thin and is therefore technically easier to implement.The HER and HÖR electrodes can be arranged as a membrane electrode assembly directly on or connected to a membrane 34 or separator 62, respectively. In this configuration, an electrochemical cell can form with the chamber 55 through the applied current.

[0094] In principle, an embodiment with reversed polarities, not shown in Figure 7, is also possible, in which, for example, one anode reaction and two switchable cathode reactions take place in the switchable HOR / HER chamber 55. Thus, one polarity is shown in Figure 7, but an electrode arrangement with reversed polarity is also encompassed by the present invention.

[0095] Figure 8 shows an electrolysis arrangement for the electrode configuration of one anode side as depicted in Figure 2. In addition to the first electrode 14, designed as an anode for hydrogen oxidation, and the second electrode 16, also designed as an anode for oxygen evolution, shown in Figure 2, the cathode side 60 is also shown. The cathode side 60 is separated from the second electrode 16 by a separator 62 and, in the embodiment shown, comprises a cathode 72 and a fluid flow 74, which can be gaseous or liquid, for supplying reactants to the cathode 72. In this embodiment, the cathode side 60 is configured as an electrode with a separator membrane 62 directly adjacent to it (a "zero-gap" arrangement). In an alternative embodiment, a liquid electrolyte flow can be provided between the separator 62 and the cathode 72. In the embodiment shown, a fluid-dense ion-conducting membrane orAn ion exchange membrane 34 is provided between at least one anode 14 and the electrolyte channel 64. Accordingly, this arrangement includes three chambers and two membranes 34, 62. In this embodiment, two anodes are provided: the first electrode 14, configured as an anode for hydrogen oxidation, and the second electrode 16, configured as an anode for an oxygen evolution reaction, are configured for different reactions.

[0096] Figure 9 shows an electrolysis arrangement for the electrode configuration depicted in Figure 3, with an additional anode side. In addition to the first electrode 14, configured as an anode for oxygen evolution, and the second electrode 16, configured as an anode for hydrogen oxidation, shown in Figure 3, the cathode side 60 is also shown. In this embodiment, the cathode side 60 is configured as an electrode with a separator membrane 62 directly attached (a "zero-gap" arrangement). In this embodiment, two anodes are provided for different reactions: the first electrode 14, configured as an anode for oxygen evolution, and the second electrode 16, configured as an anode for hydrogen oxidation. This arrangement also includes three chambers and two membranes 34 and 62.

[0097] Figure 10 shows an electrolysis arrangement for the electrode configuration of one cathode side as depicted in Figure 4. In addition to the first electrode 14, configured as a cathode for hydrogen evolution (HER), and the second electrode 16, also configured as a cathode and configured for oxygen reduction (ORR), shown in Figure 4, the anode side 66 is also shown. The anode side 66 is separated from the first electrode 14 by a separator 62 and, in the embodiment shown, comprises an anode 76 and a fluid flow 78, which can be gaseous or liquid, for supplying reactants to the anode 76. In an alternative embodiment, a liquid electrolyte flow can be provided between the separator 62 and the anode 76.

[0098] The present reaction makes it possible to switch between different reactions. This is advantageous because electrochemical processes can replace centralized, fossil-based chemical synthesis with electrification, even with fluctuating electricity prices. One approach is to modify the electrochemical reaction on either the anode or cathode side. When electricity prices are low, water is oxidized to oxygen via the oxygen evolution reaction, which operates at a standard potential of 1.23 V and exhibits slow kinetics. Conversely, when electricity prices are high, hydrogen can be oxidized via a hydrogen oxidation reaction, which operates at a standard potential of 0.8 V and exhibits faster kinetics. This is possible without complex purging processes or switching operations, making it simple, fast, and cost-effective.

[0099] An example to illustrate the present invention is given below.

[0100] Chemicals used:

[0101] Potassium sulfate (K₂SO₄, > 0.99%) was sourced from VWR, sodium sulfate (Na₂SO₄, > 0.99%), sulfuric acid (H₂SO₄, > 0.95%), and platinum (Pt) on graphited carbon (20 wt% and 40 wt% Pt / C) were sourced from Sigma-Aldrich. Nafion ionomer solution (Fumion FLN-905) was sourced from Fumatech.

[0102] Example 1

[0103] Switching an Electrolysis Setup: The anode side of the electrolysis cell was an electrode arrangement as schematically shown in Figure 1. An electrochemical flow cell "Flex-E-Cell" (FXC Engineering GmbH) was used in the experiments. H₂ gas flowed through a titanium flow field with a serpentine channel, which was in contact with a first anode for HÖR (HOR anode) and served as the current collector. The HOR anode was a gas diffusion electrode (GDE) made of commercially available carbon paper (CP) as the gas diffusion layer (Sigracet 39BB, Fuel Cell Store) in contact with a custom-made catalyst-coated membrane (CCM). The CCM was produced using a film coater (FOM Technologies) with a wet film thickness of 50 pm, a substrate velocity of 0.3 m / min, a coating distance of 150 pm, and a substrate bed temperature of 50 °C. Nafion 115 was used as the membrane with a coating of 0.25 mg / cm². 2Pt / C (40 wt%) is used as a catalyst.

[0104] An anolyte of 2 M H₂SO₄ was passed through the second flow frame, which was filled with a spacer in contact with a second anode for OER (OER anode). A hydrophilized GDE measuring 5 x 5 cm was spray-coated with iridium oxide-IrO₂ catalyst ink (IrO₂ nanoparticles, isopropanol, and Nafion) at a target loading of 2 mg / cm². 2 and used as the OER anode. A titanium mesh was used as the current collector for the second anode. A second catalyst-coated cation-conducting membrane (Nafion 117, Fumatech) was applied as the next layer, separating the OER anode from the cathode compartment. A commercially available GDL (Sigracet 39BB, Fuel Cell Store) was loaded with 20 wt% Pt / C at a concentration of 1 mg / cm². 2 spray-coated and served as a cathode in contact with 1 M H2SO4 solution for the HER reaction as a proof-of-principle demonstration.

[0105] Before entering the module, the H₂ gas was humidified by a water column at a flow rate of 100 sccm. At the outlet, the gas stream passed through a gas cooler and then through an O₂ and H₂ analyzer. The anolyte (2 M H₂SO₄) was first passed through a heat exchanger to reach a temperature of 60 °C before entering the electrochemical flow cell. The anolyte stream from the flow cell was directed to a phase separator to remove bubbles formed by OER. A feed-and-bleed mode was used for the anolyte, with a circulation flow rate of 50 mL / min and a feed flow rate of 2 mL / min. The reference electrode (RE) was placed in the anolyte stream before entering the flow cell. The catholyte was used in a circulation mode with a flow rate of 50 mL / min. The two HER and OER anodes served as working electrodes that could be controlled independently of each other.

[0106] Two different approaches to control the switching between HOR anode (hydrogen oxidation reaction, hydrogen mode) and OER anode (oxygen evolution reaction, oxygen mode) were tested: Control via the gas flow to the HOR anode (gas flow controlled) and electrical control via the potentiostat used (electrically controlled).

[0107] In the gas flow-controlled system, both the HÖR and OER anodes were connected to a potentiostat channel during electrolysis, through which a constant current density of 100 mA / cm² was maintained. 2The operating mode and the anode reactions were controlled by the availability of hydrogen gas. As long as sufficient hydrogen is available, the HOR anode is active. If the hydrogen supply is interrupted (gas flow rate = 0 sccm), the existing hydrogen is first consumed until the OER anode becomes active. Figure 11 shows the electrical power consumption over time for several switching operations between HOR operation (low power consumption of approximately 0.03 W / cm³) and OER operation (low power consumption of approximately 0.03 W / cm³). 2 ) and OER operation (high power consumption of approx. 0.16 W / cm²) 2 In an alternative configuration of the gas flow-controlled system, the gas flow can be switched between hydrogen and an inert gas (e.g., nitrogen), allowing the remaining hydrogen to be purged from the system, which, depending on the residence time distribution of the gas flow, can enable a shorter switching time.

[0108] In the electrically controlled system, each anode was connected to a separate potentiostat channel, allowing the current across the two anodes to be set independently. Both experiments were conducted at a constant cathodic current density of 100 mA / cm². 2 This was carried out by repeatedly switching between the anodes at 100 mA / cm² via the potentiostat. 2 LISTEN (0 mA / cm 2 OER) and 100 mA / cm 2 OER (0 mA / cm 2 HOR) was switched. Figure 12 shows 10 switching operations between HOR operation with a low electrical power consumption of approximately 0.01 W / cm². 2 and OER operation with a high power consumption of 0.16 W / cm² 2 . Furthermore, Figure 13 shows the stability of the system over 120 switching operations and 4 hours of operating time.

[0109] Thus, successful switching could be demonstrated both when controlled by the material flow and when electrically controlled by the applied voltage or specified current.

[0110] The electrical control also allows for mixed operation of both anodes, for example parallel operation at 50 mA / cm². 2 LISTEN and 50 mA / cm 2 OER, which allows the cell to be operated with variable electrical power input. To demonstrate the variable electrical power input, the current density for HÖR and OER was measured in 10 mA / cm² steps, as illustrated in Figure 14a). 2 The current density varies across the potentiostat, with the total current density (HÖR + OER) remaining constant at 100 mA / cm². 2 Figure 14b) shows the required electrical power over time and the contributions of HÖR and OER. The required electrical power also changed from approximately 0.025 W / cm² according to the stepwise variation in current density.2 (100% HÖR, 0% OER) from approx. 0.08 W (50% HÖR, 50% OER) to approx. 0.16 W / cm 2 (0% HÖR, 100% OER). Figures 14c) and 14d) additionally show the potential of the two anodes and the cell potential over time.

[0111] Reference sign

[0112] 10 Electrode arrangement

[0113] 12 Electrolysis setup

[0114] 14 first electrode

[0115] 16 second electrode

[0116] 18 first electrode chamber

[0117] 20 second electrode chamber

[0118] 22 Separator

[0119] 24 Base plate

[0120] 26 Sealing layer

[0121] 28 sheets

[0122] 30 Flow channel

[0123] 32 carbon paper

[0124] 34 Membran

[0125] 36 Fluid guidance

[0126] 38 plastic fabrics

[0127] 40 sealing layer

[0128] 42 Carbon paper

[0129] 44 ion exchange membrane

[0130] 47 tissues

[0131] 46 Arrow

[0132] 48 Arrow

[0133] 50 River

[0134] 52 River

[0135] 54 first power source

[0136] 55th Chamber

[0137] 56 second power source

[0138] 58 Channel 60 Cathode side

[0139] 62 Separator

[0140] 63 electrode

[0141] 64 Channel 66 Anode side

[0142] 68-channel

[0143] 70 Electrolyte gap

[0144] 72 Cathode

[0145] 74 Fluid flow 76 Anode

[0146] 78 Fluid flow

Claims

Claims 1. Electrode arrangement (10) for an electrochemical cell, wherein the electrode arrangement comprises at least a first electrode (14) and a second electrode (16), wherein the first electrode (14) and the second electrode (16) can be operated in the same polarity, wherein the first electrode (14) is arranged in a first electrode chamber (18) and wherein the second electrode (16) is arranged in a second electrode chamber (20) separated from the first electrode chamber (18) by a separator (22), wherein the first electrode (14) and the second electrode (16) can be operated separately such that the first electrode (14) can be operated in contact with a first fluid and the second electrode (16) can be operated in contact with a second fluid different from the first fluid, and wherein the first electrode (14) is configured for a first reaction and wherein the second electrode (16) is provided for a second reaction different from the first reaction.

2. Electrode arrangement (10) according to claim 1, characterized in that a first fluid supply is provided to selectively supply the first electrode (14) with a first fluid flow and that a second fluid supply is provided to selectively supply the second electrode (16) with a second fluid flow different from the first fluid flow.

3. Electrode arrangement (10) according to claim 1 or 2, characterized in that the first electrode (14) and the second electrode (16) can be electrically separated and controlled.

4. Electrode arrangement (10) according to one of claims 1 to 3, characterized in that at least two anodes are provided as the first electrode (14) and as the second electrode (16).

5. Electrode arrangement (10) according to claim 4, characterized in that the anodes are separated from each other by a fluid-tight and ion-conducting membrane (34).

6. Electrode arrangement (10) according to one of claims 1 to 5, characterized in that at least two cathodes are provided as the first electrode (14) and as the second electrode (16).

7. Electrolysis arrangement (12) comprising a first electrode arrangement (10) configured as an anode arrangement with at least one electrode and a second electrode arrangement (10) configured as a cathode arrangement with at least one electrode, wherein at least one voltage source or current source (54, 56) is further provided, which is connected to the first electrode arrangement (10) and to the second electrode arrangement (10), characterized in that at least one of the first electrode arrangement (10) and the second electrode arrangement (10) is configured according to one of claims 1 to 6.

8. Electrolysis arrangement (12) according to claim 7, characterized in that the electrolysis arrangement (10) comprises a current source (54, 56) or a voltage source, wherein in a first switching state the current source (54) or the voltage source can be connected to a first electrode (14) of the first electrode arrangement (10) and in a second switching state the current source (56) or the voltage source can be connected to a second electrode (16) of the first electrode arrangement (10), or wherein in a first switching state the current source (54, 56) or the voltage source can be connected to a first electrode (14) of the second electrode arrangement (10) and in a second switching state the current source (54, 56) or the voltage source can be connected to a second electrode (16) of the second electrode arrangement (10), and wherein the first switching state or the second switching state can be selected selectively.

9. Electrolysis arrangement (12) according to claim 7, characterized in that the electrolysis arrangement (12) has two current sources (54, 56) or two voltage sources, wherein in a first switching state a first current source (54) or a first voltage source can be connected to a first electrode (14) of the first electrode arrangement (12) and in a second switching state a second current source (56) or second voltage source can be connected to a second electrode (16) of the first electrode arrangement (10), or wherein in a first switching state a first current source (54) or a first voltage source can be connected to a first electrode (14) of the second electrode arrangement (10) and in a second switching state a second current source (56) or second voltage source can be connected to a second electrode (16) of the second electrode arrangement (10), and wherein the first switching state or the second switching state can be selected selectively.

10. Electrolysis arrangement (12) according to one of claims 7 or 8, characterized in that a first fluid supply is provided for supplying a first fluid to a first electrode (14) of the first electrode arrangement (10) and a second fluid supply is provided for supplying a second fluid, different from the first fluid, to a second electrode (16) of the first electrode arrangement (10), or that a first fluid supply is provided for supplying a first fluid to a first electrode (14) of the second electrode arrangement (10) and a second fluid supply is provided for supplying a second fluid, different from the first fluid, to a second electrode (16) of the second electrode arrangement (10).

11. Electrolysis arrangement according to one of claims 7 to 10, characterized in that a chamber (55) through which a reactant can flow, which is bounded by two electrodes, at least one of which is the first electrode (14) or the second electrode (16) is provided with an electrically conductive element that connects the electrodes limiting the chamber (55) and allows a fluid to flow through it.

12. Use of at least one of an electrode arrangement (10) according to one of claims 1 to 6 and an electrolysis arrangement (12) according to one of claims 7 to 11 for selectively carrying out a reduction of carbon dioxide, a chlor-alkali electrolysis or a hydrochloric acid electrolysis.

13. Use of at least one of an electrode arrangement (10) according to one of claims 1 to 6 and an electrolysis arrangement (12) according to one of claims 7 to 11 for selectably carrying out at least one electrolysis reaction, wherein the selectable carrying out of at least one electrolysis reaction is controlled by the selectable carrying out of an anode reaction or two parallel anode reactions or a cathode reaction or two parallel cathode reactions, in particular wherein the at least one anode reaction is selected from an oxygen evolution reaction and a hydrogen oxidation reaction and the cathode reaction is selected from a hydrogen evolution reaction and an oxygen reduction.

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