Electrodes for CDI, water treatment apparatus including electrodes for CDI, and manufacturing method for electrodes for cdi

Abstract

A water treatment apparatus comprises at least one CDI module including a first channel including a first electrode, a second channel including a second electrode, and a third channel formed between the first channel and the second channel, wherein each of the first electrode and the second electrode includes a current collector and an active material layer coupled to at least one of both surfaces of the current collector, and the active material layer contains activated carbon, a conductive material, and vanadium oxide, the proportion of vanadium oxide in the active material layer being 25% to 30% by weight.

Description

Electrode for CDI, water treatment device including electrode for CDI, and method for manufacturing electrode for CDI

[0001] The disclosed invention relates to an electrode for CDI used in a capacitive desalination technology, a water treatment device including the CDI electrode, and a method for manufacturing the CDI electrode.

[0002] An example of a water treatment process is the capacitive deionization (CDI) process. This process generally involves applying a voltage between two electrodes to remove ions from the water flowing between the two electrodes by adsorbing them on the electrodes, and then reversing the electrode voltage to desorb the ions adsorbed on the electrodes from the electrodes. In other words, when a fluid such as water passes between two porous carbon electrode layers made of activated carbon, anions move to the anode due to electrostatic force, and cations move to the cathode, resulting in charging. The water is discharged as treated water in a pure form with the ions removed.

[0003] The capacitive deionization (CDI) process is environmentally friendly due to its low energy consumption, but the deionization efficiency may vary depending on the type of ion dissolved in the water.

[0004] To maximize energy efficiency, the capacitive deionization (CDI) process must minimize side reactions such as scale formation and water decomposition. This is because scale formation can cause clogging and performance degradation, which can be detrimental to the desalination system's performance. Furthermore, the hydrogen ions generated by water decomposition can rapidly change the pH, rendering the treated water unusable.

[0005] Therefore, a method for manufacturing an electrode made of a material that can minimize side reactions such as scale formation and water decomposition is required.

[0006] The disclosed invention relates to an electrode for CDI used in a capacitive desalination technology, a water treatment device including the CDI electrode, and a method for manufacturing the CDI electrode.

[0007] A water treatment device according to one embodiment of the present disclosure comprises: a first channel including a first electrode;

[0008] A second channel including a second electrode; and a third channel formed between the first channel and the second channel; wherein the first electrode and the second electrode include a current collector and an active material layer bonded to at least one of both surfaces of the current collector, the active material layer including activated carbon, a conductive material, and vanadium oxide, and the proportion of the vanadium oxide in the active material layer may be 25% or more and 30% or less in weight %.

[0009] An electrode for CDI according to one embodiment of the present disclosure comprises: a porous carbon structure; a current collector; an active material layer bonded to at least one of both surfaces of the current collector; and a binder that increases a bonding force between the current collector and the active material layer; wherein the active material layer comprises activated carbon, a conductive material, or vanadium oxide, and the proportion of the vanadium oxide in the active material layer may be 25% or more and 30% or less in weight %.

[0010] A method for manufacturing an electrode for CDI according to one embodiment of the present disclosure may include the steps of: dry mixing an active material layer material including, in wt%, vanadium oxide: 25% or more and 30% or less, the remainder C and other impurities; mixing the electrode material with a binder; ball milling the mixed electrode material and the binder to form a slurry; setting up an area on a current collector where the slurry is to be applied, and applying the slurry using a blade; and vacuum drying the current collector on which the slurry is applied.

[0011] According to one embodiment, by determining the optimal vanadium oxide ratio of the active material layer and the optimal driving voltage according to the voltage drop, the formation of scale on the electrode surface can be minimized, thereby maintaining the performance of the electrode even during repeated desalination operations.

[0012] Additionally, according to one embodiment, by determining the optimal vanadium oxide ratio of the active material layer and the optimal driving voltage according to the voltage drop, side reactions such as water decomposition can be minimized.

[0013] Furthermore, according to one embodiment, by determining the optimal vanadium oxide ratio in the active material layer and the optimal operating voltage based on the voltage drop, safety issues such as fire or electric shock, and electrical shock or short circuits due to insulation problems that may arise when using metal as a current collector can be prevented. Accordingly, the use of metal as a current collector can minimize the volume of the CDI module and increase the process efficiency of electrode production.

[0014] However, the effects that can be achieved by the water treatment electrode and the water treatment device including the same according to the above embodiments are not limited to those mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention pertains from the description below.

[0015] Figure 1 illustrates an example of a conceptual diagram of a water treatment device according to one embodiment.

[0016] FIG. 2 is a conceptual diagram for explaining the movement of ions generated at both electrodes when a water treatment device according to one embodiment performs deionization operation.

[0017] FIG. 3 is a conceptual diagram for explaining the movement of ions generated at both electrodes when a water treatment device according to one embodiment performs regenerative operation.

[0018] Figure 4 is a conceptual diagram explaining the structure of vanadium oxide.

[0019] Figure 5 is a conceptual diagram for explaining capacitive adsorption and the resulting movement of ions among the reactions occurring around the electrode for CDI.

[0020] Figure 6 is a conceptual diagram for explaining Faradaic Adsorption and the resulting movement of ions among the electrochemical reactions occurring around the electrode (11abd) for CDI.

[0021] Figure 7 is a graph showing the potential change of the electrode for working CDI according to Experimental Example 1.

[0022] Figure 8 is a graph showing the potential change of the electrode for CDI according to Experimental Example 2.

[0023] Figure 9 is a graph showing the potential change of the electrode for CDI according to Experimental Example 3.

[0024] Figure 10 is a graph showing the potential change of the electrode for CDI according to Experimental Example 4.

[0025] Figure 11 is a graph showing the potential change trend of the CDI electrode in Experimental Examples 1 to 4.

[0026] Figure 12 is a graph showing the IR drop of the electrode for working CDI according to Experimental Example 1.

[0027] Figure 13 is a graph showing the IR drop of the electrode for working CDI according to Experimental Example 1.

[0028] Figure 14 is a graph showing the IR drop of the electrode for working CDI according to Experimental Example 1.

[0029] Figure 15 is a graph showing the IR drop of the electrode for working CDI according to Experimental Example 1.

[0030] Figure 16 is a graph showing the change in driving voltage and IR drop according to the change in vanadium oxide ratio of the electrode for working CDI.

[0031] FIG. 17 is a schematic diagram illustrating a water treatment device including an electrode for monopolar CDI according to one embodiment.

[0032] FIG. 18 is a conceptual diagram illustrating a water treatment device (1) including an electrode for bipolar CDI according to one embodiment.

[0033] FIG. 19 is a conceptual diagram illustrating an example of an electrode for bipolar CDI of the water treatment device of FIG. 18 according to one embodiment.

[0034] FIG. 20 is a conceptual diagram illustrating a CDI module including the electrode for the bipolar CDI of FIG. 19 according to one embodiment.

[0035] FIG. 21 is a conceptual diagram illustrating another example of an electrode for bipolar CDI of the water treatment device of FIG. 18 according to one embodiment.

[0036] FIG. 22 is a conceptual diagram illustrating a CDI module including the electrode for the bipolar CDI of FIG. 21 according to one embodiment.

[0037] It should be understood that the various embodiments and terms used in this document are not intended to limit the technical features described in this document to specific embodiments, but rather to include various modifications, equivalents, or substitutes of the embodiments.

[0038] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0039] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0040] In this document, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof.

[0041] The term “and / or” includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0042] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0043] When a component (e.g., a first component) is referred to as being "coupled" or "connected" to another component (e.g., a second component), with or without the terms "functionally" or "communicatively," it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0044] The terms “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in this document, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0045] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0046] When we say that a component is "on" another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0047] Water treatment devices, according to various embodiments, can purify contaminated water and make it clean. Water treatment devices are used in sewage treatment facilities, industrial processes, and water supply systems in homes and offices, playing a vital role in environmental protection and human health. Water purified by water treatment devices can be released back into the environment, used for cleaning, used as drinking water, or reused in industrial processes.

[0048] According to various embodiments, the water treatment device may include not only a household water treatment device such as a water purifier or a water softener, but also an industrial water treatment device.

[0049] According to various embodiments, the water treatment device may be installed inside a household appliance such as a refrigerator, a washing machine, or a dishwasher.

[0050] For example, a water treatment device may be installed inside a washing machine and may remove impurities contained in water supplied to or discharged from the washing machine drum.

[0051] This not only improves washing performance, but also allows for efficient washing cycles by reusing contaminated water after washing.

[0052] It will be readily apparent to those skilled in the art that the operation of the water treatment device installed in the aforementioned washing machine is equally applicable to other household appliances, such as refrigerators and dishwashers. Water treatment devices can purify contaminated water through a variety of methods, including biological, chemical, and physical treatment.

[0053] A water treatment device according to one embodiment can purify contaminated water through a capacitive deionization (CDI) method and an electrode deionization (EDI) method.

[0054] The capacitive desalination method refers to a method for removing ions from contaminated water by utilizing the principle of ions being adsorbed and desorbed from the surface of electrodes by the electrical force generated between the electrodes. In the present specification, removing ions from contaminated water may include removing ionic substances from the contaminated water.

[0055] A water treatment device may include various components such as a plurality of pipes through which water flows, a plurality of valves to control the flow of water, and a capacitive desalination module to purify water using a capacitive desalination method.

[0056] A capacitive desalination module may include a housing, electrodes and ion exchange membranes provided within the housing. Depending on the voltage supplied to the electrodes, ions contained in water flowing into the housing may be adsorbed onto or desorbed from the electrodes.

[0057] According to various embodiments, the water treatment device may further include various components, such as a pretreatment filter for pretreating raw water and supplying it to the capacitive desalination module, and / or a posttreatment filter for filtering water purified by the capacitive desalination module once again.

[0058] Figure 1 illustrates an example of a conceptual diagram of a water treatment device according to one embodiment.

[0059] Referring to FIG. 1, a water treatment device (1) according to one embodiment may include a CDI module (100), at least one flow path (20) formed by a pipe, and at least one valve unit (30) for controlling the flow of water within the at least one flow path (20).

[0060] The CDI module (100) may include two electrodes (i.e., a first electrode (11ab) and a second electrode (12ab)) to which voltage is applied during desalination operation to adsorb and desorb ions.

[0061] The first electrode (11ab) and the second electrode (12ab) can be arranged to face each other, and the first electrode (11ab) and the second electrode (12ab) arranged to face each other can form a capacitor.

[0062] The first electrode (11ab) may include a first current collector (11a) and a first porous carbon structure (11b) (porous electrode).

[0063] The first electrode (11ab) can be a negative electrode (cathode) during deionization operation of the water treatment device (1) and can be a positive electrode (anode) during regeneration operation.

[0064] In one embodiment, the first current collector (11a) may include a plate electrically connected to the first porous carbon structure (11b). The plate may include a metal plate and / or a non-metal plate.

[0065] The material of the first current collector (11a) may be a conductor. For example, the material of the first current collector (11a) may be graphite, but the material of the first current collector (11a) is not limited thereto.

[0066] The first porous carbon structure (11b) may include a solid electrode including void space. The first porous carbon structure (11b) may be formed of a material that is easy to adsorb ions. For example, the first porous carbon structure (11b) may be a carbon porous electrode, and the first porous carbon structure (11b) (porous electrode) is a carbon structure formed of a fine porous structure, so that it has a large specific surface area and can effectively store and transfer charges. However, the type of the first porous carbon structure (11b) is not limited thereto.

[0067] The second electrode (12ab) may include a second current collector (12a) and a second porous carbon structure (12b) (porous electrode).

[0068] As will be described later, the second electrode can be an anode (positive electrode) during deionization operation of the water treatment device (1), and can be a cathode (negative electrode) during regeneration operation or scale removal operation.

[0069] In one embodiment, the second current collector (12a) may include a plate electrically connected to the second porous carbon structure (12b). The plate may include a metal plate and / or a non-metal plate.

[0070] The material of the second collector (12a) may also be the same as that of the first collector (11a).

[0071] However, for economic reasons, in one embodiment, the materials of the first current collector (11a) and the second current collector (12a) may be different from each other. For example, the material of the first current collector (11a) may be selected from the group consisting of a transition metal, a transition metal oxide, a transition metal alloy, aluminum, an aluminum oxide, an aluminum alloy, graphene, a catalytic oxide electrode (Dimensionally Stable Anode, DSA), and a Boron doped diamond (BDD) electrode, and the material of the second current collector (12a) may be graphite.

[0072] The second porous carbon structure (12b) may include a solid electrode including void space. The second porous carbon structure (12b) may be formed of a material that is easy to adsorb ions. For example, the second porous carbon structure (12b) may be a carbon porous electrode, like the first porous electrode (12a), but the type of the second porous carbon structure (12b) is not limited thereto.

[0073] The CDI module (100) may further include a cation exchange membrane (11c) that allows only cations to pass through and an anion exchange membrane (12c) that allows only anions to pass through.

[0074] The CDI module (100) may include a first channel (11) formed by a first current collector (11a) and a cation exchange membrane (11c), a second channel (12) formed by a second current collector (12a) and an anion exchange membrane (12c), and a third channel (13) formed by a cation exchange membrane (11c) and an anion exchange membrane (12c).

[0075] The first channel (11) may include a space between the first current collector (11a) and the cation exchange membrane (11c). The second channel (12) may include a space between the second current collector (12a) and the anion exchange membrane (12c). The third channel (13) may include a space between the cation exchange membrane (11c) and the anion exchange membrane (12c).

[0076] The first channel (11), the second channel (12), and the third channel (13) can be separated from each other by ion exchange membranes (11c, 12c), and thus terms such as compartment, space, room, or chamber may be substituted.

[0077] The first channel (11), the second channel (12), and the third channel (13) may be fluidically connected to each other. For example, fluid in the third channel (13) may be able to move to the first channel (11) and / or the second channel (12), and conversely, fluid in the first channel (11) and / or the second channel (12) may be able to move to the third channel (13).

[0078] The cation exchange membrane (11c) may include a membrane that allows only cations to pass through among cations and anions. The cation exchange membrane (11c) has a negative charge, so it repels anions and does not allow only cations to pass through.

[0079] The anion exchange membrane (12c) may include a membrane that allows only anions to pass through among cations and anions. The anion exchange membrane (12c) has a positive charge, so it repels cations and does not allow them to pass through, but only allows anions to pass through.

[0080] The ion exchange membranes (11c, 12c) may include a synthetic resin membrane.

[0081] The water treatment device (1) may include a housing (101) having a third channel inlet (102) through which water flows in, and an outlet (103) through which deionized water with hardness components removed from the inflowing water or wastewater with hardness components dissolved in the inflowing water is discharged.

[0082] In one embodiment, at least a portion of the surface of the housing (101) may be formed of a current collector (11a, 12a). However, at least a portion of the surface of the housing (101) may also be formed of a pad for supporting the current collector (11a, 12a).

[0083] In one embodiment, the housing (101) may include a third channel inlet (102) through which water can flow into the third channel (13), and an outlet (103) through which deionized water or waste water within the third channel (13) can be discharged.

[0084] Water can be introduced into the third channel (13) from the outside of the CDI module (100) through the third channel inlet (102). Water within the third channel (13) can be discharged to the outside of the CDI module (100) through the outlet (103).

[0085] The water treatment device (1) may store raw water or include a water source (15) from which raw water is supplied from an external source. The raw water may include water to be treated by the water treatment device (1).

[0086] The water treatment device (1) may include a pump (16a) that pumps external water (e.g., water supplied from a water source).

[0087] The water treatment device (1) may include at least one flow path (20) and at least one flow path valve unit (30). At least one flow path (20) may be branched by at least one valve unit (30).

[0088] Water pumped by the pump (16a) can flow into the flow paths (20) of the water treatment device (1).

[0089] In one embodiment, external water may be pumped by a pump (16a) and flow into the first flow path (21). The first flow path (21) may be configured to allow external water to flow into it.

[0090] The first euro (21) can be connected to the third channel third channel inlet (102).

[0091] The first flow valve (30a) can open and close the first flow path (21). The first flow valve (30a) can block or allow the flow of water from the first flow path (21) to the third channel (13).

[0092] Water flowing into the third channel (13) through the first flow path (21) can be discharged through the second flow path (22). The second flow path (22) can be connected to the third channel outlet (103).

[0093] The second flow valve (30b) can allow water flowing into the second flow path (22) to flow into either the third flow path (23) or the fourth flow path (24). That is, the second flow path valve (30b) can allow water discharged from the third channel (13) to flow into either the third flow path (23) or the fourth flow path (24). In one embodiment, the second flow path valve (30b) can also close the second flow path (22) to prevent water flowing into the second flow path (22) from flowing into the third flow path (23) or the fourth flow path (24).

[0094] The third flow path (23) may include a flow path through which purified water (or deionized water) is discharged. The fourth flow path (24) may include a flow path through which contaminated water (or wastewater) is discharged.

[0095] According to various embodiments, the number of third channel inlets (101), the number of third channel outlets (103), the type of the flow path (20) and / or the type of the valve unit (30) are not limited to the example illustrated in FIG. 1.

[0096] According to various embodiments, the water treatment device (1) may include at least one CDI module (100).

[0097] At this time, the plurality of CDI modules (100) form a capacitor by two monopolar electrodes (e.g., 11ab, 12ab) acting as cathodes or anodes, and the plurality of CDI modules (100) may be implemented in a form in which they are connected in series or in parallel with each other. In addition, the plurality of CDI modules (100) may be implemented in a form in which bipolar electrodes are stacked and spaced apart from each other.

[0098] When including multiple CDI modules (100), a spacer may be further included to secure space between each CDI module (100).

[0099] A water treatment device (1) according to one embodiment may have at least two operating modes. For example, a water treatment device (1) according to one embodiment may have a deionization operating mode and a regeneration operating mode.

[0100] In addition, the water treatment device (1) may further have a post-treatment operation mode.

[0101] The desalination operation mode includes a deionization operation mode, a regeneration operation mode, and a post-treatment operation mode, and the desalination operation mode can be repeatedly performed from the time the water treatment device (1) starts to the time it is terminated.

[0102] The water treatment device (1) can perform a deionization process on water provided to the CDI module (100) in deionization operation.

[0103] The water treatment device (1) can perform a regeneration process to desorb ions adsorbed on the positive electrodes (11ab, 12ab) of the CDI module (100) during regeneration operation.

[0104] The water treatment device (1) can perform various processes for performing a deionization operation again, including a scale removal process for removing scale generated on the electrodes (11ab, 12ab) of the CDI module (100) in the post-treatment operation.

[0105] Hereinafter, the movement of ions at both electrodes (11ab, 12ab) in deionization operation or regeneration operation will be described with reference to FIGS. 2 and 3.

[0106] FIG. 2 is a conceptual diagram for explaining the movement of ions generated at both electrodes (11ab, 12ab) when a water treatment device (1) according to one embodiment performs deionization operation.

[0107] According to one embodiment, when a negative voltage is applied between the first current collector (11a) and the second current collector (12a), the first electrode (11ab) becomes a positive electrode (anode) and the second electrode (12ab) becomes a negative electrode (cathode).

[0108] Accordingly, when a negative voltage is applied between the first collector (11a) and the second collector (12a), the positive ions in the third channel (13) can move to the first channel (11), and the negative ions in the third channel (13) can move to the second channel (12).

[0109] By applying a negative voltage between the first collector (11a) and the second collector (12a), positive ions moved to the first channel (11) can be adsorbed to the first electrode (11ab), and negative ions moved to the second channel (12) can be adsorbed to the second electrode (12ab).

[0110] In other words, when a negative voltage is applied between the first collector (11a) and the second collector (12a), the positive ions moved to the first channel (11) can be stored in the first electrode (11ab), and the negative ions moved to the second channel (12) can be stored in the second electrode (12ab).

[0111] Applying a negative voltage between the first current collector (11a) and the second current collector (12a) may include making the potential of the first current collector (11a) lower than the potential of the second current collector (12a).

[0112] Additionally, applying a negative voltage between the first current collector (11a) and the second current collector (12a) may include applying a negative voltage to the first current collector (11a) and applying a positive voltage to the second current collector (11b).

[0113] Accordingly, deionized water can be generated in which cations are removed from water (i.e., deionized) as cations dissolved in water are adsorbed (or stored) in the first porous carbon structure (11b).

[0114] In other words, deionization operation may mean an operation in which a deionization reaction occurs to remove cations contained in water flowing into the CDI module (100) through the inlet (102), and the deionized water from which ions have been removed is discharged to the outside of the CDI module (100).

[0115] FIG. 3 is a conceptual diagram for explaining the movement of ions generated at both electrodes (11ab, 12ab) when a water treatment device (1) according to one embodiment performs regenerative operation.

[0116] When a positive voltage is applied between the first current collector (11a) and the second current collector (12a), the first electrode (11ab) becomes a negative electrode (cathode) and the second electrode (12ab) becomes a positive electrode (anode). Accordingly, when a positive voltage is applied between the first current collector (11a) and the second current collector (12a), positive ions in the first channel (11) can move to the third channel (13), and negative ions in the second channel (12) can move to the third channel (13).

[0117] Applying a positive voltage between the first current collector (11a) and the second current collector (12a) may include making the potential of the first current collector (11a) higher than the potential of the second current collector (12a).

[0118] Applying a positive voltage between the first current collector (11a) and the second current collector (12a) may include applying a positive voltage to the first current collector (11a) and applying a negative voltage to the second current collector (11b).

[0119] By applying a positive voltage between the first current collector (11a) and the second current collector (12a), the positive ions adsorbed on the first electrode (11ab) can be desorbed from the first electrode (11ab), and the negative ions adsorbed on the second electrode (12ab) can be desorbed from the second electrode (12ab).

[0120] Accordingly, the cations desorbed from the first electrode (11ab) and the anions desorbed from the second electrode (12ab) can be dissolved in water flowing in from the third channel inlet (102) so that the first electrode (11ab) and the second electrode (12ab) can be regenerated to a state in which they can adsorb ions again.

[0121] Additionally, ions desorbed from the first electrode (11ab) and the second electrode (12ab) produce dissolved water, i.e., wastewater.

[0122] That is, the regeneration operation may mean an operation in which a deionization reaction occurs to desorb cations adsorbed on the first electrode (11ab) used as a cathode in the deionization operation, the desorbed cations are moved to the third channel (13), and wastewater containing a large amount of cations is discharged to the outside of the CDI module (100) through the outlet (103).

[0123] The above describes the movement of ions in the CDI module (100) during desalination operation. Hereinafter, vanadium oxide as an electrode material for increasing the efficiency of desalination operation and the movement of ions and electrochemical reactions occurring around the electrode containing vanadium oxide will be described with reference to FIGS. 4 to 6.

[0124] Figure 4 is a conceptual diagram explaining the structure of vanadium oxide.

[0125] According to one embodiment, the material of the electrode included in the CDI module (100) may include vanadium oxide. In this case, the vanadium oxide that may be included as the material of the electrode included in the CDI module (100) may be V2O5 or V2O3 having a lower oxidation state.

[0126] Specifically, the CDI module (100) may include an electrode (hereinafter referred to as a “CDI electrode”) in which an active material layer including vanadium oxide is bonded to at least one surface of a current collector.

[0127] The general crystal structure of V2O5 is a perovskite block (4c) structure in which oxygen (4a) anions form an octahedral lattice, with vanadium (4b) positioned at the center, and a simple cubic lattice of cations and an octahedral lattice of anions interpenetrate each other. Due to the structural characteristics of V2O5, cations (4d) in water can be intercalated into its crystal structure.

[0128] Accordingly, the electrode combined with the active material layer containing V2O5 has a crystal structure in which cations in water (e.g., Ca) 2+ ) can have an improved ion storage capacity than an electrode (hereinafter referred to as an 'activated carbon electrode') in which an active material layer containing only activated carbon is bonded to at least one side of a current collector.

[0129] Next, a method for manufacturing an electrode for CDI according to another aspect of the disclosed invention will be described in detail.

[0130] A method for manufacturing an electrode for CDI according to one embodiment may include a step of preparing vanadium oxide (e.g., V2O5 or V2O3), activated carbon (C), and / or a conductive material, which is a material for an active material layer bonded to a first electrode (11ab) or a second electrode (12ab) and a current collector (11a, 12a) of the electrode (11ab or 12ab). Carbon black may be used as a conductive material to compensate for the low electrical conductivity of vanadium oxide.

[0131] A method for manufacturing an electrode for CDI according to one embodiment may further include a step of dry mixing vanadium oxide (e.g., V2O5 or V2O3), activated carbon (C), and / or a conductive material corresponding to the material of the active material layer.

[0132] A method for manufacturing an electrode for CDI according to one embodiment may further include a step of mixing the material of the dry-mixed active material layer and a binder.

[0133] The above binder is intended to provide bonding strength between materials of the active material layer to prevent them from being peeled off from the electrode (11ab or 12ab), and may include at least one of polyvinylidene fluoride as an organic binder, or styrene-butadiene rubber or carboxymethyl cellulose as an inorganic binder.

[0134] A method for manufacturing an electrode for CDI according to one embodiment may further include a step of ball milling to process the mixed electrode material and the binder into a slurry form.

[0135] At this time, the mixed electrode material and the binder can be ground into fine particle sizes and mixed uniformly through a ball milling process.

[0136] A method for manufacturing an electrode for CDI according to one embodiment may further include a step of pre-setting an area on which the slurry is applied to a current collector (11a or 12a) and applying the slurry to the pre-set area using a blade.

[0137] A method for manufacturing an electrode for CDI according to one embodiment may further include a step of vacuum drying the current collector to which the slurry is applied.

[0138] In order to explain the principle that the electrode for CDI manufactured by the above-described manufacturing method has improved desalination efficiency (i.e., efficiency of removing ions from raw water) compared to the activated carbon electrode, the electrochemical reactions occurring around the electrode for CDI are explained with reference to FIGS. 5 and 6.

[0139] Figure 5 is a conceptual diagram for explaining capacitive adsorption and the resulting movement of ions among the reactions occurring around the electrode for CDI.

[0140] During desalination operation, a capacitive adsorption reaction may occur at the CDI electrode (11abd) of the CDI module (100) due to electrostatic attraction without chemical bonding.

[0141] Below, the movement of ions is described based on the CDI electrode (11abd) acting as the cathode among the two electrodes of the CDI module (100), but it is easy for a person skilled in the art to understand that the same electrostatic action can also occur at the anode.

[0142] The water treatment device (1) may include a power supply device (not shown) that supplies driving voltage to at least one CDI module (100).

[0143] The CDI module (100) receives voltage from a power supply and can remove positive ions in water introduced through the inlet (102) by electrostatic attraction without chemical bonding by adsorbing them on the surface of the CDI electrode (11abd).

[0144] In this process, the hydration shell (H) made up of water molecules surrounding each cation is charged positively on the electrode side and negatively on the opposite side due to electrostatic attraction, forming an electrical double layer (EDL), and more cations can be removed.

[0145] The more specific surface area that can form an electrical double layer (EDL) exists on each electrode of the CDI module (100), the more ions can be removed. Therefore, even if the CDI electrode (11abd) includes a porous carbon structure (11b), ions can be removed through a capacitive adsorption reaction.

[0146] Figure 6 is a conceptual diagram for explaining Faradaic Adsorption and the resulting movement of ions among the electrochemical reactions occurring around the electrode (11abd) for CDI.

[0147] During desalination operation, a capacitive adsorption reaction may occur at the CDI electrode (11abd) of the CDI module (100) due to chemical bonding resulting from an oxidation-reduction reaction.

[0148] Below, the movement of ions is described based on the CDI electrode (11abd) that acts as the cathode among the two electrodes, but it is easy for a person skilled in the art to know that the same chemical reaction can also occur at the anode.

[0149] When voltage is applied from a power supply, the vanadium (V) of the vanadium oxide included in the active material layer (11d) of the CDI module (100) reacts with surrounding cations (e.g., Ca)2+ ) and a divalent cation). That is, when voltage is applied to the CDI module (100), the electrode (11abd) for CDI can exchange electrons between the electrode and the cation through vanadium oxide.

[0150] In addition, as described above in FIG. 3, vanadium oxide (e.g., V2O5) provides a space in its structure where cations are stored by intercalation, so that cations can be stored within the vanadium oxide structure by chemical bonding, separate from adsorption of cations by electrostatic attraction.

[0151] Accordingly, even when the same driving voltage is applied, the electrode for CDI (11abd) can have a higher electrostatic capacity than the activated carbon electrode due to the Faradaic Adsorption reaction.

[0152] That is, the electrode (11abd) for CDI can have the same desalination efficiency as the activated carbon electrode even when a lower voltage is applied, thereby minimizing the occurrence of side reactions such as scale formation or water decomposition reaction caused by applying a high driving voltage.

[0153] In order to optimize the ratio of vanadium oxide in the electrode (11abd) for CDI and to drive the water treatment device (1) with the optimal driving voltage accordingly, it is necessary to detect the change in potential or voltage loss (IR drop) of the electrode (11abd) for CDI according to the ratio of vanadium oxide.

[0154] Hereinafter, through examples 1 to 4 of charge / discharge experiments of electrodes (11abd) for CDI, the potential change according to the vanadium oxide ratio of the electrodes (11abd) for CDI is explained with reference to FIGS. 7 to 11, and the IR drop change according to the vanadium oxide ratio of the electrodes (11abd) for CDI is explained with reference to FIGS. 12 to 15.

[0155] <Charging and discharging experiments on electrodes for CDI>

[0156] Experiments 1 to 4 detected changes in the potential (V) and IR drop (V) of the electrode when the electrode was charged and discharged once by varying the ratio of vanadium oxide (V2O5) in the active material in the electrode.

[0157] The experimental configuration used a CDI electrode containing both vanadium oxide and activated carbon as a working electrode, an activated carbon electrode containing only activated carbon as a counter electrode, an Ag / AgCl electrode as a reference electrode, and a 1 M CaCl2 aqueous solution as an electrolyte. The charge / discharge rate of the CDI module (100) was set to 200 mA / g, and the total charge amount was 0.7 mAh / cm2. Charging was started when the potential of the working electrode became -1 V, and discharging was performed when the charge amount became 0.7 mAh / cm2. Discharging was terminated when the potential of the working electrode became -1 V again, and the potential change of the CDI module (100) was observed throughout the entire process. At this time, the potential of the working electrode was determined based on the potential of the reference electrode.

[0158] At this time, the CDI electrodes of Experimental Examples 1 to 4 were each set in weight %, and the ratio of vanadium oxide contained in the active material layer was set as Experimental Example 1: 0%, Experimental Example 2: 10%, Experimental Example 3: 30%, and Experimental Example 4: 70%. That is, the working electrode of Experimental Example 1 refers to an activated carbon electrode made purely of activated carbon.

[0159] Figure 7 is a graph showing the potential change of the electrode for working CDI according to Experimental Example 1.

[0160] Figure 8 is a graph showing the potential change of the electrode for CDI according to Experimental Example 2.

[0161] Figure 9 is a graph showing the potential change of the electrode for CDI according to Experimental Example 3.

[0162] Figure 10 is a graph showing the potential change of the electrode for CDI according to Experimental Example 4.

[0163] Figure 11 is a graph showing the potential change trend of the CDI electrode in Experimental Examples 1 to 4.

[0164] Table 1 below shows the ratio of vanadium oxide and the maximum potential (V) - minimum potential (V) according to the weight % of Experimental Examples 1 to 4 according to FIGS. 7 to 10.

[0165] Vanadium oxide ratio (%) Maximum potential (V) - Minimum potential (V) Experimental example 103.03 Experimental example 2102.89 Experimental example 3302.55 Experimental example 4702.23

[0166] According to Fig. 11, it was confirmed that the potential (hereinafter referred to as “maximum potential”) when the charge amount reached 0.7 mAh / cm2 decreased as the ratio of vanadium oxide included in the active material layer increased in weight % for each electrode for CDI.

[0167] In addition, in Figs. 7 to 10, when the maximum potential of Experimental Example 1, which is an experimental example regarding an electrode made purely of activated carbon, is V0, as the ratio of vanadium oxide included in the active material layer increases, the difference between the maximum potential and the minimum potential of each experimental example (Experimental Example 2: V 10 , Experimental Example 3: V 30 , Experimental Example 4: V 70 ) and V0 were confirmed to be increasing.

[0168] In each experimental example, the difference between the maximum potential and the minimum potential (-1 V) (i.e., cell voltage) may correspond to the voltage (hereinafter referred to as “driving voltage”) applied from the power supply to the CDI module (100) to perform the movement of ions having a total amount of positive charges corresponding to the charge amount of the CDI module (100).

[0169] Accordingly, it can be confirmed that as the proportion of vanadium oxide included in the active material layer increases, the driving voltage applied to the CDI module (100) decreases when removing the same amount of ions. In other words, it can be confirmed that as the proportion of vanadium oxide included in the active material layer increases, the same desalination efficiency can be obtained even when a lower driving voltage is applied.

[0170] Through this, it was confirmed that a drop in the operating voltage of a water treatment device is possible by including an electrode for CDI containing vanadium oxide. In addition, it was confirmed that the water treatment device (1) can be operated at a lower operating voltage as the proportion of vanadium oxide included in the electrode for CDI is increased.

[0171] Hereinafter, with reference to FIGS. 12 to 15, when the electrode for CDI is charged and discharged once in Experimental Examples 1 to 4 (i.e., when performing a regeneration operation after a deionization operation once in the water treatment device (1)), the change in voltage loss that occurs according to the ratio of vanadium oxide included in the active material layer is detected.

[0172] Figure 12 is a graph showing the IR drop of the electrode for working CDI according to Experimental Example 1.

[0173] Figure 13 is a graph showing the IR drop of the electrode for working CDI according to Experimental Example 1.

[0174] Figure 14 is a graph showing the IR drop of the electrode for working CDI according to Experimental Example 1.

[0175] Figure 15 is a graph showing the IR drop of the electrode for working CDI according to Experimental Example 1.

[0176] When a CDI module (100) applies a positive voltage for deionization operation and then applies a reverse voltage for regeneration operation, the internal resistance may increase as ions are desorbed from the CDI electrode. At this time, the internal resistance generated by the bonding according to the capacitive adsorption reaction at the CDI electrode is minimal, but a large internal resistance may be generated due to the bonding according to the relatively strong Faradaic adsorption reaction.

[0177] Accordingly, voltage loss (hereinafter referred to as ‘IR drop’) occurs due to internal resistance in the CDI module (100).

[0178] Table 2 below shows the ratio of vanadium oxide and the maximum IR drop (V) according to the weight % of Experimental Examples 1 to 4 according to Figs. 12 to 15.

[0179] Vanadium oxide ratio (%) IR drop (V) Experimental example 100.018 Experimental example 2100.04 Experimental example 3300.187 Experimental example 4700.281

[0180] In Fig. 11 to Fig. 15, when the IR drop of Experimental Example 1, which is an experimental example of an electrode made purely of activated carbon, is IRD0, as the ratio of vanadium oxide included in the active material layer increases, the IR drop of each experimental example (Experimental Example 2: IRD 10 , Experimental Example 3: IRD 30 , Experimental Example 4: IRD 70 ) and it was confirmed that the difference between V0 and V1 was increasing.

[0181] According to Table 2, the IR drop was the lowest in Experimental Example 1 for an electrode composed of only activated carbon, and it was confirmed that the IR drop increased by approximately 7 times when the ratio of vanadium oxide included in the active material layer increased from 10% to 70%.

[0182] In each experimental example, the IR drop can correspond to the voltage loss occurring in the CDI module (100) when the operation mode of the water treatment device (1) is switched from deionization operation to regeneration operation. That is, it was confirmed that the voltage loss due to internal resistance increases as the proportion of vanadium oxide included in the active material layer of the CDI electrode increases.

[0183] Through this, it was confirmed that power loss occurred due to increased internal resistance by including an electrode for CDI containing vanadium oxide.

[0184] That is, it was confirmed that in the active material layer constituting the electrode for CDI, as the proportion of vanadium oxide increases, the driving voltage can be lowered, but a trade-off may occur in which the IR drop increases and the power efficiency decreases.

[0185] Simply increasing the proportion of vanadium oxide in the active material layer to reduce the operating voltage may result in power loss. Therefore, the optimal vanadium oxide proportion and operating voltage of the water treatment device (1) can be determined by considering the operating voltage drop and voltage loss due to increased internal resistance as the proportion of vanadium oxide in the active material layer increases.

[0186] Figure 16 is a graph showing changes in driving voltage and IR drop according to changes in the vanadium oxide ratio of the electrode for working CDI.

[0187] The change trend of the driving voltage and the change trend of the IR drop according to the ratio of vanadium oxide in the active material layer constituting the electrode for CDI may vary depending on the specific surface area of ​​the activated carbon included in the active material layer, the type and concentration of ions dissolved in water flowing into the water treatment device (1), and the distance between the two electrodes constituting the CDI module (100). According to various embodiments, in order to drive the CDI module (100) at an optimal driving voltage, the ratio (R) of vanadium oxide in the active material layer may be 0% or more and 100% or less, expressed as wt%.

[0188] FIG. 16 is a graph showing changes in driving voltage and IR drop under the conditions that, in Experimental Examples 1 to 4, the specific surface area of ​​activated carbon is 2598.3 m2 / g, the cation to be removed by the water treatment device (1) is Ca2+, the molar concentration of Ca2+ is 1 M, and the distance between the two electrodes constituting the CDI module (100) is 2 cm.

[0189] According to Fig. 16, in order to drive the CDI module (100) at the optimal driving voltage under the above conditions, it was confirmed that the ratio (R) of vanadium oxide in the active material layer was 25% or more and 30% or less in weight %.

[0190] At this time, it was confirmed that the optimal driving voltage for driving the CDI module (100) was 1.25 V or more and 1.35 V or less. Preferably, it was confirmed that the optimal driving voltage for driving the CDI module (100) was 1.3 V. The optimal driving voltage can be determined within a predetermined error range from the voltage at which water decomposition occurs.

[0191] In the present disclosure, the optimal vanadium oxide ratio and the optimal operating voltage were determined under the conditions that the specific surface area of ​​the activated carbon is 2598.3 m2 / g, the cation to be removed by the water treatment device (1) is Ca2+, the molar concentration of Ca2+ is 1 M, and the distance between the two electrodes constituting the CDI module (100) is 2 cm. However, by differently controlling the specific surface area of ​​the activated carbon included in the active material layer, the type and concentration of the ions dissolved in the water flowing into the water treatment device (1), and the distance between the two electrodes constituting the CDI module (100), other optimal vanadium oxide ratios and optimal operating voltages can be determined.

[0192] According to one embodiment, by determining the optimal vanadium oxide ratio of the active material layer and the optimal driving voltage according to the voltage drop, the formation of scale on the electrode surface can be minimized, thereby maintaining the performance of the electrode even during repeated desalination operations.

[0193] Additionally, according to one embodiment, by determining the optimal vanadium oxide ratio of the active material layer and the optimal driving voltage according to the voltage drop, side reactions such as water decomposition can be minimized.

[0194] Furthermore, according to one embodiment, by determining the optimal vanadium oxide ratio of the active material layer and the optimal operating voltage according to the voltage drop, safety issues such as fire or electric shock, and electrical collisions or short circuits due to insulation issues that may occur when using metal as a current collector can be prevented. Accordingly, by enabling the use of metal as a current collector, the volume of the CDI module (100) can be minimized, and the process efficiency of electrode production can be increased.

[0195] Fig. 17 is a conceptual diagram illustrating a water treatment device (1) including an electrode for monopolar CDI according to one embodiment.

[0196] According to one embodiment, the water treatment device (1) may include at least one CDI module (120). At this time, at least one CDI module (120) may correspond to the CDI module (100) described above. A plurality of CDI modules (M 1, M 2쪋 M n )(120) can be implemented in a form connected in series or parallel.

[0197] At least one CDI module (120) can be implemented in a form in which two CDI electrodes (12) are spaced apart from each other, and the CDI electrode (12) can be a monopolar electrode in which an active material layer (12d) is bonded to only one side of a current collector (12b). In this case, the CDI electrode (12) can correspond to the aforementioned CDI electrode (11abd).

[0198] In the CDI module (120), the surface facing the third channel, through which raw water flows in (P1) and deionized water flows out (P2) of the current collector (12b), is referred to as the inner surface, and the surface facing in the opposite direction to the inner surface is referred to as the outer surface. In the aforementioned unipolar CDI electrode (12), one surface of the current collector (12d) to which the active material layer (12b) is bonded may include the inner surface.

[0199] Accordingly, according to one embodiment, the CDI module (120) may be configured in a form in which an active material layer including vanadium oxide is bonded to the inner surface of a current collector of an electrode acting as a cathode, and an active material layer including vanadium oxide is bonded to the inner surface of a current collector of an electrode acting as a positive electrode.

[0200] Additionally, according to various embodiments, the CDI module (120) may be configured such that an active material layer including vanadium oxide is bonded only to the inner surface of the current collector of the electrode acting as the negative electrode, and an active material layer composed only of activated carbon is bonded only to the inner surface of the current collector of the electrode acting as the positive electrode.

[0201] The electrode for CDI included in the CDI module (100) according to one embodiment can be implemented as a bipolar electrode in which active material layers are bonded to both sides of a current collector, and will be described below with reference to FIGS. 18 to 20.

[0202] FIG. 18 is a conceptual diagram illustrating a water treatment device (1) including an electrode for bipolar CDI according to one embodiment.

[0203] FIG. 19 is a conceptual drawing illustrating an example of an electrode for bipolar CDI of the water treatment device (1) of FIG. 18 according to one embodiment.

[0204] FIG. 20 is a conceptual diagram illustrating a CDI module including the electrode for the bipolar CDI of FIG. 19 according to one embodiment.

[0205] According to one embodiment, the water treatment device (1) may include at least one CDI module (130). In this case, at least one CDI module (130) may correspond to the aforementioned CDI module (100).

[0206] At least one CDI module (130) may include a pair of CDI electrodes (13), which may be bipolar electrodes in which active material layers (13d) are bonded to both sides of a current collector (13b). Referring to FIG. 19, the composition of the active material layers (13d) bonded to both sides of the current collector (13b) may be the same. In this case, the two sides of the current collector (13b) refer to two sides facing other bipolar electrodes that are spaced apart from each other. The CDI electrode (13) may correspond to the aforementioned CDI electrode (11abd).

[0207] According to one embodiment, the CDI module (120) may be implemented in a form in which a pair of bipolar CDI electrodes (13) are spaced apart and stacked. A plurality of bipolar CDI electrodes (E1, E2) n-1 , E n)(13) can be stacked and spaced apart to form a plurality of CDI modules (130).

[0208] As illustrated in FIG. 20, in a CDI module (130) implemented by stacking two bipolar CDI electrodes (13) spaced apart from each other, when voltage is applied, one bipolar CDI electrode (13) can act as a cathode to which cations are adsorbed, and the other bipolar CDI electrode (13) can act as an anode to which cations are adsorbed.

[0209] Since the water treatment device (1) according to one embodiment has the main purpose of removing metal cations corresponding to hardness components dissolved in water, the desalination efficiency of anions may be treated as being inferior to the desalination efficiency of cations in the electrode manufacturing process of the water treatment device (1).

[0210] Therefore, for economic reasons, the active material layer on the positive electrode side (inner or outer surface) of the bipolar CDI electrode (13) may contain less vanadium oxide than the negative electrode side, or may contain only activated carbon. Hereinafter, the bipolar CDI electrode (13), which corresponds to an asymmetric electrode, will be described with reference to FIGS. 21 and 22.

[0211] FIG. 21 is a conceptual diagram illustrating another example of an electrode for bipolar CDI of the water treatment device (1) of FIG. 18 according to one embodiment.

[0212] According to one embodiment, the electrode (13) for bipolar CDI constituting the water treatment device (1) can be implemented as an asymmetric electrode having different compositions of active material layers bonded to both sides.

[0213] For example, one side of the current collector (13b) of the electrode (13) for bipolar CDI may be bonded with an active material layer (13d) containing vanadium oxide, and the other side facing in the opposite direction may be bonded with an active material layer (13d') containing only pure activated carbon without vanadium oxide.

[0214] In addition, one side of the current collector (13b) of the electrode (13) for bipolar CDI may be bonded with an active material layer (13d) containing vanadium oxide, and the other side facing in the opposite direction to the one side may be bonded with an active material layer (13d') having a vanadium oxide ratio different from the vanadium oxide ratio of the active material layer bonded to the one side. At this time, the vanadium oxide ratio of the active material layer bonded to the other side may be less than the vanadium oxide ratio of the active material layer bonded to the one side.

[0215] At this time, each side can act as a cathode or an anode in a different CDI module (100).

[0216] FIG. 22 is a conceptual diagram illustrating a CDI module including the electrode for the bipolar CDI of FIG. 21 according to one embodiment.

[0217] Two electrodes (13) for asymmetric bipolar CDI described with reference to Fig. 21 can be spaced apart to form one CDI module (100).

[0218] At this time, among the two sides of the current collector (13b), the side where the active material layer (13d') having a relatively small vanadium oxide ratio is combined acts as the positive electrode, and the side where the active material layer (13d) having a relatively large vanadium oxide ratio is combined acts as the negative electrode, so that the side with a larger electrostatic capacity can perform desalination operation as the negative electrode that adsorbs cations.

[0219] According to one embodiment, by manufacturing the electrode (13) for bipolar CDI as an asymmetric electrode, the manufacturing cost can be reduced.

[0220] According to one embodiment, by determining the optimal vanadium oxide ratio of the active material layer and the optimal driving voltage according to the voltage drop, the formation of scale on the electrode surface can be minimized, thereby maintaining the performance of the electrode even during repeated desalination operations.

[0221] Additionally, according to one embodiment, by determining the optimal vanadium oxide ratio of the active material layer and the optimal driving voltage according to the voltage drop, side reactions such as water decomposition can be minimized.

[0222] Furthermore, according to one embodiment, by determining the optimal vanadium oxide ratio in the active material layer and the optimal operating voltage based on the voltage drop, safety issues such as fire or electric shock, and electrical shock or short circuits due to insulation problems that may arise when using metal as a current collector can be prevented. Accordingly, the use of metal as a current collector can minimize the volume of the CDI module and increase the process efficiency of electrode production.

Claims

1. A water treatment device comprising at least one CDI module including a first channel including a first electrode, a second channel including a second electrode, and a third channel formed between the first channel and the second channel; The above first electrode and the above second electrode, Comprising a collector and an active material layer bonded to at least one of both sides of the collector, A water treatment device wherein the active material layer comprises activated carbon, a conductive material, and vanadium oxide, and the proportion of vanadium oxide in the active material layer is 25% or more and 30% or less in weight %.

2. In paragraph 1, A water treatment device, characterized in that the above vanadium oxide is V2O5.

3. In paragraph 1, The above water treatment device, A power supply unit for supplying a driving voltage to at least one CDI module; The above driving voltage is, A water treatment device, wherein the potential change of the cathode constituting the CDI stack according to the ratio of the vanadium oxide during the desalination operation and the IR drop in the CDI stack according to the ratio of the vanadium oxide between the deionization operation and the regeneration operation of the desalination operation are determined.

4. In paragraph 3, The above water treatment device, A water treatment device characterized in that the driving voltage is 1.25 V or more and 1.35 V or less.

5. In paragraph 4, The above water treatment device, A water treatment device wherein the surface area of the activated carbon is 2598.3 m2 / g, the cation removed by the water treatment device is Ca2+, the molar concentration of Ca2+ is 1 M, and the distance between the two electrodes constituting the CDI stack is 2 cm.

6. In paragraph 1, The first electrode and the second electrode, A water treatment device having a monopolar electrode in which the active material layer is bonded to only one side of the above-mentioned collector.

7. In paragraph 1, The first electrode and the second electrode, A water treatment device having a bipolar electrode in which the active material layer is bonded to both sides of the above-mentioned collector.

8. In paragraph 7, The above bipolar electrodes are, A water treatment device having an asymmetric electrode having different compositions of an active material layer bonded to one side of the above-mentioned collector and an active material layer bonded to the other side facing in the opposite direction to the above-mentioned one side.

9. In paragraph 1, The above water treatment device, A water treatment device further comprising a spacer between the CDI modules.

10. In paragraph 9, The above CDI module, A water treatment device further comprising an ion exchange membrane between the first channel and the third channel and between the second channel and the third channel.

11. Porous carbon structure; The whole house; An active material layer bonded to at least one of both sides of the above-mentioned collector; and A binder that increases the bonding strength between the above-mentioned collector and the active material layer; The above active material layer is, Containing activated carbon, conductive agent or vanadium oxide, An electrode for CDI, wherein the ratio of vanadium oxide in the active material layer is 25% or more and 30% or less in weight %.

12. In paragraph 11, The above vanadium oxide is, An electrode for CDI characterized by being V2O5.

13. In paragraph 11, The electrode for the above CDI is, An electrode for CDI, which is a monopolar electrode in which the active material layer is bonded to only one of the two surfaces of the above-mentioned collector.

14. In paragraph 11, The electrode for the above CDI is, An electrode for CDI, which is a bipolar electrode in which the active material layers are bonded to both sides of the above-mentioned collector.

15. In paragraph 14, The above bipolar electrodes are, An electrode for CDI, which is an asymmetric electrode in which the composition of the active material layer bonded to one surface of the above-mentioned collector and the composition of the active material layer bonded to the other surface facing the one surface are different.

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