Electrochemical cell comprising channel-type flowable electrode units

Abstract

The present invention relates to an electrochemical cell having a channel-type flow-electrode unit. The channel-type flow-electrode structure according to the present invention, which has at least two channel-type flow-electrode units, can significantly reduce manufacturing costs and installation space by reducing the number of parts while extending the electrode capacity to be suitable for large-scale plants for electricity generation, energy storage, desalination, etc. In addition, the channel-type flow-electrode structure can be applied not only to a capacitive flow-electrode device and/or a redox flow battery device, but also to all of the devices for electricity generation, energy storage, and desalination while moving ions or protons.

Claims

1. A channel-type flow-electrode structure comprising at least two channel-type flow-electrode units; wherein the two adjacent channel-type flow-electrode units share an integral liquid-permeable wall; wherein a basic frame comprising a plurality of channels, in which a fluid is introduced from an inlet and discharged to an outlet, is formed by said liquid-permeable wall and then some or all of the channels confined by the liquid-permeable wall constitute the flow-electrode unit; and wherein said channel-type flow-electrode unit comprises: a channel-type liquid-permeable wall confining a structure of the electrode unit as a scaffold; an ion-exchangeable current collector passing a positive ion or a negative ion and having electrical conductivity, which is placed on an inner surface of the liquid-permeable wall; and an electrode flow channel separated from the liquid-permeable wall by the ion-exchangeable current collector, along an inside of which an electrode active material-containing fluid introduced from a channel inlet and discharged to a channel outlet flows.

2. A channel-type flow-electrode unit structure comprising at least two channel-type flow-electrode units; wherein the two adjacent channel-type flow-electrode units share an integral liquid-permeable wall; wherein a basic frame comprising a plurality of channels, in which a fluid is introduced from an inlet and discharged to an outlet, is formed by said liquid-permeable wall and then some or all of the channels confined by the liquid-permeable wall constitute the flow-electrode unit; and wherein said channel-type flow-electrode unit comprises: a channel-type liquid-permeable wall confining a structure of the electrode unit as a scaffold; an ion-exchangeable material applied to an inner surface or an outer surface of the channel-type liquid-permeable wall, the liquid-permeable wall itself, or a combined position thereof to allow a positive ion or a negative ion to pass therethrough; a porous current collector applied to an inner surface of the liquid-permeable wall to which the ion-exchange material has been applied; and an electrode flow channel separated from the liquid-permeable wall by the porous current collector, along an inside of which an electrode active material-containing fluid introduced from a channel inlet and discharged to a channel outlet flows.

3. The channel-type flow-electrode structure of claim 1, wherein the ion-exchangeable current collector is formed by stacking an ion-exchangeable membrane and a porous current collector.

4. The channel-type flow-electrode structure of claim 1, wherein the channel-type flow-electrode units are assembled in the form of a block.

5. The channel-type flow-electrode structure of claim 2, wherein the channel-type flow-electrode units are assembled in the form of a block.

6. The channel-type flow-electrode structure of claim 1, further comprising an electrolyte flow channel.

7. The channel-type flow-electrode structure of claim 2, further comprising an electrolyte flow channel.

8. The channel-type flow-electrode structure of claim 1, wherein an electrolyte is supplied through a separate channel-type flow channel for the electrolyte, a liquid-permeable wall, or through both; and with reference to the channel, the electrolyte is supplied in a longitudinal direction of the channel, a lateral direction of the channel, or in both directions.

9. The channel-type flow-electrode structure of claim 2, wherein an electrolyte is supplied through a separate channel-type flow channel for the electrolyte, a liquid-permeable wall, or through both; and with reference to the channel, the electrolyte is supplied in a longitudinal direction of the channel, a lateral direction of the channel, or in both directions.

10. A cell equipped with a channel-type flow-electrode structure of claim 1, comprising: a channel-type flow-cathode unit confined by a channel-type liquid-permeable wall, wherein a cathode ion-exchangeable current collector passing a positive ion and having electrical conductivity is placed on an inner surface of the channel-type liquid-permeable wall; a channel-type flow-anode unit confined by a channel-type liquid-permeable wall, wherein an anode ion-exchangeable current collector passing a negative ion and having electrical conductivity is placed on an inner surface of a channel-type liquid-permeable wall; and an electrode flow channel separated from the liquid-permeable wall by the ion-exchangeable current collector, along an inside of which an electrode active material-containing fluid introduced from a channel inlet and discharged to a channel outlet flows.

11. A cell equipped with a channel-type flow-electrode structure of claim 2, comprising: a channel-type flow-cathode unit confined by a channel-type liquid-permeable wall, wherein an ion-exchangeable material is applied to an inner surface or an outer surface of the channel-type liquid-permeable wall, the liquid-permeable wall itself, or a combined position thereof to allow a positive ion to pass therethrough and then a porous current collector is applied to an inner surface of the liquid-permeable wall to which the ion-exchangeable material has been applied; a channel-type flow-anode unit confined by a channel-type liquid-permeable wall, wherein an ion-exchangeable material is applied to an inner surface or an outer surface of a channel-type channel-type wall, a channel-type wall itself, or a combined position thereof to allow a negative ion to pass therethrough and then a porous current collector is applied to an inner surface of the channel-type wall to which the ion-exchangeable material has been applied; and an electrode flow channel separated from the liquid-permeable wall by the ion-exchangeable current collector, along an inside of which an electrode active material-containing fluid introduced from a channel inlet and discharged to a channel outlet flows.

12. A channel-type flow-electrode structure, comprising: an ion-exchangeable membrane scaffold which forms a basic frame for a plurality of channels, in which a fluid is introduced from an inlet and discharged to an outlet; the channel-type flow-cathode unit of claim 2, comprising: a porous cathode plate arranged on an inner surface of channel(s) confined by the ion-exchangeable membrane scaffold, and a cathode flow channel separated from the channel-type ion-exchangeable membrane scaffold by the porous cathode plate, along an inside of which a cathode active material-containing fluid introduced from a channel inlet and discharged to a channel outlet flows; and the channel-type flow-anode unit of claim 2, comprising: a porous anode plate arranged on an inner surface of other channel(s) confined by the ion-exchangeable membrane scaffold, and an anode flow channel separated from the channel-type ion-exchangeable membrane scaffold by the porous anode plate, along an inside of which an anode active material-containing fluid introduced from a channel inlet and discharged to a channel outlet flows.

13. A capacitive flow-electrode device comprising the channel-type flow-electrode structure of claim 12.

14. A redox flow battery device comprising the channel-type flow-electrode structure of claim 12.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

(2) FIG. 1 is a schematic diagram of a plate-type capacitive flow-electrode device, from which the basic frame and operation principle of the present invention is derived.

(3) FIG. 2 is a schematic diagram of a channel-type flow-electrode structure integrally provided with two or more channel-type flow-electrode units according to an exemplary embodiment of the present invention.

(4) FIG. 3 is schematic diagrams of the channel-type flow-cathode unit and the channel-type flow-anode unit according to an exemplary embodiment of the present invention.

(5) FIG. 4 is a schematic diagram of a channel-type flow-electrode structure, in which two or more channel-type flow-electrode units are assembled according to an exemplary embodiment of the present invention.

(6) FIG. 5a is schematic diagrams showing the distribution and flow of positive and negative ions in the flows of an electrode active material and an electrolyte at each channel when a separate electrolyte flow channel is present between the channel-type flow-cathode unit and the channel-type flow-anode unit according to an exemplary embodiment of the present invention.

(7) FIG. 5b is a cross-sectional diagram of the channel-type flow-electrode structure when a separate electrolyte flow channel is present between the channel-type flow-cathode unit and the channel-type flow-anode unit according to an exemplary embodiment of the present invention.

(8) FIG. 6 is a schematic diagram showing the operation principle of the channel-type flow-electrode structure when an electrolyte flow channel is arranged between the channel-type flow-cathode unit and the channel-type flow-anode unit according to an exemplary embodiment of the present invention.

(9) FIG. 7 is a schematic diagram showing the flow of an electrolyte through the liquid-permeable wall when a separate electrolyte flow channel is not present between the channel-type flow-cathode unit and the channel-type flow-anode unit according to an exemplary embodiment of the present invention.

(10) FIG. 8 is a schematic diagram showing a method of producing three channel-type flow-electrode structures of Example 1.

(11) FIG. 9 is an arrangement of the channel-type flow-cathode unit and the channel-type flow-anode unit in the channel-type flow-electrode structure according to an exemplary embodiment of the present invention.

(12) FIG. 10 is an arrangement of each channel in the channel-type flow-electrode structure having the channel-type electrolyte flow channel (marked with hatched lines) according to an exemplary embodiment of the present invention.

(13) FIG. 11 is schematic diagrams of the channel-type flow-electrode structures having the electrolyte flow channels (marked with black circles) according to various exemplary embodiments of the present invention.

(14) FIG. 12 is a schematic diagram showing the structure of a general redox flow battery.

(15) FIG. 13 is a schematic diagram of the redox flow-electrode device according to an exemplary embodiment of the present invention.

(16) FIG. 14 is a graph showing a change in current values according to a reaction time using the three channel-type flow-electrode structures produced in Example 1.

(17) FIG. 15 is a graph showing a change in current values according to a reaction time using the nine channel-type flow-electrode structures manufactured in Example 2.

(18) FIG. 16 is schematic diagrams of the lattice-type capacitive desalination cell according to an exemplary embodiment of the present invention ((a) top view (13-channel cell); (b) 33-channel cell; (c) desalination process).

(19) FIG. 17 shows (a) the constitution of the lattice-type capacitive desalination cell operated in a batch mode and (b) the change in the salt concentration thereof according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENT

(20) Hereinbelow, the present invention will be described in detail with accompanying exemplary embodiments. However, the exemplary embodiments disclosed herein are only for illustrative purposes and should not be construed as limiting the scope of the present invention.

Example 1

Three Channel-Type Flow-Electrode Structures

(21) A channel-type electrode structure having three channels was manufactured as shown in FIG. 8.

(22) Specifically, three-square-column-type channel scaffold was molded to prepare a liquid-permeable microporous honeycomb structure. The first square column channel was coated with a positive ion-exchangeable membrane, and the third square column channel was coated with a negative ion-exchangeable membrane. Thus, the positive ion-exchangeable membrane and the negative-exchangeable membrane respectively were formed on an inner wall surface of the channels. Additionally, graphene was coated on the inner wall surfaces of the first square column channel and third square column channel, which had been coated with the ion-exchangeable membranes, to form a porous current collector.

(23) Therefore, a channel-type flow-electrode structure, in which the first square column channel provides a cathode flow channel along an inside of which a fluid containing a cathode active material flows, the second square column channel provides a electrolyte flow channel, and the third square column channel provides an anode flow channel along an inside of which a flow containing an anode active material flows, was prepared.

(24) On the other hand, activated carbons were used for the cathode active material and the anode active material, and the cathode active material-containing fluid and the anode active material-containing fluid were prepared by adding activated carbon (10 wt %) and 0.1 M NaCl to water.

(25) The cell prepared as described above was placed in a vessel containing saline solution (35 g/L), and a reaction was initiated. The amount of NaCl in the saline solution can be estimated by measuring the conductivity of the saline solution. The conductivity of the initial saline solution (35 g/L) without a desalination reaction was 55 mS/cm, but the conductivity thereof after the desalination reaction was decreased to 37 mS/cm. As a result, the concentration of the saline solution was estimated to be 23.5 g/L.

(26) As shown in FIG. 14, the three channel-type flow-electrode structure manufactured in Example 1 have their salt removal efficiency as about 33%, and thereby this can be operated as desalination devices.

Example 2

Nine Channel-Type Flow-Electrode Structures

(27) Nine channel-type flow-electrode structures as shown in FIG. 5a was manufactured in the same manner as in Example 1.

(28) Additionally, the result of the experiment conducted in the same manner as in Example 1 is shown in Table 1 and FIG. 15.

(29) The prepared cell was placed in a vessel containing saline solution (35 g/L), and a reaction was initiated. The amount of NaCl in the saline solution can be estimated by measuring the conductivity of the saline solution. In the case of the three-channel type cells, the conductivity of the initial saline solution (35 g/L) without a desalination reaction was 62 mS/cm, but the conductivity thereof after the desalination reaction was decreased to 50 mS/cm. As a result, the concentration of the saline solution was estimated to be 28 g/L, and the salt removal efficiency was 20%. When the cell was expanded to have nine channels, the conductivity was reduced to 8.15 mS/cm; the concentration of the saline solution was 8.1 g/L; and the salt removal efficiency was 87%.

(30) TABLE-US-00001 TABLE 1 Salt Salt Removal Conductivity Concentration Efficiency (mS/cm) (g/L) (%) Pristine 62 35 Desalinated 50 28 20 (3 Cell Type) Desalinated 8.15 8.1 87 (9 Cell Type) Operating Condition: @ 1.2 V for 90 min 3.5 mL

Example 3

Measurement of Desalination Parameters of 13 Cell and 33 Cell in Batch Mode

(31) As described in a literature (i.e., A novel three-dimensional desalination system utilizing honeycomb-shaped lattice structures for flow-electrode capacitive deionization, Energy Environ. Sci., 2017, 10, 1746 to 1750), a desalination experiment was conducted in the batch mode of FIG. 17, and the literature above is included in the present invention.

(32) The dimensions of lattice structures were 3 mm in width, 0.5 mm in wall thickness, and 120 mm in height. The cordierite was used to form porous channels with the size ranging from 10 m to 30 m, and an ion-exchangeable membrane was coated on its surface. On the top thereof, about 30 m of a graphene layer was coated to serve as a conducting current collector. The prepared cell was immersed in the chamber containing saline solution (35 g/L), and then the desalination experiment was conducted in the batch mode. The salt removal efficiency was calculated by the equation below. The result of the experiment is shown in Table 2.

(33) TABLE-US-00002 TABLE 2 Current Current Desalination after density after Salt removal efficiency after 100 min 100 min capacity 100 min (mA) (A/m.sup.2) (mol/min) (%) 1 3 cell 5.8 17.6 9 5.6 3 3 cell 21.1 15.9 33 18.3

(34) Although the present invention has been described in connection with the exemplary embodiments illustrated in the drawings, it is only illustrative. It will be understood by those skilled in the art that various modifications and equivalents can be made to the present invention. Therefore, the true technical scope of the present invention should be defined by the appended claims.

DESCRIPTION OF REFERENCE NUMERALS

(35) 100,200,418: Flow-electrode device

(36) 102,216,416: Electrolyte flow channel

(37) 104,204: Cathode ion-exchangeable membrane

(38) 106,206: Porous cathode plate

(39) 108,208: Anode ion-exchangeable membrane

(40) 110,210: Porous anode plate

(41) 111: Cathode active material

(42) 112,201,401: Flow-cathode

(43) 113: Anode active material

(44) 114,203,403: Flow-anode

(45) 116,118: Closing plate

(46) 202,402: Scaffold

(47) 212,214,412,414: Electrode solution