Electrode continuous modification method and modification device

Abstract

The invention relates to an electrode continuous modification method and device, and the method comprises the steps: arranging a carbon felt electrode on a roller, and sequentially placing the carbon felt electrode in a first modification tank and a first cleaning tank through the roller for first modification and first cleaning; after first cleaning, first spraying and first blowing are carried out through a spraying device and a blowing device in sequence; after first purging, sequentially placing in a second modification tank and a second cleaning tank for second modification and second cleaning respectively; after the second cleaning, second spraying and second purging are respectively carried out through the spraying device and the purging device in sequence; and carrying out heat treatment on the carbon felt electrode subjected to the second purging to obtain the modified carbon felt electrode. The electrode is cleaned after being modified, so that the pollution of the previous-stage modification solution to the next-stage modification solution can be avoided, and the modification effect is improved.

Description

Technical Field

[0001] This invention relates to the field of electrode material technology, and more specifically, to a method and apparatus for continuous electrode modification. Background Technology

[0002] Vanadium redox flow batteries, as a novel electrochemical energy storage device suitable for large-scale application, offer advantages such as flexible design, high safety, and long service life. Within the battery assembly, the electrodes, as the sites of redox reactions between vanadium ions of different valence states in the electrolyte, are key components affecting battery performance. Currently, the electrode materials used in vanadium redox flow batteries are mostly porous carbon materials such as carbon felt, graphite felt, carbon cloth, and carbon paper. However, these materials suffer from poor electrochemical activity, which impacts battery performance.

[0003] To improve battery performance, modification of electrode materials is inevitable. Existing technologies generally include surface treatment of electrode materials and catalyst loading. Surface treatment can increase the specific surface area of ​​electrode materials or add oxygen-containing energetic groups through methods such as chemical etching, heat treatment, and electrochemical oxidation, thereby increasing the number of active sites on the electrode surface and improving battery efficiency. Catalyst loading involves introducing metals, metal oxides, or carbon nanomaterials to lower the reaction barrier, thus improving battery efficiency.

[0004] Patent CN115538148A discloses a method for modifying electrode materials for vanadium redox flow batteries. The method involves passing carbon felt raw materials sequentially through several processing tanks, cleaning tanks, and a graded heat treatment system in the processing equipment. This enables continuous switching between multiple modification processes of the carbon felt electrode, avoiding the original intermittent processing method and eliminating complicated operation procedures.

[0005] However, existing methods lack cleaning devices between modification steps, leading to the easy introduction of the modification solution from the previous stage into the modification solution of the next stage during electrode movement. This contamination not only increases the uncertainty of the modification process and causes unstable modification effects, but also results in waste of the contaminated modification solution, increasing the frequency and cost of solution replacement. Furthermore, existing technologies employ a staged modification process where electrodes pass horizontally through each modification tank, using a method of sealing with flexible sealing strips and carbon felt. Because the carbon felt is soft, there is a risk of incomplete adhesion, allowing the modification solution to seep out and leak from the tank. Summary of the Invention

[0006] The purpose of this invention is to provide a method and apparatus for continuous electrode modification, which avoids contamination of the subsequent modification solution by the previous modification solution, improves the modification effect, reduces the number of times the modification solution is replaced, reduces costs, and at the same time prevents leakage or seepage of the modification solution.

[0007] To achieve the above objectives, the present invention provides a method for continuous electrode modification, the method comprising: A carbon felt electrode is placed on a roller and then sequentially placed in a first modification tank and a first cleaning tank through the roller for first modification and first cleaning, respectively. After the first cleaning, the water is sequentially sprayed and purged by a spraying device and a purging device, respectively. After the first purging, the sample is placed in the second modification tank and the second cleaning tank in sequence for the second modification and the second cleaning, respectively. After the second cleaning, the device sequentially passes through a spraying device and a purging device for the second spraying and the second purging, respectively. The carbon felt electrode after the second purging is heat-treated to obtain the modified carbon felt electrode.

[0008] Optionally, the first modification tank contains a first modification solution, and the second modification tank contains a second modification solution; the first modification solution and the second modification solution are each independently one of hydrogen peroxide solution, boric acid solution, potassium permanganate solution, sulfuric acid solution, nitric acid solution, and Fenton's reagent; the first modification solution and the second modification solution are different from each other.

[0009] Optionally, the first and second cleaning tanks are each filled with pure water independently.

[0010] Optionally, the first modified solution is preferably a hydrogen peroxide solution with a concentration of 15-30%; the second modified solution is preferably a boric acid solution with a concentration of 1-5 mol / L.

[0011] Optionally, the liquid level height h of the first modified solution, the second modified solution, and pure water are calculated according to the following formulas:

[0012] In the formula, v is the speed of the carbon felt electrode moving on the roller, t is the modification time or cleaning time, r is the radius of the roller, and h1 is the distance from the center of the roller to the bottom of the modification tank or cleaning tank.

[0013] Optionally, the distance from the center of the roller to the bottom of the modification tank or cleaning tank is 0.5-0.8m; the radius of the roller is 0.3-0.5m.

[0014] Optionally, the modification time is 2-5 hours; the cleaning time is 3-6 hours.

[0015] Optionally, the carbon felt electrode moves at a speed of 0.02-0.05 m / min on the roller.

[0016] Optionally, the heat treatment temperature is 300-600℃ and the time is 2-6h.

[0017] Another aspect of the present invention provides an electrode continuous modification apparatus, the apparatus comprising: a carbon felt electrode, a roller, a tank, a partition, a spraying device, and a purging device; the tank comprises a first modification tank, a first cleaning tank, a second modification tank, and a second cleaning tank arranged horizontally in sequence; the carbon felt electrode is disposed on the roller, and the roller drives the carbon felt electrode to move vertically; the first modification tank and the first cleaning tank, the second modification tank and the second cleaning tank are respectively separated by the partition; the spraying device is disposed in the first cleaning tank and the second cleaning tank, and the purging device is disposed above the spraying device.

[0018] Optionally, the spraying device includes a magnetic pump, a spray pipe, a flushing pipe, and a nozzle; the flushing pipe is disposed on the partition plate, the nozzle is disposed on the flushing pipe, and the nozzle is provided with multiple spray holes.

[0019] Optionally, the purging device includes a gas pipeline, a pressure reducing valve, and a gas outlet.

[0020] Through the above technical solution, the carbon felt electrode of the present invention is cleaned in a cleaning tank after modification in the modification tank. After cleaning, it is sprayed and purged by a spraying device and a purging device, respectively, which avoids the contamination of the modification solution of the previous stage to the modification solution of the next stage, prevents the instability of the modification effect and the mutual influence between the modification effects caused by the contamination of the modification solution, reduces the number of times the modification solution is replaced, and reduces the cost. At the same time, the carbon felt electrode of the present invention moves vertically with the roller and is modified in stages in the vertical direction of travel. The bottom and sides of the modification tank are closed, with good sealing performance, and will not cause leakage or seepage of the modification solution.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the electrode continuous modification device of the present invention; Figure 2 This is a schematic diagram of the solution height in the modification tank or cleaning tank of this invention.

[0023] Explanation of reference numerals in the attached figures 1-Carbon felt electrode; 2-Roller; 3-Tank body; 4-Baffle; 5-First modification tank; 6-First cleaning tank; 7-Second modification tank; 8-Second cleaning tank; 9-Magnetic pump; 10-Spraying device; 11-Rinsing pipe; 12-Purge device. Detailed Implementation

[0024] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0025] This invention provides a method for continuous modification of an electrode, the method comprising: The carbon felt electrode 1 is placed on the roller 2 and then sequentially placed in the first modification tank 5 and the first cleaning tank 6 through the roller 2 for first modification and first cleaning respectively. After the first cleaning, the water is sequentially sprayed by the spray device 10 and purged by the purging device 12, and then purged by the first spray and the first purging, respectively. After the first purging, the samples are sequentially placed in the second modification tank 7 and the second cleaning tank 8 for the second modification and the second cleaning, respectively. After the second cleaning, the water is sequentially sprayed by the spray device 10 and purged by the purging device 12, and then purged by the second spray and the second purging, respectively. The carbon felt electrode after the second purging is heat-treated to obtain the modified carbon felt electrode.

[0026] According to the present invention, optionally, the carbon felt electrode can be sprayed by a spraying device after cleaning to speed up the cleaning efficiency, and then the carbon felt electrode can be simply dried by a purging device so that the carbon felt electrode will not cause dilution of the modification solution when it enters the next stage of modification solution.

[0027] According to the present invention, optionally, the rollers of the present invention are arranged in an alternating pattern, one above the other, and the carbon felt electrodes enter the modification tank and the cleaning tank vertically on the rollers.

[0028] According to the present invention, optionally, the first modification tank 5 is filled with a first modification solution, and the second modification tank 7 is filled with a second modification solution; the first modification solution and the second modification solution can each independently be a solution with a modification effect, such as one of hydrogen peroxide solution, boric acid solution, potassium permanganate solution, sulfuric acid solution, nitric acid solution, and Fenton's reagent; the first modification solution and the second modification solution are different from each other.

[0029] According to the present invention, optionally, the first modification tank 5 contains a hydrogen peroxide solution, and the second modification tank 7 contains a boric acid solution. The concentration of the hydrogen peroxide solution is 15-30%; the concentration of the boric acid solution is 1-5 mol / L. Modification with hydrogen peroxide and boric acid solutions can increase the content of functional groups on the surface of the carbon felt electrode, thereby improving the electrode's electrochemical activity.

[0030] According to the present invention, optionally, the first cleaning tank 6 and the second cleaning tank 8 are each independently filled with pure water.

[0031] According to the present invention, optionally, such as Figure 2 As shown, the liquid level height h of the first modified solution, the second modified solution, and pure water are calculated according to the following formulas:

[0032] In the formula, v is the speed of the carbon felt electrode moving on the roller, t is the modification time or cleaning time, r is the radius of the roller, and h1 is the distance from the center of the roller to the bottom of the modification tank or cleaning tank.

[0033] According to the present invention, optionally, during the modification process, it is necessary to replenish the liquid in a timely manner to keep the liquid level in the modification tank and the cleaning tank at a set height to ensure the stability of the processing time.

[0034] According to the present invention, optionally, the distance from the center of the roller to the bottom of the modification tank or cleaning tank is 0.5-0.8m; the radius of the roller is 0.3-0.5m.

[0035] According to the present invention, optionally, the modification time is 2-5 hours; the cleaning time is 3-6 hours.

[0036] According to the present invention, optionally, the carbon felt electrode moves at a speed of 0.02-0.05 m / min on the roller.

[0037] According to the present invention, optionally, the heat treatment temperature is 300-600℃ and the time is 2-6 hours. Heat treatment can induce boron doping into the carbon felt electrode, thereby improving its electrochemical activity.

[0038] Another aspect of the present invention provides an electrode continuous modification apparatus, such as... Figure 1As shown, the device includes: a carbon felt electrode 1, a roller 2, a tank 3, a partition 4, a spraying device 10, and a purging device 12; the tank 3 includes a first modification tank 5, a first cleaning tank 6, a second modification tank 7, and a second cleaning tank 8 arranged horizontally in sequence; the carbon felt electrode 1 is disposed on the roller 2, and the roller 2 drives the carbon felt electrode 1 to move vertically; the first modification tank 5 and the first cleaning tank 6, the second modification tank 7 and the second cleaning tank 8 are respectively separated by the partition 4; the spraying device 10 is disposed in the first cleaning tank 6 and the second cleaning tank 8 respectively, and the purging device 12 is disposed above the spraying device 10.

[0039] According to the present invention, optionally, the number of modification tanks and cleaning tanks can be adjusted according to the actual modification process, and it can also be applied to the modification of different types of porous carbon-based electrode materials.

[0040] According to the present invention, optionally, the spraying device 10 includes a magnetic pump 9, a flushing pipe 11 and a nozzle; the flushing pipe 11 is disposed on the partition 4, the nozzle is disposed on the flushing pipe 11, and the nozzle is provided with a plurality of spray holes.

[0041] According to the present invention, optionally, the rinsing pipe and the magnetic pump are used for the circulation of clean water in the cleaning tank, which can reduce the amount of rinsing water used and save water.

[0042] According to the present invention, the nozzle structure may optionally be a strip structure, a circular structure, or an arc structure, etc., to better clean the electrode material passing through and improve cleaning efficiency.

[0043] According to the present invention, optionally, the purging device 12 includes a gas pipeline, a pressure reducing valve, and a gas outlet. The purging direction of the gas outlet corresponds to the electrode moving on the roller, in order to dry and clean the electrode, and the purging flow rate can be controlled by the pressure reducing valve.

[0044] The carbon felt electrode of this invention is cleaned in a cleaning tank after modification in the modification tank. After cleaning, it is sprayed and purged by a spraying device and a purging device, respectively, to avoid contamination of the modification solution of the previous stage to the modification solution of the next stage. This prevents the instability of the modification effect and the mutual influence between modification effects caused by the contamination of the modification solution, reduces the number of times the modification solution needs to be replaced, and lowers the cost. At the same time, the carbon felt electrode of this invention moves vertically with the roller and is modified in stages in the vertical direction of travel. The bottom and sides of the modification tank are closed, with good sealing performance, so as not to cause leakage or seepage of the modification solution.

[0045] The present invention will be further illustrated by the following examples, but the present invention is not limited thereto.

[0046] Example 1 A method for continuous electrode modification, comprising the following steps: A carbon felt electrode 1 is placed on a roller 2 with a radius of 0.4m. The moving speed of the carbon felt electrode is set to 0.03m / min. The electrode is placed in a first modification tank 5 containing hydrogen peroxide solution through the roller 2 for first modification, and then placed in a first cleaning tank 6 containing pure water for first cleaning. The distance from the center of the roller to the bottom of the modification tank or cleaning tank is 0.6m. The first modification time is 2h, the first cleaning time is 3h, the height of the hydrogen peroxide solution is 1.77m, the concentration is 20%, and the height of the pure water is 2.67m. After the first cleaning, the water is sequentially sprayed by the spray device 10 and purged by the purging device 12, and then purged by the first spray and the first purging, respectively. After the first purging, the sample is sequentially placed in the second modification tank 7 containing boric acid solution for the second modification, and then placed in the second cleaning tank 8 containing pure water for the second cleaning; wherein, the second modification time is 3 hours, the second cleaning time is 3 hours, the height of the boric acid solution is 2.67 m, the concentration is 3 mol / L, and the height of the pure water is 2.67 m; After the second cleaning, the water is sequentially sprayed by the spray device 10 and purged by the purging device 12, and then purged by the second spray and the second purging, respectively. The carbon felt electrode after the second purging was heat-treated at 500℃ for 3 hours to obtain the modified carbon felt electrode.

[0047] Example 2 A method for continuous electrode modification, comprising the following steps: A carbon felt electrode 1 is placed on a roller 2 with a radius of 0.4m. The moving speed of the carbon felt electrode is set to 0.03m / min. The electrode is placed in a first modification tank 5 containing hydrogen peroxide solution through the roller 2 for first modification, and then placed in a first cleaning tank 6 containing pure water for first cleaning. The distance from the center of the roller to the bottom of the modification tank or cleaning tank is 0.6m. The first modification time is 4h, the first cleaning time is 5h, the height of the hydrogen peroxide solution is 3.57m, the concentration is 20%, and the height of the pure water is 4.47m. After the first cleaning, the water is sequentially sprayed by the spray device 10 and purged by the purging device 12, and then purged by the first spray and the first purging, respectively. After the first purging, the sample is sequentially placed in the second modification tank 7 containing boric acid solution for the second modification, and then placed in the second cleaning tank 8 containing pure water for the second cleaning; wherein, the second modification time is 5 hours, the second cleaning time is 5 hours, the height of the boric acid solution is 4.47 m, the concentration is 3 mol / L, and the height of the pure water is 4.47 m. After the second cleaning, the water is sequentially sprayed by the spray device 10 and purged by the purging device 12, and then purged by the second spray and the second purging, respectively. The carbon felt electrode after the second purging was heat-treated at 600℃ for 4 hours to obtain the modified carbon felt electrode.

[0048] Example 3 An apparatus used in the continuous electrode modification method of Embodiment 1 or Embodiment 2, the apparatus comprising: a carbon felt electrode 1, a roller 2, a tank 3, a partition 4, a spraying device 10, and a purging device 12; the tank 3 includes a first modification tank 5, a first cleaning tank 6, a second modification tank 7, and a second cleaning tank 8 arranged horizontally in sequence; the carbon felt electrode 1 is disposed on the roller 2, and the roller 2 drives the carbon felt electrode 1 to move vertically; the first modification tank 5 and the first cleaning tank 6, the second modification tank 7, and the second cleaning tank 8 are respectively separated by the partition 4; the first cleaning tank 6 and the second cleaning tank 8 are respectively provided with a spraying device 10, the spraying device 10 including a magnetic pump 9, a rinsing pipe 11, and a nozzle; the rinsing pipe 11 is disposed on the partition 4, and the rinsing pipe 11 is provided with a nozzle, the nozzle being provided with multiple nozzles, the nozzle structure being a strip structure; the purging device 12 is disposed above the spraying device 10, the purging device 12 including a gas pipeline, a pressure reducing valve, and a gas outlet.

[0049] Comparative Example 1 A method for continuous electrode modification, comprising the following steps: A carbon felt electrode 1 is placed on a roller 2 with a radius of 0.4 m. The moving speed of the carbon felt electrode is set to 0.03 m / min. The electrode is placed in a first modification tank 5 containing hydrogen peroxide solution for first modification, then in a second modification tank 7 containing boric acid solution for second modification, and finally in a second cleaning tank 8 containing pure water for second cleaning. The distance from the center of the roller to the bottom of the modification tank or cleaning tank is 0.6 m. The first modification time is 2 h, the second modification time is 3 h, the second cleaning time is 3 h, the height of the hydrogen peroxide solution is 1.77 m and the concentration is 20%, the height of the boric acid solution is 2.67 m and the concentration is 3 mol / L, and the height of the pure water is 2.67 m. The cleaned carbon felt electrode was heat-treated at 500℃ for 3 hours to obtain the modified carbon felt electrode.

[0050] Comparative Example 2 An apparatus used in the continuous electrode modification method of Comparative Example 1 includes: a carbon felt electrode 1, a roller 2, a tank 3, and a partition 4; the tank 3 includes a first modification tank 5, a second modification tank 7, and a second cleaning tank 8 arranged horizontally in sequence; the carbon felt electrode 1 is disposed on the roller 2, and the roller 2 drives the carbon felt electrode 1 to move vertically; the first modification tank 5, the second modification tank 7, and the second cleaning tank 8 are separated by the partition 4.

[0051] Test case The functional group content of the modified carbon felt electrodes obtained in Example 1 and Comparative Example 1 was tested. It was found that the content of -OH functional groups in Comparative Example 1 was lower than that in Example 1, as shown in Table 1. The reason may be that the carbon felt electrode in Comparative Example 1, which did not undergo the first cleaning, was directly transferred from the hydrogen peroxide solution to the boric acid solution. Due to the hydrophilicity of the electrode material, it carried hydrogen peroxide solution into the boric acid solution, thus weakening the modification effect of boric acid.

[0052] Table 1.

[0053]

[0054] Therefore, this invention not only enables continuous modification of electrode materials but also adds a cleaning step between the continuous modification processes. Specifically, the electrode material treated in the previous modification tank enters the cleaning tank instead of directly entering the next modification tank. This method ensures that the electrode material, after undergoing modification in one stage, does not carry the previous modification solution into the next, avoiding contamination of the lower modification solution by the upper one, improving the modification effect, reducing the need for solution replacement, and lowering costs.

[0055] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0056] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0057] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for continuous electrode modification, characterized in that, The method includes: The carbon felt electrode (1) is placed on the roller (2) and then sequentially placed in the first modification tank (5) and the first cleaning tank (6) through the roller (2) for first modification and first cleaning respectively. After the first cleaning, the water is sequentially sprayed and purged by the spraying device (10) and the purging device (12) respectively. After the first purging, the samples are placed in the second modification tank (7) and the second cleaning tank (8) respectively for the second modification and the second cleaning. After the second cleaning, the water is sequentially sprayed and purged by the spraying device (10) and the purging device (12) respectively. The carbon felt electrode after the second purging is heat-treated to obtain the modified carbon felt electrode.

2. The method according to claim 1, wherein, The first modification tank (5) contains a first modification solution, and the second modification tank (7) contains a second modification solution; The first modified solution and the second modified solution are each independently one of hydrogen peroxide solution, boric acid solution, potassium permanganate solution, sulfuric acid solution, nitric acid solution, and Fenton's reagent; the first modified solution and the second modified solution are different from each other; The first cleaning tank (6) and the second cleaning tank (8) are each filled with pure water independently.

3. The method according to claim 2, wherein, The first modified solution is preferably a hydrogen peroxide solution with a concentration of 15-30%; the second modified solution is preferably a boric acid solution with a concentration of 1-5 mol / L.

4. The method according to claim 2, wherein, The liquid level height h of the first modified solution, the second modified solution, and pure water are calculated according to the following formulas: In the formula, v is the speed of the carbon felt electrode moving on the roller, t is the modification time or cleaning time, r is the radius of the roller, and h1 is the distance from the center of the roller to the bottom of the modification tank or cleaning tank.

5. The method according to claim 4, wherein, The distance from the center of the roller to the bottom of the modification tank or cleaning tank is 0.5-0.8m; the radius of the roller is 0.3-0.5m.

6. The method according to claim 4, wherein, The modification time is 2-5 hours; the cleaning time is 3-6 hours.

7. The method according to claim 4, wherein, The carbon felt electrode moves at a speed of 0.02-0.05 m / min on the roller.

8. The method according to claim 1, wherein, The heat treatment temperature is 300-600℃, and the time is 2-6 hours.

9. An electrode continuous modification apparatus, characterized in that, The device includes: carbon felt electrode (1), roller (2), tank (3), partition (4), spray device (10) and purging device (12); the tank (3) includes a first modification tank (5), a first cleaning tank (6), a second modification tank (7) and a second cleaning tank (8) arranged horizontally in sequence. The carbon felt electrode (1) is disposed on the roller (2), and the roller (2) drives the carbon felt electrode (1) to move vertically; The first modification tank (5) and the first cleaning tank (6), the second modification tank (7) and the second cleaning tank (8) are separated by the partition (4); The first cleaning tank (6) and the second cleaning tank (8) are respectively equipped with the spray device (10), and the blowing device (12) is provided above the spray device (10).

10. The apparatus according to claim 9, wherein, The spraying device (10) includes a magnetic pump (9), a flushing pipe (11) and a nozzle; the flushing pipe (11) is disposed on the partition (4), the nozzle is disposed on the flushing pipe (11), and the nozzle is provided with multiple nozzles; The purging device (12) includes a gas pipeline, a pressure reducing valve, and a gas outlet.

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