KR102202979B1 - Method of manufacturing dual atoms doped carbon felt - Google Patents

Abstract

Disclosed is a method for manufacturing carbon felt doped with double atoms, the method comprising: (a) a step of manufacturing the carbon felt including surface-treated carbon fiber by immersing the carbon felt including carbon fiber in a surface treating solution including compound 1 represented by chemical formula 1 below and compound 2 represented by chemical formula 2 below, and irradiating ultrasonic waves; and (b) a step of manufacturing the carbon felt including the carbon fiber doped with nitrogen atoms and sulfur atoms by heat-treating the carbon felt including the surface-treated carbon fiber. In the chemical formulas 1 and 2, R^1 is a C1 to C5 alkylene group and R^2 is a C1 to C5 alkylene group. The method for manufacturing carbon felt doped with double atoms which are the nitrogen atoms and the sulfur atoms of the present invention provides a short surface treatment process time and uniform surface treatment. A vanadium redox flow battery including the carbon felt doped with the nitrogen atoms and the sulfur atoms according to the present invention provides high energy efficiency by reversibly performing an oxidation-reduction reaction of vanadium through the surface treatment of the carbon felt.

Description

Manufacturing method of carbon felt doped with a double atom{METHOD OF MANUFACTURING DUAL ATOMS DOPED CARBON FELT}

The present invention relates to a method for producing a carbon felt doped with a double atom.

In general, a redox flow battery is attracting attention as an electric energy storage system that has a long life, is safe, and can be designed independently of output and capacity, and is easy to increase capacity. In particular, since vanadium redox flow batteries use vanadium ions as the same active material in the positive/negative electrode electrolyte, there is no contamination problem due to ion-crossover, which is a problem in other types of redox flow batteries, thus exhibiting high battery efficiency. In the case of a vanadium redox flow battery, since the oxidation/reduction reaction of the active material occurs only on the electrode surface, research on improving electrode reactivity is considered an important part.

In particular, the electrode used in the vanadium redox flow battery must have a large surface area, high electrical conductivity, a suitable porous structure for electrolyte flow, and high vanadium oxidation/reduction activity. However, since the redox flow battery uses a strong acid electrolyte, an electrode material having acid resistance must be used. Therefore, carbon felt that is most suitable for these conditions is widely used.

However, the carbon felt electrode surface has a limitation in increasing the energy efficiency and discharge capacity of the battery because the electrochemical activity for the active material is low. In order to solve this problem, research on surface treatment such as heat treatment, acid treatment, oxide coating, carbon-based material coating, and nitrogen substitution has been conducted to impart functional groups to the surface of the carbon felt electrode.

In the previously reported liquid surface treatment technology, the carbon electrode is stirred and reacted in the surface treatment solution, resulting in uneven surface functional groups due to the flow of the liquid phase during the stirring process, and the reaction time takes more than 12 hours. There is a problem that is improved.

It is an object of the present invention to provide a method for manufacturing carbon felt doped with nitrogen atoms and sulfur atoms through a short surface treatment process time and uniform surface treatment.

In addition, an object of the present invention is to provide a vanadium redox flow battery having high energy efficiency by allowing the oxidation-reduction reaction of vanadium to occur reversibly through the surface treatment of carbon felt.

According to an aspect of the present invention, (a) carbon felt containing carbon fibers is supported in a surface treatment solution containing compound 1 represented by formula 1 below and compound 2 represented by formula 2 below, and subjected to surface treatment by ultrasonic irradiation. Producing a carbon felt containing the carbon fiber; And (b) heat-treating the carbon felt containing surface-treated carbon fibers to produce a carbon felt containing carbon fibers doped with nitrogen and sulfur atoms; and a method for producing a double atom doped carbon felt comprising do.

[Formula 1]

[Formula 2]

In Formulas 1 and 2,

R ¹ is a C1 to C5 alkylene group,

R ² is a C1 to C5 alkylene group.

In addition, the surface-treated carbon fiber polymerizes the compound 1 to coat a part or all of the carbon fiber to produce a carbon fiber coated with the compound 1 polymer, and the carbon fiber coated on the carbon fiber The compound 1 polymer and the compound 2 by Michael addition reaction may include a carbon fiber coated with the compound 1 polymer compound 2 is grafted.

In addition, in the compound 1 polymer grafted with compound 2, the thiol group of compound 2 may be bonded to the catechol group of the compound 1 polymer, so that the compound 2 may be grafted to the compound 1 polymer.

In addition, in Formula 1, R ¹ is a C2 or C3 alkylene group, and the compound 1 polymer may be self-polymerized.

In addition, the compound 1 is dopamine, and the compound 1 polymer may self-polymerize the dopamine.

In addition, in Formula 2, R ² may be a C2 or C3 alkylene group.

In addition, the compound 2 may be 2-mercaptoethanol (2-mercaptoethanol).

In addition, the ultrasonic treatment may be performed at a frequency of 20 to 100 kHz.

In addition, the ultrasonic treatment may be performed for 10 to 120 minutes.

In addition, the surface treatment solution may have a concentration of Compound 1 of 0.1 to 3 mM.

In addition, the surface treatment solution may have a concentration of the compound 2 of 5 to 10 mM.

In addition, the surface treatment solution may include a solvent and a buffer solution.

In addition, the solvent may include at least one selected from the group consisting of methanol, ethanol, propanol, isopropyl alcohol, tert-butanol, isobutanol, 2-ethyl hexanol, and 2-ethoxy ethanol.

In addition, the surface treatment solution may have a pH of 8.0 to 9.0.

In addition, in step (b), the heat treatment may be performed at 500 to 1,000°C.

According to another aspect of the present invention, (1) carbon containing carbon fibers 1 surface-treated by supporting a carbon felt containing carbon fibers in a surface treatment solution containing compound 1 represented by Formula 1 below and irradiating with ultrasonic waves Preparing felt 1; (2) preparing carbon felt 2 including carbon fiber 2 surface-treated by supporting the carbon felt 1 in a surface treatment solution containing compound 2 represented by Formula 2 below and irradiating with ultrasonic waves; And (3) heat-treating the carbon felt 2 to prepare a carbon felt 3 including carbon fibers 3 doped with nitrogen and sulfur atoms. A method for producing a double atom doped carbon felt is provided.

[Formula 1]

[Formula 2]

In Formulas 1 and 2,

R ¹ is a C1 to C5 alkylene group,

R ² is a C1 to C5 alkylene group.

In addition, the surface-treated carbon fiber 1 is a carbon fiber 1 coated with the compound 1 polymer by polymerizing the compound 1 and coating a compound 1 polymer on some or all of the carbon fiber, and the surface-treated carbon fiber 2 May be carbon fiber 2 coated with compound 1 polymer coated with compound 1 and compound 2 by Michael addition reaction of compound 2 coated on carbon fiber 1 with compound 1 polymer.

In addition, in the compound 1 polymer grafted with compound 2, the thiol group of compound 2 may be bonded to the catechol group of the compound 1 polymer, so that the compound 2 may be grafted to the compound 1 polymer.

According to another aspect of the present invention, there is provided a double atom doped carbon felt manufactured by the above manufacturing method.

According to another aspect of the present invention, there is provided a vanadium redox flow battery comprising the double atom doped carbon felt.

The method of manufacturing a carbon felt doped with a double atom, that is, a nitrogen atom and a sulfur atom of the present invention, has an effect of shortening the surface treatment process time and enabling a uniform surface treatment.

In addition, the vanadium redox flow battery including the carbon felt doped with nitrogen and sulfur atoms according to the present invention has a high energy efficiency effect by allowing the oxidation-reduction reaction of vanadium to occur reversibly through the surface treatment of the carbon felt.

1 is an SEM analysis result of carbon felts prepared according to Example 1 and Comparative Examples 1 to 3.
2 is an SEM analysis result of carbon felt prepared according to Example 2.
3 is an XPS result of carbon felt prepared according to Example 1, Comparative Example 1, and Comparative Example 2.
4 is a result of Cyclic Voltammetry (CV) analysis of carbon felts prepared according to Example 1, Comparative Example 1, and Comparative Example 2. FIG.
5 is a result of Cyclic Voltammetry (CV) analysis of carbon felts prepared according to Examples 1 and 2.
6 is an EIS analysis result of carbon felt prepared according to Example 1, Comparative Example 1, and Comparative Example 2.
7 is a result of charging/discharging capacity of vanadium redox flow batteries manufactured according to Device Example 1, Device Comparative Example 1, and Device Comparative Example 2. FIG.
8 is an energy efficiency result for each current density of a vanadium redox flow battery manufactured according to Device Example 1, Device Comparative Example 1, and Device Comparative Example 2. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention.

However, the following description is not intended to limit the present invention to a specific embodiment, and in describing the present invention, when it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. .

The terms used herein are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, elements, or combinations thereof described in the specification, but one or more other features or It is to be understood that the possibility of the presence or addition of numbers, steps, actions, elements, or combinations thereof is not preliminarily excluded.

Hereinafter, a method of manufacturing a double atom doped carbon felt of the present invention will be described.

First, in a surface treatment solution containing compound 1 represented by formula 1 below and compound 2 represented by formula 2 below Carbon fiber Included Carbon felt Carrying it By ultrasonic irradiation, a carbon felt containing the surface-treated carbon fibers is prepared (step a).

[Formula 1]

[Formula 2]

In Formulas 1 and 2,

R ¹ is a C1 to C5 alkylene group, preferably a C2 or C3 alkylene group,

R ² may be a C1 to C5 alkylene group, preferably a C2 or C3 alkylene group.

The surface-treated carbon fiber polymerizes the compound 1 to coat a part or all of the carbon fiber with a compound 1 polymer to produce a carbon fiber coated with the compound 1 polymer, and the compound coated on the carbon fiber A carbon fiber coated with the compound 1 polymer to which compound 2 is grafted by Michael addition reaction of the polymer 1 and compound 2 may be included.

In the compound 1 polymer grafted with compound 2, the thiol group of compound 2 may be bonded to the catechol group of the compound 1 polymer, so that the compound 2 may be grafted onto the compound 1 polymer.

The Compound 1 polymer to which Compound 2 is grafted may include a main chain in which Compound 1 is polymerized and Compound 2 grafted to the main chain.

The compound 1 polymer may be self-polymerized.

The compound 1 is dopamine, and the compound 1 polymer may self-polymerize the dopamine.

The compound 2 may be 2-mercaptoethanol (2-mercaptoethanol).

The ultrasonic treatment may be performed at a frequency of 20 to 100 kHz, and preferably may be performed at a frequency of 20 to 50 kHz. When ultrasonic waves are applied to a liquid, bubbles are repeatedly generated and destroyed by compression and expansion forces on the surface of objects in the liquid. When the generated bubbles exceed a certain size, the bubbles contract and explodes (cavitation phenomenon), instantaneously generating shock waves and heat, causing various physical and chemical reactions. Since cavitation usually occurs above 20 kHz, if the frequency is less than 20 kHz, the physical and chemical reaction effects of ultrasonic waves cannot be obtained, which is not desirable. If the frequency exceeds 100 kHz, there is no time allowance for the bubbles to become sufficiently large, thus effectively reducing the cavitation phenomenon. It is not preferable because it is difficult to use.

The ultrasonic treatment may be performed for 10 to 120 minutes, and preferably may be performed for 20 to 40 minutes. If the ultrasonic treatment time is less than 10 minutes, the polymerization of dopamine and the chemical reaction between dopamine and 2-mercaptoethanol do not sufficiently occur, which is not preferable. .

The surface treatment solution may have a concentration of Compound 1 of 0.1 to 3 mM. If the concentration of Compound 1 is less than 0.1mM, the amount of polymerization on the surface of the carbon felt is small, and sufficient performance cannot be expressed.If it exceeds 3mM, it is not preferable because the layer coated on the carbon felt is thick and the electrical conductivity is reduced. not.

The surface treatment solution may have a concentration of compound 2 of 5 to 10 mM. If the concentration of Compound 2 is less than 5mM, the amount grafted to dopamine is small, which is not preferable because the performance is poor, and if it exceeds 10mM, it is not preferable because it is sufficiently grafted to dopamine and the remaining residues aggregate to decrease performance. .

The surface treatment solution may include a solvent and a buffer solution.

The solvent may include at least one selected from the group consisting of methanol, ethanol, propanol, isopropyl alcohol, tert-butanol, isobutanol, 2-ethyl hexanol and 2-ethoxy ethanol, preferably methanol. Can include.

The surface treatment solution may have a pH of 8.0 to 9.0, and preferably 8.5.

to the next, Surface treated Carbon fiber Containing the above Carbon felt Heat treatment is performed to prepare a carbon felt containing carbon fibers doped with nitrogen atoms and sulfur atoms (step b).

The heat treatment may be performed in at least one inert gas atmosphere selected from the group consisting of nitrogen, helium, neon, argon, krypton, xenon, and radon.

The heat treatment may be performed at 500 to 1,000°C, preferably 600 to 800°C. If the heat treatment temperature is less than 500°C, thermal decomposition of dopamine and 2-mercaptoethanol does not occur, which is not preferable. If it exceeds 1,000°C, nitrogen and sulfur elements remaining after thermal decomposition disappear, which is not preferable.

Hereinafter, a method of manufacturing a double atom doped carbon felt according to another embodiment of the present invention will be described.

First, in the surface treatment solution containing compound 1 represented by the following formula (1) Carbon fiber Included Carbon felt Carrying it By ultrasonic irradiation Surface treated Carbon fiber To prepare a carbon felt 1 containing 1 (step 1).

[Formula 1]

In Formula 1,

R ¹ is a C1 to C5 alkylene group.

The surface-treated carbon fiber 1 may be a carbon fiber 1 coated with the compound 1 polymer by coating the compound 1 polymer on part or all of the carbon fiber by polymerizing compound 1.

Next, in a surface treatment solution containing compound 2 represented by Formula 2 below, Carbon felt 1 Carrying it By ultrasonic irradiation Surface treated Carbon fiber To prepare a carbon felt 2 containing 2 (step 2).

[Formula 2]

In Chemical Formula 2,

R ² is a C1 to C5 alkylene group.

The surface-treated carbon fiber 2 may be a carbon fiber 2 coated with a compound 1 polymer coated with compound 2 by Michael addition reaction of the compound 1 polymer coated on the carbon fiber 1 and the compound 2 to be grafted.

In the compound 1 polymer grafted with compound 2, the thiol group of compound 2 may be bonded to the catechol group of the compound 1 polymer, so that the compound 2 may be grafted onto the compound 1 polymer.

Finally, the carbon felt 2 is heat-treated to prepare a carbon felt 3 comprising carbon fibers 3 doped with nitrogen and sulfur atoms (step 3).

In addition, the present invention provides a double atom doped carbon felt prepared by the above manufacturing method.

In addition, the present invention provides a vanadium redox flow battery comprising the double atom doped carbon felt.

[Example]

Hereinafter, the present invention will be described in more detail with reference to examples. However, this is for illustrative purposes, and the scope of the present invention is not limited thereby.

Example 1: nitrogen atom and sulfur valence Doped Of carbon felt (NSGF) Manufacturing (PDA, simultaneous injection of 2-mercaptoethanol)

Surface treatment by adding 0.5 mM Dopamine hydrochloride and 6.4 mM 2-mercaptoethanol to 100 ml of methanol/Tris-buffer (50:50, v/v, pH = 8.5) solution The solution was prepared.

After immersing the rectangular carbon felt (GF) (50 × 50 × 4.2 mm, JNTG Co., Ltd.) in the surface treatment solution, sonication with 40 kHz, 700 W ultrasonic wave at room temperature for 40 minutes (Powersonic 620, Hwashin Tech Co. Ltd.).

At this time, because of the pH of the surface treatment solution, dopamine adheres to the GF surface while self-polymerizing, and at the same time, the thiol group of 2-mercaptoethanol is the catechol group of polydopamine (PDA) and It is grafted by the Michael addition reaction.

After the sonication reaction is complete, the sample is washed with distilled water, dried in an oven at 80°C, and then heat-treated at 700°C for 1 hour in an argon (Ar) atmosphere to prepare carbon felt (NSGF) doped with nitrogen and sulfur atoms. I did.

Example 2: nitrogen atom and sulfur valence Doped Of carbon felt (NSGF) Manufacturing (PDA line input, 2-mercaptoethanol then input)

A first surface treatment solution was prepared by adding 0.5 mM Dopamine hydrochloride to 100 ml of a methanol/Tris buffer (50:50, v/v, pH = 8.5) solution.

Rectangular carbon felt (Graphite felt, GF) (50 × 50 × 4.2 mm, JNTG Co., Ltd.) was immersed in the first surface treatment solution, and then sonicated with an ultrasonic wave of 40 kHz and 700 W for 40 minutes at room temperature ( sonication) (Powersonic 620, Hwashin Tech Co. Ltd.) and then GF was washed with distilled water.

A second surface treatment solution was prepared by adding 6.4 mM 2-mercaptoethanol to 100 ml of a new methanol/Tris buffer (50:50, v/v, pH = 8.5) solution.

After immersing the GF washed with distilled water in the second surface treatment solution, sonicating at room temperature with 40 kHz, 700 W ultrasonic waves for 40 minutes, washing with distilled water and drying in an oven at 80°C, argon (Ar) atmosphere Heat treatment at 700° C. for 1 hour to prepare carbon felt (NSGF) doped with nitrogen and sulfur atoms.

Comparative Example 1: Carbon Felt (Bare GF)

Rectangular carbon felt (Graphite felt, GF) (50 × 50 × 4.2 mm, JNTG Co., Ltd.) was used as Comparative Example 1.

Comparative Example 2: Preparation of carbon felt (NGF) doped with nitrogen atoms

In Example 1, a nitrogen atom-doped carbon felt (NGF) was prepared in the same manner as in Example 1, except that 2-mercaptoethanol was not added to the surface treatment solution.

Comparative Example 3: Preparation of carbon felt (SGF) doped with sulfur atoms

In Example 1, a sulfur atom-doped carbon felt (SGF) was prepared in the same manner as in Example 1, except that dopamine hydrochloride was not added to the surface treatment solution.

Manufacture of vanadium redox flow battery

Device Example 1

Carbon felt doped with nitrogen and sulfur atoms prepared according to Example 1 was used as an electrode of a vanadium redox flow battery.

An end plate, a bipolar plate, a flow path frame, and a carbon felt doped with a nitrogen atom and a sulfur atom prepared according to Example 1 were stacked in this order to produce an anode cell and a cathode cell, respectively. The anode cell and the cathode cell were stacked to face each other with an ion exchange membrane interposed therebetween to form one cell. A vanadium redox flow battery was manufactured by connecting a cathode electrolyte tank to one side of the cell and a cathode electrolyte tank to the other side of the cell using a tube, and then allowing the electrolyte to circulate inside the cell using a pump.

Device Example 2

A vanadium redox flow battery was manufactured in the same manner as in Device Example 1, except for using the carbon felt prepared according to Example 2 instead of using the carbon felt prepared according to Example 1.

Device Comparative Example 1

A vanadium redox flow battery was manufactured in the same manner as in Device Example 1, except for using the carbon felt prepared according to Comparative Example 1 instead of using the carbon felt prepared according to Example 1.

Device Comparative Example 2

A vanadium redox flow battery was manufactured in the same manner as in Device Example 1, except for using the carbon felt prepared according to Comparative Example 2 instead of using the carbon felt prepared according to Example 1.

[Test Example]

Test Example 1: SEM (Scanning Electron Microscope) analysis

1 is an SEM analysis result of carbon felts prepared according to Example 1 and Comparative Examples 1 to 3. Referring to FIG. 1, in the case of SGF prepared by adding only 2-mercaptoethanol to the surface treatment solution in Comparative Example 3, Michael addition reaction did not occur due to the absence of dopamine, so it was confirmed that they were lumped together on the surface. there was. Therefore, SGF prepared according to Comparative Example 3 was excluded from subsequent analysis and testing.

In addition, referring to FIG. 1, in the case of Comparative Example 1, a smooth surface was shown, whereas in the case of Comparative Example 2, it was confirmed that nanoparticles were uniformly attached to the surface. In the case of Example 1, as in the case of Comparative Example 2, it was confirmed that the nanoparticles were uniformly attached to the surface of the carbon felt. In the case of Example 1, even though 2-mercaptoethanol was added as in Comparative Example 3, there was no aggregation phenomenon as in Comparative Example 3, which caused Michael addition reaction by dopamine added together, and dopamine and 2 on the carbon felt surface. -It was confirmed that mercaptoethanol was evenly attached together.

2 is an SEM analysis result of carbon felt prepared according to Example 2. Referring to FIG. 2, it can be seen that the surface appearance is similar to that of Example 1, which means that dopamine and 2-mercaptoethanol do not have a significant effect.

Test Example 2: XPS (X-ray photoelectron spectroscopy) analysis

3 is an XPS result of carbon felt prepared according to Example 1, Comparative Example 1, and Comparative Example 2. Referring to FIG. 3, in Comparative Example 1, nitrogen and sulfur atoms were not present on the surface, whereas in Comparative Example 2 in which only dopamine was added, it was confirmed that only nitrogen atoms were present on the surface. When compared with Comparative Examples 1 and 2, in the case of Example 1, it was confirmed that both nitrogen and sulfur atoms exist on the surface, which is nitrogen and sulfur by Michael addition reaction of dopamine and 2-mercaptoethanol added together. It was confirmed that atoms were imparted to the surface of the carbon felt.

Test Example 3: Cyclic Voltammetry (CV) analysis

4 is a result of Cyclic Voltammetry (CV) analysis of carbon felts prepared according to Example 1, Comparative Example 1 and Comparative Example 2, showing the oxidation reaction peak and reduction reaction peak of each sample. Referring to FIG. 4, a Delta Ep value that is a difference between two peaks and an Ipa/Ipc value that is a current density ratio of the two peaks can be confirmed. It can be seen that the Delta Ep value of Comparative Example 2 decreases compared to Comparative Example 1, and it was confirmed that the Ipa/Ipc value approaches 1. This means that by imparting nitrogen to the carbon felt surface, resistance to reaction is reduced and reversibility between oxidation and reduction reactions is improved. In the case of Example 1, it can be seen that the Delta Ep value decreases compared to Comparative Example 2, and it can be confirmed that the Ipa/Ipc value is closer to 1. This means that when nitrogen and sulfur are simultaneously applied to the carbon felt surface, the resistance reduction and reversibility effect are superior to that of providing nitrogen atoms alone.

5 is a result of Cyclic Voltammetry (CV) analysis of carbon felts prepared according to Examples 1 and 2. Referring to FIG. 5, it can be seen that there is little difference between the Delta Ep value and the Ipa/Ipc value of Example 1 and Example 2, which is the order of dopamine and 2-mercaptoethanol addition significantly affects electrode performance. It means not to give.

Test Example 4: Electrochemical impedance spectroscopy (EIS) analysis

6 is an EIS analysis result of carbon felt prepared according to Example 1, Comparative Example 1, and Comparative Example 2. Referring to FIG. 6, it can be seen that the resistance value of Comparative Example 2 is significantly reduced compared to Comparative Example 1, which means that nitrogen imparted to the surface of the carbon felt plays a role in reducing the surface resistance. It can be seen that the resistance value of Example 2 is further reduced compared to Comparative Example 2, which indicates that applying nitrogen and sulfur at the same time is excellent in reducing the surface resistance rather than providing nitrogen alone to the carbon felt surface. it means.

Test Example 5: Analysis of charge/discharge capacity

7 is a result of charging/discharging capacity of vanadium redox flow batteries manufactured according to Device Example 1, Device Comparative Example 1, and Device Comparative Example 2. FIG. Referring to FIG. 7, it can be seen that the capacity of Device Comparative Example 2 is significantly increased compared to Device Comparative Example 1, which means that nitrogen imparted to the surface of the carbon felt acts as a catalyst and is effective in improving the electrolyte utilization rate. . It can be seen that the capacity of Device Example 1 is increased compared to Device Comparative Example 2, which is that the simultaneous application of nitrogen and sulfur to the carbon felt surface maximizes the catalytic activity and improves the electrolyte utilization rate, rather than providing nitrogen alone. It means more excellent.

Test Example 6: Analysis of energy efficiency by current density

8 is an energy efficiency result for each current density of a vanadium redox flow battery manufactured according to Device Example 1, Device Comparative Example 1, and Device Comparative Example 2. FIG. Referring to FIG. 8, it can be seen that the energy efficiency for each current density of the device comparative example 2 is significantly improved compared to that of the device comparative example 1, which improves energy efficiency by improving the reactivity and reversibility of nitrogen imparted to the carbon felt surface. It means that it works. It can be seen that the energy efficiency for each current density of Device Example 1 is improved compared to Device Comparative Example 2, which is more reactivity and reversibility when nitrogen and sulfur are simultaneously applied to the carbon felt surface than nitrogen alone. It means that it is more excellent at improving energy efficiency by improving it.

In the above, preferred embodiments of the present invention have been described, but those of ordinary skill in the relevant technical field can add, change, delete or add components within the scope not departing from the spirit of the present invention described in the claims. Various modifications and changes may be made to the present invention by addition or the like, and it will be said that this is also included within the scope of the present invention. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form. The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

Claims (20)

(a) Carbon fiber surface-treated by supporting a carbon felt containing carbon fiber in a surface treatment solution containing compound 1 represented by Formula 1 below, compound 2 represented by Formula 2 below, methanol and a buffer solution, and subjected to ultrasonic irradiation Preparing a carbon felt comprising a; And
(b) heat treating the carbon felt containing surface-treated carbon fibers to prepare a carbon felt containing carbon fibers doped with nitrogen atoms and sulfur atoms; including,
The ultrasonic treatment is performed at a frequency of 20 to 100 kHz,
The method of manufacturing a double atom-doped carbon felt, wherein the ultrasonic treatment is performed for 20 to 40 minutes.
[Formula 1]

[Formula 2]

In Formulas 1 and 2,
R ¹ is a C1 to C5 alkylene group,
R ² is a C1 to C5 alkylene group. The method of claim 1,
The surface-treated carbon fiber
The compound 1 is polymerized to produce a carbon fiber coated with the compound 1 polymer by coating a compound 1 polymer on part or all of the carbon fiber, and the compound 1 polymer and the compound 2 coated on the carbon fiber A method for producing a double atom-doped carbon felt, characterized in that it comprises carbon fibers coated with a compound 1 polymer to which compound 2 is grafted by Michael addition reaction. The method of claim 2,
The compound 1 polymer to which the compound 2 is grafted is the catechol group of the compound 1 polymer is bonded to the thiol group of the compound 2 to prepare a double atom doped carbon felt, wherein the compound 2 is grafted to the compound 1 polymer Way. The method of claim 2,
In Formula 1,
R ¹ is a C2 or C3 alkylene group, and the compound 1 polymer is self-polymerized. The method of claim 4,
The compound 1 is dopamine, and the compound 1 polymer is a method for producing a double atom-doped carbon felt, characterized in that the dopamine is self-polymerized. The method of claim 1,
In Chemical Formula 2,
R ² is a method for producing a double atom doped carbon felt, characterized in that a C2 or C3 alkylene group. The method of claim 6,
The method for producing a double atom doped carbon felt, characterized in that the compound 2 is 2-mercaptoethanol. delete delete The method of claim 1,
The surface treatment solution is a method of producing a double atom doped carbon felt, characterized in that the concentration of the compound 1 is 0.1 to 3mM. The method of claim 1,
The surface treatment solution is a method of producing a double atom doped carbon felt, characterized in that the concentration of the compound 2 is 5 to 10mM. delete delete The method of claim 1,
The method for producing a double atom doped carbon felt, wherein the surface treatment solution has a pH of 8.0 to 9.0. The method of claim 1,
In step (b),
Method for producing a double atom doped carbon felt, characterized in that the heat treatment is carried out at 500 to 1,000 ℃. (1) Carbon felt 1 including carbon fiber 1 was prepared by supporting a carbon felt containing carbon fiber in a surface treatment solution containing compound 1 represented by the following formula (1), methanol and a buffer solution and irradiating with ultrasonic waves Step to do;
(2) preparing a carbon felt 2 including a surface-treated carbon fiber 2 by supporting the carbon felt 1 in a surface treatment solution containing compound 2 represented by Formula 2 below, methanol, and a buffer solution, followed by ultrasonic irradiation; And
(3) heat-treating the carbon felt 2 to prepare a carbon felt 3 including carbon fibers 3 doped with nitrogen and sulfur atoms; including,
The ultrasonic treatment is performed at a frequency of 20 to 100 kHz,
The method for producing a double atom-doped carbon felt, wherein the ultrasonic treatment is performed for 20 to 40 minutes.
[Formula 1]

[Formula 2]

In Formulas 1 and 2,
R ¹ is a C1 to C5 alkylene group,
R ² is a C1 to C5 alkylene group. The method of claim 16,
The surface-treated carbon fiber 1 is a carbon fiber 1 coated with the compound 1 polymer by polymerizing the compound 1 to coat a part or all of the carbon fiber with a compound 1 polymer,
The surface-treated carbon fiber 2 is a carbon fiber 2 coated with a compound 1 polymer coated with compound 2 by Michael addition reaction of the compound 1 polymer coated on the carbon fiber 1 and the compound 2 Method for producing doped carbon felt. The method of claim 17,
The compound 1 polymer to which the compound 2 is grafted is the catechol group of the compound 1 polymer is bonded to the thiol group of the compound 2 to prepare a double atom doped carbon felt, wherein the compound 2 is grafted to the compound 1 polymer Way. The double-atom-doped carbon felt prepared by the method of claim 1 or 16. A vanadium redox flow battery comprising the double atom doped carbon felt of claim 19.

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