Carbon-carbon composite material electrode, preparation method and all-vanadium redox flow battery

Abstract

The invention relates to a carbon-carbon composite material electrode, a preparation method and an all-vanadium redox flow battery, and relates to the technical field of all-vanadium redox flow batteries, and the preparation method comprises the following steps: S1, mixing acetaldehyde and hydroquinone, adding deionized water and a catalyst, stirring the obtained mixed solution at 30-90 DEG C for 0.5-3 h, and carrying out a polymerization reaction to obtain an organic gel precursor solution; s2, uniformly permeating a pickling solution on the carbon felt or the pre-oxidized felt, and carrying out heat treatment to obtain a pickled felt; s3, uniformly permeating or dipping the organic gel precursor solution on the pickling felt, and then sequentially performing aging, solvent replacement, carbonization and graphitization treatment to obtain a graphite felt-carbon aerogel semi-finished product; and S4, activating the graphite felt-carbon aerogel semi-finished product to obtain a carbon-carbon composite material electrode finished product. The all-vanadium redox flow battery has the advantage that the voltage efficiency and the energy efficiency of the all-vanadium redox flow battery can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of all-vanadium redox flow batteries, and in particular, to a carbon-carbon composite material electrode, a preparation method thereof, and an all-vanadium redox flow battery. Background Art

[0002] As an efficient energy storage technology, the all-vanadium redox flow battery (VRFB) has attracted much attention due to its long life, scalability, and flexible operating characteristics. In such a battery system, the electrode material is one of the key factors affecting the battery performance, and its selection is crucial for the battery performance. When the existing electrode materials are applied to the all-vanadium redox flow battery, there are problems of low voltage efficiency and energy efficiency. Summary of the Invention

[0003] Aiming at the deficiencies of the existing technology, one of the purposes of the present application is to provide a carbon-carbon composite material electrode, a preparation method thereof, and an all-vanadium redox flow battery, which have the advantages of improving the voltage efficiency and energy efficiency when used in the all-vanadium redox flow battery.

[0004] The above object of the present application is achieved through the following technical solutions:

[0005] A preparation method of a carbon-carbon composite material electrode for an all-vanadium redox flow battery includes the following steps.

[0006] S1. Mix acetaldehyde and hydroquinone, add deionized water and a catalyst, and stir the obtained mixed solution at 30 - 90 °C for 0.5 - 3 h to undergo a polymerization reaction to obtain an organic gel precursor solution.

[0007] S2. Uniformly infiltrate the acid cleaning solution on the carbon felt or pre-oxidized felt, and perform heat treatment to obtain an acid-cleaned felt.

[0008] S3. Uniformly infiltrate or impregnate the organic gel precursor solution on the acid-cleaned felt, and then successively perform aging, solvent replacement, carbonization, and graphitization treatments to obtain a graphite felt-carbon aerogel semi-finished product.

[0009] S4. Activate the graphite felt-carbon aerogel semi-finished product to obtain a finished carbon-carbon composite material electrode.

[0010] In a preferred example of the present application, it can be further configured that: in S1, the molar ratio of acetaldehyde to hydroquinone is 1 - 3:3 - 1, the catalyst is sodium hydroxide or anhydrous sodium carbonate, and the mass fraction of the mixed solution is 10 - 50%.

[0011] In a preferred example of the present application, it can be further configured that: in S2, the acid cleaning solution is one of nitric acid, hydrochloric acid, and acetic acid, the concentration of the acid cleaning solution is 0.1 - 2.0 mol / L, the heat treatment temperature is 80 - 150 °C, and the treatment time is 30 - 90 min.

[0012] In a preferred embodiment of the present application, it can be further configured that: the mass ratio of the precursor solution infiltrated or impregnated in S3 to the acid-washed felt is 1-5:5-1.

[0013] In a preferred embodiment of the present application, it can be further configured that: the aging temperature in S3 is 50-85 °C, the time is 2-72 h, and the solvent for solvent replacement in S3 is acetone or ethanol.

[0014] In a preferred embodiment of the present application, it can be further configured that: the carbonization treatment temperature in S3 is 1000-1600 °C, the treatment time is 30-90 min, the atmosphere includes nitrogen or argon, the graphitization treatment temperature is 2000-3000 °C, the treatment time is 10-30 min, and the atmosphere includes nitrogen or argon.

[0015] In a preferred embodiment of the present application, it can be further configured that: the activation treatment in S4 is heat treatment under water vapor, the water vapor contains one of the media of nitrogen, phosphorus, sulfur or no medium, the treatment temperature is 300-950 °C, and the treatment time is 45-720 min.

[0016] In a preferred embodiment of the present application, it can be further configured that: the carbon felt or pre-oxidized felt in S2 is one of viscose-based, PAN-based, pitch-based, and phenolic-based.

[0017] The present application also discloses a carbon-carbon composite electrode obtained by the above-mentioned carbon-carbon composite electrode preparation method.

[0018] The present application also discloses a vanadium redox flow battery, and the electrode adopts the above-mentioned carbon-carbon composite electrode.

[0019] The present application has the following beneficial effects:

[0020] By infiltrating the organic gel precursor solution into the acid-washed carbon felt or pre-oxidized felt, the bonding force between the organic aerogel and the felt is significantly enhanced. Through a series of process steps such as aging, solvent replacement, carbonization, graphitization treatment, and activation treatment, a carbon-carbon composite electrode is successfully prepared. The carbon-carbon composite electrode prepared by the present application has a larger specific surface area, thereby effectively improving the voltage efficiency and energy efficiency of the vanadium redox flow battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a flowchart of the preparation of the carbon-carbon composite for the vanadium redox flow battery of the present invention.

[0022] Figure 2Figure for comparing the energy efficiency in the rate performance test of current density from 80 to 200 after assembling the full vanadium redox flow battery with Example 1 and Comparative Example 1 as electrodes. Detailed implementation mode

[0023] The following further elaborates on this application in conjunction with the attached drawings.

[0024] Refer to Figure 1 and Figure 2 , a preparation method of a carbon-carbon composite material electrode disclosed in this application, includes the following steps:

[0025] S1. Mix acetaldehyde and hydroquinone, add deionized water and a catalyst, and stir the obtained mixed solution at 30 - 90 °C for 0.5 - 3 h to carry out a polymerization reaction, then obtain an organic gel precursor solution;

[0026] S2. Uniformly infiltrate the acid cleaning solution on the carbon felt or pre-oxidized felt, and carry out heat treatment to obtain an acid-cleaned felt. The carbon felt or pre-oxidized felt is one of viscose-based, PAN-based, pitch-based, and phenolic-based;

[0027] S3. Uniformly infiltrate or impregnate the organic gel precursor solution on the acid-cleaned felt, and then successively carry out aging, solvent replacement, carbonization, and graphitization treatments to obtain a graphite felt-carbon aerogel semi-finished product;

[0028] S4. Subject the graphite felt-carbon aerogel semi-finished product to activation treatment to obtain a finished carbon-carbon composite material electrode.

[0029] In S1, the molar ratio of acetaldehyde to hydroquinone is 1 - 3:3 - 1, the catalyst is sodium hydroxide or anhydrous sodium carbonate, and the mass fraction of the mixed solution is 10 - 50%.

[0030] In S2, the acid cleaning solution is one of nitric acid, hydrochloric acid, and acetic acid, the concentration of the acid cleaning solution is 0.1 - 2.0 mol / L, the heat treatment temperature is 80 - 150 °C, and the treatment time is 30 - 90 min.

[0031] In S3, the mass ratio of the infiltrated or impregnated precursor solution to the acid-cleaned felt is 1 - 5:5 - 1, the aging temperature is 50 - 85 °C, and the time is 2 - 72 h. The solvent for solvent replacement in S3 is acetone or ethanol, the carbonization treatment temperature is 1000 - 1600 °C, the treatment time is 30 - 90 min, and the atmosphere includes nitrogen or argon. The graphitization treatment temperature is 2000 - 3000 °C, the treatment time is 10 - 30 min, and the atmosphere includes nitrogen or argon.

[0032] In S4, the activation treatment is heat treatment under water vapor, and the water vapor contains one of nitrogen, phosphorus, and sulfur media or no medium. The treatment temperature is 300 - 950 °C, and the treatment time is 45 - 720 min.

[0033] The present invention will be further described below in conjunction with embodiments.

[0034] Embodiment 1

[0035] This embodiment is a preparation method of a carbon-carbon composite electrode for an all-vanadium redox flow battery. The preparation method includes the following steps:

[0036] S1. Mix acetaldehyde (1 mol, 44.06 g) and hydroquinone (1 mol, 110.10 g), add deionized water (500 mL) and catalyst sodium hydroxide (1 mmol, 40 mg). After the obtained mixed solution is stirred at 60 °C for 3 h to undergo a polymerization reaction, an organic gel precursor solution is obtained;

[0037] S2. Uniformly infiltrate dilute nitric acid (0.5 mol / L, 10 mL) on a viscose-based pre-oxidized felt (200 g), and perform heat treatment at 120 °C for 60 min to obtain an acid-washed felt;

[0038] S3. Uniformly infiltrate the organic gel precursor solution (200 g) on the above-mentioned acid-washed felt. Next, perform an aging treatment. Seal the felt with a sealed bag and place it in an oven at a temperature of 60 °C for 3 days. Then perform solvent replacement. Immerse the felt in absolute ethanol (3 L) for 2 days. Next, perform carbonization treatment on the felt. The carbonization treatment temperature is 1300 °C, the treatment time is 60 min, and the atmosphere is nitrogen. Finally, perform graphitization treatment on the felt. The carbonization treatment temperature is 2000 °C, the treatment time is 30 min, and the atmosphere is nitrogen to obtain a graphite felt-carbon aerogel semi-finished product.

[0039] S4. Put the graphite felt-carbon aerogel semi-finished product into an activation furnace and perform heat treatment under steam. The steam flow rate is 180 m 3 / h, the temperature is 500 °C, and the treatment is carried out for 120 min.

[0040] Embodiment 2

[0041] This embodiment is a preparation method of a carbon-carbon composite electrode for an all-vanadium redox flow battery. The preparation method includes the following steps:

[0042] S1. Mix acetaldehyde (1 mol, 44.06 g) and hydroquinone (3 mol, 330.30 g), add deionized water (500 mL) and catalyst sodium hydroxide (1 mmol, 40 mg). After the obtained mixed solution is stirred at 60 °C for 3 h to undergo a polymerization reaction, an organic gel precursor solution is obtained;

[0043] S2. Uniformly infiltrate dilute nitric acid (0.5 mol / L, 10 mL) on a viscose-based pre-oxidized felt (200 g), and perform heat treatment at 120 °C for 60 min to obtain an acid-washed felt;

[0044] S3. Uniformly infiltrate the organic gel precursor solution (200 g) into the above-mentioned pickled felt. Next, perform an aging treatment. Seal the felt with a sealed bag and place it in an oven at a temperature of 60 °C for 3 days of static placement. Then, perform solvent replacement by soaking the felt in absolute ethanol (3 L) for 2 days. Next, perform a carbonization treatment on the felt at a carbonization temperature of 1300 °C, a treatment time of 60 min, and an atmosphere of nitrogen. Finally, perform a graphitization treatment on the felt at a carbonization temperature of 2000 °C, a treatment time of 30 min, and an atmosphere of nitrogen to obtain a graphite felt-carbon aerogel semi-finished product.

[0045] S4. Put the graphite felt-carbon aerogel semi-finished product into an activation furnace and perform a heat treatment under steam with a steam flow rate of 180 m3 / h, a temperature of 500 °C, and a treatment time of 120 min.

[0046] Example 3

[0047] This example is a preparation method of a carbon-carbon composite electrode for an all-vanadium redox flow battery. The preparation method includes the following steps:

[0048] S1. Mix acetaldehyde (1 mol, 44.06 g) and hydroquinone (1 mol, 110.10 g), add deionized water (500 mL) and a catalyst sodium hydroxide (1 mmol, 40 mg). After the obtained mixed solution is stirred at 60 °C for 3 h to undergo a polymerization reaction, an organic gel precursor solution is obtained;

[0049] S2. Uniformly infiltrate dilute nitric acid (0.5 mol / L, 10 mL) onto a viscose-based pre-oxidized felt (200 g) and perform a heat treatment at 120 °C for 60 min to obtain a pickled felt;

[0050] S3. Uniformly infiltrate the organic gel precursor solution (40 g) into the above-mentioned pickled felt. Next, perform an aging treatment. Seal the felt with a sealed bag and place it in an oven at a temperature of 60 °C for 3 days of static placement. Then, perform solvent replacement by soaking the felt in absolute ethanol (3 L) for 2 days. Next, perform a carbonization treatment on the felt at a carbonization temperature of 1300 °C, a treatment time of 60 min, and an atmosphere of nitrogen. Finally, perform a graphitization treatment on the felt at a carbonization temperature of 2000 °C, a treatment time of 30 min, and an atmosphere of nitrogen to obtain a graphite felt-carbon aerogel semi-finished product.

[0051] S4. Put the graphite felt-carbon aerogel semi-finished product into an activation furnace and perform a heat treatment under steam with a steam flow rate of 180 m 3 / h, a temperature of 500 °C, and a treatment time of 120 min.

[0052] Example 4

[0053] S1. Mix acetaldehyde (1 mol, 44.06 g) and hydroquinone (1 mol, 110.10 g), add deionized water (500 mL) and catalyst sodium hydroxide (1 mmol, 40 mg). After the obtained mixed solution undergoes a polymerization reaction by stirring at 60 °C for 3 h, an organic gel precursor solution is obtained;

[0054] S2. Uniformly infiltrate dilute nitric acid (0.5 mol / L, 10 mL) onto a viscose-based carbon felt (200 g), and perform a heat treatment at 120 °C for 60 min to obtain an acid-washed felt;

[0055] S3. Uniformly infiltrate the organic gel precursor solution (200 g) onto the above-mentioned acid-washed felt. Next, perform an aging treatment. Seal the felt with a sealed bag and place it in an oven at 60 °C for 3 days. Then perform solvent replacement by soaking the felt in absolute ethanol (3 L) for 2 days. Next, perform a carbonization treatment on the felt. The carbonization treatment temperature is 1300 °C, the treatment time is 60 min, and the atmosphere is nitrogen. Finally, perform a graphitization treatment on the felt. The carbonization treatment temperature is 2000 °C, the treatment time is 30 min, and the atmosphere is nitrogen to obtain a graphite felt-carbon aerogel semi-finished product.

[0056] S4. Put the graphite felt-carbon aerogel semi-finished product into an activation furnace and perform a heat treatment under steam. The steam flow rate is 180 m 3 / h, the temperature is 500 °C, and the treatment is for 120 min.

[0057] Example 5

[0058] This example is a preparation method of a carbon-carbon composite electrode for an all-vanadium redox flow battery. The preparation method includes the following steps:

[0059] S1. Mix acetaldehyde (1 mol, 44.06 g) and hydroquinone (1 mol, 110.10 g), add deionized water (500 mL) and catalyst sodium hydroxide (1 mmol, 40 mg). After the obtained mixed solution undergoes a polymerization reaction by stirring at 60 °C for 3 h, an organic gel precursor solution is obtained;

[0060] S2. Uniformly infiltrate dilute nitric acid (0.5 mol / L, 10 mL) onto a viscose-based pre-oxidized felt (200 g), and perform a heat treatment at 120 °C for 60 min to obtain an acid-washed felt;

[0061] S3. Uniformly infiltrate the organic gel precursor solution (200 g) into the above-mentioned pickled felt. Next, perform an aging treatment. Seal the felt with a sealed bag and place it in an oven at a temperature of 60 °C for 3 days of static placement. Then, perform a solvent replacement by soaking the felt in absolute ethanol (3 L) for 2 days. Next, perform a carbonization treatment on the felt at a carbonization temperature of 1300 °C, a treatment time of 60 min, and an atmosphere of nitrogen. Finally, perform a graphitization treatment on the felt at a carbonization temperature of 2000 °C, a treatment time of 30 min, and an atmosphere of nitrogen to obtain a semi-finished product of graphite felt-carbon aerogel.

[0062] S4. Put the semi-finished product of graphite felt-carbon aerogel into an activation furnace and perform a heat treatment under steam. The steam contains a nitrogen medium (ammonia), with a steam flow rate of 120 m 3 / h and an ammonia flow rate of 60 m 3 / h, at a temperature of 500 °C for 120 min.

[0063] The preparation process of Comparative Example 1 is the same as that of Example 1, with the only difference being that the pre-oxidized felt does not add the organic gel precursor solution and only undergoes carbonization, graphitization, and activation treatments.

[0064] Performance testing

[0065] Detect the performance of Example 1 and Comparative Example 1. The specific detection items are as follows:

[0066] 1. Perform a specific surface area test on Example 1 and Comparative Example 1, and record the obtained data in Table 1.

[0067] Table 1 Specific surface area and average pore diameter of Example 1 and Comparative Example 1

[0068] <![CDATA[Specific surface area (m 2 / g)]]> Average pore diameter (nm) Example 1 3.014 1.914 Comparative Example 1 49.242 4.314

[0069] 2. Use Example 1 and Comparative Example 1 as electrodes to assemble a full vanadium redox flow battery, and detect the discharge capacity at a current density of 80 - 200 mA / cm 2 . The results are as Figure 2 shown.

[0070] It can be seen from the data in Table 1 that the specific surface area and pore diameter of Example 1 are both higher than those of Comparative Example 1, indicating that introducing carbon aerogel into graphite felt can significantly increase its specific surface area, which is beneficial to increasing the contact area between the electrolyte and the electrode. In addition, as Figure 2 shown, the voltage efficiency of Example 1 is significantly higher than that of Comparative Example 1, indicating that the electrode performance of Example 1 is superior to that of Comparative Example 1. Introducing carbon aerogel into the pre-oxidized felt to prepare a carbon-carbon composite material electrode can significantly increase the specific surface area of the electrode, increase the contact area between the electrolyte and the electrode, and thus improve the voltage efficiency of the battery.

[0071] The present application also discloses a carbon-carbon composite material electrode, which is obtained by the above-mentioned method for preparing a carbon-carbon composite material electrode.

[0072] The present application also discloses a vanadium redox flow battery, the electrode of which adopts the above-mentioned carbon-carbon composite material electrode.

[0073] The implementation principle of this embodiment is that introducing carbon aerogel into the pre-oxidized felt to prepare the carbon-carbon composite material electrode can significantly increase the specific surface area of the electrode and the contact area between the electrolyte and the electrode, thereby improving the voltage efficiency of the battery.

[0074] The embodiments of this specific implementation manner are all preferred embodiments of the present application, and do not limit the protection scope of the present application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A method for preparing a carbon-carbon composite electrode, characterized in that: The following steps are included: S1. Mix acetaldehyde and hydroquinone, add deionized water and a catalyst, and stir the obtained mixed solution at 30-90° C. for 0.5-3 h to cause a polymerization reaction to obtain an organogel precursor solution; S2, uniformly infiltrating the pickling liquid on the carbon felt or pre-oxidized felt, and performing heat treatment to obtain the pickled felt; S3, uniformly infiltrating or impregnating the organic gel precursor solution on the acid-washed felt, and then sequentially performing aging, solvent replacement, carbonization and graphitization treatments to obtain a graphite felt-carbon aerogel semi-finished product; S4. Activate the graphite felt-carbon aerogel semi-finished product to obtain a finished carbon-carbon composite electrode.

2. The method for preparing a carbon-carbon composite material electrode according to claim 1, characterized in that: The molar ratio of acetaldehyde to hydroquinone in S1 is 1-3:3-1, the catalyst is sodium hydroxide or anhydrous sodium carbonate, and the mass fraction of the mixed solution is 10-50%.

3. The method for preparing a carbon-carbon composite material electrode according to claim 1, characterized in that: The pickling solution in S2 is one of nitric acid, hydrochloric acid and acetic acid, the concentration of the pickling solution is 0.1-2.0 mol / L, the heat treatment temperature is 80-150°C, and the treatment time is 30-90 min.

4. The method for preparing a carbon-carbon composite material electrode according to claim 1, characterized in that: The mass ratio of the precursor solution infiltrated or impregnated in S3 to the acid-washed felt is 1-5:5-1.

5. The method for preparing a carbon-carbon composite material electrode according to claim 1, characterized in that: The aging temperature in S3 is 50-85° C., the time is 2-72 h, and the solvent for solvent replacement in S3 is acetone or ethanol.

6. The method for preparing a carbon-carbon composite material electrode according to claim 1, characterized in that: In S3, the carbonization treatment temperature is 1000-1600°C, the treatment time is 30-90 minutes, and the atmosphere includes nitrogen or argon. The graphitization treatment temperature is 2000-3000°C, the treatment time is 10-30 minutes, and the atmosphere includes nitrogen or argon.

7. The method for preparing a carbon-carbon composite material electrode according to claim 1, characterized in that: The activation treatment in S4 is heat treatment under water vapor, the water vapor contains one of nitrogen, phosphorus and sulfur or no such medium, the treatment temperature is 300-950°C, and the treatment time is 45-720min.

8. The method for preparing a carbon-carbon composite material electrode according to claim 1, characterized in that: The carbon felt or pre-oxidized felt in S2 is one of viscose-based, PAN-based, asphalt-based, and phenolic-based.

9. A carbon-carbon composite material electrode, characterized in that: The method is obtained by the method for preparing a carbon-carbon composite material electrode as described in any one of claims 1 to 8.

10. An all-vanadium liquid flow battery, characterized in that: The electrode adopts a carbon-carbon composite material electrode as claimed in claim 9.

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