CN115241466A - Modified carbonaceous fibrofelt electrode material for flow battery and preparation method thereof - Google Patents

Modified carbonaceous fibrofelt electrode material for flow battery and preparation method thereof Download PDF

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CN115241466A
CN115241466A CN202210809023.1A CN202210809023A CN115241466A CN 115241466 A CN115241466 A CN 115241466A CN 202210809023 A CN202210809023 A CN 202210809023A CN 115241466 A CN115241466 A CN 115241466A
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carbonaceous
dispersion liquid
fiber felt
electrode material
fibrofelt
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丁鹏
杨晓慧
徐同乐
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University of Shanghai for Science and Technology
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/8605—Porous electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/96—Carbon-based electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/18—Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
    • H01M8/184—Regeneration by electrochemical means
    • H01M8/188—Regeneration by electrochemical means by recharging of redox couples containing fluids; Redox flow type batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

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Abstract

The invention discloses a modified carbonaceous fibrofelt electrode material for a flow battery and a preparation method thereof, wherein the method comprises the following steps: s1: preparing a carbonaceous fiber felt: carbonizing the precursor at low temperature under the action of a catalyst to obtain a carbonaceous fiber felt; s2: preparing a modified carbonaceous fiber felt; s3: and (3) carbonizing at high temperature to prepare the electrode material. The surface of the carbonaceous fibrofelt electrode material prepared by the invention is connected with a modifier in a pi-pi conjugate form, and the carbonaceous fibrofelt is modified and modified, so that the specific surface area of the carbonaceous fibrofelt is enlarged, the carbonaceous fibrofelt electrode material has a unique microstructure, the surface resistivity of the material is obviously reduced, stable electroactive sites are increased to accelerate the electron transfer speed, and the overall electrochemical performance of the carbonaceous fibrofelt as a redox flow battery electrode material can be effectively improved.

Description

Modified carbonaceous fibrofelt electrode material for flow battery and preparation method thereof
Technical Field
The invention relates to the technical field of flow battery materials, in particular to a modified carbonaceous fibrofelt electrode material for a flow battery and a preparation method thereof.
Background
With the increasingly exhaustion of fossil energy sources relied on by social and economic development, environmental deterioration caused by the traditional energy utilization mode is more and more serious, fossil energy is saved, and the large-scale research and development of renewable energy sources are urgent. The random and intermittent unsteady characteristics of renewable energy sources such as wind energy and solar energy during power generation output cannot meet the dispatching requirement of power grid load and power generation balance, and the enhancement of the stability of the renewable energy sources is an important premise for large-scale wind energy and solar energy effective power generation. Flow batteries have received much attention as a new type of energy storage system that provides desirable electrical energy storage characteristics: long cycle life, flexible design, high safety, low maintenance cost, etc. The flow battery can change intermittent, unstable and uncontrollable renewable energy into stable, controllable and high-quality energy with high electric energy quality. Since the positive and negative half-cell reactions of the cell occur at the inert electrode, the electrochemical activity of the electrode material is critical to the energy conversion of the flow battery.
The carbon fiber felt has super flexibility, excellent conductivity and high mechanical strength, so that the carbon fiber felt is widely applied to the fields of electrochemistry and composite materials, and has a wide application prospect in the aspect of flow batteries as a common electrode material. However, since the specific surface area of the carbon fiber felt is small, in order to solve the problem, in the prior art, chinese patent application with the patent application number of 201810342586.8 discloses a preparation method of a graphite felt for a flow battery, wherein a pre-oxidized felt raw material is adopted, so that ablation caused by over-high local temperature is avoided, and the production cost is reduced; the pre-oxidized felt with a specific specification is selected, so that the quality of a finished product is improved; the finished product obtained by the method has high electrode porosity, large specific surface area and stable electrode quality. However, the method needs pre-oxidation of the filament mat in advance, although the specific surface area is enlarged, the effective microstructure cannot be formed on the surface of the material, and sufficient active sites are lacked, so that the surface resistivity of the material is relatively large, and the high requirements of the flow battery cannot be met well in practical application.
Disclosure of Invention
In view of the above disadvantages, the present invention aims to provide a modified carbonaceous fibrofelt electrode material for a flow battery and a preparation method thereof, wherein a formula and a process are reasonably designed, a precursor is carbonized at a low temperature in the presence of a catalyst to obtain a carbonaceous fibrofelt, and the carbonaceous fibrofelt electrode material with a unique microstructure is formed on the surface of the material after modification.
The invention also aims to provide the modified carbonaceous fiber felt electrode material prepared by the preparation method, and the microstructure on the surface of the material greatly increases active sites, accelerates electron transfer rate, remarkably reduces surface resistivity, enables the material to have high conductivity and excellent electrochemical performance, and can better meet the high requirements of electrode materials of flow batteries.
The technical scheme adopted by the invention to achieve the aim is as follows:
a preparation method of a modified carbonaceous fibrofelt electrode material for a flow battery is characterized in that the modified carbonaceous fibrofelt electrode material is obtained by adopting a three-step impregnation-high temperature carbonization method, and comprises the following steps:
s1: preparing a carbonaceous fiber felt: carbonizing the precursor at low temperature under the action of a catalyst to obtain a carbonaceous fiber felt;
s2: preparing a modified carbonaceous fiber felt: respectively preparing modifier dispersion liquid 1, dispersion liquid 2 and KOH solution, firstly soaking the carbonaceous fiber felt in the dispersion liquid 1, then slowly adding the dispersion liquid 2, taking out and drying at 120 ℃ for 5 hours, finally soaking in the KOH solution, taking out and drying at 120 ℃ for 5 hours;
wherein the dispersion liquid 1 is a solution prepared from one of dextrin, polyvinyl alcohol, glass micropowder and PDA, and the concentration of the solution is 3 mg/ml-10 mg/ml;
the dispersion liquid 2 is a solution prepared from one of redox graphene, graphene oxide, expandable graphite and activated carbon fiber, and the concentration of the dispersion liquid is 10 mg/ml-18 mg/ml;
s3: preparing an electrode material by high-temperature carbonization: under the protection of argon atmosphere, carbonizing at high temperature to obtain the modified carbonaceous fiber felt electrode material which is formed by connecting modifiers in a pi-pi conjugate mode and has multiple active point positions and a unique microstructure on the surface of the carbonaceous fiber felt.
The precursor in the step S1 is one of asphalt, lignin, ultra-high molecular weight polyethylene, polyacrylonitrile and cellulose; the catalyst is one of zinc oxide, copper oxide, nitrogen-doped carbon nanotube, cerium oxide and cobaltosic oxide.
The catalyst in the step S1 accounts for 2-10% of the mass of the precursor, and the catalyst and the precursor are sequentially added into one of solutions of N, N-dimethylformamide, thionyl chloride, ethylene carbonate or dimethylacetamide and soaked for 2-3 h.
And drying the impregnated precursor, putting the dried precursor into a tubular furnace, and burning the dried precursor for 2 hours at the temperature of between 400 and 600 ℃ to obtain the carbonaceous fiber felt.
In the step S1, the catalyst accounts for 5-7% of the mass of the precursor; the concentration of the dispersion liquid 1 is 5 mg/ml-7 mg/ml; the concentration of the dispersion 2 is 12mg/ml to 16mg/ml.
In the step S2, the concentration of the KOH solution is 2mg/ml to 10mg/ml, the carbonaceous fiber felt is firstly soaked in the dispersion liquid 1 for 20min, then the dispersion liquid 2 is added for soaking for 20min to 40min, and the carbon fiber felt is soaked in the KOH solution for 15min to 30min after being dried.
The concentration of the KOH solution is 3mg/ml to 7mg/ml.
In the step S3, the modified carbonaceous fiber felt is carbonized in a tubular furnace at the high temperature of 1100-1300 ℃ for 2-3 h.
The surface of the modified carbonaceous fibrofelt electrode material for the flow battery prepared by the method has a unique microstructure which is formed by connecting modifiers in a pi-pi conjugate mode and has multiple active point positions.
The modified carbonaceous fibrofelt electrode material for the flow battery and the preparation method thereof have the beneficial effects that:
1. according to the invention, the carbonaceous fibrofelt electrode material is obtained by low-temperature carbonization in the presence of a catalyst, the carbonaceous fibrofelt is modified and matched with a specific preparation process, so that a microstructure with fiber drawing textures, concave-convex point positions, local surface damage, local adhesion among multiple fibers and large pore structure is formed on the surface of the carbonaceous fibrofelt electrode material, and the modifier is connected in a pi-pi conjugate form and has multiple active point positions, so that the specific surface area is enlarged, stable electroactive point positions are increased to accelerate the electron transfer speed, and the overall electrochemical performance of the carbonaceous fibrofelt as the electrode material of the flow cell can be effectively improved.
2. The stability of the modifier on the carbonaceous fiber felt is improved by using substances such as dextrin, polyvinyl alcohol, glass micropowder, PDA and the like, and the modifier is prevented from falling off in the current circulation process to influence the performance of the battery.
3. The method further improves the porosity of the carbonaceous fiber felt by using the KOH solution, improves the specific surface roughness of the carbonaceous fiber felt, and enlarges the specific surface area of the carbonaceous fiber felt;
4. according to the preparation method of the high-conductivity modified carbonaceous fibrofelt electrode material for the flow battery, the carbon nano material is used for modifying the carbonaceous fibrofelt, so that the specific surface area of the carbonaceous fibrofelt is enlarged, the active sites are increased, the electron transfer rate is increased, and the electrochemistry of applying the carbonaceous fibrofelt as the electrode material to the flow battery is improved.
5. According to the invention, the surface of the fiber is modified by the carbon nano materials such as graphene oxide, reduced graphene oxide and graphene and combining with a preparation process, so that a unique microstructure is formed on the surface of the material fiber and among fibers, and the material fiber has excellent conductivity, high electron transfer rate and high specific surface area; namely, the unique combination of the carbon material and the carbonaceous fiber felt can remarkably improve the defect of exposure of the carbonaceous fiber felt as an electrode material, thereby preparing the ideal electrode material with high conductivity and multiple functions for the flow battery.
6. The preparation method provided by the invention has the advantages of few steps and simple operation, shortens the time cost of the preparation process, and is easy for industrialization so as to meet the market demand.
The foregoing is a summary of the technical solutions of the present invention, and the present invention is further described below with reference to specific embodiments.
Drawings
Fig. 1 is a surface SEM image of a modified carbonaceous fibrous mat material prepared in example 1 of the present invention.
Detailed Description
To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined purposes, the following detailed description of the embodiments of the present invention is provided with the accompanying drawings and the preferred embodiments.
The preparation method of the modified carbonaceous fiber felt electrode material for the flow battery provided by the embodiment of the invention comprises the following steps:
s1: preparing a carbonaceous fiber felt: the method comprises the following steps of carbonizing a precursor at a low temperature in the presence of a catalyst to obtain a carbonaceous fiber felt, specifically:
firstly, simultaneously dipping a precursor and a catalyst in any solution of N, N-dimethylformamide, thionyl chloride, ethylene carbonate or dimethylacetamide for 2-3 h. Ultrasonic agitation may also be selected to promote mixing of the substances. Taking out the impregnated precursor, drying for later use, and putting the dried precursor into a tubular furnace, and firing for 2 hours at 400-600 ℃ to prepare the carbonaceous fiber felt.
The precursor can be selected from one of asphalt, lignin, ultra-high molecular weight polyethylene, polyacrylonitrile and cellulose, and the catalyst can be selected from one of zinc oxide, copper oxide, nitrogen-doped carbon nanotube, cerium oxide and cobaltosic oxide. The catalyst accounts for 2-10% of the mass of the precursor, preferably 5-7%, and the catalyst in the proportion has the best effect, so that the catalyst can play a good catalytic effect to promote the low-temperature carbonization of the precursor, and cannot cause the waste of the catalyst.
S2: preparing a modified carbon fiber felt by a three-step impregnation method: respectively preparing modifier dispersion liquid 1, dispersion liquid 2 and KOH solution, firstly soaking a carbonaceous fiber felt obtained after low-temperature carbonization in the dispersion liquid 1 for 20min to enable the dispersion liquid 1 to soak the carbonaceous fiber felt, creating conditions for the subsequent dispersion liquid 2 to be adhered to the carbonaceous fiber felt, then slowly adding the dispersion liquid 2, controlling the soaking time to be 20-40 min, taking out the soaked carbonaceous fiber felt, drying the carbonaceous fiber felt at 120 ℃ for 5h, finally soaking in the KOH solution for 15-30 min, taking out and drying at 120 ℃ for 5h.
The dispersion liquid 1 can be prepared from one of dextrin, polyvinyl alcohol, glass micropowder and PDA, and the dispersion liquid 2 can be prepared from one of reduced graphene oxide, graphene oxide, expandable graphite and activated carbon fiber.
The ethanol solution is used for dispersing the substances, the concentration of the dispersion liquid 1 is controlled within the range of 3 mg/ml-10 mg/ml, preferably 5 mg/ml-7 mg/ml, and the dispersion liquid 1 within the concentration range can well increase the adhesiveness of the carbonaceous fiber felt.
The concentration of the dispersion liquid 2 is controlled within the range of 10 mg/ml-18 mg/ml, preferably 12 mg/ml-16 mg/ml, and substances in the dispersion liquid 2 can adhere to the carbonaceous fiber felt to enlarge the specific surface area of the carbonaceous fiber felt and improve the conductivity, and the substances cannot be excessively accumulated in gaps of the carbonaceous fiber felt to reduce the electron transfer rate.
The KOH solution concentration is controlled to be 2 mg/ml-10 mg/ml, preferably 3 mg/ml-7 mg/ml, and the KOH solution in the concentration range can improve the porosity of the carbonaceous fiber felt and improve the surface roughness of the carbonaceous fiber felt without excessively corroding and damaging the structure of the carbonaceous fiber felt.
S3: preparing a modified carbonaceous fibrofelt electrode material by a high-temperature carbonization method: and carbonizing the dried modified carbonaceous fibrofelt at high temperature under the protection of argon atmosphere to obtain the modified carbonaceous fibrofelt electrode material.
The modified carbon fiber felt is carbonized at high temperature in a tubular furnace, the temperature is controlled to be 1100-1300 ℃, and the burning time is controlled to be 2-3 h.
The modified carbonaceous fiber felt for the flow battery, which is obtained by the preparation method, is used as an electrode material of the flow battery, has a unique modifier, is formed by connecting II-II conjugation, has a micro surface structure with multiple active points, and has excellent electrochemical properties such as high conductivity and cycling stability.
Example 1
Referring to fig. 1, the embodiment of the invention provides a modified carbonaceous fiber felt electrode material for a flow battery and a preparation method thereof, which are specifically applied to the basis of the foregoing embodiment, and the preparation method thereof includes the following steps:
s1: preparing a carbonaceous fiber felt: adding 2g of ultra-high molecular weight polyethylene and 100mg of zinc oxide accounting for 5% of the weight of the ultra-high molecular weight polyethylene into 20ml of thionyl chloride for soaking for 2 hours, taking out the soaked ultra-high molecular weight polyethylene, drying the ultra-high molecular weight polyethylene at 120 ℃ for 5 hours, and putting the polyethylene into a tubular furnace to be burned for 2 hours at 400 ℃ to obtain the carbonaceous fibrofelt.
S2: respectively preparing modifier dispersion liquid 1 and dispersion liquid 2, and dispersing 175mg of dextrin in 25ml of absolute ethyl alcohol, namely, the concentration of the dispersion liquid 1 is 7mg/ml. 350mg of graphene oxide is taken and dispersed in 25ml of absolute ethyl alcohol, namely the concentration of the dispersion liquid 2 is 14mg/ml.
Firstly, soaking a carbonaceous fiber felt in dextrin dispersion liquid for 20min, and then slowly adding graphene oxide dispersion liquid, wherein the soaking time is 40min. Taking out and drying at 120 ℃ for 5h.
The dried modified carbonaceous fiber mat was immersed in 5mg/ml KOH solution for 25min and dried again at 120 ℃ for 5h.
S3: and under the protection of argon atmosphere, burning the dried carbonaceous fiber felt in a tubular furnace at 1300 ℃ for 2h to obtain the modified carbonaceous fiber felt electrode material.
Compared with the unmodified carbonaceous fiber felt, the carbonaceous fiber felt obtained in the embodiment has the advantages that the electrochemical performance of the battery is obviously improved, and the resistivity of the modified carbonaceous fiber felt is only 9.8 multiplied by 10 -4 Omega cm, and the battery capacity retention rate is up to 87% after the battery is assembled in the flow battery and cycled for 100 times.
Example 2
The modified carbonaceous fiber felt electrode material for the flow battery and the preparation method thereof provided by the embodiment of the invention are specifically applied to the basis of the embodiment 1, and the preparation method comprises the following steps:
s1: preparing a carbonaceous fiber felt: adding 2g of asphalt and 60mg of copper oxide accounting for 3% of the mass of the asphalt into 20ml of dimethylacetamide for dipping for 2h, taking out the dipped asphalt, drying the dipped asphalt at 120 ℃ for 5h, and putting the asphalt into a tubular furnace to burn for 2h at 400 ℃ to obtain the carbonaceous fiber felt.
S2: modifier dispersion 1 and dispersion 2 were prepared separately, and 125mg of PDA was dispersed in 25ml of absolute ethanol, i.e., the concentration of dispersion 1 was 5mg/ml. 300mg of graphene is taken and dispersed in 25ml of absolute ethyl alcohol, namely the concentration of the dispersion liquid 2 is 12mg/ml.
Firstly, soaking a carbon fiber felt in a PDA dispersion liquid for 20min, and then slowly adding a graphene dispersion liquid, wherein the soaking time is 30min. The carbonaceous fiber mat was taken out and dried at 120 ℃ for 5 hours.
The dried modified carbonaceous fiber mat was immersed in 3mg/ml KOH solution for 20min and dried again at 120 ℃ for 5h.
S3: and under the protection of argon atmosphere, firing the dried carbonaceous fiber felt in a tubular furnace at 1200 ℃ for 2.5h to obtain the modified carbonaceous fiber felt electrode material.
Example 3
The modified carbonaceous fiber felt electrode material for the flow battery and the preparation method thereof provided by the embodiment of the invention are specifically applied to the basis of the embodiment 1-2, and the preparation method comprises the following steps:
s1: preparing a carbonaceous fiber felt: 2g of polyacrylonitrile and 40mg of nitrogen-doped carbon nano tubes accounting for 2 percent of the mass of the polyacrylonitrile are added into 20ml of N, N-dimethylformamide to be soaked for 2 hours, the soaked polyacrylonitrile is taken out to be dried for 5 hours at the temperature of 120 ℃, and the polyacrylonitrile is placed into a tube furnace to be burned for 2 hours at the temperature of 400 ℃ to obtain a carbon fiber felt.
S2: modifier dispersion 1 and dispersion 2 were prepared separately, and 75mg of polyvinyl alcohol was dispersed in 25ml of absolute ethanol, i.e., the concentration of dispersion 1 was 3mg/ml. And (3) taking 250mg of reduced graphene oxide to disperse in 25ml of absolute ethyl alcohol, wherein the concentration of the dispersion liquid 2 is 10mg/ml.
Firstly, soaking a carbonaceous fiber felt in a polyvinyl alcohol dispersion liquid for 20min, and then slowly adding a reduced graphene oxide dispersion liquid, wherein the soaking time is 20min. And taking out the impregnated carbonaceous fiber felt and drying the impregnated carbonaceous fiber felt at 120 ℃ for 5 hours.
The dried modified carbonaceous fiber mat was immersed in 2mg/ml KOH solution for 15min and dried again at 120 ℃ for 5h.
S3: and under the protection of argon atmosphere, burning the dried carbonaceous fiber felt in a tubular furnace at 1100 ℃ for 3h to obtain the modified carbonaceous fiber felt electrode material.
Example 4
The embodiment of the invention provides a modified carbonaceous fiber felt electrode material for a flow battery and a preparation method thereof, which are particularly applied to the basis of the embodiment, and the preparation method comprises the following steps:
s1: preparing a carbonaceous fiber felt: adding 2g of ultra-high molecular weight polyethylene and 140mg of cerium oxide accounting for 7% of the mass of the ultra-high molecular weight polyethylene into 20ml of ethylene carbonate for soaking for 2 hours, taking out the soaked ultra-high molecular weight polyethylene, drying for 5 hours at 120 ℃, and putting the ultra-high molecular weight polyethylene into a tubular furnace to burn for 2 hours at 400 ℃ to obtain the carbonaceous fibrofelt.
S2: respectively preparing modifier dispersion liquid 1 and dispersion liquid 2, and taking 225mg of glass micropowder to disperse in 25ml of absolute ethyl alcohol, namely the concentration of the dispersion liquid 1 is 9mg/ml. 400mg of expandable graphite is taken and dispersed in 25ml of absolute ethyl alcohol, namely, the concentration of the dispersion liquid 2 is 16mg/ml.
Firstly, soaking a carbon fiber felt in a glass micro powder dispersion liquid for 20min, then slowly adding an expandable graphite dispersion liquid, soaking for 40min, taking out and drying for 5h at 120 ℃.
The dried modified carbonaceous fiber mat was soaked in 7mg/ml KOH solution for 20min and dried again at 120 ℃ for 5h.
S3: and under the protection of argon atmosphere, burning the dried carbonaceous fiber felt in a tubular furnace at 1100 ℃ for 3h to obtain the modified carbonaceous fiber felt electrode material.
Example 5
The modified carbonaceous fiber felt electrode material for the flow battery and the preparation method thereof provided by the embodiment of the invention are specifically applied to the basis of the embodiments 1 to 4, and the preparation method comprises the following steps:
s1: preparing a carbonaceous fiber felt: adding 2g of polyacrylonitrile and 180mg of cobaltosic oxide accounting for 9% of the mass of the polyacrylonitrile into 20ml of thionyl chloride for soaking for 2 hours, taking out the soaked polyacrylonitrile, drying the polyacrylonitrile at 120 ℃ for 5 hours, and putting the polyacrylonitrile in a tubular furnace to be burned for 2 hours at 400 ℃ to obtain the carbonaceous fiber felt.
S2: modifier dispersion 1 and dispersion 2 were prepared separately, and 125mg of polyvinyl alcohol was dispersed in 25ml of absolute ethanol, i.e., the concentration of dispersion 1 was 10mg/ml. 450mg of activated carbon fiber is taken and dispersed in 25ml of absolute ethyl alcohol, namely, the concentration of the dispersion liquid 2 is 18mg/ml.
Firstly, soaking a carbon fiber felt in polyvinyl alcohol dispersion liquid for 10min, and then slowly adding activated carbon fiber dispersion liquid, wherein the soaking time is 30min. Taking out and drying at 120 ℃ for 5h.
Soaking the dried modified carbon fiber felt in 9mg/ml KOH solution for 30min, and drying at 120 deg.C for 5h.
S3: and under the protection of argon atmosphere, firing the dried carbonaceous fiber felt in a tubular furnace at 1200 ℃ for 2.5h to obtain the modified carbonaceous fiber felt electrode material.
Example 6
The modified carbonaceous fiber felt electrode material for the flow battery and the preparation method thereof provided by the embodiment of the invention are specifically applied on the basis of the embodiments 1-5, and the preparation method comprises the following steps:
s1: preparing a carbonaceous fiber felt: 2g of asphalt and 200mg of nitrogen-doped carbon nano-tubes accounting for 10 percent of the asphalt are added into 20ml of N, N-dimethylformamide for impregnation for 2h, the impregnated asphalt is taken out and dried for 7h at the temperature of 120 ℃, and the mixture is placed into a tube furnace to burn a carbon fiber felt for 2h at the temperature of 400 ℃.
S2: modifier dispersion 1 and dispersion 2 were prepared separately, and 125mg of polyvinyl alcohol was dispersed in 25ml of absolute ethanol, i.e. the concentration of dispersion 1 was 5mg/ml. 300mg of reduced graphene oxide is taken and dispersed in 25ml of ethanol, namely the concentration of the dispersion liquid 2 is 12mg/ml.
Firstly, soaking a carbonaceous fiber felt in a polyvinyl alcohol dispersion liquid for 20min, and then slowly adding a reduced graphene oxide dispersion liquid, wherein the soaking time is 30min. The carbonaceous fiber felt is taken out and dried for 5 hours at the temperature of 120 ℃.
The dried modified carbonaceous fiber felt is soaked in 10mg/ml KOH solution for 30min and dried again at 120 ℃ for 5h.
S3: and under the protection of argon atmosphere, burning the dried carbonaceous fiber felt in a tubular furnace at 1300 ℃ for 2h to obtain the modified carbonaceous fiber felt electrode material.
The performance of the modified carbonaceous fiber felt electrode materials obtained in examples 1 to 6 was measured, and the results are shown in table 1.
Table 1: performance test results of modified carbonaceous fiber mats
Resistivity (omega cm) Conservation rate of flow battery capacity (100 circles)
Example 1 9.8×10 -4 87％
Example 2 1.1×10 -3 84％
Example 3 3.1×10 -3 73％
Example 4 1.9×10 -3 79％
Example 5 2.8×10 -3 75％
Example 6 2.6×10 -3 76％
As can be seen from table 1, the modified carbonaceous fiber felt electrode materials prepared in embodiments 1 to 6 of the present invention all have low surface resistivity, and have excellent electrochemical properties such as high conductivity and cycling stability.
The embodiments described above are only a part of the embodiments of the present invention, and not all of them. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Claims (10)

1. A preparation method of a modified carbonaceous fibrofelt electrode material for a flow battery is characterized in that the modified carbonaceous fibrofelt electrode material is obtained by adopting a three-step impregnation-high temperature carbonization method, and comprises the following steps:
s1: preparing a carbonaceous fiber felt: carbonizing the precursor at low temperature under the action of a catalyst to obtain a carbonaceous fiber felt;
s2: preparing a modified carbonaceous fiber felt: respectively preparing a modifier dispersion liquid 1, a dispersion liquid 2 and a KOH solution, firstly soaking the carbonaceous fiber felt in the dispersion liquid 1, then slowly adding the dispersion liquid 2, taking out and drying at 120 ℃ for 5 hours, finally soaking in the KOH solution, taking out and drying at 120 ℃ for 5 hours;
wherein the dispersion liquid 1 is a solution prepared from one of dextrin, polyvinyl alcohol, glass micropowder and PDA, and the concentration of the dispersion liquid is 3 mg/ml-10 mg/ml;
the dispersion liquid 2 is a solution prepared from one of redox graphene, graphene oxide, expandable graphite and activated carbon fiber, and the concentration of the dispersion liquid is 10 mg/ml-18 mg/ml;
s3: preparing an electrode material by high-temperature carbonization: and carbonizing at high temperature under the protection of argon atmosphere to obtain the modified carbonaceous fibrofelt electrode material which is formed by connecting modifiers in a pi-pi conjugated form on the surface and has a unique microstructure with multiple active points.
2. The preparation method according to claim 1, wherein the precursor in step S1 is one of pitch, lignin, ultra-high molecular weight polyethylene, polyacrylonitrile and cellulose.
3. The method according to claim 1, wherein the catalyst in step S1 is one of zinc oxide, copper oxide, nitrogen-doped carbon nanotubes, cerium oxide, and tricobalt tetraoxide.
4. The preparation method according to claim 1, wherein the catalyst accounts for 2-10% of the mass of the precursor in the step S1, and the catalyst and the precursor are sequentially added into a solution of one of N, N-dimethylformamide, thionyl chloride, ethylene carbonate or dimethylacetamide, and are immersed for 2-3 h.
5. And drying the impregnated precursor, and then putting the precursor into a tubular furnace to be burned for 2 hours at the temperature of 400-600 ℃ to obtain the carbonaceous fiber felt.
6. The preparation method according to any one of claims 1 to 5, wherein in the step S1, the catalyst accounts for 5 to 7 percent of the mass of the precursor; the concentration of the dispersion liquid 1 is 5 mg/ml-7 mg/ml; the concentration of the dispersion liquid 2 is 12 mg/ml-16 mg/ml.
7. The preparation method according to claim 1, wherein in the step S2, the concentration of the KOH solution is 2mg/ml to 10mg/ml, the carbonaceous fiber mat is firstly immersed in the dispersion liquid 1 for 20min, then the dispersion liquid 2 is immersed for 20min to 40min, and after drying, the carbonaceous fiber mat is immersed in the KOH solution for 15min to 30min.
8. The method according to claim 7, wherein the KOH solution has a concentration of 3 to 7mg/ml.
9. The preparation method according to claim 1, wherein in the step S3, the modified carbonaceous fiber felt is carbonized at high temperature in a tubular furnace at the temperature of 1100 to 1300 ℃ and the burning time is 2 to 3h.
10. A modified carbonaceous fiber mat for use in flow batteries prepared according to any of claims 1 to 9, having a unique microstructure of multiple active sites on its surface consisting of the attachment of modifiers in the pi-pi conjugate form.
CN202210809023.1A 2022-07-11 2022-07-11 Modified carbonaceous fibrofelt electrode material for flow battery and preparation method thereof Pending CN115241466A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116231024A (en) * 2023-04-11 2023-06-06 西安西域美唐电竞科技有限公司 Energy storage method of all-vanadium liquid flow energy storage device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116231024A (en) * 2023-04-11 2023-06-06 西安西域美唐电竞科技有限公司 Energy storage method of all-vanadium liquid flow energy storage device
CN116231024B (en) * 2023-04-11 2023-11-10 西安西域美唐电竞科技有限公司 Energy storage method of all-vanadium liquid flow energy storage device

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