Catalyst material for zinc-bromine flow battery and preparation method of catalyst material

Abstract

The invention discloses a catalyst material for a zinc-bromine flow battery and a preparation method of the catalyst material, and belongs to the technical field of zinc-bromine batteries. The catalyst material for the zinc-bromine flow battery comprises polyacrylonitrile and nitrogen-doped carbon spheres, wherein the nitrogen-doped carbon spheres are embedded and hung on the polyacrylonitrile. The preparation method comprises the following steps: dissolving glucose in deionized water, uniformly stirring, carrying out hydrothermal reaction, washing, drying and calcining to obtain nitrogen-doped carbon spheres; the preparation method comprises the following steps: dissolving polyacrylonitrile in N, N-dimethylformamide to obtain a uniform suspension; and adding the nitrogen-doped carbon spheres into the suspension, uniformly stirring to form an electrospinning solution, and carrying out electrostatic spinning and drying to obtain the catalyst material for the zinc-bromine flow battery. The carbon spheres are prepared by adopting a solvothermal method, the nitrogen-doped carbon spheres and an organic solution of polyacrylonitrile are mixed, and the polyacrylonitrile fiber loaded nitrogen-doped carbon sphere composite catalytic material prepared by adopting an electrostatic spinning process is stable in structure, simple in preparation process, excellent in catalytic performance and suitable for industrial large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field of zinc-bromine batteries, and in particular relates to a catalyst material for zinc-bromine liquid flow batteries and a preparation method thereof. Background Art

[0002] With the acceleration of the global industrialization process and the rapid development of science and technology, the importance of electricity as the most basic and indispensable secondary energy in modern society has become increasingly prominent. From daily household electricity consumption to industrial production, from transportation to information technology, electricity supports all aspects of human society. Especially in the context of the growing use of renewable energy (such as solar energy and wind energy), the stable supply and efficient storage of electricity have become key links in ensuring energy security and promoting sustainable development. Therefore, as an important bridge connecting energy production and consumption, the research and development and application of energy storage technology are particularly important and urgent. The energy storage system can not only balance the supply and demand of the power grid and improve energy utilization efficiency, but also provide solid support for the widespread application of renewable energy. Among the many energy storage technologies, flow batteries are regarded as an important development direction in the field of large-scale energy storage in the future due to their unique advantages, such as long life, flexible adjustment, and environmental friendliness.

[0003] Liquid flow battery technology, especially zinc-bromine liquid flow battery, has become a hot topic of current research due to its unique electrolyte solution flow design, which can realize the chemical storage and release of electrical energy, and has the advantages of deep charge and discharge capability, flexible modular regulation, and no geographical restrictions. The working principle of zinc-bromine liquid flow battery is based on the reversible redox reaction between zinc ions and bromide ions between positive and negative electrodes. The positive electrode usually uses a bromide solution, and the negative electrode is zinc metal or zinc ion solution. The biggest attraction of this system is that its raw materials, zinc and bromine, are widely present in nature, inexpensive and easy to obtain, thus reducing the production cost of the battery. In addition, zinc-bromine liquid flow battery has a high energy density, which means that more electrical energy can be stored at the same volume or weight, which is crucial to improving the economy and practicality of energy storage systems. Therefore, zinc-bromine liquid flow battery shows great potential and market value in large-scale energy storage applications.

[0004] Although zinc-bromine flow batteries have many advantages, they still face some key technical difficulties in practical applications, especially in terms of performance at high current density. When the battery operates at a higher current density, the electrode polarization phenomenon becomes particularly serious. Electrode polarization refers to the phenomenon that the electrode potential deviates from its equilibrium potential due to the limitation of electrode reaction kinetics, which not only reduces the charge and discharge efficiency of the battery, but also causes a large amount of energy loss, seriously affecting the overall performance and economy of the battery. In addition, electrode polarization may also accelerate the corrosion of electrode materials and the consumption of active substances in the electrolyte, further shortening the service life of the battery. Therefore, how to effectively inhibit electrode polarization and improve the energy conversion efficiency and cycle stability of zinc-bromine flow batteries at high current density has become a key issue that needs to be solved urgently. The development of electrode materials with high catalytic activity, good stability and corrosion resistance is one of the effective ways to alleviate this problem, and it is also an important direction to promote the commercialization of zinc-bromine flow battery technology. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a catalyst material for zinc-bromine flow batteries and a preparation method thereof, so as to solve the technical problems of low electrocatalytic efficiency of zinc-bromine flow batteries at high current density and energy loss easily caused by electrode polarization phenomenon.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The invention discloses a catalyst material for zinc-bromine liquid flow battery, comprising nitrogen-doped carbon balls and polyacrylonitrile, wherein the polyacrylonitrile is in fiber shape and the nitrogen-doped carbon balls are embedded in the polyacrylonitrile.

[0007] Preferably, the mass ratio of nitrogen-doped carbon balls to polyacrylonitrile is (30%~35%): (65%~70%).

[0008] The present invention also discloses a method for preparing the catalyst material for zinc-bromine flow battery, comprising the following steps: 1) Dissolve glucose in deionized water, stir evenly, perform hydrothermal reaction, wash, dry and calcine to obtain nitrogen-doped carbon balls; 2) dissolving polyacrylonitrile in N,N-dimethylformamide to obtain a uniform suspension; 3) Adding the nitrogen-doped carbon balls obtained in step 1) to the suspension obtained in step 2), stirring evenly to form an electrospinning solution, and obtaining a catalyst material for a zinc-bromine flow battery after electrospinning and drying.

[0009] Preferably, in step 1), the dosage ratio of glucose to deionized water is 1 g: (10-15) mL.

[0010] Preferably, in step 1), the conditions of the hydrothermal reaction are: 160-200° C. for 6-12 h.

[0011] Preferably, in step 1), the drying temperature is 50-80° C. and the drying time is 12-18 hours.

[0012] Preferably, in step 1), the calcination conditions are: in a nitrogen atmosphere, heating to 800-1200° C. at a heating rate of 5-10° C. / min, and keeping warm for 2-6 hours; the flow rate of nitrogen is 20-60 mL / min.

[0013] Preferably, in step 2), the usage ratio of polyacrylonitrile and N,N-dimethylformamide is (40-80) g:1L.

[0014] Preferably, in step 3), the amount ratio of nitrogen-doped carbon balls to N,N-dimethylformamide is (20-40) g:1L.

[0015] Preferably, in step 3), the electrospinning conditions include: the spinning voltage is 15-18 kV, the syringe injection rate is 0.8-1.2 mL·h -1 The receiving distance of the roller to collect the electrospinning liquid is 10~20cm; the vacuum drying temperature is 50~80℃, and the vacuum drying time is 12~18h.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a catalyst material for zinc-bromine liquid flow battery, comprising nitrogen-doped carbon balls and polyacrylonitrile, wherein the polyacrylonitrile is in a fibrous form and the nitrogen-doped carbon balls are embedded in the polyacrylonitrile. The excellent catalytic performance of the nitrogen-doped carbon balls and the cross-linked structure of the polyacrylonitrile are combined to significantly improve the catalytic efficiency and conductivity of the zinc-bromine liquid flow battery. The nitrogen-doped carbon balls are used as the active part of the catalyst, and the nitrogen atoms on the surface can serve as active sites for the catalytic reaction, thereby promoting the electrochemical reaction in the zinc-bromine liquid flow battery. The nitrogen-doped carbon balls are embedded in the polyacrylonitrile fibers, so that the catalyst material has a larger specific surface area, thereby providing more catalytic active sites, which helps to form a stable catalytic structure, so that the catalyst material has a unique three-dimensional structure, which is conducive to the penetration of the electrolyte and the transmission of ions, thereby improving the reaction rate and efficiency of the battery. It can also effectively prevent the agglomeration and growth of the catalyst particles, keep the active sites of the catalyst evenly distributed, and further improve the catalytic performance. The polyacrylonitrile fiber itself has a certain conductivity, and as a supporting structure of the catalyst material, it can form a continuous conductive network. The combination of nitrogen-doped carbon balls and polyacrylonitrile fibers makes the catalyst material as a whole have better conductivity, which is beneficial to the transmission of electrons in the catalyst material, thereby improving the stability and durability of the catalyst, further improving the catalytic efficiency, improving conductivity and reducing costs.

[0017] Furthermore, by optimizing the mass ratio of nitrogen-doped carbon spheres to polyacrylonitrile, the catalytic performance and conductivity can be further balanced to achieve the best catalytic effect, which helps to ensure sufficient catalytic sites while also providing a good electron transfer path.

[0018] The invention discloses a method for preparing the catalyst material for zinc-bromine flow battery. The method is simple and feasible, and can prepare high-performance zinc-bromine flow battery catalyst material at low cost. Glucose is used as a carbon source and deionized water is used as a solvent. Both are common and cheap materials, which are easy to obtain, and the preparation cost of the catalyst material is reduced. Nitrogen-doped carbon balls can be prepared relatively simply through the steps of hydrothermal reaction, washing, drying and calcination. The process parameters of these steps are relatively easy to control, which is conducive to the large-scale production of catalyst materials. When glucose is carbonized at high temperature, nitrogen atoms can be doped into the carbon structure to form nitrogen-doped carbon balls. The doping of nitrogen atoms can change the electronic structure of the carbon material, increase its catalytic active sites, and thus improve the catalytic performance. N,N-dimethylformamide (DMF) is a good organic solvent that can dissolve polyacrylonitrile to form a uniform suspension. The volatility of DMF is moderate, which is conducive to the subsequent electrospinning process. Polyacrylonitrile has a high solubility in DMF and is not easy to agglomerate or precipitate, thereby ensuring the stability of the suspension. The stable suspension is conducive to the subsequent preparation of the electrospinning solution and the smooth progress of the electrospinning process. Nitrogen-doped carbon balls are added to a polyacrylonitrile suspension, and an electrospinning solution can be formed by simple stirring. The preparation method is simple and easy, and can ensure the uniform distribution of nitrogen-doped carbon balls in the electrospinning solution. By electrospinning, polyacrylonitrile and nitrogen-doped carbon balls in the electrospinning solution can be spun into fibrous catalyst materials. This fibrous structure is conducive to the penetration of electrolyte and the transmission of ions, thereby improving the catalytic efficiency of the catalyst. The prepared catalyst material combines the excellent catalytic performance of nitrogen-doped carbon balls and the cross-linked structure of polyacrylonitrile. This structure makes the catalyst material have higher catalytic efficiency, better conductivity and stability. The raw materials and solvents used in the entire preparation process are relatively environmentally friendly, and less waste is generated during the preparation process. This is conducive to reducing environmental pollution and is in line with the development trend of green chemistry. The prepared catalyst material for zinc-bromine liquid flow battery can be applied in the field of zinc-bromine liquid flow battery; the excellent catalytic performance of nitrogen-doped carbon balls is used to improve the electrocatalytic effect, and the cross-linking structure provided by polyacrylonitrile is used to improve the conductivity; the solvent thermal method and the electrostatic spinning method are used to change the content of polyacrylonitrile and nitrogen-doped carbon balls to obtain better catalytic performance; the preparation method is simple, the production cost is low, the subsequent treatment is simple and no complicated synthesis equipment is required. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] The present invention is described in further detail below in conjunction with embodiments: The invention discloses a catalyst material for zinc-bromine liquid flow battery, comprising nitrogen-doped carbon balls and polyacrylonitrile, wherein the polyacrylonitrile is in fiber form and the nitrogen-doped carbon balls are embedded in the polyacrylonitrile fibers.

[0022] The mass of nitrogen-doped carbon balls is 30% to 35% of the catalytic material used for zinc-bromine flow batteries, and the mass of polyacrylonitrile is 65% to 70% of the catalytic material used for zinc-bromine flow batteries.

[0023] The present invention discloses a catalyst material for zinc-bromine flow batteries, which combines the catalytic activity of nitrogen-doped carbon balls with the mechanical strength and conductivity of polyacrylonitrile to form a composite catalyst with excellent performance. It is beneficial to the penetration of electrolyte and the transmission of ions, and increases the contact area between the catalyst and the electrolyte, thereby enhancing the catalytic efficiency. At the same time, the fibrous structure also enhances the mechanical strength of the catalyst. The optimization of the proportion ensures that the catalyst has good mechanical properties and conductivity while ensuring catalytic activity. The moderate proportion of nitrogen-doped carbon balls ensures sufficient catalytic active sites; the high proportion of polyacrylonitrile provides good structural support and conductive network.

[0024] The present invention discloses a method for preparing a catalyst material for a zinc-bromine flow battery, comprising the following steps: 1) Dissolve glucose in deionized water and stir evenly with magnetic force to obtain a mixed solution; 2) The mixed solution is transferred to a high pressure reactor and placed in an oven, the temperature of which is gradually raised to 160-200°C and kept at this temperature for 6-12 hours; 3) After the reaction, the solution was washed with ethanol several times and dried in an oven at 50-80°C for 12-18 hours to obtain a solid product; 4) Put the solid product into a crucible, transfer it to a muffle furnace, introduce nitrogen, and cool it down to obtain nitrogen-doped carbon balls; 5) dissolving polyacrylonitrile in N,N-dimethylformamide to obtain a uniform suspension; 6) adding nitrogen-doped carbon balls into the above suspension and stirring evenly to form an electrospinning solution; 7) electrospinning the electrospinning liquid; 8) Vacuum drying in a drying oven at 50-80°C for 12-18 hours to obtain the final composite catalytic material.

[0025] Glucose was used as the carbon source and deionized water as the solvent, and a uniform mixed solution was obtained by magnetic stirring, which provided a good foundation for the subsequent hydrothermal reaction.

[0026] The hydrothermal reaction is carried out under high temperature and high pressure, which is conducive to the carbonization of glucose and the doping of nitrogen atoms. The control of the insulation time ensures the full progress of the reaction and the stability of the product.

[0027] Ethanol washing can remove impurities and unreacted substances in the product and improve the purity of the product. The drying process ensures the stability of the product and the convenience of subsequent processing.

[0028] The calcination by introducing nitrogen into the muffle furnace can further promote the doping of nitrogen atoms and the stabilization of the carbon structure. The cooling process ensures the integrity of the product.

[0029] Polyacrylonitrile has good solubility in N,N-dimethylformamide and can form a uniform suspension, providing a good foundation for the subsequent electrospinning process.

[0030] The addition of nitrogen-doped carbon balls ensures that the electrospinning solution contains both the fiber-forming components of polyacrylonitrile and the nitrogen-doped carbon balls with catalytic activity, which makes it possible to prepare composite catalysts by subsequent electrospinning.

[0031] Electrospinning technology can produce catalyst materials with a fibrous structure, which is conducive to the penetration of electrolyte and the transmission of ions, thereby improving the catalytic efficiency of the catalyst.

[0032] Vacuum drying can remove solvents and moisture from electrospinning materials, improving the stability and mechanical strength of the materials. At the same time, the appropriate drying temperature also ensures the integrity of the materials and the maintenance of catalytic activity.

[0033] Preferably, in step 1), the dosage ratio of glucose to deionized water is 1 g: (10-15) mL.

[0034] This ensures that glucose is fully dissolved in deionized water to form a uniform mixed solution. Too concentrated or too dilute solutions may affect the subsequent hydrothermal reaction and the quality of the product. The appropriate ratio helps to evenly disperse the glucose molecules, providing a good foundation for carbonization and nitrogen doping in the subsequent steps.

[0035] Preferably, in step 4), the heating rate of the muffle furnace is 5-10°C / min, the temperature is raised to 800-1200°C, the holding time is 2-6h, and the flow rate of nitrogen is 20-60mL / min; Controlling the heating rate helps avoid excessive internal stress and possible incomplete pyrolysis of the product caused by too fast heating. Appropriate heating rate and high temperature holding time ensure the full carbonization of glucose and effective doping of nitrogen atoms. At the same time, the flow rate of nitrogen is also crucial, which can provide the necessary inert atmosphere to prevent oxidation during carbonization and help exhaust the gases produced by the reaction. The optimization of these conditions helps to obtain high-quality, high-catalytic activity nitrogen-doped carbon balls.

[0036] Preferably, in step 6), the usage ratio of polyacrylonitrile and N,N-dimethylformamide is (40-80) g:1L.

[0037] Ensure that polyacrylonitrile is fully dissolved in N,N-dimethylformamide to form a stable suspension. The appropriate concentration helps to form continuous and uniform fibers during the electrospinning process. Too concentrated solutions may cause nozzle blockage during the spinning process, while too dilute solutions may form discontinuous fibers or dripping.

[0038] Preferably, in step 6), the usage ratio of nitrogen-doped carbon balls and N,N-dimethylformamide is (20-40) g:1L.

[0039] The uniform dispersion of nitrogen-doped carbon spheres in the suspension is ensured, which is conducive to the uniform embedding of carbon spheres into polyacrylonitrile fibers during the electrospinning process. The appropriate concentration of carbon spheres helps to increase the number of catalytic active sites of the catalyst material while maintaining the continuity and stability of the fiber.

[0040] Preferably, in step 7), the spinning voltage is 15-18 kV, and the syringe injection rate is 0.8-1.2 mL·h -1 , the receiving distance of the roller to collect the electrospun fibers is 10~20cm.

[0041] The spinning voltage is one of the key factors affecting the fiber formation during the electrospinning process. The appropriate voltage can ensure the continuity and uniformity of the fibers while avoiding fiber breakage or agglomeration. The control of the syringe push rate helps to maintain a stable spinning rate, thereby obtaining a uniform fiber diameter. The receiving distance affects the drying and curing process of the fibers, and the appropriate distance helps to form continuous, defect-free fibers. The optimization of the above conditions helps to obtain high-quality composite catalyst materials with excellent catalytic performance and mechanical strength.

[0042] Example 1 A method for preparing a catalyst material for a zinc-bromine flow battery comprises the following steps: Step 1: Dissolve 3 g of glucose in 30 mL of deionized water and stir evenly with magnetic force to obtain a mixed solution; Step 2: The mixed solution was transferred to a high-pressure reactor and placed in an oven, the temperature of which was gradually raised to 160°C and kept warm for 12 hours. After the reaction was completed, the solution was washed with ethanol several times and placed in an oven at 50°C for 18 hours to obtain a solid product; Step 3: Place the above solid product into a crucible, transfer it to a muffle furnace, introduce nitrogen at a flow rate of 20 mL / min, increase the temperature to 800°C at a heating rate of 5°C / min, keep warm for 6 hours, and then cool down to obtain nitrogen-doped carbon balls.

[0043] Step 4: Dissolve 0.2 g of polyacrylonitrile in 5 mL of N,N-dimethylformamide to obtain a uniform suspension.

[0044] Step 5: Take 0.086 g of the nitrogen-doped carbon balls obtained in step 3 and add them to the suspension obtained in step 4, stir evenly to form an electrospinning solution.

[0045] Step 6: Electrospin the electrospinning solution with a spinning voltage of 15 kV and a syringe injection rate of 0.8 mL·h -1 The receiving distance of the roller to collect the electrospun fibers was 10 cm. The collected fibers were then vacuum dried in a drying oven at 50° C. for 18 h to obtain a catalytic material for zinc-bromine flow batteries.

[0046] Among them, the mass of nitrogen-doped carbon balls is 30% of the catalytic material used for zinc-bromine flow batteries, and the mass of polyacrylonitrile is 70% of the catalytic material used for zinc-bromine flow batteries.

[0047] Example 2 A method for preparing a catalyst material for a zinc-bromine flow battery comprises the following steps: Step 1: Dissolve 3 g of glucose in 45 mL of deionized water and stir evenly with magnetic force to obtain a mixed solution; Step 2: The mixed solution was transferred to a high-pressure reactor and placed in an oven, the temperature of which was gradually raised to 200°C and kept warm for 6 hours. After the reaction was completed, the solution was washed several times with ethanol and placed in an oven at 80°C for 12 hours to obtain a solid product; Step 3: Place the above solid product into a crucible, transfer it to a muffle furnace, introduce nitrogen at a flow rate of 60 mL / min, increase the temperature to 1200°C at a heating rate of 10°C / min, keep warm for 2 hours, and then cool down to obtain nitrogen-doped carbon balls.

[0048] Step 4: Dissolve 0.4 g of polyacrylonitrile in 5 mL of N,N-dimethylformamide to obtain a uniform suspension.

[0049] Step 5: Take 0.2 g of the nitrogen-doped carbon balls obtained in step 3 and add them to the suspension obtained in step 4, stir evenly to form an electrospinning solution.

[0050] Step 6: Electrospin the electrospinning solution with a spinning voltage of 18 kV and a syringe injection rate of 1.2 mL·h -1 The receiving distance of the roller to collect the electrospun fibers was 20 cm. The collected fibers were then vacuum dried in a drying oven at 80° C. for 12 h to obtain a catalytic material for zinc-bromine flow batteries.

[0051] Among them, the mass of nitrogen-doped carbon balls is 33% of the catalytic material used for zinc-bromine flow batteries, and the mass of polyacrylonitrile is 67% of the catalytic material used for zinc-bromine flow batteries.

[0052] Example 3 A method for preparing a catalyst material for a zinc-bromine flow battery comprises the following steps: Step 1: Dissolve 3 g of glucose in 40 mL of deionized water and stir evenly with magnetic force to obtain a mixed solution; Step 2: The mixed solution was transferred to a high-pressure reactor and placed in an oven, the temperature of which was gradually raised to 180°C and kept warm for 8 hours. After the reaction was completed, the solution was washed with ethanol several times and placed in an oven at 60°C for 16 hours to obtain a solid product; Step 3: Place the above solid product into a crucible, transfer it to a muffle furnace, introduce nitrogen at a flow rate of 30 mL / min, increase the temperature to 1000°C at a heating rate of 5°C / min, keep warm for 3 hours, and then cool down to obtain nitrogen-doped carbon balls.

[0053] Step 4: Dissolve 0.25 g of polyacrylonitrile in 5 mL of N,N-dimethylformamide to obtain a uniform suspension.

[0054] Step 5: Take 0.12 g of the nitrogen-doped carbon balls obtained in step 3 and add them to the suspension obtained in step 4, stir evenly to form an electrospinning solution.

[0055] Step 6: Electrospin the electrospinning solution with a spinning voltage of 16 kV and a syringe injection rate of 1 mL·h -1 The receiving distance of the roller to collect the electrospun fibers was 15 cm. The collected fibers were then vacuum dried in a drying oven at 60° C. for 16 h to obtain a catalytic material for zinc-bromine flow batteries.

[0056] Among them, the mass of nitrogen-doped carbon balls is 32% of the catalytic material used for zinc-bromine flow batteries, and the mass of polyacrylonitrile is 68% of the catalytic material used for zinc-bromine flow batteries.

[0057] Example 4 A method for preparing a catalyst material for a zinc-bromine flow battery comprises the following steps: Step 1: Dissolve 3 g of glucose in 35 mL of deionized water and stir evenly with magnetic force to obtain a mixed solution; Step 2: The mixed solution was transferred to a high-pressure reactor and placed in an oven, the temperature of which was gradually raised to 180°C and kept warm for 8 hours. After the reaction was completed, the solution was washed with ethanol several times and placed in an oven at 70°C for 14 hours to obtain a solid product; Step 3: Place the above solid product into a crucible, transfer it to a muffle furnace, introduce nitrogen at a flow rate of 40 mL / min, increase the temperature to 900°C at a heating rate of 5°C / min, keep warm for 4 hours, and then cool down to obtain nitrogen-doped carbon balls.

[0058] Step 4: Dissolve 0.3 g of polyacrylonitrile in 5 mL of N,N-dimethylformamide to obtain a uniform suspension.

[0059] Step 5: Take 0.16 g of the nitrogen-doped carbon balls obtained in step 3 and add them to the suspension obtained in step 4, stir evenly to form an electrospinning solution.

[0060] Step 6: Electrospin the electrospinning solution with a spinning voltage of 17 kV and a syringe injection rate of 1 mL·h -1 The receiving distance of the roller to collect the electrospun fibers was 15 cm. The collected fibers were then vacuum dried in a drying oven at 60° C. for 16 h to obtain a catalytic material for zinc-bromine flow batteries.

[0061] Among them, the mass of nitrogen-doped carbon balls is 35% of the catalytic material used for zinc-bromine flow batteries, and the mass of polyacrylonitrile is 65% of the catalytic material used for zinc-bromine flow batteries.

[0062] In summary, the catalyst material for zinc-bromine liquid flow battery disclosed in the present invention adopts a solvent thermal method to prepare carbon balls, mixes nitrogen-doped carbon balls with an organic solution of polyacrylonitrile, and prepares a polyacrylonitrile fiber-supported nitrogen-doped carbon ball composite catalyst material through an electrostatic spinning process. The catalyst material for zinc-bromine liquid flow battery prepared by the present invention has a stable structure, a simple preparation process, and excellent catalytic performance, and the preparation method is simple, low-cost, and has no pollution to the environment, and is suitable for industrial large-scale production.

[0063] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A catalyst material for zinc-bromine flow battery, characterized in that: It includes two parts: nitrogen-doped carbon balls and polyacrylonitrile. The polyacrylonitrile is in fiber shape, and the nitrogen-doped carbon balls are embedded in the polyacrylonitrile.

2. The catalyst material for zinc-bromine flow battery according to claim 1, characterized in that: The mass ratio of the nitrogen-doped carbon balls to polyacrylonitrile is (30%-35%): (65%-70%).

3. The method for preparing the catalyst material for zinc-bromine flow battery according to any one of claims 1 or 2, characterized in that: The following steps are involved: 1) Dissolve glucose in deionized water, stir evenly, perform hydrothermal reaction, wash, dry and calcine to obtain nitrogen-doped carbon balls; 2) dissolving polyacrylonitrile in N,N-dimethylformamide to obtain a uniform suspension; 3) Adding the nitrogen-doped carbon balls obtained in step 1) to the suspension obtained in step 2), stirring evenly to form an electrospinning solution, and obtaining a catalyst material for a zinc-bromine flow battery after electrospinning and vacuum drying.

4. The method for preparing a catalyst material for a zinc-bromine flow battery according to claim 3, characterized in that: In step 1), the dosage ratio of glucose to deionized water is 1 g: (10-15) mL.

5. The method for preparing a catalyst material for a zinc-bromine flow battery according to claim 3, characterized in that: In step 1), the conditions of the hydrothermal reaction are: 160-200° C. for 6-12 hours.

6. The method for preparing a catalyst material for a zinc-bromine flow battery according to claim 3, characterized in that: In step 1), the drying temperature is 50-80° C. and the drying time is 12-18 hours.

7. The method for preparing a catalyst material for a zinc-bromine flow battery according to claim 3, characterized in that: In step 1), the calcination conditions are: in a nitrogen atmosphere, heating to 800-1200° C. at a heating rate of 5-10° C. / min, and keeping the temperature for 2-6 hours; the flow rate of the nitrogen is 20-60 mL / min.

8. The method for preparing a catalyst material for a zinc-bromine flow battery according to claim 3, characterized in that: In step 2), the usage ratio of polyacrylonitrile and N,N-dimethylformamide is (40-80) g:1L.

9. The method for preparing a catalyst material for a zinc-bromine flow battery according to claim 3, characterized in that: In step 3), the amount ratio of the nitrogen-doped carbon balls to N,N-dimethylformamide is (20-40) g:1L.

10. The method for preparing a catalyst material for a zinc-bromine flow battery according to claim 3, characterized in that: In step 3), the electrospinning conditions include: the spinning voltage is 15-18 kV, the syringe injection rate is 0.8-1.2 mL·h -1 The receiving distance of the roller to collect the electrospinning liquid is 10-20 cm; the vacuum drying temperature is 50-80° C., and the vacuum drying time is 12-18 hours.