A flow battery catalyst, and methods of making and using the same

Abstract

The application discloses a kind of liquid flow battery catalyst and its preparation method and application, it is related to liquid flow battery technical field.The preparation method of liquid flow battery catalyst disclosed in the application includes the following steps: S1, fluxing agent, pore-forming agent, carbon source, metal source are mixed, grinding, drying, and obtain mixture material;S2, the mixture material is ball milled, then tabletting, and obtain mould piece;S3, the mould piece is heated, control heating rate is 373 DEG C / s~727 DEG C / s, then washing, drying, and obtain the liquid flow battery catalyst.The preparation raw material of liquid flow battery catalyst is selected in the application, and the preparation method is controlled, the preparation rate of liquid flow battery catalyst can be effectively improved, and the prepared liquid flow battery catalyst has higher redox activity and stability, and is suitable for industrial application.

Description

Technical Field

[0001] This invention relates to the field of flow battery technology, and more specifically, to a flow battery catalyst, its preparation method, and its application. Background Technology

[0002] Flow batteries, as an electrochemical energy storage technology, store energy in two electrolytes and achieve charging and discharging through the transfer of electrons between electrodes via chemical reactions. The energy storage capacity of flow batteries can be increased by increasing the volume of the electrolyte, making them scalable. Furthermore, flow batteries have low self-discharge rates, long cycle lives, and can be designed in different shapes and sizes as needed, offering high flexibility and good safety, and have already been applied in large-scale energy storage fields. However, the low energy density of traditional flow batteries limits their widespread adoption. In contrast, multi-electron pair flow batteries offer superior performance and low cost. The participation of multiple electrons in the redox reaction can significantly improve energy density, providing great potential for the practical application of flow batteries. Nevertheless, in actual charging and discharging processes, the slow charge transfer kinetics of the redox pairs lead to severe electrochemical polarization problems, resulting in a large redox peak potential difference and poor redox reversibility. This causes multi-electron pair flow batteries to exhibit low current density and energy efficiency during operation. Therefore, developing catalysts for flow batteries that can rapidly perform multi-electron pair redox processes is currently the key to the research and development of multi-electron pair flow batteries.

[0003] In addition, the current method for preparing flow battery catalysts is mostly based on high-temperature melting, which usually involves placing the precursor in a tube furnace and heating it for several hours to more than ten hours to prepare the flow battery catalyst, which is time-consuming and costly. Therefore, there is an urgent need to explore a preparation method that is fast and produces flow battery catalysts with good performance. Summary of the Invention

[0004] The main objective of this invention is to provide a flow battery catalyst, its preparation method, and its application, in order to solve the problems of slow preparation rate and poor redox reversibility of flow battery catalysts in the prior art.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a method for preparing a flow battery catalyst is provided, comprising the following steps:

[0006] S1, the flux, pore-forming agent, carbon source and metal source are mixed, ground and dried to obtain a mixture;

[0007] S2, the mixture is ball-milled and then pressed into tablets to obtain a molded tablet;

[0008] S3, the template is heated at a rate of 373℃ / s to 727℃ / s, then washed and dried to obtain the flow battery catalyst.

[0009] This invention rapidly heats the template to the required temperature, completing the reaction in a short time to obtain a flow battery catalyst. Furthermore, by increasing the heating rate, a flow battery catalyst with good redox activity can be prepared. In addition, by controlling the raw materials used in the preparation of the flow battery catalyst, this invention can obtain a catalyst with a porous structure, which is beneficial for improving the rate and efficiency of the electrode reaction. It also facilitates better diffusion of active materials from the electrolyte to the surface of the flow battery catalyst, thereby improving the charging and discharging performance of the flow battery.

[0010] Furthermore, in S3, the temperature is heated to 800℃~1200℃, and the holding time is 0.5min~3min.

[0011] By controlling the heating conditions, the preparation efficiency of flow battery catalysts can be effectively improved, and the flow battery can also have good redox activity.

[0012] Furthermore, in S3, Joule heating is employed.

[0013] Joule heating has high thermal efficiency and a fast heating rate, and is often used for rapid heating.

[0014] Furthermore, the flux is sodium chloride, the pore-forming agent is zinc chloride, the carbon source is a nitrogen-containing carbon source, and the metal source is at least one of iron salt, cobalt salt, manganese salt, iron oxide, cobalt oxide, and manganese oxide.

[0015] This invention uses sodium chloride as a flux and zinc chloride as a pore-forming agent to form a flow battery catalyst with the desired pore structure. Using a carbon source containing nitrogen to prepare the flow battery catalyst can improve its electrochemical performance. Iron, cobalt, and manganese have high catalytic activity, which is beneficial to improving the energy density and stability of the flow battery.

[0016] Furthermore, the nitrogen-containing carbon source is at least one of adenine and melamine; the iron salt is ferric chloride; the cobalt salt is at least one of cobalt chloride and cobalt acetylacetonate; and the manganese salt is manganese acetate. Using the above-mentioned nitrogen-containing carbon sources to prepare flow battery catalysts can significantly improve the catalytic activity of flow battery catalysts.

[0017] Furthermore, the molar ratio of metal elements in the flux, pore-forming agent, carbon source, and metal source is (3-8):(3-8):1:(0.01-0.1).

[0018] By limiting the molar ratios of flux, pore-forming agent, carbon source, and metal source as described above, the catalyst for flow batteries exhibits high stability, which is beneficial for improving the cycle stability of flow batteries.

[0019] Furthermore, in S2, the ball milling conditions are: 300 r / min to 800 r / min, 3 min to 10 min; and / or, the tableting conditions are: 25 MPa to 35 MPa, 0.5 min to 3 min.

[0020] Under the above conditions, ball milling and tableting can produce a mold that eliminates gaseous impurities, saves sample volume, reduces errors, and allows for a more complete reaction.

[0021] Furthermore, in S3, the washing process includes acid washing and water washing. The acid washing uses at least one of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid for cleaning.

[0022] Acid washing can remove impurities from the surface of the flow battery catalyst, giving it good electrolyte wettability.

[0023] According to a second aspect of the present invention, a flow battery catalyst is provided, which is prepared by the method for preparing the flow battery catalyst of the first aspect of the present invention.

[0024] According to a third aspect of the present invention, a flow battery is provided, comprising a flow battery catalyst prepared by the preparation method of the first aspect of the present invention or a flow battery catalyst of the second aspect of the present invention.

[0025] By applying the technical solution of this invention to screen the raw materials for the preparation of flow battery catalysts, on the one hand, the preparation efficiency of flow battery catalysts can be improved and the time cost reduced; on the other hand, the flow battery catalysts prepared by this method have high redox activity and stability, which is beneficial to improving the overall electrochemical performance of flow batteries. Attached Figure Description

[0026] Figure 1 This is an electron microscope image of the flow battery catalyst in Example 1;

[0027] Figure 2 The first cycle voltage-ampere curves are for the electrode loaded with the flow battery catalyst in Example 1 and the electrode without the flow battery catalyst.

[0028] Figure 3 The current-voltage curve of the electrode loaded with the flow battery catalyst in Example 1 after 100 cycles;

[0029] Figure 4The volt-ampere curves are for the first and 100th cycles of the electrode loaded with the flow battery catalyst of Example 1.

[0030] The above figures include the following reference numerals: 0, Volt-ampere curve of the electrode without flow battery catalyst for the first cycle; 1, Volt-ampere curve of the electrode with flow battery catalyst in Example 1 for the first cycle; Volt-ampere curve of the electrode with flow battery catalyst in Example 1 for the 100th cycle. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0032] As described in the background section of this invention, existing technologies suffer from slow preparation rates and poor redox reversibility of flow battery catalysts. To address these technical problems, in a typical embodiment of this invention, a method for preparing a flow battery catalyst is provided, comprising the following steps:

[0033] S1, the flux, pore-forming agent, carbon source and metal source are mixed, ground and dried to obtain a mixture;

[0034] S2, the mixture is ball-milled and then pressed into tablets to obtain a molded tablet;

[0035] S3, the template is heated at a rate of 373℃ / s to 727℃ / s, then washed and dried to obtain the flow battery catalyst.

[0036] The preparation steps of the flow battery catalyst provided by this invention are simple. By controlling the raw materials and preparation conditions, rapid heating can be achieved, reducing time costs. Furthermore, the prepared flow battery catalyst has high catalytic activity, and when applied to a flow battery, the redox potential difference during charging and discharging is small.

[0037] In some embodiments, in step S3, the heating temperature is 800℃ to 1200℃, specifically 800℃, 850℃, 900℃, 1000℃, 1100℃, 1200℃, etc., or other values ​​within this range, without special limitation; the holding time is 0.5min to 3min, specifically 0.5min, 1min, 2min, 3min, etc., or other values ​​within this range, without special limitation.

[0038] Heating under the above conditions yields a flow battery catalyst with good structural stability and a suitable pore structure, which is beneficial for improving catalytic activity.

[0039] In some implementations, in S3, Joule heating is used.

[0040] The Joule heating method is a method that uses the heat generated when an electric current passes through a conductor to heat a substance. It can directly convert electrical energy into heat energy with little energy loss, thus resulting in high thermal efficiency. In addition, the temperature generated by the Joule heating method can be precisely controlled by adjusting the current, voltage, or resistance, which greatly helps to improve the macroscopic performance of flow battery catalysts. It can improve their structural stability during charging and discharging, thereby improving the cycle stability of flow batteries.

[0041] In some embodiments, in step S1, the drying temperature is 60°C to 90°C, specifically 60°C, 65°C, 70°C, 80°C, 90°C, or other values ​​within this range, which are not limited here; the drying time is 8h to 20h, specifically 8h, 10h, 15h, 20h, or other values ​​within this range, which are not specifically limited here. The drying process is carried out under vacuum.

[0042] In some embodiments, the flux is sodium chloride, the pore-forming agent is zinc chloride, the carbon source is a nitrogen-containing carbon source, and the metal source is at least one of iron salt, cobalt salt, manganese salt, iron oxide, cobalt oxide, and manganese oxide.

[0043] Sodium chloride, as a flux, can improve molding performance and also plays a role in improving the structural stability of the subsequently prepared flow battery catalyst. In this invention, zinc chloride decomposes at high temperature and reacts with carbon materials to generate a porous structure, which helps to prepare a porous flow battery catalyst and improve its catalytic activity. Using a nitrogen-containing carbon source to prepare the flow battery catalyst can change the electronic structure of the catalyst, thereby improving its catalytic activity. In addition, nitrogen doping can increase the conductivity of the flow battery catalyst, which helps to improve the charge-discharge rate and cycle stability of the flow battery. Iron, cobalt, and manganese are commonly used catalytically active metals in flow battery catalysts. Selecting these metal sources can prepare flow battery catalysts with good catalytic activity.

[0044] In some embodiments, the nitrogen-containing carbon source is at least one of adenine and melamine; the iron salt is ferric chloride; the cobalt salt is at least one of cobalt chloride and cobalt acetylacetonate; and the manganese salt is manganese acetate.

[0045] Flow battery catalysts were prepared using at least one of adenine and melamine as carbon sources. A moderate proportion of nitrogen in the catalyst improved both its conductivity and stability, thus enhancing the cycle stability of the flow battery. The flow battery catalysts prepared using the aforementioned iron, cobalt, and manganese salts exhibited relatively high catalytic activity.

[0046] In some embodiments, the molar ratio of metal elements in flux, pore-forming agent, carbon source, and metal source is (3-8):(3-8):1:(0.01-0.1), specifically 5:5:1:0.05, 3:8:1:0.08, 8:3:1:0.01, etc., or other values ​​within this range, without special limitation here.

[0047] Limiting the molar ratio of each component is intended to prepare a flow battery catalyst with both good stability and catalytic activity. It also helps to make the mixture more homogeneous, which is beneficial to improving the preparation efficiency of the flow battery catalyst.

[0048] In some embodiments, in S2, the rotational speed of the ball mill is 300 r / min to 800 r / min, specifically 300 r / min, 500 r / min, 700 r / min, 800 r / min, etc., or other values ​​within this range, without special limitation here; the ball milling time is 3 min to 10 min, specifically 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, etc., or other values ​​within this range, without special limitation here.

[0049] Ball milling under the above conditions can make the components mix more evenly, which has a significant effect on improving the stability of flow battery catalysts.

[0050] In some embodiments, in S2, the tableting pressure is 25MPa to 35MPa, specifically 25MPa, 28MPa, 30MPa, 32MPa, 35MPa, etc., or other values ​​within this range, which are not limited here; the tableting time is 0.5min to 3min, specifically 0.5min, 1min, 2min, 3min, etc., or other values ​​within this range, which are not specifically limited here.

[0051] By applying the above-mentioned limitations to the tableting conditions, a flow battery catalyst with good stability can be prepared.

[0052] In some embodiments, in S3, the washing process includes acid washing and water washing, wherein the acid washing is performed using at least one of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid.

[0053] Acid washing of flow battery catalysts removes inorganic salts and reaction residues, which is beneficial to improving the catalytic activity of the catalysts. In addition, it can expose more active sites, further improving the catalytic activity of the flow battery catalysts. Furthermore, acid washing can change the chemical state of the surface of the flow battery catalyst, giving it higher reduction activity.

[0054] In another typical embodiment of the present invention, a flow battery catalyst is provided, which is prepared by the preparation method described in the above embodiments of the present invention.

[0055] In some embodiments, the particle size of the flow battery catalyst is 100 nm to 1000 nm, and the difference in redox potential during charging and discharging is 70 mV to 200 mV.

[0056] In another typical embodiment of the present invention, a flow battery is provided, which includes a flow battery catalyst prepared by the preparation method in the above embodiments or a flow battery catalyst in the above embodiments.

[0057] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0058] Example 1

[0059] An embodiment of the preparation method of a flow battery catalyst according to the present invention includes the following steps:

[0060] S1. Sodium chloride, zinc chloride, adenine, and cobalt trioxide are mixed and ground thoroughly in a mortar. Then, the mixture is placed in a vacuum oven and dried under vacuum at 80°C for 10 hours to obtain a mixture. The molar ratio of sodium chloride, zinc chloride, adenine, and cobalt trioxide is 5:5:1:0.05.

[0061] S2, transfer the mixture to a ball mill and process it at 600 r / min for 5 min. Then take 1 g of the ball-milled material and fill it into a circular tablet mold. After sealing, pressurize it to 30 MPa and hold it for 1 min to obtain a circular tablet.

[0062] S3. The template is placed in a Joule furnace and heated to 900°C at a rate of 500°C / s. It is held at this temperature for 1 minute, then cleaned with hydrochloric acid and deionized water, and dried to obtain the flow battery catalyst.

[0063] Example 2

[0064] An embodiment of the preparation method of a flow battery catalyst according to the present invention includes the following steps:

[0065] S1. Sodium chloride, zinc chloride, adenine, cobalt trioxide, and ferric oxide are mixed and ground thoroughly in a mortar. Then, the mixture is placed in a vacuum oven and dried under vacuum at 80°C for 10 hours to obtain a mixture. The molar ratio of sodium chloride, zinc chloride, adenine, cobalt trioxide, and ferric oxide is 5:5:1:0.04:0.03.

[0066] S2, transfer the mixture to a ball mill and process it at 600 r / min for 5 min. Then take 1 g of the ball-milled material and fill it into a circular tablet mold. After sealing, pressurize it to 30 MPa and hold it for 1 min to obtain a circular tablet.

[0067] S3. The template is placed in a Joule furnace and heated to 900°C at a rate of 500°C / s. It is held at this temperature for 1 minute, then cleaned with hydrochloric acid and deionized water, and dried to obtain the flow battery catalyst.

[0068] Example 3

[0069] An embodiment of the preparation method of a flow battery catalyst according to the present invention includes the following steps:

[0070] S1. Sodium chloride, zinc chloride, adenine, cobalt trioxide, and ferric oxide are mixed and ground thoroughly in a mortar. Then, the mixture is placed in a vacuum oven and dried under vacuum at 80°C for 10 hours to obtain a mixture. The molar ratio of sodium chloride, zinc chloride, adenine, cobalt trioxide, and ferric oxide is 5:5:1:0.03:0.05.

[0071] S2, transfer the mixture to a ball mill and process it at 600 r / min for 5 min. Then take 1 g of the ball-milled material and fill it into a circular tablet mold. After sealing, pressurize it to 30 MPa and hold it for 1 min to obtain a circular tablet.

[0072] S3. The template is placed in a Joule furnace and heated to 1000°C at a rate of 500°C / s. It is held at this temperature for 1 minute, then cleaned with hydrochloric acid and deionized water, and dried to obtain the flow battery catalyst.

[0073] Example 4

[0074] An embodiment of the preparation method of a flow battery catalyst according to the present invention includes the following steps:

[0075] S1. Sodium chloride, zinc chloride, adenine, and cobalt trioxide are mixed and ground thoroughly in a mortar. Then, the mixture is placed in a vacuum oven and dried under vacuum at 80°C for 10 hours to obtain a mixture. The molar ratio of sodium chloride, zinc chloride, adenine, and cobalt trioxide is 3:8:1:0.03.

[0076] S2, transfer the mixture to a ball mill and process it at 600 r / min for 5 min. Then take 1 g of the ball-milled material and fill it into a circular tablet mold. After sealing, pressurize it to 30 MPa and hold it for 1 min to obtain a circular tablet.

[0077] S3. The template is placed in a Joule furnace and heated to 900°C at a rate of 500°C / s. It is held at this temperature for 1 minute, then cleaned with hydrochloric acid and deionized water, and dried to obtain the flow battery catalyst.

[0078] Example 5

[0079] An embodiment of the preparation method of a flow battery catalyst according to the present invention includes the following steps:

[0080] S1. Sodium chloride, zinc chloride, adenine, and cobalt trioxide are mixed and ground thoroughly in a mortar. Then, the mixture is placed in a vacuum oven and dried under vacuum at 80°C for 10 hours to obtain a mixture. The molar ratio of sodium chloride, zinc chloride, adenine, and cobalt trioxide is 8:3:1:0.01.

[0081] S2, transfer the mixture to a ball mill and process it at 600 r / min for 5 min. Then take 1 g of the ball-milled material and fill it into a circular tablet mold. After sealing, pressurize it to 30 MPa and hold it for 1 min to obtain a circular tablet.

[0082] S3. The template is placed in a Joule furnace and heated to 900°C at a rate of 500°C / s. It is held at this temperature for 1 minute, then cleaned with hydrochloric acid and deionized water, and dried to obtain the flow battery catalyst.

[0083] Example 6

[0084] An embodiment of the preparation method of a flow battery catalyst according to the present invention includes the following steps:

[0085] S1. Sodium chloride, zinc chloride, adenine, and cobalt trioxide are mixed and ground thoroughly in a mortar. Then, the mixture is placed in a vacuum oven and dried under vacuum at 80°C for 10 hours to obtain a mixture. The molar ratio of sodium chloride, zinc chloride, adenine, and cobalt trioxide is 2:8:1:0.05.

[0086] S2, transfer the mixture to a ball mill and process it at 600 r / min for 5 min. Then take 1 g of the ball-milled material and fill it into a circular tablet mold. After sealing, pressurize it to 30 MPa and hold it for 1 min to obtain a circular tablet.

[0087] S3. The template is placed in a Joule furnace and heated to 900°C at a rate of 500°C / s. It is held at this temperature for 1 minute, then cleaned with hydrochloric acid and deionized water, and dried to obtain the flow battery catalyst.

[0088] Example 7

[0089] An embodiment of the preparation method of a flow battery catalyst according to the present invention includes the following steps:

[0090] S1. Sodium chloride, zinc chloride, adenine, and cobalt trioxide are mixed and ground thoroughly in a mortar. Then, the mixture is placed in a vacuum oven and dried under vacuum at 80°C for 10 hours to obtain a mixture. The molar ratio of sodium chloride, zinc chloride, adenine, and cobalt trioxide is 8:2:1:0.05.

[0091] S2, transfer the mixture to a ball mill and process it at 600 r / min for 5 min. Then take 1 g of the ball-milled material and fill it into a circular tablet mold. After sealing, pressurize it to 30 MPa and hold it for 1 min to obtain a circular tablet.

[0092] S3. The template is placed in a Joule furnace and heated to 900°C at a rate of 500°C / s. It is held at this temperature for 1 minute, then cleaned with hydrochloric acid and deionized water, and dried to obtain the flow battery catalyst.

[0093] Example 8

[0094] An embodiment of the preparation method of a flow battery catalyst according to the present invention includes the following steps:

[0095] S1. Sodium chloride, zinc chloride, melamine, and cobalt trioxide are mixed and ground thoroughly in a mortar. Then, the mixture is placed in a vacuum oven and dried under vacuum at 80°C for 10 hours to obtain a mixture. The molar ratio of sodium chloride, zinc chloride, adenine, and cobalt trioxide is 5:5:1:0.05.

[0096] S2, transfer the mixture to a ball mill and process it at 600 r / min for 5 min. Then take 1 g of the ball-milled material and fill it into a circular tablet mold. After sealing, pressurize it to 30 MPa and hold it for 1 min to obtain a circular tablet.

[0097] S3. The template is placed in a Joule furnace and heated to 900°C at a rate of 500°C / s. It is held at this temperature for 1 minute, then cleaned with hydrochloric acid and deionized water, and dried to obtain the flow battery catalyst.

[0098] Comparative Example 1

[0099] A method for preparing a flow battery catalyst, comprising the following steps:

[0100] S1. Sodium chloride, adenine, and cobalt trioxide are mixed and ground thoroughly in a mortar. Then, the mixture is placed in a vacuum oven and dried under vacuum at 80°C for 10 hours to obtain a mixture. The molar ratio of sodium chloride, adenine, and cobalt trioxide is 5:1:0.05.

[0101] S2, transfer the mixture to a ball mill and process it at 600 r / min for 5 min. Then take 1 g of the ball-milled material and fill it into a circular tablet mold. After sealing, pressurize it to 30 MPa and hold it for 1 min to obtain a circular tablet.

[0102] S3. The template is placed in a Joule furnace and heated to 900°C at a rate of 500°C / s. It is held at this temperature for 1 minute, then cleaned with hydrochloric acid and deionized water, and dried to obtain the flow battery catalyst.

[0103] Comparative Example 2

[0104] A method for preparing a flow battery catalyst, comprising the following steps:

[0105] S1. Sodium chloride, zinc chloride, adenine, and cobalt trioxide are mixed and ground thoroughly in a mortar. Then, the mixture is placed in a vacuum oven and dried under vacuum at 80°C for 10 hours to obtain a mixture. The molar ratio of sodium chloride, zinc chloride, adenine, and cobalt trioxide is 5:5:1:0.05.

[0106] S2, transfer the mixture to a ball mill and process it at 600 r / min for 5 min. Then take 1 g of the ball-milled material and fill it into a circular tablet mold. After sealing, pressurize it to 30 MPa and hold it for 1 min to obtain a circular tablet.

[0107] S3. The template is placed in a tube furnace and heated to 900°C at a rate of 100°C / s. It is held at this temperature for 5 minutes, then cleaned with hydrochloric acid and deionized water, and dried to obtain the flow battery catalyst.

[0108] Performance testing

[0109] 1. Morphology: The morphology of the flow battery catalyst was observed using an electron microscope.

[0110] 2. Electrochemical performance: Redox scans were performed in the Na2S2 electrolyte system. The catalytic activity was determined by comparing the difference in redox peaks between the electrode loaded with the catalyst to be tested and the electrode without the catalyst to be tested. The stability and redox reversibility of the flow battery were determined by comparing the voltammetric curves of the first cycle and the first 100 cycles.

[0111] Table 1 shows the performance test results of the flow battery catalysts in the examples and comparative examples.

[0112] Table 1

[0113]

[0114] As shown in Table 1, the electrodes loaded with the multi-electron pair flow battery catalyst prepared in this invention exhibit high oxidation and reduction peak current densities, and the difference between the oxidation and reduction potentials is small after 100 cycles, demonstrating good cycle stability. Furthermore, comparing the performance test results of Examples 1 and 2-3, it can be found that the redox activity is higher when the metal source is a compound of cobalt trioxide and ferric oxide. Additionally, comparing the performance test results of Examples 1 and 4-7, it can be found that when the molar ratio of the metal elements in the flux, pore-forming agent, carbon source, and metal source in the preparation raw materials is (3-8):(3-8):1:(0.01-0.08), the catalytic activity is high and the cycle stability is good.

[0115] Figure 1 The image shows an electron microscope image of the flow battery catalyst in Example 1. As can be seen from the image, the particle size is small and there are many pores in the catalyst, which plays a significant role in improving the wettability of the electrolyte to the electrode.

[0116] Figure 2 The figure shows the volt-ampere curves of the electrode loaded with the flow battery catalyst in Example 1 and the electrode without the flow battery catalyst during the first cycle. As can be seen from the figure, the flow battery catalyst in Example 1 has high catalytic activity.

[0117] Figure 3 The figure shows the volt-ampere curves of the electrode loaded with the flow battery catalyst of Example 1 after 100 cycles. As can be seen from the figure, the volt-ampere curves do not change much after 100 cycles, which indicates that the flow battery catalyst prepared by the present invention has high stability.

[0118] Figure 4 The figure shows the volt-ampere curves of the electrode loaded with the flow battery catalyst in Example 1 for the first cycle and the 100th cycle. As can be seen from the figure, the difference between the oxidation potential and the reduction potential of the electrode is small, only 89mV, which shows good redox reversibility.

[0119] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a flow battery catalyst, characterized in that, Includes the following steps: S1, the flux, pore-forming agent, carbon source and metal source are mixed, ground and dried to obtain a mixture; S2, the mixture is ball-milled and then pressed into tablets to obtain a molded tablet; S3, the template is heated at a rate of 373℃ / s to 727℃ / s, then washed and dried to obtain the flow battery catalyst; In step S3, the temperature is heated to 800℃~1200℃ and held for 0.5 min~3 min.

2. The method for preparing the flow battery catalyst according to claim 1, characterized in that, In step S3, Joule heating is used for heating.

3. The method for preparing the flow battery catalyst according to claim 1, characterized in that, The flux is sodium chloride, the pore-forming agent is zinc chloride, the carbon source is a nitrogen-containing carbon source, and the metal source is at least one of iron salt, cobalt salt, manganese salt, iron oxide, cobalt oxide, and manganese oxide.

4. The method for preparing the flow battery catalyst according to claim 3, characterized in that, The nitrogen-containing carbon source is at least one of adenine and melamine; the iron salt is ferric chloride; the cobalt salt is at least one of cobalt chloride and cobalt acetylacetonate; and the manganese salt is manganese acetate.

5. The method for preparing the flow battery catalyst according to claim 1, characterized in that, The molar ratio of the metal elements in the flux, the pore-forming agent, the carbon source, and the metal source is (3~8):(3~8):1:(0.01~0.1).

6. The method for preparing the flow battery catalyst according to claim 1, characterized in that, In S2, the ball milling conditions are: 300 r / min to 800 r / min, 3 min to 10 min; and / or, the tableting conditions are: 25 MPa to 35 MPa, 0.5 min to 3 min.

7. The method for preparing the flow battery catalyst according to claim 1, characterized in that, In step S3, the washing process includes acid washing and water washing. The acid washing is performed using at least one of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid.

8. A flow battery catalyst, characterized in that, Prepared by the preparation method according to any one of claims 1 to 7.

9. A flow battery, characterized in that, The catalyst comprises a flow battery catalyst prepared by any one of claims 1 to 7 or the flow battery catalyst of claim 8.

Images