Preparation method of vanadium electrolyte for all-vanadium redox flow battery, vanadium electrolyte and application

Abstract

The application provides a preparation method of vanadium electrolyte for a vanadium redox flow battery, the vanadium electrolyte and application. The provided method comprises the following steps: (1) dissolving concentrated sulfuric acid in water to obtain a sulfuric acid solution with a predetermined concentration, and then adding vanadium pentoxide into the sulfuric acid solution to obtain a first vanadium solution through reaction; (2) keeping the temperature of the first vanadium solution to a predetermined temperature, adding low-valence vanadium oxide into the first vanadium solution to react, and supplementing water or hydrochloric acid during the reaction to obtain a second vanadium solution, wherein the low-valence vanadium oxide is vanadium oxide with a valence of 3-3.5; and (3) filtering the second vanadium solution to obtain the vanadium electrolyte. The provided method can save energy consumption, reduce cost and improve dissolution efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vanadium battery, and particularly relates to a preparation method of vanadium electrolyte for all-vanadium redox flow battery, vanadium electrolyte and application. BACKGROUND

[0002] All-vanadium redox flow battery is a kind of battery which uses circulating flow vanadium solution as energy storage medium, and has the advantages of intrinsic safety, long cycle life, low full life cycle cost, suitable for long-time energy storage, rich resources, etc. It is the most promising liquid flow battery for commercialization. Vanadium electrolyte is an important part of all-vanadium redox flow battery, accounting for more than 50% of the cost of vanadium battery. The production cost and quality of vanadium electrolyte directly affect the cost and performance of vanadium battery. Therefore, an excellent vanadium electrolyte preparation method is the guarantee for reducing production cost and improving product quality.

[0003] The preparation method of vanadium electrolyte can be divided into physical dissolution method, chemical reduction method and electrolysis method. The physical dissolution method is to directly dissolve high-purity VOSO4 solid in sulfuric acid to obtain the electrolyte. The chemical reduction method is to use reducing agents (such as hydrogen, methane, sulfur, alcohol, etc.) to reduce high-valence vanadium oxide or vanadate to prepare the electrolyte. The electrolysis method can be further divided into direct electrolysis and indirect electrolysis. The direct electrolysis method is to pass V2O5 dissolved in sulfuric acid into the negative electrode of the electrolytic cell, and after power supply, the negative electrode undergoes a reduction reaction to obtain a 3.5-valence electrolyte. The indirect electrolysis is to electrolyze the tetravalent vanadyl sulfate obtained by reduction dissolution or extraction to obtain a 3.5-valence electrolyte. Both methods have the characteristics of high energy consumption and slow kinetics process.

[0004] Patent document CN 116154244 A discloses a preparation method of vanadium electrolyte, which uses ammonium metavanadate to prepare vanadium oxide, uses the vanadium oxide to prepare electrolyte precursor, and uses an asymmetric electrolysis device to electrolyze the electrolyte precursor to obtain a 3.5-valence electrolyte. This method uses electrolysis method, which has high energy consumption.

[0005] Patent document CN 106941186 A discloses a vanadium electrolyte and a preparation method thereof. The vanadium electrolyte is prepared by using ammonium metavanadate with a purity of 99.0-99.5wt% as raw material, dissolving vanadium, filtering to obtain purified vanadium solution, and acid-ammonia precipitation to obtain ammonium polyvanadate solid phase; (2) calcining the ammonium polyvanadate solid phase in a reducing atmosphere to obtain a mixture containing divanadium tetraoxide and divanadium trioxide, wherein the molar ratio of divanadium tetraoxide to divanadium trioxide is (0.95-1.05):1; (3) acid dissolving the mixture to obtain the vanadium electrolyte. This method directly dissolves the mixture of divanadium tetraoxide and divanadium trioxide, which has slow kinetics process and poor dissolution efficiency.

[0006] Patent document CN 117832565 A discloses a method for preparing 3.5-valence vanadyl sulfate electrolyte by reducing ammonium polyvanadate with gas. The method comprises: ammonium polyvanadate is reduced and calcined by reducing gas to obtain vanadium oxide; the vanadium oxide contains V4O7; the reducing gas comprises a mixed gas of NH3, CO and H2; (2) a mixed sulfuric acid solution and vanadium oxide are dissolved to obtain 3.5-valence vanadyl sulfate electrolyte. The method directly dissolves V4O7, the kinetic process is slow, and the dissolution efficiency is poor.

[0007] The poor dissolution efficiency of vanadium oxide can increase the insoluble matter of the electrolyte, easily block the pipeline of the reaction kettle, and increase the difficulty of removing the insoluble matter of the finished electrolyte, thereby increasing the cost of removing the insoluble matter and finally affecting the quality of the electrolyte. Therefore, it is necessary to develop a vanadium electrolyte preparation technology with high dissolution efficiency and low cost to reduce the cost of the all-vanadium redox flow battery. SUMMARY

[0008] The present application aims to at least solve one of the technical problems in the related art. The present application provides a preparation method of vanadium electrolyte for all-vanadium redox flow battery, vanadium electrolyte and application. The vanadium electrolyte can be quickly prepared by the method provided by the present application, the cost is very low, and the dissolution rate of the prepared vanadium electrolyte is very high. The method provided by the present application can be used for industrial preparation of vanadium electrolyte, and the cost is low and the process is controllable.

[0009] Specifically, the present application provides the following technical solutions:

[0010] In a first aspect of the present application, a preparation method of vanadium electrolyte for all-vanadium redox flow battery is provided, comprising:

[0011] (1) dissolving concentrated sulfuric acid in water to obtain a sulfuric acid solution with a predetermined concentration, then adding vanadium pentoxide to the sulfuric acid solution to obtain a first vanadium solution;

[0012] (2) keeping the temperature of the first vanadium solution at a predetermined temperature, adding low-valence vanadium oxide to the first vanadium solution to react, and supplementing water or hydrochloric acid during the reaction to obtain a second vanadium solution, wherein the low-valence vanadium oxide is vanadium oxide with a valence of 3-3.5;

[0013] (3) filtering the second vanadium solution to obtain vanadium electrolyte.

[0014] The method provided first dissolves concentrated sulfuric acid in water. In the process of dissolving in water, concentrated sulfuric acid generates heat, so that the sulfuric acid solution itself has a certain temperature. Then vanadium pentoxide is added to obtain a first vanadium solution. The temperature of the first vanadium solution is kept at a certain temperature, low-valence vanadium oxide is slowly added, and water or hydrochloric acid is supplemented to obtain a second vanadium solution, which is filtered to obtain vanadium electrolyte.

[0015] According to the embodiment of the present application, the preparation method of vanadium electrolyte for all-vanadium redox flow battery described above can further comprise the following technical features:

[0016] According to the embodiment of the present application, the predetermined concentration of the sulfuric acid solution in step (1) is 40-80%.

[0017] According to the embodiment of the present application, the mass ratio of the vanadium pentoxide to the sulfuric acid solution is (1-6):100.

[0018] According to the embodiment of the present application, the time for adding the low-valence vanadium oxide to the first vanadium solution in step (2) is controlled within 2 hours.

[0019] The reaction time in step (2) is 6-8 hours.

[0020] According to the embodiment of the present application, the mass ratio of the low-valence vanadium oxide to the vanadium pentoxide is (2-15):1.

[0021] According to the embodiment of the present application, the predetermined temperature in step (2) is 80-150℃, for example, 90℃-140℃. The first vanadium solution can be kept at the predetermined temperature by continuous heating.

[0022] According to the embodiment of the present application, the concentration of the vanadium electrolyte is 1.5-4.0 mol / L, the concentration of sulfate radical is 3-10 mol / L, and the concentration of chloride ion is 0-6 mol / L.

[0023] The second aspect of the present application provides a vanadium electrolyte for all-vanadium redox flow battery, which is obtained by the preparation method according to any one of the first aspect.

[0024] The third aspect of the present application provides the use of the vanadium electrolyte for all-vanadium redox flow battery according to the second aspect in the field of all-vanadium redox flow battery.

[0025] The fourth aspect of the present application provides an all-vanadium redox flow battery, comprising: an electric pile system, a positive electrode storage tank, a negative electrode storage tank, a circulating pump and a management system.

[0026] The positive electrode storage tank stores a positive electrode electrolyte; the negative electrode storage tank stores a negative electrode electrolyte, and the positive electrode electrolyte and the negative electrode electrolyte each comprise the vanadium electrolyte for all-vanadium redox flow battery according to the second aspect.

[0027] The present application has at least the following beneficial effects:

[0028] The application provides a preparation method of vanadium electrolyte for a full vanadium liquid flow battery. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The application provides a preparation method of vanadium electrolyte for a full vanadium liquid flow battery.

[0030] Figure 2 The application provides a preparation method of vanadium electrolyte for a full vanadium liquid flow battery. 2 The application provides a preparation method of vanadium electrolyte for a full vanadium liquid flow battery. DETAILED DESCRIPTION

[0031] The application provides a preparation method of vanadium electrolyte for a full vanadium liquid flow battery.

[0032] The application provides a preparation method of vanadium electrolyte for a full vanadium liquid flow battery.

[0033] S10: dissolving concentrated sulfuric acid in water to obtain a sulfuric acid solution with a predetermined concentration, then adding vanadium pentoxide into the sulfuric acid solution to obtain a first vanadium solution.

[0034] S20: keeping the temperature of the first vanadium solution to a predetermined temperature, adding low-valence vanadium oxide into the first vanadium solution to react, and supplementing water or hydrochloric acid during the reaction to obtain a second vanadium solution, wherein the low-valence vanadium oxide is vanadium oxide with a valence of 3-3.5.

[0035] S30: filtering the second vanadium solution to obtain vanadium electrolyte.

[0036] S10: dissolving concentrated sulfuric acid in water to obtain a sulfuric acid solution with a predetermined concentration, then adding vanadium pentoxide into the sulfuric acid solution to obtain a first vanadium solution.

[0037] The pentavalent vanadium ions after the dissolution of vanadium pentoxide will hydrolyze at a higher temperature to form a loose and porous hydrated vanadium pentoxide flocculent precipitate, and the obtained first vanadium solution is a suspension. The loose and porous vanadium pentoxide is more conducive to the reaction with low-valence vanadium oxide.

[0038] According to the specific embodiment, the concentration of the sulfuric acid solution is 40-80%, for example 50%, 60%, 70%, 80%.

[0039] According to the specific embodiment, the mass ratio of the vanadium pentoxide to the sulfuric acid solution is (1-6):100, for example 1:100, 2:100, 3:100, 4:100, 5:100, 6:100. The amount of vanadium pentoxide is determined according to the amount of low-valence vanadium oxide and the valence state. After adding the vanadium pentoxide to the sulfuric acid solution, stirring is performed, and the stirring time is 0.5-2h, for example 0.5h, 1h, 1.5h, 2h.

[0040] S20: maintaining the temperature of the first vanadium solution to a predetermined temperature, adding low-valence vanadium oxide to the first vanadium solution, reacting, and supplementing water or hydrochloric acid during the reaction to obtain a second vanadium solution.

[0041] According to the specific embodiment, the low-valence vanadium oxide is vanadium oxide with a valence of 3-3.5. According to the preferred embodiment, the low-valence vanadium oxide mentioned is vanadium oxide with a valence of 3.1-3.3. The low-valence vanadium oxide mentioned is obtained by calcining vanadium pentoxide reduction or ammonium metavanadate reduction, and according to the preferred embodiment, the low-valence vanadium oxide mentioned is low-valence vanadium oxide obtained by ammonium metavanadate reduction. These low-valence vanadium oxides are loose and porous, and are more conducive to the dissolution reaction. The mass ratio of the low-valence vanadium oxide to the vanadium pentoxide is (2-15):1, for example 3:1, 5:1, 7:1, 9:1, 11:1, etc. Under this ratio, the dissolution rate of the prepared vanadium electrolyte can be high.

[0042] The low-valence vanadium oxide can be slowly added to the first vanadium solution (stirring can be performed while adding), and the slow-adding time is 0.5-4h, for example 0.5h, 1h, 2h, 3h, 4h. If the low-valence vanadium oxide is added too quickly, the powder of the entire solution will be too much, and the wear of the stirring paddle will be relatively large; if the addition is too slow, the dissolution time will be increased, which will affect the cost to some extent. It is found in the research process that if the low-valence vanadium oxide is not slowly added but directly added, the dissolution rate of the prepared vanadium electrolyte will be significantly reduced.

[0043] The mass ratio of the water or hydrochloric acid to the sulfuric acid solution in step a is 20-70%, for example 20%, 30%, 40%, 50%, 60%, 70%. The concentration of the added hydrochloric acid is 10-38%.

[0044] The reaction time is 4-12 h. The predetermined temperature is 80-140℃ (for example, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, etc.). According to a preferred embodiment, the predetermined temperature is 100-140℃, more preferably 110-130℃. At this temperature and time, the reaction can be complete, and the production cost will not be increased, and if the reaction time is increased, the energy consumption will be increased, the production cost will be greatly improved, and the reaction efficiency will not be improved. According to a preferred embodiment, the predetermined temperature is 120-130℃.

[0045] S30: filtering the second vanadium solution to obtain a vanadium electrolyte.

[0046] The vanadium electrolyte is obtained by filtration, and the concentration of the obtained vanadium electrolyte is 1.5-4.0 mol / L, the sulfate concentration is 3-10 mol / L, and the chloride ion concentration is 0-6 mol / L (for example, 1-2 mol / L).

[0047] The provided vanadium electrolyte can be used to prepare a full vanadium flow battery. To this end, the present application provides a full vanadium flow battery, comprising: a stack system, a positive electrode storage tank, a negative electrode storage tank, a circulating pump and a management system; the positive electrode storage tank stores a positive electrode electrolyte; the negative electrode storage tank stores a negative electrode electrolyte; the positive electrode electrolyte and the negative electrode electrolyte each comprise the vanadium electrolyte for a full vanadium flow battery mentioned in the present application. The positive electrode electrolyte and the negative electrode electrolyte can contain vanadium electrolytes with different valence states of vanadium ions as needed for the preparation of a full vanadium flow battery.

[0048] The stack system is the core part of the battery, including electrodes, ion exchange membranes, bipolar plates, current collectors and the like. The stack system is the place where electrochemical reactions occur, and the charging and discharging process is realized through the oxidation-reduction reaction on the surface of the electrode. The positive electrode electrolyte and the negative electrode electrolyte act as active materials and circulate in the stack through the circulating pump to participate in the electrochemical reaction. The circulating pump is used to transport the electrolyte from the storage tank to the stack and make it circulate in the battery system to ensure that the electrolyte fully reacts on the surface of the electrode. The management system is used to monitor and manage the state of the battery to ensure safe operation and performance optimization of the battery. In addition, the full vanadium flow battery can further comprise a power conversion system, which can be used to convert the direct current of the battery into alternating current for external devices.

[0049] The technical solutions of the present application are described below by specific examples. It should be noted that these examples are only used to facilitate the understanding of those skilled in the art and should not be regarded as a limitation on the scope of protection of the present application. Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0050] Example 1

[0051] Example 1 prepares a vanadium electrolyte by the following method, comprising:

[0052] Take 60 mL of concentrated sulfuric acid slowly into 60 mL of water and stir until uniform, add 5.5 g of vanadium pentoxide, stir for 2 h, to obtain vanadium solution 1.

[0053] Heat vanadium solution 1 to 120°C, continuously stir, slowly add 34 g of 3.3-valence vanadium oxide reduced by ammonium metavanadate, control to add completely within 2 h.

[0054] Heat the reaction for 6 h, add 80 mL of pure water during the process, cool and filter, make up to 200 mL, to obtain a 2.43 mol / L vanadium electrolyte, with a sulfate concentration of 6.3 mol / L.

[0055] Example 2

[0056] Example 2 prepares a vanadium electrolyte by the following method, comprising:

[0057] Take 60 mL of concentrated sulfuric acid slowly into 60 mL of water and stir until uniform, add 5.5 g of vanadium pentoxide, stir for 2 h, to obtain vanadium solution 1.

[0058] Heat vanadium solution 1 to 120°C, continuously stir, slowly add 34 g of 3.3-valence vanadium oxide reduced by ammonium metavanadate, control to add completely within 2 h.

[0059] Heat the reaction for 6 h, add 80 mL of pure water during the process, cool and filter, make up to 200 mL, to obtain a 2.43 mol / L vanadium electrolyte, with a sulfate concentration of 6.3 mol / L.

[0060] Example 3

[0061] Example 3 prepares a vanadium electrolyte by the following method, comprising:

[0062] Take 60 mL of concentrated sulfuric acid slowly into 60 mL of water and stir until uniform, add 5.5 g of vanadium pentoxide, stir for 2 h, to obtain vanadium solution 1.

[0063] Heat vanadium solution 1 to 120°C, continuously stir, slowly add 34 g of 3.3-valence vanadium oxide reduced by ammonium metavanadate, control to add completely within 2 h.

[0064] Heat the reaction for 6 h, add 80 mL of pure water during the process, cool and filter, make up to 200 mL, to obtain a 2.43 mol / L vanadium electrolyte, with a sulfate concentration of 6.3 mol / L.

[0065] Example 4

[0066] Example 4 prepares a vanadium electrolyte by the following method, comprising:

[0067] Take 60 mL of concentrated sulfuric acid slowly into 60 mL of water, stirring evenly, add vanadium pentoxide 5.5 g, stirring 2 h, to obtain vanadium solution 1.

[0068] Heat vanadium solution 1 to 90°C, constantly stirring, slowly add 34 g of 3.3 valence vanadium oxide reduced by ammonium metavanadate, control to add up within 2 h.

[0069] Heat the reaction for 6 h, add 52 mL of 19% hydrochloric acid during the process, cool and filter, make up to 200 mL, to obtain 2.45 mol / L vanadium electrolyte, sulfate concentration 6.3 mol / L, chloride 2 mol / L.

[0070] Example 5

[0071] Example 5 prepares vanadium electrolyte by the following method, including:

[0072] Take 60 mL of concentrated sulfuric acid slowly into 60 mL of water, stirring evenly, add vanadium pentoxide 5.5 g, stirring 2 h, to obtain vanadium solution 1.

[0073] Heat vanadium solution 1 to 130°C, constantly stirring, slowly add 34 g of 3.1 valence vanadium oxide reduced by ammonium metavanadate, control to add up within 2 h.

[0074] Heat the reaction for 6 h, add 80 mL of pure water during the process, cool and filter, make up to 200 mL, to obtain 2.48 mol / L vanadium electrolyte, sulfate concentration 6.3 mol / L.

[0075] Comparative Example 1

[0076] Comparative Example 1 prepares vanadium electrolyte by the following method, including:

[0077] Take 60 mL of concentrated sulfuric acid slowly into 60 mL of water, stirring evenly. Heat to keep the solution 100°C, add vanadium pentoxide 5.5 g, stirring 2 h, add 34 g of 3.3 valence vanadium oxide reduced by ammonium metavanadate.

[0078] Heat to 100°C for 6 h, add 80 mL of pure water during the process, cool and filter, make up to 200 mL, to obtain 2.35 mol / L vanadium electrolyte, sulfate concentration 6.3 mol / L.

[0079] Comparative Example 2

[0080] Comparative Example 2 prepares vanadium electrolyte by the following method, including:

[0081] Take 60 mL of concentrated sulfuric acid slowly into 60 mL of water, stirring evenly. Heat to keep the solution 120°C, add vanadium pentoxide 5.5 g, stirring 2 h, add 34 g of 3.3 valence vanadium oxide reduced by vanadium pentoxide.

[0082] Heated to 120℃ for 6h, process to add pure water 80mL, cooling filter, constant volume to 200mL, 2.2mol / L vanadium electrolyte, sulfate concentration 6.3mol / L.

[0083] Comparative Example 3

[0084] Comparative Example 3 prepared vanadium electrolyte by the following method, including:

[0085] Take 60mL concentrated sulfuric acid slowly added to 60mL water stirring uniform. Heating to keep the solution 120℃, adding vanadium pentoxide 5.5g, synchronous adding 34g ammonium metavanadate reduced 3.3 valence vanadium oxide.

[0086] Heated to 120℃ for 6h, process to add pure water 80mL, cooling filter, constant volume to 200mL, 2.2mol / L vanadium electrolyte, sulfate concentration 6.3mol / L.

[0087] Then the above example 1~example 5 and comparative example 1~comparative example 2 prepared vanadium electrolyte respectively as follows. The solubility of vanadium electrolyte refers to under certain conditions, the degree of dissolution of vanadium oxide (this application refers to vanadium pentoxide and low valence vanadium oxide) in sulfuric acid solution. Solubility can be used to describe the dissolution effect of vanadium oxide, is one of the important indicators to evaluate the electrolyte preparation process. The solubility of vanadium electrolyte is high, the process method is more advanced.

[0088] Table 1 characterization results

[0089]

[0090]

[0091] The above results show that example 1~5 compared with comparative example 1 and 2, the solubility is higher. Example 4 because of the addition of hydrochloric acid, so also detected the chloride ion concentration.

[0092] Then example 5 as an example, according to the following method to prepare vanadium electrolyte, vanadium electrolyte is diluted to 2.0mol / L, charge and discharge test, the results are shown in Figure 2 Figure 2 ​Three curves represent discharge capacity (Ah), current efficiency (%) and energy efficiency (%), respectively. (1) Discharge capacity (Ah): In the initial stage, when the cycle number is small (about 0 to 100 times), the discharge capacity decreases rapidly from about 8 Ah to about 4 Ah. In the stable stage, after the cycle number reaches 100 times, the discharge capacity tends to be stable, with small fluctuations, about 4 Ah. (2) Current efficiency (%): In the stable stage, the current efficiency remains relatively stable throughout the cycle, about 11%, with no obvious fluctuations or changes. (3) Energy efficiency (%): In the initial stage, when the cycle number is small (about 0 to 100 times), the energy efficiency decreases from about 80% to about 60%. In the stable stage, after the cycle number reaches 100 times, the energy efficiency tends to be stable, with small fluctuations, about 60%.

[0093] The results show that the vanadium electrolyte prepared by the method of the application has excellent performance.

[0094] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific embodiment" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0095] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A method for the preparation of vanadium electrolytes for a vanadium redox flow battery, characterized in that, Comprising: (1) dissolving concentrated sulfuric acid in water to obtain a sulfuric acid solution with a predetermined concentration, then adding vanadium pentoxide to the sulfuric acid solution, stirring for 0.5-2 hours, and obtaining a first vanadium solution, wherein the pentavalent vanadium ions dissolved from the vanadium pentoxide hydrolyze to form a loose and porous hydrated vanadium pentoxide flocculent precipitate, and the obtained first vanadium solution is a suspension; (2) maintaining the temperature of the first vanadium solution to a predetermined temperature, slowly adding low-valence vanadium oxide to the first vanadium solution for 0.5-4 hours, reacting, and supplementing water or hydrochloric acid during the reaction to obtain a second vanadium solution, wherein the low-valence vanadium oxide is a 3-3.5 valence vanadium oxide reduced from ammonium metavanadate; (3) filtering the second vanadium solution to obtain a vanadium electrolyte; In step (1), the predetermined concentration of the sulfuric acid solution is 40-80%; the mass ratio of the vanadium pentoxide to the sulfuric acid solution in step (1) is (1-6):100; In step (2), the predetermined temperature is 110-130℃, the first vanadium solution is maintained at the predetermined temperature by continuous heating, and the reaction time is 4-12 hours.

2. The production method according to claim 1, characterized by, The supplementing amount of the water or hydrochloric acid is (0.2-0.7):1 relative to the mass of the sulfuric acid solution.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the low-valence vanadium oxide to the vanadium pentoxide is (2-15):

1.

4. The production method according to claim 1, characterized by, The concentration of the vanadium electrolyte is 1.5-4.0 mol / L, the concentration of sulfate is 3-10 mol / L, and the concentration of chloride is 0-6 mol / L.

5. A vanadium electrolyte for a vanadium redox flow battery, characterised in that, Obtained according to the preparation method in any one of claims 1-4.

6. An all-vanadium redox flow battery characterised in that, Comprising: a stack system, a positive electrode storage tank, a negative electrode storage tank, a circulating pump, and a management system; the positive electrode storage tank stores a positive electrode electrolyte, the negative electrode storage tank stores a negative electrode electrolyte, and the positive electrode electrolyte and the negative electrode electrolyte each comprise the vanadium electrolyte for a full vanadium redox flow battery according to claim 5.

Images