Preparation method and application of vanadium electrolyte

Abstract

The invention discloses a preparation method and application of a vanadium electrolyte, and the preparation method comprises the following steps: S1, adding a sulfuric acid solution into a mixture containing a V2O5 solid, elemental sulfur and an adsorption material, and carrying out heating reaction, sulfur removal and filtration to obtain a high-purity hydrated alum sulfate solid; and S2, the high-purity hydrated vitriol sulfate solid in the step S1 is dissolved in a dilute acid solution, electrolysis is conducted, and the vanadium electrolyte is obtained. According to the preparation method, preparation of the solid vanadium sulfate hydrate can be achieved, the electrolyte for the all-vanadium redox flow battery is prepared through electrolysis on the basis, the preparation method is easy and convenient to operate and rapid in reaction, the prepared electrolyte is high in purity and few in impurity ions, the preparation time is greatly shortened, and the obtained electrolyte can meet the application requirements of current vanadium batteries.

Description

Technical Field

[0001] The present application relates to a preparation method and application of a vanadium electrolyte, belonging to the technical field of electrolyte preparation. Background Art

[0002] All-vanadium redox flow battery is a new type of electrochemical energy storage system. Compared with traditional batteries, it has the characteristics of fast and large-capacity charging and discharging, low self-discharge rate and simple battery structure. It has shown great advantages in the application of fixed energy storage devices for renewable energy. The positive and negative electrolytes of vanadium batteries are sulfuric acid solutions containing V(V) / V(IV) and V(III) / V(II) vanadium compounds, respectively. It is not only a conductive medium, but also an electroactive substance for energy storage. It is the core of vanadium battery energy storage and energy conversion. The mutual conversion of electrical energy and chemical energy is achieved through the transformation of the valence state of vanadium ions.

[0003] As the energy storage medium of flow batteries, electrolyte is an important component of the entire flow battery system. Therefore, the preparation of electrolyte for all-vanadium flow batteries is an important part of the entire industry chain of all-vanadium flow batteries. At present, the preparation of electrolyte for all-vanadium flow batteries is mainly divided into electrolysis method, reduction method, etc., and the operation range and preparation cycle are long during the preparation process. Summary of the invention

[0004] According to one aspect of the present application, a method for preparing a vanadium electrolyte and its application are provided to solve the problems existing in the prior art such as complicated operation process and long preparation cycle.

[0005] This application adopts the following technical solutions:

[0006] A method for preparing a vanadium electrolyte comprises the following steps:

[0007] S1, in the presence of V 2 O 5 A sulfuric acid solution is added to a mixture of solid, elemental sulfur and adsorbent material, heated for reaction, desulfurized and filtered to obtain a high-purity hydrated alum sulfate solid;

[0008] S2, dissolving the high-purity hydrated alum sulfate solid in step S1 in a dilute acid solution, and electrolyzing to obtain the vanadium electrolyte.

[0009] In the present application, elemental sulfur is selected as the reducing agent because it will volatilize into sulfur dioxide gas after the reaction without introducing impurities, while other reducing agents cannot have the same reducing effect without introducing impurities.

[0010] Optionally, the V 2 O 5 The molar ratio of solid to elemental sulfur is 1:1 to 1.2.

[0011] Optionally, the V 2 O 5 The molar ratio of solid to elemental sulfur is selected from any value among 1:1, 1:1.01, 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07, 1:1.08, 1:1.09, 1:1.1, 1:1.11, 1:1.12, 1:1.13, 1:1.14, 1:1.15, 1:1.16, 1:1.17, 1:1.18, 1:1.19, 1.2, or any range therebetween.

[0012] Optionally, in the mixture, the amount of adsorbent material is V 2 O 5 0.1-1% of the total weight of solid and elemental sulfur.

[0013] Optionally, in the mixture, the amount of adsorbent material is V 2 O 5 Any value among 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% of the total weight of solid and elemental sulfur, or any range therebetween.

[0014] Optionally, the adsorption material is a silicon-based adsorption material;

[0015] Optionally, the adsorption material is selected from at least one of all-silicon ZSM-5 and all-silicon β molecular sieve.

[0016] Optionally, in step S1, the sulfuric acid solution is a solution containing sulfuric acid, wherein the sulfuric acid concentration is 60-95 wt %, and the remaining components are selected from at least one of water, phosphoric acid and hydrochloric acid.

[0017] Optionally, in step S1, the sulfuric acid solution is a solution containing sulfuric acid, wherein the sulfuric acid concentration is 70-95 wt %, and the remaining components are selected from at least one of water, phosphoric acid and hydrochloric acid.

[0018] Optionally, in step S2, the dilute acid solution is an aqueous solution of sulfuric acid, wherein the sulfuric acid concentration is 1 to 5 mol / L, or the dilute acid solution is a mixed solution of sulfuric acid and hydrochloric acid, wherein the sulfuric acid concentration is 0.1 to 3 mol / L and the hydrochloric acid concentration is 1 to 8 mol / L.

[0019] Optionally, the conditions for the heating reaction include: a reaction temperature of 150 to 220° C. and a reaction time of 10 to 40 hours.

[0020] Optionally, the reaction process is stirred.

[0021] Optionally, the step S1 further includes post-processing steps such as dilution, impurity removal, and drying.

[0022] Optionally, the reaction temperature of the heating reaction is 160-200°C.

[0023] Optionally, the reaction temperature of the heating reaction is selected from any value of 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, or any range therebetween.

[0024] Optionally, the reaction time of the heating reaction is 20 to 30 hours.

[0025] Optionally, the reaction time of the heating reaction is selected from any value of 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h, 30h, or any range value therebetween.

[0026] Optionally, the solid-to-liquid ratio of the mixture to the sulfuric acid solution is 0.1 to 1 g:1 mL.

[0027] Optionally, the concentration of vanadium ions in the vanadium electrolyte is 1 to 2.5 mol / L, wherein the concentration of trivalent vanadium ions is equal to that of tetravalent vanadium ions;

[0028] The concentration of sulfate ions is 1 to 5 mol / L.

[0029] Optionally, the concentration of vanadium ions in the vanadium electrolyte is 1.5 to 2.5 mol / L.

[0030] Optionally, the concentration of sulfate ions in the vanadium electrolyte is 3-5 mol / L.

[0031] According to another aspect of the present application, there is provided a use of the vanadium electrolyte prepared by the above preparation method as an electrolyte for an all-vanadium liquid flow battery.

[0032] The beneficial effects of this application include:

[0033] The preparation method of the vanadium electrolyte provided by the invention can realize the preparation of solid hydrated vanadium sulfate, and on this basis, electrolysis is used to prepare and apply the vanadium battery electrolyte. After adding the adsorption material, the purity of the product can be improved and the content of impurity ions can be reduced. The scheme is simple to operate, has a rapid reaction, and can greatly shorten the preparation cycle. The obtained vanadium electrolyte can meet the current application requirements of vanadium batteries. DETAILED DESCRIPTION

[0034] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0035] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0036] Unless otherwise specified, conventional methods were used for testing and instrument settings were those recommended by the manufacturer.

[0037] Example 1

[0038] Weigh V 2 O 5 9.1g of solid, add 2.4g of elemental sulfur and 0.1g of all-silicon ZSM-5 molecular sieve, then add 20mL of sulfuric acid solution with a mass fraction of 80%, continue stirring at 150℃, react for 10h, perform desulfurization, filtration, drying and other operations, and then dissolve the solid reactant in dilute sulfuric acid and dilute to 50mL. After testing, the content of impurity elements is 0.053%. The obtained solution is electrolyzed at a constant current of 2A for 40.14min to obtain a vanadium battery electrolyte, in which the concentration of trivalent vanadium ions is 1mol / L, the concentration of tetravalent vanadium ions is 1mol / L, and the concentration of sulfate ions is 4.6mol / L.

[0039] Example 2

[0040] Weigh V 2 O 5 9.1g of solid, add 2.4g of elemental sulfur and 0.1g of all-silicon beta molecular sieve, then add 20mL of 90% sulfuric acid solution, stir continuously at 150℃, react for 10h, remove sulfur, filter, dry and other operations, then dilute the solid reactant to 40mL with de-diluted sulfuric acid, filter, and then adjust the filtrate to 50mL. After testing, the content of impurity elements is 0.055%. The obtained solution is electrolyzed at a constant current of 2A for 40.14min to obtain a vanadium battery electrolyte, in which the concentration of trivalent vanadium ions is 1mol / L, the concentration of tetravalent vanadium ions is 1mol / L, and the concentration of sulfate ions is 4.6mol / L.

[0041] Example 3

[0042] Weigh V 2 O 5 14.56g of solid, add 3.2g of elemental sulfur and 0.1g of all-silicon beta molecular sieve, then add 40mL of sulfuric acid solution with a mass fraction of 80%, continue stirring at 150℃, react for 10h, perform desulfurization, filtration, drying and other operations, then dissolve the solid reactant in dilute sulfuric acid and dilute to 80mL, filter, and then adjust the filtrate to 100mL. After testing, the content of impurity elements is 0.051%. The obtained solution is electrolyzed at a constant current of 4A for 32.11min to obtain a vanadium battery electrolyte, in which the concentration of trivalent vanadium ions is 0.8mol / L, the concentration of tetravalent vanadium ions is 0.8mol / L, and the concentration of sulfate ions is 4.6mol / L.

[0043] Example 4

[0044] Weigh V2 O 5 9.1g of solid, add 2.4g of elemental sulfur and 0.1g of all-silicon ZSM-5 molecular sieve, then add 20mL of sulfuric acid solution with a mass fraction of 80%, continue stirring at 170℃, react for 12h, perform desulfurization, filtration, drying and other operations, then dissolve the solid reactant in dilute sulfuric acid and dilute to 40mL, filter, and then adjust the filtrate to 50mL. After testing, the content of impurity elements is 0.049%. The resulting solution is electrolyzed at a constant current of 2A for 40.14min to obtain a vanadium battery electrolyte, in which the concentration of trivalent vanadium ions is 1mol / L, the concentration of tetravalent vanadium ions is 1mol / L, and the concentration of sulfate ions is 4.6mol / L.

[0045] Example 5

[0046] Weigh V 2 O 5 9.1g of solid, add 2.4g of elemental sulfur and 0.1g of all-silicon ZSM-5 molecular sieve, then add 32.2mL of 90% sulfuric acid solution, stir continuously at 120℃, react for 30h, remove sulfur, filter, dry and other operations, then dissolve the solid reactant in dilute sulfuric acid and dilute to 40mL, filter, and then adjust the filtrate to 50mL. After testing, the content of impurity elements is 0.054%. The obtained solution is electrolyzed at a constant current of 2A for 40.14min to obtain a vanadium battery electrolyte, in which the concentration of trivalent vanadium ions is 1mol / L, the concentration of tetravalent vanadium ions is 1mol / L, and the concentration of sulfate ions is 4.6mol / L.

[0047] Example 6

[0048] Weigh V 2 O 5 9.1g of solid, add 2.4g of elemental sulfur and 0.1g of all-silicon ZSM-5 molecular sieve, then add 18.3mL of 95% sulfuric acid solution, stir continuously at 200℃, react for 25h, remove sulfur, filter, dry and other operations, then dissolve the solid reactant in dilute sulfuric acid and dilute to 40mL, filter, and then adjust the filtrate to 50mL. After testing, the content of impurity elements is 0.054%. The obtained solution is electrolyzed at a constant current of 2A for 40.14min to obtain a vanadium battery electrolyte, in which the concentration of trivalent vanadium ions is 1mol / L, the concentration of tetravalent vanadium ions is 1mol / L, and the concentration of sulfate ions is 4.2mol / L.

[0049] Example 7

[0050] Weigh V 2 O 59.1g of solid, add 2.4g of elemental sulfur and 0.08g of all-silicon ZSM-5 molecular sieve, then add 18.3mL of 95% sulfuric acid solution, stir continuously at 200℃, react for 25h, remove sulfur, filter, dry and other operations, then dissolve the solid reactant in dilute sulfuric acid and dilute to 40mL, filter, and then adjust the filtrate to 50mL. After testing, the content of impurity elements is 0.049%. The obtained solution is electrolyzed at a constant current of 2A for 40.14min to obtain a vanadium battery electrolyte, in which the concentration of trivalent vanadium ions is 1mol / L, the concentration of tetravalent vanadium ions is 1mol / L, and the concentration of sulfate ions is 4.2mol / L.

[0051] Comparative Example 1

[0052] Weigh V 2 O 5 9.1g of solid, 2.4g of elemental sulfur and 0.08g of all-silicon ZSM-5 molecular sieve were added, followed by 30mL of 98% sulfuric acid solution, stirring continuously at 180°C, reacting for 12h, desulfurization, filtration, drying and other operations, then the solid reactant was dissolved and diluted to 40mL with dilute sulfuric acid, filtered, and a yellow substance was found to be generated, which was insoluble in water. It was impossible to perform electrolysis to prepare the electrolyte for the all-vanadium redox flow battery.

[0053] Comparative Example 2

[0054] Weigh V 2 O 5 To 9.1 g of solid, 2.4 g of elemental sulfur and 0.08 g of all-silicon ZSM-5 molecular sieve were added, followed by 30 mL of 40% sulfuric acid solution by mass. The mixture was stirred continuously at 180 °C and reacted for 25 h. After desulfurization, filtration, drying and other operations, the reactant was dissolved and diluted to 40 mL with dilute sulfuric acid and filtered. A blue solution was generated, but the target hydrated vanadium sulfate solid was not obtained.

[0055] Comparative Example 3

[0056] Weigh V 2 O 5 9.1g of solid, add 2.4g of elemental sulfur, then add 20mL of 80% sulfuric acid solution, continue stirring at 150℃, react for 10h, perform desulfurization, filtration, drying and other operations, dilute the reactant with deionized water to 40mL, filter, and then make the filtrate to 50mL. After testing, the impurity element content is 0.092%.

[0057] Comparative Example 4

[0058] Weigh V 2 O 59.1g of solid, add 5g of oxalic acid and 0.1g of all-silicon ZSM-5 molecular sieve, then add 20mL of 50% sulfuric acid solution, stir continuously at 70℃, react for 2h, and generate a blue solution. The reactant is dissolved and diluted to 40mL with de-diluted sulfuric acid, filtered, and the filtrate is fixed to 50mL. After testing, the content of impurity elements is 0.055%. The concentration of tetravalent vanadium ions is 2mol / L, and the concentration of sulfate ions is 4.6mol / L.

[0059] It can be seen from Comparative Examples 1 to 4 that if the sulfuric acid concentration is too high during the reaction, the product is a yellow substance, and if the sulfuric acid concentration is too low, the product is blue, and the target hydrated vanadium sulfate solid cannot be obtained. If no adsorbent is added, the impurity content in the product is high. If non-elemental sulfur is used as a reducing agent, the product is also a blue solution. Therefore, outside the protection range, a satisfactory product cannot be obtained.

[0060] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a vanadium electrolyte, It is characterized in that The steps include: S1, in the presence of V 2 O 5 A sulfuric acid solution is added to a mixture of solid, elemental sulfur and adsorbent material, heated for reaction, desulfurized and filtered to obtain a high-purity hydrated alum sulfate solid; S2, dissolving the high-purity hydrated alum sulfate solid in step S1 in a dilute acid solution, and electrolyzing to obtain the vanadium electrolyte.

2. The preparation method according to claim 1, It is characterized in that The V 2 O 5 The molar ratio of solid to elemental sulfur is 1:1 to 1.

2.

3. The preparation method according to claim 1, It is characterized in that In the mixture, the amount of adsorbent material is V 2 O 5 0.1-1% of the total weight of solid and elemental sulfur.

4. The preparation method according to claim 1, It is characterized in that The adsorption material is a silicon-based adsorption material.

5. The preparation method according to claim 4, It is characterized in that The adsorption material is selected from at least one of all-silicon ZSM-5 and all-silicon β molecular sieve.

6. The preparation method according to claim 1, It is characterized in that In step S1, the sulfuric acid solution is a solution containing sulfuric acid, wherein the sulfuric acid concentration is 60-95 wt %, and the remaining components are selected from at least one of water, phosphoric acid, and hydrochloric acid; In step S2, the dilute acid solution is an aqueous solution of sulfuric acid, wherein the concentration of sulfuric acid is 1-5 mol / L, or the dilute acid solution is a mixed solution of sulfuric acid and hydrochloric acid, wherein the concentration of sulfuric acid is 0.1-3 mol / L, and the concentration of hydrochloric acid is 1-8 mol / L.

7. The preparation method according to claim 1, It is characterized in that The conditions of the heating reaction include: a reaction temperature of 150 to 220° C. and a reaction time of 10 to 40 hours.

8. The preparation method according to claim 1, It is characterized in that The solid-to-liquid ratio of the mixture to the sulfuric acid solution is 0.1-1 g:1 mL.

9. The preparation method according to claim 1, It is characterized in that The concentration of vanadium ions in the vanadium electrolyte is 1-2.5 mol / L, wherein the concentration of trivalent vanadium ions is equal to that of tetravalent vanadium ions; The concentration of sulfate ions is 1 to 5 mol / L.

10. Use of the vanadium electrolyte prepared by the preparation method according to any one of claims 1 to 9 as an electrolyte for all-vanadium redox flow batteries.