High-concentration sulfamyl ammonium metavanadate electrolyte as well as preparation method and application thereof

Abstract

The invention relates to an ammonium metavanadate high-concentration vanadium electrolyte and a preparation method thereof. The supporting electrolyte of the electrolyte is sulfamic acid, and the positive electrode electrolyte and the negative electrode electrolyte comprise vanadium ions, sulfonic acid ions and ammonium ions. The positive electrolyte mainly contains tetravalent V (VI) and pentavalent V (V) vanadium ions, and the negative electrolyte mainly contains trivalent V (III) and divalent V (II) vanadium ions. The preparation method comprises the following steps: firstly, preparing a sulfamic acid-based ammonium metavanadate electrolyte precursor with the vanadium ion concentration of 2.0-4.0 mol / L through a sectional reduction method, specifically, dissolving ammonium metavanadate and an optional reducing agent in a sulfamic acid solution, controlling the pH value of the reaction to be 1.0-3.0, and controlling the temperature of the reaction to be 60-100 DEG C to obtain a positive electrode electrolyte precursor and a negative electrode electrolyte precursor; and further obtaining a positive electrode electrolyte and a negative electrode electrolyte of the redox battery through the electrolyte precursor, wherein the positive electrode electrolyte and the negative electrode electrolyte can be used as active substances to form various redox batteries.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical energy storage, and in particular relates to a high-concentration aminosulfonic acid-based ammonium metavanadate electrolyte for positive electrode electrolyte and negative electrode electrolyte of a redox battery and a preparation method thereof. Background Art

[0002] Redox flow battery is a special type of redox battery. The positive and negative active materials of this type of battery are stored in two liquid storage tanks respectively. During operation, the positive and negative electrolytes flow through the positive half-cell and the negative half-cell respectively under the external force of the pump. The capacity of this type of battery is determined by the volume of the liquid storage tank. The power and capacity are decoupled, the configuration is flexible, and it can be adjusted according to user requirements. Due to its long cycle life, high energy efficiency, and environmental friendliness, the redox flow battery is considered to be one of the most promising intermittent renewable energy storage systems. In redox batteries, the concentration of the electrolyte determines the amount of energy stored per unit volume (or mass) of the redox battery, and the composition and properties of the electrolyte determine the rate discharge characteristics, voltage efficiency, and energy efficiency of the liquid flow energy storage system. Therefore, the concentration and electrochemical activity of the electrolyte solution are key factors in battery performance.

[0003] In 1985, Maria Skyllas-Kazacos of the University of New South Wales in Australia proposed the concept of the all-vanadium redox flow battery. In an acidic medium, V(V) and V(IV) form a redox pair VO2 + NO 2+ , whose redox potential is 1.004 volts, can be used as the positive electrode electrolyte of the battery; V(III) and V(II) form a redox pair V 2+ N 3+ , its redox potential is -0.255 volts, and it can be used as the negative electrolyte of the battery. The above-mentioned positive electrolyte and negative electrolyte are used as the positive and negative active materials respectively to form a redox battery, that is, an all-vanadium liquid flow battery. At present, the stable all-vanadium liquid flow battery electrolyte reported in domestic and foreign literatures all uses sulfuric acid as the main solvent, which is a sulfuric acid solution system with a total vanadium concentration of 1.4-2.0 mol / L and a sulfuric acid concentration of 2.0-5.0 mol / L. In sulfuric acid solution, the stability of V(II), V(III), and V(IV) increases with increasing temperature, but V(V) will produce a thermal precipitation effect at temperatures of 40°C and above, so the final concentration of the electrolyte used in the all-vanadium liquid flow battery is limited by the solubility of vanadium in different valence states in the range of 10°C to 40°C. The total vanadium concentration of the electrolyte is generally in the range of 2.0 mol / L, which restricts the improvement of specific energy. How to obtain a high-stability, high-concentration electrolyte and increase the battery voltage is a key issue in realizing a high-energy density redox battery.

[0004] Aminosulfonic acid is an inorganic solid acid formed by replacing the hydroxyl group of sulfuric acid with an amino group. It is a non-volatile, non-corrosive, environmentally friendly, low-cost reagent with low toxicity to the human body. The aqueous solution of aminosulfonic acid has the same strong acidity as hydrochloric acid and sulfuric acid, so it is also called solid sulfuric acid. Single crystal X-ray and neutron diffraction of aminosulfonic acid show that aminosulfonic acid exists in the form of zwitterions. In terms of battery additives and electrolyte applications, aminosulfonic acid can be used as an additive for solid-state batteries, especially in the field of lithium batteries, where it can improve the performance of batteries as an additive and electrolyte. In addition, studies have shown that aminosulfonic acid electrolytes exhibit good performance in redox batteries, and the charge and discharge cycle performance of the battery system is further improved by adding additives. The use of aminosulfonic acid as an electrolyte to prepare all-vanadium liquid flow batteries can reduce the corrosiveness to the equipment.

[0005] At present, the main vanadium raw material for producing vanadium electrolyte is vanadium pentoxide, which is generally produced by high-temperature calcination (above 550°C) of ammonium polyvanadate or ammonium metavanadate and deammoniation. The production conditions and production environment are extremely harsh. Using ammonium metavanadate as a raw material to directly prepare vanadium electrolyte can shorten the preparation process and reduce the production cost of electrolyte. Summary of the invention

[0006] The purpose of the present invention is to expand the production formula and process of vanadium electrolyte in view of the characteristics of the current all-vanadium liquid flow battery electrolyte preparation process, which is high in cost, single in raw materials, and the supporting electrolyte is mainly concentrated sulfuric acid, so as to prepare for the industrial application of all-vanadium liquid flow batteries. The present invention provides a high-concentration vanadium electrolyte for a redox flow battery using ammonium metavanadate as a raw material for supplying vanadium ion electroactive substances and aminosulfonic acid as a supporting electrolyte, and a preparation method thereof. This technology can obtain a high-concentration, high-stability electrolyte in one step, thereby improving the specific energy and energy density of the redox battery including the electrolyte.

[0007] The positive electrode electrolyte and the negative electrode electrolyte provided by the present invention can be applied to all-vanadium redox batteries, and can also be applied to other redox batteries respectively.

[0008] The technical solution of the present invention is achieved by providing a high-concentration electrolyte for a redox battery and a redox battery comprising the electrolyte, wherein the main components of the electrolyte are vanadium ions, hydrogen ions, ammonium ions and sulfonate ions. The electrolyte uses aminosulfonic acid as a solvent, and the introduction of ammonium ions can theoretically improve the electrochemical kinetics of the vanadium electrode pair, while the sulfonic acid and amine groups can form complex ions with V (V) to prevent its precipitation, thereby achieving a high-concentration stable vanadium electrolyte, and the total vanadium concentration can be as high as 2.0 to 4.0 mol / L.

[0009] Another aspect of the present invention provides a method for preparing an electrolyte for a redox battery, comprising the following steps: dissolving ammonium metavanadate and an optional reducing agent in a certain concentration of aminosulfonic acid solution, respectively, and reacting at 60-100°C to obtain an electrolyte precursor with a total vanadium concentration of 2.0 to 4.0 mol / L; and electrolyzing the electrolyte precursor to obtain a positive electrode electrolyte and a negative electrode electrolyte for a redox battery.

[0010] The positive electrolyte precursor contains III-valent vanadium, or IV-valent vanadium, or a mixture of III-valent vanadium and IV-valent vanadium, or a mixture of IV-valent vanadium and V-valent vanadium.

[0011] The negative electrode electrolyte precursor comprises III-valent vanadium, or IV-valent vanadium, or a mixture of III-valent vanadium and IV-valent vanadium. The reducing agent is selected from one of ascorbic acid, tartaric acid, citric acid, hydrogen peroxide, formic acid, acetic acid and sodium sulfite.

[0012] The invention discloses a method for preparing a high-concentration vanadium electrolyte for a redox battery. The obtained electrolyte has a higher total vanadium concentration, good stability and electrochemical activity.

[0013] The positive electrode electrolyte and the negative electrode electrolyte of the present invention can form an all-vanadium redox battery. The positive electrode electrolyte can also form a new redox battery with another negative electrode active material. The negative electrode electrolyte can also form a new redox battery with another positive electrode active material.

[0014] The electrolyte of the redox battery may be of a liquid flow type or a non-liquid flow type.

[0015] Compared with the prior art, the method of the present invention has the following advantages:

[0016] (1) The present invention utilizes the difference in the solubility of vanadate at different temperatures and pH values, controls the temperature and multiple additions to ensure the solubility of vanadate, and obtains a high concentration, thereby eliminating the process of crystallization and re-dissolution, being environmentally friendly and low in cost.

[0017] (2) The entire process of the technology of the present invention is a wet process, physical crystallization and purification, no high temperature reaction, calcination process is required, low energy consumption, easy operation, no waste gas and waste residue are generated, the liquid in the whole process can be recycled, and the process is clean.

[0018] (3) The present invention uses ammonium metavanadate as the vanadium raw material to prepare the electrolyte and aminosulfonic acid as the supporting electrolyte, which broadens the range of raw materials for preparing the vanadium battery electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1: The change diagram of the efficiency (current efficiency, voltage efficiency, energy efficiency) of the all-vanadium liquid flow battery after 20 charge and discharge cycles. The positive and negative electrolytes are both vanadium electrolytes with a total vanadium ion concentration of 2.1 mol / L and an aminosulfonic acid concentration of 3.0 mol / L. DETAILED DESCRIPTION

[0020] The high concentration vanadium electrolyte for redox battery of the present invention and its preparation method, as well as the redox battery including the electrolyte are specifically described. Those skilled in the art should understand that the following specific description is for the purpose of facilitating the understanding of the present invention. The technical solution of the present invention is not limited to the specific implementation methods listed below, but also includes any combination of the specific methods.

[0021] Since the concentration of active materials in a redox battery determines the energy density of the battery, and the total vanadium concentration in the vanadium-containing ions as active materials in the electrolyte obtained using the above preparation method is relatively high, the redox battery containing the above electrolyte has a relatively high energy density.

[0022] Example 1

[0023] Weigh 29.1g aminosulfonic acid, add 100ml water, stir at 30℃ for 10 minutes, stirring rate is 500r / min, add 7.8g ammonium metavanadate, heat to 70℃, stir for 30 minutes, add 11.7g ascorbic acid, react at 70℃ for 2h, add 29.1g aminosulfonic acid to the above solution, stir at 70℃ for 10 minutes, add 7.8g ammonium metavanadate, stir at 70℃ for 30 minutes, add 11.7g ascorbic acid, react at 70℃ for 2h h, add 29.1 g of aminosulfonic acid to the above solution, stir at 70 ° C for 10 minutes, add 7.8 g of ammonium metavanadate, stir at 70 ° C for 30 minutes, add 11.7 g of ascorbic acid, and react at 70 ° C for 2 hours to finally obtain ammonium metavanadate / aminosulfonic acid electrolyte with an electrolyte vanadium concentration of 2.1 mol / L and an aminosulfonic acid concentration of 3.0 mol / L, which meets the requirements of GB / T37204-2018 "Electrolyte for All-vanadium Redox Flow Batteries" for quadrivalent electrolyte.

[0024] Example 2

[0025] Weigh 31.8g of aminosulfonic acid, add 100ml of water, stir at 30℃ for 10 minutes, stirring rate is 500r / min, add 11.7g of ammonium metavanadate, heat to 90℃, stir for 30 minutes, add 18g of tartaric acid, react at 90℃ for 2h, add 31.5g of aminosulfonic acid to the above solution, stir at 90℃ for 10 minutes, add 11.7g of ammonium metavanadate, stir at 90℃ for 30 minutes, add 18g of tartaric acid, react at 90℃ for 2h, add 31.5g of aminosulfonic acid to the above solution, stir at 90℃ for 10 minutes, add 11.7g of ammonium metavanadate, stir at 90℃ for 30 minutes, add 18g of tartaric acid, react at 90℃ for 2h, add 31.5g of aminosulfonic acid to the above solution, stir at 90℃ for 10 minutes, add .7g ammonium metavanadate, stirred at 90℃ for 30 minutes, added 18g tartaric acid, reacted at 90℃ for 2h, added 31.5g aminosulfonic acid to the above solution, stirred at 90℃ for 10 minutes, added 11.7g ammonium metavanadate, stirred at 90℃ for 30 minutes, added 18g tartaric acid, reacted at 90℃ for 2h, finally obtained ammonium metavanadate / aminosulfonic acid electrolyte, the vanadium concentration of the electrolyte was 4.0mol / L, and the aminosulfonic acid concentration was 1.0mol / L, which met the requirements of GB / T37204-2018 "Electrolyte for All-vanadium Redox Flow Batteries" for quadrivalent electrolyte.

[0026] Example 3

[0027] Weigh 26.7g of aminosulfonic acid, add 100ml of water, stir at 30℃ for 10 minutes, stirring rate is 500r / min, add 8.8g of ammonium metavanadate, heat to 85℃, stir for 30 minutes, add 14.4g of citric acid, react at 85℃ for 2h, add 26.7g of aminosulfonic acid to the above solution, stir at 85℃ for 10 minutes, add 8.8g of ammonium metavanadate, stir at 85℃ for 30 minutes, add 14.4g of citric acid, react at 85℃ for 2h, add 26.7g of aminosulfonic acid to the above solution, stir at 85℃ for 10 minutes, add 8. 8g of ammonium metavanadate was stirred at 85°C for 30 minutes, 14.4g of citric acid was added, and the reaction was carried out at 85°C for 2h. 26.7g of aminosulfonic acid was added to the above solution, and the mixture was stirred at 85°C for 10 minutes. 8.8g of ammonium metavanadate was added, and the mixture was stirred at 85°C for 30 minutes. 14.4g of citric acid was added, and the reaction was carried out at 85°C for 2h. Finally, an ammonium metavanadate / aminosulfonic acid electrolyte was obtained. The vanadium concentration of the electrolyte was 3.3mol / L, and the aminosulfonic acid concentration was 2.2mol / L, which met the requirements of GB / T37204-2018 "Electrolytes for All-vanadium Liquid Flow Batteries" for quadrivalent electrolytes.

[0028] Example 4

[0029] Weigh 25.8g of aminosulfonic acid, add 100ml of water, stir at 30℃ for 10 minutes, stirring rate is 500r / min, add 7.8g of ammonium metavanadate, heat to 60℃, stir for 30 minutes, add 6.8g of hydrogen peroxide, react at 60℃ for 2h, add 25.8g of aminosulfonic acid to the above solution, stir at 60℃ for 10 minutes, add 7.8g of ammonium metavanadate, stir at 60℃ for 30 minutes, add 6.8g of hydrogen peroxide, react at 60℃ for 2h ; Add 25.8g of aminosulfonic acid to the above solution, stir at 60°C for 10 minutes, add 7.8g of ammonium metavanadate, stir at 60°C for 30 minutes, add 6.8g of hydrogen peroxide, and react at 60°C for 2h; finally, ammonium metavanadate / aminosulfonic acid electrolyte is obtained, the vanadium concentration of the electrolyte is 2.3mol / L, and the aminosulfonic acid concentration is 2.4mol / L, which meets the requirements of GB / T37204-2018 "Electrolyte for All-vanadium Liquid Flow Batteries" for quadrivalent electrolyte.

[0030] Example 5

[0031] Weigh 32.7g of aminosulfonic acid, add 100ml of water, stir at 30℃ for 10 minutes, stirring at a rate of 500r / min, add 11.7g of ammonium metavanadate, heat to 100℃, stir for 30 minutes, add 9.2g of formic acid, react at 100℃ for 2h; add 32.7g of aminosulfonic acid to the above solution, stir at 100℃ for 10 minutes, add 11.7g of ammonium metavanadate, stir at 100℃ for 30 minutes, add 9.2g of formic acid, react at 100℃ for 2h; add 32.7g of aminosulfonic acid to the above solution, stir at 100℃ for 10 minutes, add 1 1.7g of ammonium metavanadate was stirred at 100°C for 30 minutes, 9.2g of formic acid was added, and the mixture was reacted at 100°C for 2h. 32.7g of aminosulfonic acid was added to the above solution, and the mixture was stirred at 100°C for 10 minutes. 11.7g of ammonium metavanadate was added, and the mixture was stirred at 100°C for 30 minutes. 9.2g of formic acid was added, and the mixture was reacted at 100°C for 2h. Finally, an ammonium metavanadate / aminosulfonic acid electrolyte was obtained, and the vanadium concentration of the electrolyte was 4.0mol / L, and the aminosulfonic acid concentration was 1.5mol / L, which met the requirements of GB / T37204-2018 "Electrolyte for All-vanadium Liquid Flow Batteries" for quadrivalent electrolytes.

[0032] Example 6

[0033] Weigh 29.1g aminosulfonic acid, add 100ml water, stir at 30℃ for 10 minutes, stirring rate is 500r / min, add 8.8g ammonium metavanadate, heat to 80℃, stir for 30 minutes, add 6.75g acetic acid, react at 80℃ for 2h, add 29.1g aminosulfonic acid to the above solution, stir at 80℃ for 10 minutes, add 8.8g ammonium metavanadate, stir at 80℃ for 30 minutes, add 6.75g acetic acid, react at 80℃ for 2h; add 29.1g aminosulfonic acid to the above solution, stir at 80℃ for 10 minutes, add 8.8g ammonium metavanadate, stir at 80℃ for 30 minutes, add 6.75g acetic acid, react at 80℃ for 2h; add 29.1g aminosulfonic acid to the above solution, stir at 80℃ for 10 minutes, add 8. 8g ammonium metavanadate was stirred at 80°C for 30 minutes, 6.75g acetic acid was added, and the reaction was carried out at 80°C for 2h; 29.1g aminosulfonic acid was added to the above solution, and the mixture was stirred at 80°C for 10 minutes. 8.8g ammonium metavanadate was added, and the mixture was stirred at 80°C for 30 minutes. 6.75g acetic acid was added, and the reaction was carried out at 80°C for 2h; finally, an ammonium metavanadate / aminosulfonic acid electrolyte was obtained, and the vanadium concentration of the electrolyte was 2.8mol / L, and the aminosulfonic acid concentration was 3.0mol / L, which met the requirements of GB / T37204-2018 "Electrolyte for All-vanadium Liquid Flow Batteries" for quadrivalent electrolytes.

[0034] Example 7

[0035] Weigh 25.5g of aminosulfonic acid, add 100ml of water, stir at 30℃ for 10 minutes, stirring at a rate of 500r / min, add 8.8g of ammonium metavanadate, heat to 70℃, stir for 30 minutes, add 11.3g of sodium sulfite, react at 70℃ for 2h; add 25.5g of aminosulfonic acid to the above solution, stir at 70℃ for 10 minutes, add 8.8g of ammonium metavanadate, stir at 70℃ for 30 minutes, add 11.3g of sodium sulfite, react at 70℃ for 2h; add 25.5g of aminosulfonic acid to the above solution, stir at 70℃ for 10 minutes, add 8.8g of ammonium metavanadate, stir at 70℃ for 30 minutes, add 11.3g of sodium sulfite, react at 70℃ for 2h; add 25.5g of aminosulfonic acid to the above solution, stir at 70℃ for 10 minutes, add 8. 8g of ammonium metavanadate was stirred at 70°C for 30 minutes, 11.3g of sodium sulfite was added, and the mixture was reacted at 70°C for 2h; 25.5g of aminosulfonic acid was added to the above solution, the mixture was stirred at 70°C for 10 minutes, 8.8g of ammonium metavanadate was added, the mixture was stirred at 70°C for 30 minutes, 11.3g of sodium sulfite was added, and the mixture was reacted at 70°C for 2h; finally, an ammonium metavanadate / aminosulfonic acid electrolyte was obtained, the vanadium concentration of the electrolyte was 3.0mol / L, and the aminosulfonic acid concentration was 1.5mol / L, which met the requirements of GB / T37204-2018 "Electrolyte for All-vanadium Liquid Flow Batteries" for quadrivalent electrolytes.

Claims

1. A sulfamic acid-based high-concentration ammonium metavanadate electrolyte and a preparation method thereof, characterized in that The electrolyte comprises a positive electrode electrolyte and a negative electrode electrolyte, and is applied to a redox battery. The main components of the electrolyte are vanadium ions and ammonium ions. The electrolyte uses aminosulfonic acid as a solvent to prepare a high-vanadium concentration electrolyte. The total vanadium concentration in the electrolyte can reach 2.0-4.0 mol / L, and the aminosulfonic acid concentration is 1.0-3.0 mol / L.

2. The aminosulfonic acid-based high-concentration ammonium metavanadate electrolyte and its preparation method according to claim 1, characterized in that The invention relates to a positive electrode electrolyte for a redox battery, wherein the vanadium ions mainly exist in tetravalent and pentavalent vanadium (V(VI), V(V)) states, and the total vanadium concentration can reach 2.0-4.0 mol / L.

3. The aminosulfonic acid-based high-concentration ammonium metavanadate electrolyte and its preparation method according to claim 1, characterized in that The invention relates to a negative electrode electrolyte for a redox battery, wherein the vanadium ions mainly exist in divalent and trivalent (V(II), V(III)) states, and the total vanadium concentration can reach 2.0 to 4.0 mol / L.

4. The method for preparing a sulfamic acid-based high-concentration ammonium metavanadate electrolyte according to claim 1, characterized in that it is used for The method for preparing the positive electrolyte and the negative electrolyte of the redox battery comprises the following steps: dissolving ammonium metavanadate and an optional reducing agent in an aminosulfonic acid solution respectively to obtain an electrolyte with a total vanadium concentration of 2.0 to 4.0 mol / L.

5. The high concentration vanadium electrolyte and the preparation method thereof according to claim 1, characterized in that A method for preparing an electrolyte for a redox battery, wherein the vanadium-containing compound is ammonium metavanadate, the positive electrode electrolyte contains IV-valent vanadium, or a mixture of IV-valent vanadium and V-valent vanadium; and the negative electrode electrolyte contains III-valent vanadium, or IV-valent vanadium, or a mixture of III-valent vanadium and IV-valent vanadium.

6. The method for preparing a sulfamic acid-based high-concentration ammonium metavanadate electrolyte for a redox battery according to claim 1, characterized in that: The purity of the ammonium metavanadate used is greater than 98%.

7. The method for preparing a sulfamic acid-based high-concentration ammonium metavanadate electrolyte for a redox battery according to claim 1, characterized in that: The reducing agent is selected from one of ascorbic acid, tartaric acid, citric acid, hydrogen peroxide, formic acid, acetic acid and sodium sulfite.

8. The aminosulfonic acid-based high-concentration ammonium metavanadate electrolyte and its preparation method according to claim 1, wherein the electrolyte Preparation of the precursor: weigh appropriate amounts of aminosulfonic acid and ammonium metavanadate in stages, place the aminosulfonic acid in a beaker and add appropriate amount of distilled water, add ammonium metavanadate to the solution, gradually add reducing agent, react at 60-100°C, pH range 1.0-3.0, and prepare an aminosulfonic acid-based high-concentration ammonium metavanadate electrolyte precursor with a total vanadium concentration of 2.0-4.0 mol / L.

9. The aminosulfonic acid-based high-concentration ammonium metavanadate electrolyte and its preparation method according to claim 1, wherein the electrolyte is prepared in such a way that the molar ratio of aminosulfonic acid to ammonium metavanadate is 2:1 to 6:1, and the molar ratio of reducing agent to ammonium metavanadate is 1:1 to 3:1.

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