Method for preparing vanadium electrolyte from vanadium trioxide

Abstract

The invention discloses a method for preparing a vanadium electrolyte by using vanadium trioxide, which comprises the following steps: S1, mixing vanadium trioxide with an acid solution, and dissolving and reacting under the conditions of heating and stirring to obtain a vanadium ion solution; s2, a pH adjusting solution is added into the vanadium ion solution and adjusted to a preset pH value, and a vanadium-containing intermediate solution is obtained; and S3, purifying the vanadium-containing intermediate solution to obtain a vanadium electrolyte, and storing the vanadium electrolyte in a dark place. Vanadium trioxide is used as a raw material, the raw material is wide in source and low in cost, the preparation process is simple and clear and easy to operate and control, and the prepared vanadium electrolyte is high in purity, good in stability and suitable for the new energy field of all-vanadium redox flow batteries and the like.

Description

Technical Field

[0001] The invention relates to the technical field of new energy materials, and in particular to a method for preparing a vanadium electrolyte by utilizing vanadium trioxide. Background Art

[0002] As the core component of all-vanadium flow batteries, the performance of vanadium electrolyte directly affects the energy density, cycle stability and service life of the battery. At present, there are many methods for preparing vanadium electrolyte, but there are generally problems such as high raw material cost, complex preparation process, low electrolyte purity or poor stability.

[0003] Therefore, it is of great significance to develop a method with easily available raw materials, simple process and the ability to prepare high-performance vanadium electrolyte. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for preparing vanadium electrolyte using vanadium trioxide. Vanadium trioxide is used as a raw material, the raw material source is wide and the cost is low, the preparation process is simple and clear, easy to operate and control, and the prepared vanadium electrolyte has high purity and good stability, and is suitable for new energy fields such as all-vanadium liquid flow batteries.

[0005] According to one aspect of the present invention, a method for preparing a vanadium electrolyte using vanadium trioxide is provided, which comprises the following steps: S1, mixing vanadium trioxide with an acidic solution, dissolving and reacting under heating and stirring conditions to obtain a vanadium ion solution; S2, adding a pH adjusting solution to the vanadium ion solution and adjusting the pH to a preset pH value to obtain a vanadium-containing intermediate solution; S3. Purify the vanadium-containing intermediate solution to obtain a vanadium electrolyte and store it in a dark place.

[0006] According to one embodiment of the present invention, the purity of vanadium trioxide is ≥99.0wt%.

[0007] According to one embodiment of the present invention, the acidic solution includes at least one of sulfuric acid and hydrochloric acid.

[0008] According to one embodiment of the present invention, the pH regulating solution includes an acidic regulating solution and / or an alkaline regulating solution and / or a buffer solution.

[0009] According to one embodiment of the present invention, the acidic regulating solution includes at least one of hydrochloric acid, sulfuric acid and nitric acid, the alkaline regulating solution includes at least one of sodium hydroxide solution, potassium hydroxide solution and ammonia water, and the buffer solution includes at least one of phosphate buffer and acetic acid-sodium acetate buffer.

[0010] According to one embodiment of the present invention, the preset pH value ranges from 1.0 to 3.0.

[0011] According to one embodiment of the present invention, in step S1, the heating temperature range is 60-90° C., and the reaction time is 5-10 min.

[0012] According to one embodiment of the present invention, the light-proof storage includes storing in a borosilicate glass container.

[0013] According to one embodiment of the present invention, the method further comprises testing and analyzing the electrolyte before use to ensure that its quality and performance meet the use requirements.

[0014] According to one embodiment of the present invention, the detection and analysis include at least one of vanadium ion valence analysis, impurity detection and conductivity measurement.

[0015] In a method for preparing a vanadium electrolyte using vanadium trioxide according to an embodiment of the present invention, vanadium trioxide is used as a raw material, the raw material source is wide and the cost is low, the preparation process is simple and clear, easy to operate and control, and the prepared vanadium electrolyte has high purity and good stability, and is suitable for new energy fields such as all-vanadium liquid flow batteries, thereby achieving maximum economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings required for use in the embodiment will be briefly introduced below. Obviously, the drawings described below are only some implementation cases of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A process flow chart of a method for preparing a vanadium electrolyte by using vanadium trioxide according to an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION

[0018] The detailed description of the following embodiments is used to exemplify the principles of the present invention, but cannot be used to limit the scope of the present invention. The present invention can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0019] The present invention provides these embodiments to make this disclosure thorough and complete, and fully express the scope of the present invention to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of materials, numerical expressions and numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, rather than as limiting.

[0020] It should be noted that, in the description of the present invention, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0021] It should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0022] All terms used in the present invention have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, for example, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0023] Technologies, methods, and apparatus known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, these technologies, methods, and apparatus should be considered part of the specification.

[0024] Vanadium trioxide (V 2 O 3 ) has potential application value in the preparation of vanadium electrolyte, which can be converted into vanadium ion solution suitable for battery use through specific chemical reactions.

[0025] V 2 O 3 +3H 2 SO 4 =V 2 (SO 4 ) 3 +3H 2 O(1) V 2 O 3 +3H 2 SO 4 =2VOSO 4 +SO2 +3H 2 O(2) 2V 2 O 3 +6H 2 SO 4 =V 2 (SO 4 ) 3 +2VOSO 4 +SO 2 +6H 2 O(1)+(2) like Figure 1 As shown, the present invention provides a method for preparing a vanadium electrolyte using vanadium trioxide, which comprises the following steps: S1, mixing vanadium trioxide with an acidic solution, dissolving and reacting under heating and stirring conditions to obtain a vanadium ion solution; S2, adding a pH adjusting solution to the vanadium ion solution and adjusting the pH to a preset pH value to obtain a vanadium-containing intermediate solution; S3. Purify the vanadium-containing intermediate solution to obtain a vanadium electrolyte and store it in a dark place.

[0026] In the method for preparing vanadium electrolyte using vanadium trioxide according to the embodiment of the present invention, vanadium trioxide has significant advantages as a raw material, and its raw material sources are wide, covering various types of ores and industrial by-products, and the cost is low; the preparation process is simple and clear, and only vanadium trioxide needs to be mixed with dilute sulfuric acid, heated and stirred, and then pH adjusting liquid is added to adjust the pH value to a suitable range; it is easy to operate, does not require complex technology and equipment, and is easy to control; the prepared vanadium electrolyte has high purity and good stability, and can meet the stringent requirements of new energy fields such as all-vanadium liquid flow batteries. This not only improves product performance, but also can significantly reduce costs and maximize economic benefits.

[0027] In some specific embodiments, the purity of vanadium trioxide is ≥99.0wt%. The presence of impurities may have an adverse effect on the performance of the electrolyte. For example, metal impurities may participate in the redox reaction in the electrolyte, change the reaction path and potential, and affect the charge and discharge performance of the battery. Therefore, for some application scenarios with high performance requirements, such as long-life, high-energy-density vanadium battery systems, the purity of vanadium trioxide may need to reach 99.5% or even higher.

[0028] Based on the above embodiment, the acidic solution includes at least one of sulfuric acid and hydrochloric acid. Specifically, dilute sulfuric acid is used for the reaction. The mass fraction of the dilute sulfuric acid is 30-40%.

[0029] Sulfuric acid and hydrochloric acid are different in properties. Sulfuric acid is strongly oxidizing and acidic, while hydrochloric acid has strong acidity and special properties of chloride ions. When vanadium trioxide reacts with sulfuric acid or hydrochloric acid, different reaction mechanisms and products will appear. For example, when sulfuric acid reacts with vanadium trioxide, sulfate ions may form specific compounds with vanadium ions, while chloride ions in hydrochloric acid may form different complexes with vanadium ions, which provides more options for the preparation of different types of vanadium compounds.

[0030] Sulfuric acid and hydrochloric acid have different acid strengths, and they have different effects on the reaction rate. Hydrochloric acid is relatively strong in acidity, and when reacting with vanadium trioxide, it can make the reaction rate faster. Sulfuric acid is relatively weak in acidity, but in some cases, its oxidizing properties can participate in the reaction, making the reaction rate different. By choosing sulfuric acid or hydrochloric acid, or a mixture of the two, the reaction rate can be adjusted to meet different experimental or production needs.

[0031] In some specific embodiments, the pH adjusting solution includes an acidic adjusting solution and / or an alkaline adjusting solution and / or a buffer solution.

[0032] Based on the above embodiments, the acidic regulating solution includes at least one of hydrochloric acid, sulfuric acid and nitric acid, the alkaline regulating solution includes at least one of sodium hydroxide solution, potassium hydroxide solution and ammonia water, and the buffer solution includes at least one of phosphate buffer and acetic acid-sodium acetate buffer.

[0033] If the pH of the solution is too high and needs to be acidified, hydrochloric acid solution can be added dropwise; sodium hydroxide is a strong base that can quickly increase the pH value of the solution; phosphate buffer is composed of sodium dihydrogen phosphate and disodium hydrogen phosphate. It can effectively resist pH changes within a certain pH range.

[0034] In some specific embodiments, the preset pH value ranges from 1.0 to 3.0. In this acidic range, vanadium ions can exist in the solution in a stable ionic form. Lower pH values ​​help prevent the hydrolysis and precipitation of vanadium ions because, in an acidic environment, hydrogen ions can inhibit the combination of vanadium ions and hydroxide ions to form hydroxide precipitates. When the pH value is higher than 3, high-valent vanadium ions may undergo hydrolysis reactions to form polyvanadic acid precipitates, thereby affecting the performance and stability of the electrolyte.

[0035] Based on the above embodiment, in step S1, the heating temperature range is 60-90° C., and the reaction time is 5-10 min.

[0036] The temperature is between 60 and 90°C, which can make the reactant molecules obtain enough energy and accelerate the reaction rate. In this temperature range, the molecular motion is intensified, the collision frequency increases, and the reaction of vanadium trioxide and dilute sulfuric acid is accelerated. For example, in this temperature range, the reaction rate is significantly higher than that at room temperature, and the reaction can be completed in a shorter time.

[0037] The reaction time of 5 to 10 minutes is sufficient for the vanadium trioxide to fully dissolve and fully react with the dilute sulfuric acid. This time length avoids incomplete reaction due to too short a reaction time and ensures the generation of sufficient vanadium ion solution. For example, within this time period, vanadium trioxide can be completely converted into soluble vanadium ions, ensuring the adequacy of the reaction.

[0038] The temperature is controlled at 60~90℃, which is relatively moderate and can avoid side reactions caused by excessively high temperatures. Within this temperature range, side reactions caused by high temperatures, such as oxidation reactions and decomposition reactions, can be effectively reduced, thereby improving product purity and quality.

[0039] This temperature range and reaction time provide good conditions for subsequent reactions. For example, for the subsequent pH adjustment step, this reaction condition can make the solution state more stable, making it easier to adjust the pH value to the desired range, thereby improving the stability and performance of the product.

[0040] In some specific embodiments, light-proof storage includes storing in a borosilicate glass container in a light-proof state. Borosilicate glass has good chemical compatibility with vanadium electrolyte. It can resist the corrosion of acid in vanadium electrolyte and will not chemically react with vanadium ions. The chemical inertness of glass can ensure that the composition of the electrolyte does not change during storage. At the same time, the glass container has good transparency, which is convenient for observing the state of the electrolyte, such as whether there is precipitation or color change.

[0041] On the basis of the above embodiments, the method also includes testing and analyzing the electrolyte before use to ensure that its quality and performance meet the use requirements. Testing and analysis include testing the composition and purity of the electrolyte and analyzing the pH, conductivity and other physical properties of the electrolyte. By testing the composition and purity of the electrolyte, it can be ensured that its impurity content meets the standards to avoid excessive impurities affecting battery performance, such as reducing the battery's charging and discharging efficiency and shortening the battery life; analyzing the pH, conductivity and other physical properties of the electrolyte helps to optimize the battery's operating environment and ensure the battery's stability and reliability; evaluating the performance indicators of the electrolyte, such as the battery's capacity and internal resistance, can timely discover potential problems, take measures in advance to adjust or replace them, and improve the safety and operating efficiency of the entire system.

[0042] Based on the above embodiments, purification includes purifying the vanadium-containing intermediate solution to remove impurities and unreacted raw materials therein, and ensuring the clarity and purity of the electrolyte by filtering, centrifuging or other suitable separation means.

[0043] On the basis of the above embodiments, the detection and analysis include at least one of vanadium ion valence analysis, impurity detection and conductivity measurement.

[0044] The valence state of vanadium ions determines the characteristics of their redox reactions in batteries. By analyzing the valence state of vanadium ions, we can ensure that the chemical reactions in the battery proceed normally, thereby improving the battery's charge and discharge efficiency. For example, in an all-vanadium liquid flow battery, vanadium ions of different valence states undergo reversible redox reactions on the electrodes, and valence state analysis helps adjust the working state of the battery, making the battery output stable and efficient.

[0045] The presence of impurities may interfere with the normal reaction of vanadium ions and affect the stability of the battery. By detecting the type and content of impurities, potential problems can be discovered in time and measures can be taken. For example, certain metal impurities may react with vanadium ions, change the electrochemical properties of the battery, and increase the self-discharge rate of the battery. Impurity detection can ensure that the battery maintains stable performance during long-term use.

[0046] Conductivity is an important indicator to measure the conductivity of electrolyte. By measuring conductivity, the transmission efficiency of ions inside the battery can be evaluated. High conductivity means that the ions inside the battery move quickly, which can quickly transfer charge and improve the charging and discharging efficiency of the battery. For example, in vanadium batteries, the level of conductivity directly affects the performance of the battery. The higher the conductivity, the greater the power output of the battery.

[0047] Using vanadium trioxide to prepare vanadium electrolyte is a feasible method, but it requires strict control of raw material purity, reaction conditions, pH adjustment, purification and filtration to ensure the quality and performance of the electrolyte. At the same time, it is also necessary to pay attention to safety and environmental protection issues to ensure the safety and environmental protection of the production process.

[0048] The present application is described in detail below through specific embodiments.

[0049] Example 1 Take 200g of high-purity vanadium trioxide and put it into a 1000ml beaker, slowly add 400ml of 40% dilute sulfuric acid and stir, put the mixed material into a heating furnace and heat it for 5 minutes, add sodium hydroxide to adjust the pH value during the heating process, and stir continuously to make the vanadium trioxide fully dissolved in the dilute sulfuric acid. After stopping the heating, let it stand for 30 minutes, filter it, and test the filtrate. The test results show that V 4+ The concentration is 0.9 mol / L, V 3+The concentration is 0.7mol / L.

[0050] Example 2 Take 200g of high-purity vanadium trioxide and put it into a 1000ml beaker, slowly add 400ml of 40% dilute sulfuric acid and stir, put the mixed material into a heating furnace and heat it for 5 minutes, add sodium hydroxide to adjust the pH value during the heating process, and stir continuously to make the vanadium trioxide fully dissolved in the dilute sulfuric acid. After stopping the heating, let it stand for 30 minutes, filter it, and test the filtrate. The test results show that V 4+ The concentration is 0.8 mol / L, V 3+ The concentration is 0.8mol / L.

[0051] After the implementation of the present invention, at least the following beneficial effects are achieved: (1) The raw material source is extremely abundant. Vanadium trioxide is widely present in nature, making its cost relatively low, providing a solid foundation for the large-scale production of vanadium electrolyte.

[0052] (2) The preparation process is simple and clear. By mixing vanadium trioxide with an appropriate amount of dilute sulfuric acid, the vanadium trioxide quickly dissolves and reacts under heating and stirring conditions. This process does not require complex equipment and technology, and can be completed with ordinary laboratory equipment. Throughout the preparation process, it is easy to operate and control, and the professional skills required of the operator are relatively low.

[0053] (3) The prepared vanadium electrolyte has high purity and good stability. During the preparation process, the purity of the vanadium electrolyte is ensured by strictly controlling the reaction conditions and performing necessary purification steps. High-purity vanadium electrolyte can effectively improve the performance and service life of the battery and reduce the side reactions and energy loss inside the battery. At the same time, the good stability enables the vanadium electrolyte to maintain stable performance under different environmental conditions, providing reliable guarantee for the application of new energy fields such as all-vanadium liquid flow batteries.

[0054] The above are exemplary embodiments disclosed in the present invention. The order disclosed in the above embodiments of the present invention is for description only and does not represent the advantages and disadvantages of the embodiments. However, it should be noted that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope disclosed in the embodiments of the present invention (including the claims) is limited to these examples. Various changes and modifications may be made without departing from the scope defined in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless explicitly limited to the singular.

[0055] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for preparing a vanadium electrolyte using vanadium trioxide, characterized in that: The following steps are involved: S1, mixing vanadium trioxide with an acidic solution, dissolving and reacting under heating and stirring conditions to obtain a vanadium ion solution; S2, adding a pH adjusting solution to the vanadium ion solution and adjusting the pH to a preset pH value to obtain a vanadium-containing intermediate solution; S3, purifying the vanadium-containing intermediate solution to obtain a vanadium electrolyte and storing it in the dark.

2. The method for preparing vanadium electrolyte using vanadium trioxide according to claim 1, characterized in that: The purity of the vanadium trioxide is ≥99.0wt%.

3. The method for preparing vanadium electrolyte using vanadium trioxide according to claim 1, characterized in that: The acidic solution includes at least one of sulfuric acid and hydrochloric acid.

4. The method for preparing vanadium electrolyte using vanadium trioxide according to claim 1, characterized in that: The pH regulating solution includes an acidic regulating solution and / or an alkaline regulating solution and / or a buffer solution.

5. The method for preparing vanadium electrolyte using vanadium trioxide according to claim 4, characterized in that: The acidic regulating solution includes at least one of hydrochloric acid, sulfuric acid and nitric acid, the alkaline regulating solution includes at least one of sodium hydroxide solution, potassium hydroxide solution and ammonia water, and the buffer solution includes at least one of phosphate buffer and acetic acid-sodium acetate buffer.

6. The method for preparing vanadium electrolyte using vanadium trioxide according to claim 1, characterized in that: The preset pH value ranges from 1.0 to 3.

0.

7. The method for preparing vanadium electrolyte using vanadium trioxide according to claim 1, characterized in that: In step S1, the heating temperature range is 60-90°C, and the reaction time is 5-10 minutes.

8. The method for preparing vanadium electrolyte using vanadium trioxide according to claim 1, characterized in that: The light-proof storage includes storing in a borosilicate glass container.

9. The method for preparing vanadium electrolyte using vanadium trioxide according to claim 1, characterized in that: The method also includes testing and analyzing the electrolyte before use to ensure that its quality and performance meet the use requirements.

10. The method for preparing vanadium electrolyte using vanadium trioxide according to claim 9, characterized in that: The detection and analysis include at least one of vanadium ion valence analysis, impurity detection and conductivity measurement.

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