Method for preparing negative electrode electrolyte of all-vanadium redox flow battery
By mixing V2O5 solid with hydrohalogenic acid and activating under the action of dilute acid and organic solvent, the negative electrode electrolyte of all vanadium liquid flow battery is prepared, which solves the problems of cumbersome preparation process and long cycles in the prior art, and efficient and simple preparation of electrolyte is achieved, improving battery performance.
Patent Information
- Application Number
- CN202311737119.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-15
- Publication Date
- 2025-06-17
AI Technical Summary
The preparation process of the negative electrode electrolyte of existing all-vanadium flow battery is cumbersome and has a long preparation cycle, making it difficult to meet the needs of fast and efficient industries.
By mixing the V2O5 solid with hydrohalogenic acid, reacting and activation, then adding dilute acid solution and organic solvent to the mixed solution, stirring and fixed capacity, a negative electrolyte of the all-vana liquid flow battery was obtained. This method is easy to operate, quick reaction, no need for high temperature and high pressure, and can greatly shorten the preparation cycle.
The electrolyte prepared by this method can improve battery performance, with the Coulomb efficiency reaching about 95%, the voltage efficiency is about 86%, and the energy efficiency is about 82%, meeting the current application requirements of vanadium batteries.
Abstract
Description
Technical Field
[0001] The present application relates to a method for preparing a negative electrode electrolyte of a vanadium redox flow battery, belonging to the field of electrolytes. Background Art
[0002] The all-vanadium redox flow battery is a new type of electrochemical energy storage system. Compared with traditional storage batteries, it has the characteristics of fast and large-capacity charge and discharge, low self-discharge rate, and simple battery structure, showing great advantages in the application of fixed energy storage devices for renewable energy. The positive and negative electrode electrolytes of the vanadium battery are sulfuric acid solutions containing V(Ⅴ) / V(Ⅳ) and V(Ⅲ) / V(Ⅱ) vanadium compounds respectively. They are not only conductive media but also electroactive substances for realizing energy storage, and are the core of energy storage and energy conversion of the vanadium battery. Through the transformation of the valence state of vanadium ions, the mutual conversion between electrical energy and chemical energy is realized.
[0003] As the energy storage medium of the flow battery, the electrolyte is an important part of the entire flow battery system. Therefore, the preparation of the electrolyte of the all-vanadium redox flow battery is an important link in the entire industrial chain of the all-vanadium redox flow battery. At present, the preparation of the electrolyte of the all-vanadium redox flow battery mainly includes electrolysis method, reduction method, etc. Vanadium pentoxide is reduced to vanadium tetraoxide through an electrolytic cell or the reduction method, and then vanadium tetraoxide is configured into a solution, and then the tetravalent solution is electrolyzed to trivalent to obtain the negative electrode electrolyte. Summary of the Invention
[0004] According to one aspect of the present application, a method for preparing a negative electrode electrolyte of a vanadium flow battery is provided. This method solves the problems existing in the prior art such as cumbersome operation process and long preparation period. This method is simple to operate, the reaction is rapid, without high temperature and high pressure, and can greatly shorten the preparation period. At the same time, the electrolyte prepared by this method can also improve the battery performance, and the obtained electrolyte can meet the application requirements of the current vanadium battery.
[0005] The method for preparing the negative electrode electrolyte of the all-vanadium redox flow battery described in the present application includes the following steps:
[0006] (1) Mix V2O5 solid and hydrohalic acid, and react for activation to obtain a mixed solution;
[0007] (2) Add a dilute acid solution to the mixed solution, dissolve it, add an organic solvent, stir, separate, and make up the volume to obtain the negative electrode electrolyte of the all-vanadium redox flow battery.
[0008] Optionally, the hydrohalic acid is hydrobromic acid and / or hydroiodic acid.
[0009] Optionally, the organic solvent is selected from any one or more of chloroform, carbon tetrachloride, and carbon disulfide.
[0010] Optionally, the dilute acid solution is dilute sulfuric acid and / or dilute hydrochloric acid.
[0011] Optionally, the addition amounts of the V2O5 solid and the hydrohalic acid are (10 - 25) g : (20 - 50) mL; preferably, the addition amounts of the V2O5 solid and the hydrohalic acid are (10 - 20) g : (25 - 40) mL.
[0012] Optionally, the concentration of the dilute acid solution is 1 - 10 mol / L; preferably, the concentration of the dilute acid solution is 2 - 8 mol / L.
[0013] Optionally, the volume ratio of the organic solvent to the dilute acid solution is 1 : (0.5 - 1.5).
[0014] Specifically, the volume ratio of the organic solvent to the dilute acid solution is 1 : 1.
[0015] Optionally, the concentration of vanadium ions in the negative electrode electrolyte of the all-vanadium redox flow battery is 1 - 2.5 mol / L, and the concentration of hydrogen ions is 1 - 10 mol / L.
[0016] Preferably, the concentration of vanadium ions in the negative electrode electrolyte of the all-vanadium redox flow battery is 1.5 - 2.5 mol / L.
[0017] Specifically, the concentration of vanadium ions in the negative electrode electrolyte of the all-vanadium redox flow battery is 2 mol / L.
[0018] Preferably, the concentration of hydrogen ions in the negative electrode electrolyte of the all-vanadium redox flow battery is 3 - 8 mol / L.
[0019] Optionally, the temperature for reaction activation is 50 - 100 °C, and preferably, the temperature for reaction activation is 60 - 80 °C.
[0020] Optionally, the temperature for reaction activation independently selects any value from 50 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 90 °C, 100 °C or the range value between any two of the above.
[0021] Optionally, the time for reaction activation is 1 - 6 h, and preferably, the time for reaction activation is 2 - 4 h.
[0022] Optionally, the time for reaction activation independently selects any value from 1 h, 2 h, 2.5 h, 3 h, 4 h, 5 h, 6 h or the range value between any two of the above.
[0023] The beneficial effects that can be produced by this application include:
[0024] The method for preparing the negative electrode electrolyte of the vanadium redox flow battery in this application solves the problems such as cumbersome operation process and long preparation cycle in the prior art. This method is simple to operate, the reaction is rapid, and it does not require high temperature and high pressure, which can greatly shorten the preparation cycle. At the same time, the electrolyte prepared by this method can also improve the battery performance. The obtained battery Coulomb efficiency is about 95%, the voltage efficiency is about 86%, and the energy efficiency is about 82%. The obtained electrolyte can meet the application requirements of current vanadium batteries. Specific embodiments
[0025] The following details this application in conjunction with embodiments, but this application is not limited to these embodiments.
[0026] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.
[0027] The electrical performance test instrument is the LBT tester of the American arbin manufacturer, and the test conditions are a voltage range of 1 - 1.55V and a current of 3.84A.
[0028] Example 1
[0029] Weigh 18.2 g of V2O5 solid, add 36.4 mL of hydroiodic acid, and activate it at 65 °C for 3 h. Then add 50 mL of 3 mol / L dilute sulfuric acid solution. After dissolution, add 50 mL of carbon disulfide and stir well for 1 h. After standing and separating, take the upper layer solution. The upper layer solution is made up to 100 mL with 3 mol / L dilute sulfuric acid solution to obtain the negative electrode electrolyte for the vanadium battery, in which the concentration of trivalent vanadium ions is 2 mol / L and the sulfuric acid concentration is 3 mol / L.
[0030] Prepare the positive electrode electrolyte for the vanadium battery with vanadyl sulfate solid, in which the concentration of tetravalent vanadium ions is 2 mol / L and the sulfuric acid concentration is 3 mol / L. Use Nafion115 membrane as the separator, carbon felt as the electrode, and graphite plate as the current collector to assemble a full vanadium flow single cell with an electrode area of 48 cm 2 The obtained battery Coulomb efficiency is 95.2%, the voltage efficiency is 86.4%, and the energy efficiency is 82.3%.
[0031] Example 2
[0032] Weigh 18.2 g of V2O5 solid, add 31.3 mL of hydrobromic acid, and activate it at 65 °C for 3 h. Then add 50 mL of 3 mol / L dilute sulfuric acid solution. After dissolution, add 50 mL of carbon disulfide and stir well for 1 h. After standing and separating, take the upper layer solution. The upper layer solution is made up to 100 mL with 3 mol / L dilute sulfuric acid solution to obtain the negative electrode electrolyte for the vanadium battery, in which the concentration of trivalent vanadium ions is 2 mol / L and the sulfuric acid concentration is 3 mol / L.
[0033] Prepare the positive electrolyte of the vanadium battery with vanadyl sulfate solid, where the concentration of tetravalent vanadium ions is 2 mol / L and the sulfuric acid concentration is 3 mol / L. Use Nafion115 membrane as the separator, carbon felt as the electrode, and graphite plate as the current collector to assemble a full vanadium redox flow single cell with an electrode area of 48 cm 2 Test it with the above positive and negative electrolytes respectively, and the Coulombic efficiency of the battery is 95.1%, the voltage efficiency is 86.3%, and the energy efficiency is 82.1%.
[0034] Example 3
[0035] Weigh 18.2 g of V2O5 solid, add 36.4 mL of hydroiodic acid, and activate it at 75 °C for 2.5 h. Then add 50 mL of 3 mol / L dilute sulfuric acid solution. After dissolution, add 50 mL of carbon disulfide and stir well for 1 h. After standing and separating, take the upper layer solution. Dilute the upper layer solution to 100 mL with 3 mol / L dilute sulfuric acid solution to obtain the negative electrolyte for the vanadium battery, where the concentration of trivalent vanadium ions is 2 mol / L and the sulfuric acid concentration is 3 mol / L.
[0036] Prepare the positive electrolyte of the vanadium battery with vanadyl sulfate solid, where the concentration of tetravalent vanadium ions is 2 mol / L and the sulfuric acid concentration is 3 mol / L. Use Nafion115 membrane as the separator, carbon felt as the electrode, and graphite plate as the current collector to assemble a full vanadium redox flow single cell with an electrode area of 48 cm 2 Test it with the above positive and negative electrolytes respectively, and the Coulombic efficiency of the battery is 95.1%, the voltage efficiency is 86.4%, and the energy efficiency is 82.2%.
[0037] Example 4
[0038] Weigh 18.2 g of V2O5 solid, add 36.4 mL of hydroiodic acid, and activate it at 65 °C for 3 h. Then add 50 mL of 3 mol / L dilute sulfuric acid solution. After dissolution, add 50 mL of carbon tetrachloride and stir well for 1 h. After standing and separating, take the upper layer solution. Dilute the upper layer solution to 100 mL with 3 mol / L dilute sulfuric acid solution to obtain the negative electrolyte for the vanadium battery, where the concentration of trivalent vanadium ions is 2 mol / L and the sulfuric acid concentration is 3 mol / L.
[0039] Prepare the positive electrolyte of the vanadium battery with vanadyl sulfate solid, where the concentration of tetravalent vanadium ions is 2 mol / L and the sulfuric acid concentration is 3 mol / L. Use Nafion115 membrane as the separator, carbon felt as the electrode, and graphite plate as the current collector to assemble a full vanadium redox flow single cell with an electrode area of 48 cm 2 Test it with the above positive and negative electrolytes respectively, and the Coulombic efficiency of the battery is 95.3%, the voltage efficiency is 86.4%, and the energy efficiency is 82.3%.
[0040] Example 5
[0041] Weigh 18.2 g of V2O5 solid, add 36.4 mL of hydroiodic acid, and activate it at 65 °C for 3 h. Then add 50 mL of a mixed solution containing 1 mol / L sulfuric acid and 5 mol / L hydrochloric acid. After dissolution, add 50 mL of carbon tetrachloride and stir well for 1 h. After standing and separating, take the upper layer solution. The upper layer solution is made up to 100 mL with a mixed solution containing 1 mol / L sulfuric acid and 5 mol / L hydrochloric acid to obtain the negative electrode electrolyte for the vanadium battery, in which the concentration of trivalent vanadium ions is 2 mol / L, the concentration of sulfuric acid is 1 mol / L, and the concentration of hydrochloric acid is 5 mol / L.
[0042] Prepare the positive electrode electrolyte for the vanadium battery with vanadyl sulfate solid, in which the concentration of tetravalent vanadium ions is 2 mol / L and the concentration of sulfuric acid is 3 mol / L. Use Nafion115 membrane as the separator, carbon felt as the electrode, and graphite plate as the current collector to assemble a vanadium redox flow single cell with an electrode area of 48 cm 2 The vanadium redox flow single cell is tested using the above positive and negative electrode electrolytes respectively, and the Coulombic efficiency of the battery is 95.0%, the voltage efficiency is 86.4%, and the energy efficiency is 82.1%.
[0043] Example 6
[0044] Weigh 13.65 g of V2O5 solid, add 27.3 mL of hydroiodic acid, and activate it at 65 °C for 3 h. Then add 50 mL of 3 mol / L dilute sulfuric acid solution. After dissolution, add 50 mL of carbon disulfide and stir well for 1 h. After standing and separating, take the upper layer solution. The upper layer solution is made up to 100 mL with 3 mol / L dilute sulfuric acid solution to obtain the negative electrode electrolyte for the vanadium battery, in which the concentration of trivalent vanadium ions is 1.5 mol / L and the concentration of sulfuric acid is 3 mol / L.
[0045] Prepare the positive electrode electrolyte for the vanadium battery with vanadyl sulfate solid, in which the concentration of tetravalent vanadium ions is 1.5 mol / L and the concentration of sulfuric acid is 3 mol / L. Use Nafion115 membrane as the separator, carbon felt as the electrode, and graphite plate as the current collector to assemble a vanadium redox flow single cell with an electrode area of 48 cm 2 The vanadium redox flow single cell is tested using the above positive and negative electrode electrolytes respectively, and the Coulombic efficiency of the battery is 95.2%, the voltage efficiency is 86.1%, and the energy efficiency is 82.0%.
[0046] Example 7
[0047] Weigh 18.2 g of V2O5 solid, add 36.4 mL of hydroiodic acid, and activate it at 40 °C for 6 h. Then add 50 mL of 3 mol / L dilute sulfuric acid solution. After dissolution, add 50 mL of carbon disulfide and stir well for 1 h. After standing and separating, take the upper layer solution. The upper layer solution is made up to 100 mL with 3 mol / L dilute sulfuric acid solution. After testing, the concentration of trivalent vanadium ions is 1.27 mol / L, the concentration of tetravalent vanadium ions is 0.73 mol / L, and the sulfuric acid concentration is 3 mol / L.
[0048] Example 8
[0049] Weigh 18.2 g of V2O5 solid, add 36.4 mL of hydroiodic acid, and activate it at 70 °C for 0.5 h. Then add 50 mL of 3 mol / L dilute sulfuric acid solution. After dissolution, add 50 mL of carbon disulfide and stir well for 1 h. After standing and separating, take the upper layer solution. The upper layer solution is made up to 100 mL with 3 mol / L dilute sulfuric acid solution. After testing, the concentration of trivalent vanadium ions is 1.45 mol / L, the concentration of tetravalent vanadium ions is 0.55 mol / L, and the sulfuric acid concentration is 3 mol / L.
[0050] In Examples 7 and 8, by changing the activation conditions (activation temperature and activation time), the obtained electrolyte solution will contain some tetravalent vanadium ions.
[0051] Comparative Example 1
[0052] Prepare the positive electrode electrolyte of the vanadium battery with vanadyl sulfate solid, where the concentration of tetravalent vanadium ions is 2 mol / L and the sulfuric acid concentration is 3 mol / L.
[0053] Electrolyze the tetravalent vanadium ion solution to obtain a trivalent vanadium ion solution, which is used as the negative electrode electrolyte of the vanadium battery.
[0054] Use Nafion115 membrane as the diaphragm, carbon felt as the electrode, and graphite plate as the current collector to assemble a all-vanadium redox flow single cell with an electrode area of 48 cm 2 and test it with the above positive and negative electrode electrolytes respectively. The Coulombic efficiency of the battery is 95.2%, the voltage efficiency is 85.2%, and the energy efficiency is 81.1%.
[0055] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the technical solution scope of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases and all fall within the technical solution scope.
Claims
1. A method for preparing the negative electrode electrolyte of a vanadium redox flow battery, characterized in that, It includes the following steps: (1) Mix solid V2O5 and hydrohalic acid, and activate the reaction to obtain a mixed solution; (2) Add a dilute acid solution to the mixed solution, dissolve it, add an organic solvent, stir, separate, and make up the volume to obtain the negative electrode electrolyte of the all-vanadium redox flow battery.
2. The method for preparing the negative electrode electrolyte of a vanadium redox flow battery according to claim 1, characterized in that, The hydrohalic acid is hydrobromic acid and / or hydroiodic acid.
3. The method for preparing the negative electrode electrolyte of a vanadium redox flow battery according to claim 1, characterized in that, The addition amounts of the solid V2O5 and the hydrohalic acid are (10 - 25) g : (20 - 50) mL; Preferably, the addition amounts of the solid V2O5 and the hydrohalic acid are (10 - 20) g : (25 - 40) mL.
4. The method for preparing the negative electrode electrolyte of a vanadium redox flow battery according to claim 1, characterized in that, The temperature for the reaction activation is 50 - 100 °C; Preferably, the temperature for the reaction activation is 60 - 80 °C.
5. The method for preparing the negative electrode electrolyte of a vanadium redox flow battery according to claim 1, characterized in that, The time for the reaction activation is 1 - 6 h; Preferably, the time for the reaction activation is 2 - 4 h.
6. The method for preparing the negative electrode electrolyte of a vanadium redox flow battery according to claim 1, characterized in that, The organic solvent is selected from any one or more of chloroform, carbon tetrachloride, and carbon disulfide.
7. The method for preparing the negative electrode electrolyte of a vanadium redox flow battery according to claim 1, characterized in that, The dilute acid solution is dilute sulfuric acid and / or dilute hydrochloric acid.
8. The method for preparing the negative electrode electrolyte of a vanadium redox flow battery according to claim 1, characterized in that, The concentration of the dilute acid solution is 1 - 10 mol / L; Preferably, the concentration of the dilute acid solution is 2 - 8 mol / L.
9. The method for preparing the negative electrode electrolyte of a vanadium redox flow battery according to claim 1, characterized in that, The volume ratio of the organic solvent to the dilute acid solution is 1 : (0.5 - 1.5).
10. The method for preparing the negative electrode electrolyte of a vanadium redox flow battery according to claim 1, characterized in that, In the negative electrode electrolyte of the all-vanadium redox flow battery, the concentration of vanadium ions is 1 - 2.5 mol / L, and the concentration of hydrogen ions is 1 - 10 mol / L; Preferably, the concentration of vanadium ions in the negative electrode electrolyte of the all-vanadium redox flow battery is 1.5 - 2.5 mol / L; Preferably, the concentration of hydrogen ions in the negative electrode electrolyte of the all-vanadium redox flow battery is 3 - 8 mol / L.