CN-121983628-A - Stable electrolyte for vanadium redox flow battery, preparation method and application thereof

Abstract

The invention discloses a stable electrolyte for a vanadium redox flow battery, a preparation method and application thereof, wherein the stable electrolyte for the vanadium redox flow battery comprises vanadium ions, sulfate ions, an additive and a solvent, and the additive comprises (2-carboxyethyl) polyethylene glycol and 2-fluoro-5-methoxybenzyl alcohol. The invention combines the (2-carboxyethyl) polyethylene glycol and the 2-fluoro-5-methoxyl benzyl alcohol for use, and simultaneously controls the concentration, so that the prepared electrolyte has higher stability and can effectively improve the electrochemical performance of the battery.

Inventors

• YIN XINGRONG
• WU XIONGWEI
• XIE HAO
• LI ZHIGANG

Assignees

• 湖南省银峰新能源有限公司

Dates

Publication Date

20260505

Application Date

20260407

Claims (9)

1. 1. A stable electrolyte for a vanadium redox flow battery is characterized by comprising vanadium ions, sulfate ions, an additive and a solvent; Wherein the additive comprises (2-carboxyethyl) polyethylene glycol and 2-fluoro-5-methoxybenzyl alcohol.
2. 2. The stable electrolyte for a vanadium redox flow battery according to claim 1, wherein the mass ratio of the (2-carboxyethyl) polyethylene glycol to the 2-fluoro-5-methoxybenzyl alcohol is (2-3): 1.
3. 3. The stable electrolyte for a vanadium redox flow battery according to claim 1, further comprising sulfamic acid, wherein the mass ratio of sulfamic acid to 2-fluoro-5-methoxybenzyl alcohol is (1-2): 1.
4. 4. The stable electrolyte for a vanadium redox flow battery according to claim 1, wherein the concentration of the additive is 1mol/L to 3mol/L.
5. 5. The stable electrolyte for a vanadium redox flow battery according to claim 1, wherein the electrolyte is a positive electrode electrolyte, the vanadium ions are at least one of VO 2 + 、VO 2+ , the concentration of the vanadium ions is 1mol/L to 3mol/L, and the concentration of the sulfate ions is 2mol/L to 5mol/L.
6. 6. The stable electrolyte for a vanadium redox flow battery according to claim 1, wherein the electrolyte is a negative electrode electrolyte, the vanadium ions are at least one of V 2+ 、V 3+ , the concentration of the vanadium ions is 1mol/L to 3mol/L, and the concentration of the sulfate ions is 2mol/L to 5mol/L.
7. 7. The stable electrolyte for a vanadium redox flow battery according to claim 1, wherein the solvent is at least one of water, ethylene glycol, and ethanol.
8. 8. The method for preparing the stable electrolyte for the vanadium redox flow battery as set forth in any one of claims 1 to 7, comprising the steps of: and uniformly mixing the vanadium ion-containing compound, sulfuric acid, an additive and a solvent to obtain the stable electrolyte for the vanadium redox flow battery.
9. 9. Use of the stable electrolyte for vanadium redox flow battery as defined in any one of claims 1 to 7 in a vanadium redox flow battery.

Description

Stable electrolyte for vanadium redox flow battery, preparation method and application thereof Technical Field The invention belongs to the technical field of vanadium redox flow batteries, and particularly relates to a stable electrolyte for a vanadium redox flow battery, a preparation method and application thereof. Background The all-vanadium redox flow battery has the advantages of high energy conversion efficiency, long service life, high safety, environmental friendliness and the like, and becomes one of the most promising modes of renewable energy sources such as wind energy, solar energy and the like. The core material of the all-vanadium redox flow battery consists of positive and negative electrolyte, an ion exchange membrane and positive and negative electrodes. The electrolyte is used as an energy storage medium of the battery, is a core of an energy unit of the battery, and generally consists of three parts of vanadium active substances, an acid supporting system and additives. The concentration and the volume of the electrolyte determine the energy density of the vanadium redox battery, and the high-concentration electrolyte can increase the capacity of the all-vanadium redox flow battery, but when the concentration of the electrolyte is high to a certain degree, the stability of vanadium ions in the solution is poor, and the problems of hydrolysis, association, precipitation and the like can be caused. In order to inhibit the precipitation of pentavalent vanadium, additives are added, and common inorganic additives are inorganic acids such as sodium hexametaphosphate, alkali metal sulfate, boric acid, hydrochloric acid and the like, and organic additives are organic acids such as urea, fructose, mannitol, methanesulfonic acid and the like. However, the addition of these additives introduces some impurity elements, and some impurity elements change the acidity of the system, which may result in enhanced corrosion ability of the electrolyte and affect the overall service life of the stack. Disclosure of Invention The invention aims to provide a stable electrolyte for a vanadium redox flow battery, a preparation method and application thereof, the stable electrolyte for the vanadium redox flow battery has excellent stability and can effectively improve the electrochemical performance of the battery. In order to achieve the above object, a specific embodiment of the present invention provides the following technical solution: A stable electrolyte for a vanadium redox flow battery comprises vanadium ions, sulfate ions, an additive and a solvent; Wherein the additive comprises (2-carboxyethyl) polyethylene glycol and 2-fluoro-5-methoxybenzyl alcohol. In one or more embodiments of the invention, the mass ratio of the (2-carboxyethyl) polyethylene glycol to the 2-fluoro-5-methoxybenzyl alcohol is (2-3): 1. In one or more embodiments of the invention, the composition further comprises sulfamic acid, wherein the mass ratio of the sulfamic acid to the 2-fluoro-5-methoxybenzyl alcohol is (1-2): 1. In one or more embodiments of the invention, the concentration of the additive is 1mol/L to 3mol/L. In one or more embodiments of the present invention, the electrolyte is a positive electrode electrolyte, the vanadium ion is at least one of VO 2+、VO2+, the concentration of the vanadium ion is 1mol/L to 3mol/L, and the concentration of the sulfate ion is 2mol/L to 5mol/L. In one or more embodiments of the present invention, the electrolyte is a negative electrode electrolyte, the vanadium ion is at least one of V 2+、V3+, the concentration of the vanadium ion is 1mol/L to 3mol/L, and the concentration of the sulfate ion is 2mol/L to 5mol/L. In one or more embodiments of the present invention, the solvent is at least one of water, ethylene glycol, and ethanol. The technical scheme provided by the other specific embodiment of the invention is as follows: A preparation method of a stable electrolyte for a vanadium redox flow battery comprises the following steps: and uniformly mixing the vanadium ion-containing compound, sulfuric acid, an additive and a solvent to obtain the stable electrolyte for the vanadium redox flow battery. The technical scheme provided by the other specific embodiment of the invention is as follows: the application of the stable electrolyte for the vanadium redox flow battery in the vanadium redox flow battery. Compared with the prior art, the invention combines the (2-carboxyethyl) polyethylene glycol and the 2-fluoro-5-methoxyl benzyl alcohol for use, and simultaneously controls the concentration, so that the prepared electrolyte has higher stability and can effectively improve the electrochemical performance of the battery. Detailed Description In order to better understand the technical solutions in the present disclosure, the following description will clearly and completely describe the technical solutions in the embodiments of the present disclosure, and it is obvious that the describ