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CN-121983627-A - High-stability vanadium electrolyte and application thereof

CN121983627ACN 121983627 ACN121983627 ACN 121983627ACN-121983627-A

Abstract

The invention relates to the technical field of vanadium battery electrolyte, and discloses a high-stability vanadium electrolyte and application thereof, wherein the high-stability vanadium electrolyte comprises a supporting electrolyte, a vanadium ion active component and a stabilizing additive, the vanadium ion active component comprises at least two of V 2+ 、V 3+ 、VO 2+ and VO 2 + , the stabilizing additive is pyrimidine-2, 4, 6-tricarboxylic acid, and an electrochemical voltage window of the electrolyte containing the stabilizing additive is 1.6V to 1.8V. According to the invention, pyrimidine-2, 4, 6-trimethyl acid is introduced as a stabilizing additive, pyrimidine ring nitrogen atoms and three carboxyl oxygen atoms in molecules form a multi-tooth strong coordination structure, and can form a stable five-membered or six-membered chelate with vanadium ions, so that hydrolytic polymerization of the vanadium ions and generation of V 2 O 5 precipitation are effectively inhibited from the source, and long-term chemical stability of the electrolyte under high-temperature and high-concentration conditions is remarkably improved.

Inventors

  • PANG HUAN
  • YANG HAIQUAN
  • SONG LIZHU

Assignees

  • 安徽海螺洁能科技有限公司
  • 安徽海螺产业技术研究院有限公司

Dates

Publication Date
20260505
Application Date
20260210

Claims (9)

  1. 1. A highly stable vanadium electrolyte comprising: a supporting electrolyte; A vanadium ion active component; a stabilizing additive; the vanadium ion active component comprises at least two of V 2+ 、V 3+ 、VO 2+ and VO 2 + ; the stabilizing additive is pyrimidine-2, 4, 6-tricarboxylic acid; Wherein the electrochemical voltage window of the electrolyte containing the stabilizing additive is 1.68V to 1.72V.
  2. 2. The high stability vanadium electrolyte of claim 1 wherein the supporting electrolyte comprises one or more of sulfuric acid, hydrochloric acid, phosphoric acid.
  3. 3. A highly stable vanadium electrolyte according to claim 1 or 2, wherein the total hydrogen ion concentration of the supporting electrolyte is 4.0 mol/L to 10.0 mol/L.
  4. 4. The high-stability vanadium electrolyte according to claim 1, wherein the vanadium ion active component is provided by VOSO 4 and V 2 O 3 according to the molar ratio of vanadium element of 1 (0.2-1).
  5. 5. The highly stable vanadium electrolyte of claim 1 wherein the total vanadium concentration of the vanadium ion active component is 1.0-3.0 mol/L.
  6. 6. The highly stable vanadium electrolyte according to claim 1, wherein the concentration of pyrimidine-2, 4, 6-trimethyl acid as the stabilizing additive is 0.01-0.1 mol/L.
  7. 7. The highly stable vanadium electrolyte according to claim 1, wherein the V 2 O 5 precipitation amount is less than 0.01 g/L after the electrolyte is left to stand for 30 days at a temperature of 60 ℃ with a total vanadium concentration of 2.0-2.5 mol/L.
  8. 8. An all-vanadium redox flow battery, comprising: a positive electrode chamber; A negative electrode chamber; an ion exchange membrane disposed between the positive electrode chamber and the negative electrode chamber; the positive electrode cavity is internally provided with positive electrode electrolyte and a positive electrode, and the negative electrode cavity is internally provided with negative electrode electrolyte and a negative electrode; The positive electrode electrolyte and/or the negative electrode electrolyte is the high-stability vanadium electrolyte as set forth in any one of claims 1 to 7.
  9. 9. The all-vanadium flow battery of claim 8, wherein the operating temperature of the battery is in the range of-20 ℃ to 60 ℃.

Description

High-stability vanadium electrolyte and application thereof Technical Field The invention belongs to the technical field of vanadium battery electrolyte, in particular relates to a high-stability vanadium electrolyte and application thereof, and particularly relates to a high-stability vanadium electrolyte containing polydentate heterocyclic carboxylic acid pyrimidine-2, 4, 6-tricarboxylic acid and application thereof in a vanadium flow battery. Background The vanadium redox flow battery as a novel large-scale energy storage battery has the remarkable advantages of capacity adjustment as required, high safety, long cycle life, environmental protection, no pollution and the like, and has wide application prospect in the fields of renewable energy grid connection, intelligent power grid peak shaving, distributed energy storage and the like. The electrolyte is used as a core component of the vanadium redox flow battery, and the performance of the electrolyte directly determines the energy density, the cycling stability, the working temperature range and the service life of the battery. At present, the vanadium electrolyte is mainly prepared by a sulfuric acid system through dissolving oxides (such as V 2O5、V2O3 and the like) or vanadium salts (such as vanadium sulfate, vanadium chloride and the like) of vanadium, and contains vanadium ions with different valence states such as V 2+、V3+、VO2+, VO 2+ and the like. The high-valence vanadium ions are easy to generate hydrolysis reaction under the conditions of high concentration, high temperature or long-term circulation to generate insoluble vanadium oxide precipitate, the solubility of vanadium salt is obviously reduced, the electrolyte is easy to generate crystallization phenomenon, and the electrolyte performance is usually improved by adopting a mode of adding organic ligands in the prior art, such as oxalic acid, citric acid, ethylenediamine tetraacetic acid (EDTA) and the like. However, the ligands have obvious defects that single-tooth or double-tooth ligands such as oxalic acid, citric acid and the like have weaker coordination capability with vanadium ions, have limited stabilizing effect and are easy to lose efficacy at high temperature or high vanadium concentration, and the ligands such as EDTA have stronger coordination capability, but have complex molecular structure and higher viscosity, can reduce the ion conduction rate of electrolyte, have higher cost and are not beneficial to large-scale application. Therefore, a vanadium electrolyte with strong coordination capability, high stability, improved high-low temperature performance and controllable cost is needed, and the industrial development of the vanadium redox flow battery is promoted. Disclosure of Invention The invention aims to provide a high-stability vanadium electrolyte and application thereof, and aims to solve the problems of poor chemical stability, narrow action temperature interval, organic ligand failure and viscosity rise. The technical scheme adopted by the invention is as follows: According to a first aspect of an embodiment of the present invention, there is provided a highly stable vanadium electrolyte, characterized by comprising: a supporting electrolyte; A vanadium ion active component; a stabilizing additive; the vanadium ion active component comprises at least two of V 2+、V3+、VO2+ and VO 2+; the stabilizing additive is pyrimidine-2, 4, 6-tricarboxylic acid; Wherein the electrochemical voltage window of the electrolyte containing the stabilizing additive is 1.6V to 1.8V. Optionally, the supporting electrolyte includes one or more of sulfuric acid, hydrochloric acid, and phosphoric acid. In some embodiments, the support electrolyte has a total hydrogen ion concentration of 4.0 mol/L to 10.0 mol/L. Further, the vanadium ion active component is provided by VOSO 4 and V 2O3 according to the molar ratio of vanadium element of 1 (0.2-1). In some embodiments, the total vanadium concentration of the vanadium ion active component is from 1.0 to 3.0 mol/L. In some embodiments, the V 2O5 precipitate amount is less than 0.01 g/L after the electrolyte is left to stand for 30 days at a total vanadium concentration of 2.0-2.5 mol/L and a temperature of 60 ℃. According to a second aspect of an embodiment of the present invention, there is provided an all-vanadium redox flow battery, including: a positive electrode chamber; A negative electrode chamber; an ion exchange membrane disposed between the positive electrode chamber and the negative electrode chamber; the positive electrode cavity is internally provided with positive electrode electrolyte and a positive electrode, and the negative electrode cavity is internally provided with negative electrode electrolyte and a negative electrode; The positive electrode electrolyte and/or the negative electrode electrolyte is the high-stability vanadium electrolyte described in any one of the above. In some embodiments, the operating temperature of