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CN-122025715-A - Electrolyte for water-based flow battery and water-based flow battery

CN122025715ACN 122025715 ACN122025715 ACN 122025715ACN-122025715-A

Abstract

The invention discloses an electrolyte for a water-based flow battery and the water-based flow battery, wherein the electrolyte comprises a supporting electrolyte and a mixed solvent, the mixed solvent is formed by combining an organic solvent with the volume fraction of 10-50% and the rest deionized water, the organic solvent is N-methylpyrrolidone and/or acetonitrile, and the supporting electrolyte is tetrabutylammonium chloride with the concentration of 0.5-1 mol/L. The electrolyte has the advantages of low cost and easy acquisition of raw materials and simple preparation method, and the solubility of the anode active substance 4-acetamido-TEMPO can be improved from 0.02mol/L to 0.79mol/L by adopting the electrolyte, so that the capacity and the energy density of the flow battery are remarkably improved, and a wide prospect is provided for the large-scale production and the market application of the water-based flow battery.

Inventors

  • HU YUXIANG
  • DU HONGLIN
  • WANG JIAWEN
  • Long Yuanchang
  • HAN MINGSHAN

Assignees

  • 北京工业大学

Dates

Publication Date
20260512
Application Date
20260115

Claims (10)

  1. 1. The electrolyte for the aqueous flow battery is characterized by comprising a supporting electrolyte and a mixed solvent, wherein the mixed solvent comprises an organic solvent with the volume fraction of 10-50% and the balance of deionized water, the organic solvent is N-methylpyrrolidone and/or acetonitrile, and the supporting electrolyte is tetrabutylammonium chloride.
  2. 2. The electrolyte according to claim 1, wherein the concentration of tetrabutylammonium chloride as the supporting electrolyte is 0.5 to 1mol/L.
  3. 3. The electrolyte according to claim 1, wherein when the electrolyte is a battery positive electrode electrolyte, the electrolyte further comprises a positive electrode active material having a concentration of 0.05 to 0.8 mol/L.
  4. 4. The electrolyte according to claim 3, wherein the positive electrode active material is 4-acetamido-TEMPO.
  5. 5. The electrolytic solution according to claim 1, wherein when the electrolytic solution is a battery negative electrode electrolytic solution, the electrolytic solution further comprises a negative electrode active material having a concentration of 0.05 to 1.5 mol/L.
  6. 6. The electrolytic solution according to claim 5, wherein the negative electrode active material is methyl viologen.
  7. 7. A water-based flow battery is characterized by comprising an end plate, a current collector, a graphite runner plate, a graphite felt, a diaphragm, positive electrolyte, negative electrolyte, a peristaltic pump and a pipeline, wherein the positive electrolyte is electrolyte containing 0.05-0.8 mol/L positive active substance, and the negative electrolyte is electrolyte containing 0.05-1.5 mol/L negative active substance; the electrolyte comprises a supporting electrolyte and a mixed solvent, wherein the mixed solvent comprises an organic solvent with the volume fraction of 10-50% and the rest deionized water, the organic solvent is N-methylpyrrolidone and/or acetonitrile, and the supporting electrolyte is tetrabutylammonium chloride with the concentration of 0.5-1 mol/L.
  8. 8. The aqueous flow battery of claim 7, wherein the volume ratio of the negative electrode electrolyte to the positive electrode electrolyte is 1-1.4.
  9. 9. The aqueous flow battery according to claim 7, wherein the positive electrode active material is 4-acetamido-TEMPO.
  10. 10. The aqueous flow battery of claim 7, wherein the negative electrode active material is methyl viologen.

Description

Electrolyte for water-based flow battery and water-based flow battery Technical Field The invention belongs to the technical field of flow batteries, and particularly relates to an electrolyte for a water-based flow battery and the water-based flow battery. Background Global warming and energy crisis have prompted the human society to move toward the development of clean renewable energy sources, such as solar and wind. Because solar energy and wind energy are intermittent and fluctuating, long-term energy storage system support is required to better incorporate into the grid. Flow batteries have become an effective long-term energy storage solution due to their high conductivity, high energy conversion efficiency, high operational feasibility and good scalability. Inorganic system flow batteries such as all-vanadium flow batteries are relatively mature in development, but are limited by the defects of shortage of metal resources, poor environmental friendliness and the like. In contrast, the water-based flow battery which adopts the organic active molecules as active substances is mainly composed of C, H, O, N and other elements, has high abundance and wide sources, and is more environment-friendly. Currently, TEMPO derivatives are commonly used positive electroactive materials in aqueous flow batteries. The 4-acetamido-TEMPO has higher oxidation-reduction potential, good dynamic performance and stability, but the solubility of the 4-acetamido-TEMPO in water is only 80mM, which is far lower than the application requirements of flow batteries. In order to improve the solubility of such organic molecules in the electrolyte, it has been reported that grafting hydrophilic groups onto electroactive molecules by molecular engineering techniques has been disclosed. However, the method relates to complex organic synthesis, and is difficult to purify, low in yield, high in energy consumption and difficult to realize large-scale production and application. Disclosure of Invention In order to solve the technical problems, the invention provides an electrolyte for an aqueous flow battery and the aqueous flow battery. The solubility of the 4-acetamido-TEMPO molecule can be greatly improved by adopting the electrolyte, so that the capacity and the energy density of the flow battery are effectively improved. In a first aspect, the invention discloses an electrolyte for an aqueous flow battery, which comprises a supporting electrolyte and a mixed solvent, wherein the mixed solvent comprises an organic solvent with the volume fraction of 10-50% and the rest of deionized water, the organic solvent is N-methylpyrrolidone (NMP) and/or Acetonitrile (ACN), and the supporting electrolyte is tetrabutylammonium chloride (TBAC). Further, the concentration of the supporting electrolyte TBAC is 0.5-1 mol/L. Further, when the electrolyte is a battery positive electrode electrolyte, the electrolyte further comprises a positive electrode active material with a concentration of 0.05-0.8 mol/L. Further, the positive electrode active material is 4-acetamido-TEMPO. Further, when the electrolyte is a battery negative electrode electrolyte, the electrolyte further comprises a negative electrode active material with a concentration of 0.05-1.5 mol/L. Further, the negative electrode active material is methyl viologen. The invention also discloses a water-based flow battery, which comprises an end plate, a current collector, a graphite runner plate, a graphite felt, a diaphragm, positive electrolyte, negative electrolyte, a peristaltic pump and a pipeline, wherein the positive electrolyte is electrolyte containing 0.05-0.8 mol/L of positive active material, and the negative electrolyte is electrolyte containing 0.05-1.5 mol/L of negative active material; the electrolyte comprises a supporting electrolyte and a mixed solvent, wherein the mixed solvent comprises an organic solvent with the volume fraction of 10-50% and the rest deionized water, the organic solvent is NMP and/or ACN, and the supporting electrolyte is TBAC with the concentration of 0.5-1 mol/L. Further, the volume ratio of the negative electrode electrolyte to the positive electrode electrolyte is 1-1.4. Further, the positive electrode active material is 4-acetamido-TEMPO. Further, the negative electrode active material is methyl viologen. The invention provides an electrolyte for an aqueous flow battery and the aqueous flow battery. Compared with the prior art, the aqueous flow battery electrolyte has the advantages that raw material components of the aqueous flow battery electrolyte are low in cost and easy to obtain, the preparation method is simple, and the solubility of the positive electrode active material 4-acetamido-TEMPO molecules can be improved from 0.02mol/L to 0.79mol/L by adopting the aqueous flow battery electrolyte, so that the working concentration requirement of the aqueous flow battery on the positive electrode active material 4-acetamido-TEMPO is met, the capaci