Preparation method for electrolyte used for vanadium flow cell

Abstract

The invention discloses a preparation method for electrolyte used for a vanadium flow cell. The preparation method comprises the steps of dissolving high-purity vanadium pentoxide into concentrated sulfuric acid to activate the vanadium pentoxide, dissolving the obtained (VO2) 2 SO4 through deionized water, obtaining catholyte, pouring the catholyte into a cathode cavity of an electrolytic bath with a membrane, pouring a sulphuric acid water solution into an anode cavity of the electrolytic bath, placing electrodes, carrying out electrolytic reduction, and obtaining the electrolyte. The electrolyte comprises divalent, trivalent or quadrivalent vanadium ions, or comprises divalent and trivalent vanadium ions, or comprises trivalent and quadrivalent vanadium ions. The preparation method for the electrolyte used for the vanadium flow cell is capable of obtaining the high-purity electrolyte used for the vanadium flow cell, and has the advantages of being simple in technical process, simple in reaction device, easy to operate, few in variety of required raw materials, low in cost, capable of being used for large-scale industrial production, free of environmental pollution and the like.

Description

technical field [0001] The invention belongs to the field of energy storage batteries, and more specifically relates to a method for preparing an electrolyte solution for a vanadium redox flow battery. Background technique [0002] The vanadium redox flow battery mainly uses all-vanadium ions as the electrolyte. When the stack is running well, the amount and concentration of the vanadium electrolyte determine the size of the battery capacity, and the performance of the electrolyte has a direct impact on the performance of the battery. influences. Therefore, it is of great significance to propose an efficient preparation method of electrolyte for vanadium redox flow battery. [0003] The preparation methods of electrolytes for vanadium redox flow batteries are mainly divided into chemical methods and electrolytic methods (or electrochemical methods). The chemical method refers to the method of using vanadium oxides or compounds in a certain sulfuric acid solution by heating...

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Problems solved by technology

The advantage of this method is that the reaction rate is fast; the disadvantage is that the experimental reactor is required to withstand 1 to 2 atmospheric pressures, and the sealing performance of the device is high, and the unreacted sulfur dioxide gas must be treated, and toxic gas treatment equipment needs to be added, which increases the cost of experimental equipment.

[0007] Another method is the oxalic acid or tartaric acid reduction method, which is to dissolve vanadium pentoxide in sulfuric acid, and after reduction with oxalic acid or tartaric acid, prepare a tetravalent vanadyl sulfate solution, but excessive oxalic acid or tartaric acid will still exist in the electrolyte. It will affect the graphite felt electrode of the vanadium redox flow battery, which is not conducive to the long-term stable operation of the vanadium redox flow battery

[0008] The problem of directly using the electrolysis method to prepare the electrolyte solution for the vanadium redox flow battery is: because the solubility of vanadium pentoxide in dilute sulfuric acid is very small, the biggest difficulty of the electrolysis method is how to convert the vanadium pentoxide into pentavalent vanadium sulfuric acid the solution

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