Alkaline zinc-iron flow battery adopting positive electrode electrolyte with tetraborate as additive

A positive electrolyte and flow battery technology, which is applied in the field of alkaline zinc-iron flow batteries, can solve problems affecting the long-term cycle stability of the stack, limit the industrialization prospects of batteries, and reduce the concentration of active materials, so as to improve cycle stability performance, expand the scope of use, and improve stability

Inactive Publication Date: 2021-06-22
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the alkaline system zinc-iron flow battery, the active substance in the positive electrolyte is ferricyanide or ferrocyanide, which will slowly decompose into iron hydroxide precipitation in a strong alkaline environment (pH>13) , resulting in a decrease in the concentration of active substances in the electrolyte, and at the same time, the precipitated ferric hydroxide will adhere to the surface of the electrode and separator, increasing the internal resistance of the battery, thereby affecting the long-term cycle stability of the stack, and limiting the flow battery of this system. Industrialization prospect

Method used

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  • Alkaline zinc-iron flow battery adopting positive electrode electrolyte with tetraborate as additive

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Experimental program
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Effect test

Embodiment 1

[0026] Weigh 422g of potassium ferrocyanide and 120g of sodium hydroxide, heat and stir at 50°C for 2h, dissolve in 750mL of deionized water, then dilute the solution to 1L, and adjust the pH of the solution to 10 by adding potassium tetraborate. The molar ratio of borate and hydroxide is 1:4, and the concentration of ferrocyanide in the solution is 1mol / L, which is used as the positive electrode electrolyte

[0027] Use the prepared electrolyte to assemble the alkaline system zinc-iron flow battery, in which the catalytic layer is activated carbon felt, the bipolar plate is graphite plate, and the ion exchange membrane is Nafion membrane produced by DuPont Company, with an effective area of ​​48cm 2 , with a current density of 80mA cm -2 , the zincate ion concentration in the negative electrode electrolyte is 0.5mol L -1 and sodium hydroxide concentration of 3mol L -1 , the Coulombic efficiency (CE) of the assembled alkaline system zinc-iron redox flow battery is 98.8%, the...

Embodiment 2

[0032] With embodiment 1, potassium tetraborate is changed into sodium tetraborate, and other conditions are unchanged.

Embodiment 3

[0034] Same as Example 1, potassium ferrocyanide is replaced by sodium ferrocyanide, potassium tetraborate is replaced by sodium tetraborate, and other conditions remain unchanged.

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Abstract

The invention discloses an alkaline zinc-iron flow battery adopting a positive electrode electrolyte with tetraborate as an additive. The positive electrode electrolyte of the alkaline zinc-iron flow battery is prepared by taking one or more than two ferrous cyanide salts as active substances and tetraborate and the like as a buffer solution additive. The positive electrode electrolyte has the characteristics of simple preparation method, environment-friendly process and the like. Compared with an original positive electrode electrolyte prepared from pure ferrous cyanide salt, the positive electrode electrolyte has higher active substance concentration and higher active substance stability, and the conductivity of the electrolyte can be effectively improved by the higher active substance concentration, so that the cycle performance and the battery efficiency of the battery are improved, and the service life of the battery is prolonged. Meanwhile, the charge-discharge capacity and the energy density of the battery are greatly improved; and the long-time cycling stability of the battery can be improved by higher active substance stability.

Description

technical field [0001] The invention relates to an alkaline zinc-iron flow battery using tetraborate as an additive positive electrode electrolyte. Background technique [0002] Liquid flow energy storage battery is a new electrochemical energy storage technology. Compared with other energy storage technologies, it has high energy conversion efficiency, flexible system design, large storage capacity, free location selection, deep discharge, safety and environmental protection, and maintenance. With the advantages of low cost, it can be widely used in wind energy, solar energy and other renewable energy generation and energy storage, emergency power system, backup power station and power system peak shaving and valley filling. Due to the advantages of high safety, good stability, long life (life > 15 years), and low cost, the alkaline system zinc-iron flow battery is considered to be a kind of flow energy storage battery with high development potential. [0003] The posit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M8/18
CPCH01M8/188H01M2300/0014Y02E60/50
Inventor 段寅琦李先锋张华民袁治章
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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