PBI membrane activation treatment method with high proton conductivity and ion selectivity

A technology of proton conductivity and ion selectivity, applied in the field of electrochemical energy storage, can solve the problems of difficult mass production, high control difficulty, poor mechanical stability, etc., and achieves increased manufacturing cost, high ion selectivity, and simple operation. Effect

Pending Publication Date: 2020-09-18
THE HONG KONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Some scholars have also improved the proton conductivity by designing porous PBI and dense PBI composite membranes, but the control is difficult, the mechanical stability is relatively poor, and it is difficult to produce in batches.

Method used

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  • PBI membrane activation treatment method with high proton conductivity and ion selectivity
  • PBI membrane activation treatment method with high proton conductivity and ion selectivity
  • PBI membrane activation treatment method with high proton conductivity and ion selectivity

Examples

Experimental program
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Effect test

preparation example Construction

[0033] The selected concentrated phosphoric acid is phosphoric acid with a mass fraction of 85%, and the dilute phosphoric acid is the dilution of the concentrated phosphoric acid with deionized water in different degrees. The preparation method includes the following steps: First, take a commercial PBI film, the thickness of which is about 55 μm. Soak it in concentrated phosphoric acid at room temperature, take it out after soaking for 2 days, the doping content of phosphoric acid in the PBI film is about 4mol%, the proton conductivity is 40.42mS / cm, the proton conductivity of Nafion212 under the same test conditions It is 27.91 mS / cm. Then, put the PBI membrane in 11mol / L dilute phosphoric acid solution and continue to soak for 1 day, so that the outer layer of the PBI membrane shrinks and becomes dense, thereby improving ion selectivity. The above soaked PBI membrane is taken out, and then rinsed with deionized water to remove the phosphoric acid adhered to the surface of ...

Embodiment 1

[0038] In this example, the PBI membrane with high proton conductivity and ion selectivity obtained by the above method was subjected to electrochemical detection and battery performance detection. In the EIS detection of the treated PBI film, 3mol / L sulfuric acid is used as electrolyte, 1×1×0.3mm platinum sheet is used as electrode, and the scanning frequency range is 1MHz~100KHz. Scan results such as figure 2 As shown, the figure shows that the conductivity of the treated PBI is higher than that of Nafion212.

[0039] Use the PBI film prepared above to assemble an all-vanadium redox flow battery. The electrolyte is a sulfuric acid mixed solution with a valence of 3.5 and a total vanadium concentration of 1.7mol / L. Take 11ml of the positive and negative electrolytes respectively, and use graphite felt for both the positive and negative electrodes. , the graphite plate engraved with the finger-type flow channel is used as the graphite plate of the all-vanadium redox flow bat...

Embodiment 2

[0044] The treatment method is the same as in Example 1, except that the commercial PBI membrane is replaced by a composite membrane of PBI and other materials, such as: a composite membrane of PBI and Nafion, a PBI membrane and sulfonated polyetheretherketone (sulfonated polyetheretherketone (SPEEK)) The composite membrane of PBI and polyacrylonitrile (polyacrylonitrile (PAN)), the composite membrane of PBI and polyimide (sulfonated polyimide (SPI)) and the composite membrane of PBI and polyphenylene sulfone (Polyphenylene sulfone (PPSU)), Polysulfone (polysulfone (PSF)), polyethersulfone (polyethersulfone (PES)), perfluoroether copolymer (polyfluoroether (PFE)), ketone sulfone copolymer (Polyfluoroether ketone sulfone (PAEK)), polyether ketone (polyphthalone ether ketone (PEK)), polyvinylidene fluoride (polyvinylidene fluoride (PVDF)), polyimide (polyimide (PI)), polyurethane (polyurethane (PU)), polyvinyl chloride (Polyvinylchloride (PVC)), poly Vinyl alcohol (polyvinyl alc...

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Abstract

The invention relates to the fields of flow batteries, fuel cells and the like, and in particular relates to a PBI membrane activation treatment method with high proton conductivity and ion selectivity. The method comprises the steps that firstly, a commercial PBI membrane is soaked in concentrated phosphoric acid, concentrated sulfuric acid or concentrated hydrochloric acid to be fully swollen, so that the doping content of phosphoric acid, sulfuric acid or hydrochloric acid in the PBI membrane is continuously increased, and the proton conductivity of the PBI membrane is further improved; andthen, by utilizing the characteristic that the PBI film which is fully swollen and doped automatically shrinks in the solution, the PBI film which is fully swollen and doped is transferred into the solution which enables the PBI film to automatically shrink, and the outer layer of the PBI film shrinks compactly to improve the ion selectivity. In the test of an all-vanadium redox flow battery, thetreatment method can realize 88.7% of energy efficiency under the electric density of 100mA / cm <2>, which is superior to the energy efficiency (87.6%) of Nafion212 under the same experimental conditions; and meanwhile, the PBI membrane treated by the method is good in stability, and no obvious performance attenuation occurs within 100 cycles.

Description

technical field [0001] The invention relates to the field of electrochemical energy storage, in particular to a PBI membrane activation treatment method with high proton conductivity and ion selectivity. Background technique [0002] In recent years, with the intensification of the greenhouse effect and global warming, people's demand for clean and renewable energy such as wind energy and solar energy has become more urgent. However, the power generation of wind and solar energy is very unstable. In China alone, about 100 billion kWh of wind and solar energy are discarded every year. Therefore, it is very necessary to establish a safe, economical and efficient energy storage system to maximize the storage of wind and solar power. All-vanadium redox flow batteries have shown great application prospects in large-scale energy storage systems due to their excellent safety, long working life and good battery performance. The proton exchange membrane plays a role in isolating th...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): H01M8/1086H01M8/1088H01M8/18
CPCH01M8/1086H01M8/1088H01M8/188Y02E60/50
Inventor赵天寿范新庄王振宇
OwnerTHE HONG KONG UNIV OF SCI & TECH