Preparing method of polyvinylidene fluoride-heteropoly acid-chitosan composite proton exchange membrane

Abstract

The invention relates to the technical field of fuel cells, and concretely discloses a preparing method of a polyvinylidene fluoride-heteropoly acid-chitosan composite proton exchange membrane. According to the method, firstly, a polyvinylidene fluoride fiber membrane is obtained through electrostatic spinning; then, heteropoly acid coats the fiber surface through poly-dopamine with ultra-strong adhesivity; next, pores of the fiber membrane are filled with positively charged natural polymer chitosan; the run-off problem of the heteropoly acid in the cell use process can be effectively solved by the strong static mutual acting force between the chitosan and the heteropoly acid; meanwhile, the mechanical performance of the fiber membrane can also be greatly improved; and the prepared composite membrane has high proton conductivity and mechanical performance at room temperature and high temperature. The polyvinylidene fluoride-heteropoly acid-chitosan composite proton exchange membrane can have wide application prospects in the field of proton exchange membrane fuel cells.

Description

technical field [0001] The invention relates to the technical field of fuel cells, in particular to a preparation method of a polyvinylidene fluoride-heteropolyacid-chitosan composite proton exchange membrane. Background technique [0002] Proton exchange membrane fuel cells have broad application prospects in electric vehicles and portable power supplies due to their advantages such as room temperature start-up, high energy conversion efficiency, and compact structure. As one of the key components of a proton exchange membrane fuel cell, the proton exchange membrane can separate fuel and oxidant, allowing protons to pass through, but insulating electrons, and it is also the substrate of electrolytes and catalysts. Therefore, an excellent proton exchange membrane must have high Proton conductivity and excellent mechanical properties. What is commonly used at present is the Nafion series perfluorosulfonic acid proton exchange membrane developed by DuPont Company, but it will...

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Problems solved by technology

In general, most of the current research focuses on the preparation of proton exchange membranes by electrospinning sulfonated polymers, but due to the strong repulsion interference between the ionic groups on the sulfonated polymer molecules, the polymers in solution Showing a rod-like conformation, the conditions of electrospinning are not easy to control, and it is difficult to produce on a large scale

[0004] Polyvinylidene fluoride (PVDF) is a semi-crystalline fluoropolymer with excellent comprehensive properties, such as excellent mechanical properties, electrochemical and thermal stability, high dielectric constant, and easy electrospinning to form films. And after film formation, the strength and flexibility are excellent, but PVDF itself does not have proton conductivity, so compounding PVDF with inorganic proton conductors such as heteropolyacids is an effective way to improve its proton conductivity, but heteropolyacids are easily soluble in water , during the operation of the proton exchange membrane fuel cell, it is easy to lose with the water generated by the electrode. Therefore, how to solve the loss of heteropolyacid in the electrospun membrane is the key problem of whether this kind of membrane can be practically applied.

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