Proton exchange membrane made from high polymer-metal complex-heteropoly acid material and preparation method thereof

Abstract

The invention discloses a proton exchange membrane made from a high polymer-metal complex-heteropoly acid material and a preparation method thereof. The preparation method comprises the following steps of: introducing a side chain onto a high polymer; introducing an organic ligand onto the side chain; preparing an organic ligand; introducing a multi-tooth ligand onto the side chain; generating a high molecular metal complex; introducing heteropoly acid at the tail end of the side chain; preparing a film with a tape casting method; and the like. As proved by testing, the proton conductivity of the proton exchange membrane prepared by the method is up to the magnitude order level of 10-2S / cm at the temperature of 100-140 DEG C, the methanol crossover coefficient is lower than the magnitude order of 10<-8>-10<-7> cm<2> / s, and the use requirement of a fuel cell, in particular a methanol fuel battery proton exchange membrane can be met.

Description

technical field [0001] The invention relates to the technical field of fuel cells, in particular to a proton exchange membrane for methanol or ethanol fuel cells and a preparation method thereof. Background technique [0002] Proton exchange membrane fuel cell is a high-efficiency and green energy device that directly converts the chemical energy of fuels such as hydrogen or methanol into electrical energy, and has extremely broad application prospects. Methanol fuel cells have potential practical application prospects in portable power sources due to the advantages of convenient feeding, simple structure of the battery stack system, and short response time. The proton exchange membrane is the core component of the fuel cell, which plays the role of isolating fuel and oxidant and providing proton channels inside the cell. Perfluorosulfonic acid proton exchange membranes represented by the Nafion series membranes produced by DuPont of the United States have the advantages of...

AI Technical Summary

Problems solved by technology

Increasing the degree of sulfonation of polyaromatic compounds can improve the proton conductivity, and even reach a level similar to that of perfluorosulfonic acid membranes, but at this time, the alcohol resistance and mechanical properties of the membranes will deteriorate, which cannot meet the working conditions of the battery.

[0004] The preparation of composite membranes is a common method for modifying existing proton exchange membranes. For example, polybenzimidazole (PBI) membranes that adsorb inorganic strong acids can still maintain the characteristics of high proton conductivity and high mechanical strength at high temperatures; Heteropolyacids are rich in crystal water and have high proton conductivity. The composite film doped with heteropolyacids can maintain high proton conductivity at over 100°C and under anhydrous conditions; however, inorganic strong acids or heteropolyacids are easily soluble in Water, under the working conditions of the fuel cell, it is easy to seep out of the membrane with the water generated by the fuel cell reaction, causing the proton conductivity of the membrane to drop sharply

Doping metal oxides (such as silicon dioxide, titanium dioxide, and zirconium dioxide, etc.) in the composite film can improve the high temperature resistance and alcohol resistance of the film, and can also slow down the dissolution of heteropolyacids to some extent. These metal oxides themselves do not have proton conductivity, and excessive addition will lead to a sharp drop in proton conductivity

Generally speaking, the performance of the composite membranes prepared at present is not perfect, and it is necessary to make a balanced selection among various properties of the membranes; the proton exchange composite membranes with excellent performance and suitable for fuel cells still need further research

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