Study Of Proton Exchange Membrane Fuel Cell Electrolyte Based On Solid Acid

This paper describes the mechanism of mid-temperature proton exchangemembrane fuel cell and the development of its research. In this paper, the novelconductor was synthesized by doping solid acid on mesoporous alumina. Theinfluence of solid acid on the proton conductivity of mesoporous alumina was studied.The proton exchange membrane was prepared based on the mesoporous alumina andthe proton conductivity and methanol permeability was detected. The mesoporousalumina was synthesized by using sol-gel method. The BET and pore size was testby N2adsorption and desorption method. The crystal structure and surfacemorphology was characterized by methods of XRD, SEM and TEM. The protonconductivity was measured by using Agilent4294A. The reason for the change of theconductivity was determined by TG-DSC method. The research was supported by thefollowing results:Mesoporous alumina power was synthesized by sol-gel method usingcyclohexane and X114as directing agent and butanol aluminum as thealuminum source. The characterization result shows that the γ-Al2O3wasformed. The pore size and the surface area were about25nm and250m2/g,respectively.The mesoporous alumnia was doped solid acid（CsHSO4，KH2PO4）by themethods of impregnation and melting. The results showed that theconductivity of doped sample using melting method is higher than that ofimpregnation method.The conductivity of doped sample was one order higher than that of samplewithout doping in the range of low temperature （30-90℃）. The TG-DSCresults show that the water content of sample was improved by doping solidacid. It is supposed that the ability of water adsorption was improved withdoping. The increase of conductivity was due to the increase of watercontent because water molecule is the carrier of proton conducting. Theconductivity of all samples decreased in the high temperature range （100-140℃） because of the evaporation of water.The conductivity of novel proton exchange membrane based on themesoporous alumina increased with increasing the temperature from100℃to140℃. The highest conductivity was obtained as4.48×10-4S.cm-1at140℃. The methanol permeability of membrane was two orders lower than thatof Nafion117, which improved the fuel efficiency.