Development of novel Nafion/Meso-silicon-oxide membranes doped with phosphotungstic acid for high temperature proton exchange membrane fuel cells

The increasing rate of depletion of fossil fuels and pollution has led to an increasing demand for alternative energy sources and more efficient energy conversion methods. Fuel cell is a kind of electrochemical device that converts chemical energy of fuels to electrical energy directly. The proton exchange membrane fuel cells are one of the most promising clean technologies under development among all fuel cells. Their high energy efficiency, of up to 64%, makes them extremely attractive for use in future transportation when compared to the traditional internal combustion engines. However, the low proton conductivity in high temperature and low relative humidity, chemical and thermal stability in high temperature, durability and low cell performance levels are still strong limitations for its widespread usage. The objective of the project is to investigate novel proton conducting nanocomposite membrane based on self-assembled meso-SiO2 inorganic electrolyte doped with phosphotungstic acid (HPW) for high temperature operation. The inorganic electrolytes were synthesized using the EISA method and the membranes prepared via a self-assembly process. The proton conductivity improved when the SBA-15 is doped with 25wt% of HPW. This improvement in conductivity should be attributed to either the continuous proton conduction channels, which were structured by the anchored HPW molecules in the well-ordered mesopores of SiO2 or the increase in hydrogen bond by the presence of HPW. It is observed that the conductivity increases with the increase in temperature. The results provide a good foundation for further design and development of high temperature proton exchange membrane fuel cell for operations of 150 °C and above in the next phase of study.Bachelor of Engineering (Mechanical Engineering