A Mesoporous Structure SnP₂O₇/Graphite Oxide Composite as Proton Conducting Electrolyte for High-Temperature Proton Exchange Membrane Fuel Cells

摘要

Proton conductors operated in over 200°C have received great interest for proton exchange membrane fuel cells (PEMFCs). The tetravalent metal ion pyrophosphates materials (MP2O7) are considered as the suitable conductor electrolyte, and the mesopores structure MP2O7 are attractive, because capillary condensation of water molecules occurs at relatively low relative humidity, allowing for fast transport of protons without excessive humidification. In this study, we report meso-SnP2O7, which is synthesized from mesoporous SnO2, as promising solid electrolyte candidate for PEMFCs in a temperatures range of 180°C to 280°C. Furthermore, graphite oxide (GO) is incorporated with the meso-SnP2O7 to further improve the proton conductivity and water retention. The structure and phase stability of the membranes are analysed by X-ray diffraction (XRD) and thermos-gravimetric analysis (TGA). The microstructure morphology of SnP2O7 particles and pellets is analysed by transmission electron microscope (TEM) and scanning electron microscopy (SEM). The obtained particles and pores size of Meso-SnP2O7 are characterized by the ETA potential meter and BET. The Meso-SnP2O7 -1 - and Meso-SnP2O7/GO electrolytes exhibit the high proton conductivities of 0.15 S cm and 0.17 S cm 1 at 220°C, respectively. Moreover, the peak power densitiy of the Meso-SnP2O7/GO membrane is 18 mWcm-2 at 220 °C with OCV of 0.83V.