A Mesoporous Structure SnP2O7/Graphite Oxide Composite as Proton Conducting Electrolyte for High-Temperature Proton Exchange Membrane Fuel Cells
International Journal of Electrochemical Science
Proton conductors operated in over 200°C have received great interest for proton exchange membrane fuel cells (PEMFCs). The tetravalent metal ion pyrophosphates materials (MP 2 O 7 ) are considered as the suitable conductor electrolyte, and the mesopores structure MP 2 O 7 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-SnP 2 O 7 ,
... t meso-SnP 2 O 7 , which is synthesized from mesoporous SnO 2 , 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-SnP 2 O 7 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 SnP 2 O 7 particles and pellets is analysed by transmission electron microscope (TEM) and scanning electron microscopy (SEM). The obtained particles and pores size of Meso-SnP 2 O 7 are characterized by the ETA potential meter and BET. The Meso-SnP 2 O 7 and Meso-SnP 2 O 7 /GO electrolytes exhibit the high proton conductivities of 0.15 S cm -1 and 0.17 S cm -1 at 220°C, respectively. Moreover, the peak power densitiy of the Meso-SnP 2 O 7 /GO membrane is 18 mWcm -2 at 220 °C with OCV of 0.83V.