Measurement of hydrogen ion conductivity through proton exchange membrane
Proton exchange membrane is the prime part of proton exchange membrane fuel cell (PEMFC). In this work, it has focused to the proton conduction through two different conductive polymer membranes such as Nafion 212 and Fumapem AM (PBI). The conductivity has measured by the two probe method with the help of electrochemical impedance spectroscopic (EIS) analysis. To increase the conductivity, Fumapem AM (PBI) membrane has been doped with 85 % concentrated H3PO4 acid at ambient temperature. Due to acid doping, it has swelled 41 % compare to prior on. The highest conductivity has recorded as 3.54 and 2.24 mS/cm under 60 °C temperature for Nafion 212 and Fumapem AM (PBI) respectively. The proton conductivity of both membranes is fully dependent on the surrounding temperature.
Development and characterization of sulfonated polysulfone membranes for direct methanol fuel cells
Abstract The development of a direct methanol fuel cell based on composite polysulfone membranes modified with silica filler is reported. The synthesis of sulfonate polysulfone samples was carried out by a mild sulfonation process using trimethyl silyl chlorosulfonate as sulfonating agent. Composites membranes with 5 wt% of silica filler were prepared and characterized. A composite membrane tested in direct methanol/oxygen fuel cell gave a maximum power density of about 180 mWcm−2 at 120°C.
Unidirectional hexagonal rare-earth disilicide nanowires on vicinal Si(100)-2×1
Rare-earth disilicide nanowires grown on vicinal Si(100) with a miscut of 2–2.5° toward the [110] azimuth at 600 °C were studied by scanning tunneling microscopy and compared with those grown on flat Si(001). In contrast to rare-earth disilicide nanowires grown on flat Si(100) surfaces, the nanowires grow unidirectionally along the [01̄1] direction of the vicinal Si(100) surface. Rare-earth disilicide nanowires form bundles composed of single nanowire units on both flat and vicinal surfaces. Yet, on the vicinal surface, the bundle width is comparable to the width of the terrace. The average nanowire length on the vicinal substrate is longer than that on the flat substrate. Scanning tunneling spectroscopy shows that the rare-earth disilicide nanowires have metallic properties.