Fabrication and Characterization of a Thin, Double-sided Air Breathing Micro Fuel Cell

An air-breathing micro fuel cell (FC) with laterally fed porous anode electrode is realized and reported. The performance of this microdevice with embedded flow channels and electrodes is characterized in ambient conditions. To realize this device, we used negative epoxy-based photoresist (SU-8) as a stamp to transfer a microchannel pattern into a Nafion 1110 membrane by micro hot embossing. A Nafion 212 layer served to seal the device as a blanket top layer. The fabrication process of microchannels and FC assembly is evaluated with optical and scanning electron microscopy (SEM) step by step. Variations of hydrogen feed rate on performance are investigated. The cell is composed of two individual fuel cells with a shared anode. The characteristics of the cell are further studied by performance and electrochemical impedance spectroscopy (EIS) measurements of the separate constituent cells and compared with data for the complete cell. The maximum power density per superficial (footprint) area is 68.4 mW cm(-2) for the shared anode stack. In the present FC architecture, the external packaging is Nafion polymer, which results in a thin and light energy source with simplicity of manufacturing. The device performance offers a high volumetric and gravimetric energy density for portable applications.