The Production of a Silicon-Based Proton-Exchange Membrane with Different Porosity Layers

The aim of this study, which combines renewable energy and porous silicon – two prominent issues in recent years – was to make a porous proton exchange membrane for a proton exchange membrane fuel cell. To make a membrane of the desired thickness, wet etching was performed on the 4.41 cm2 rear side of a double-sided, polished, p-type silicon wafer with a thickness of 200 μm and a resistivity of 0.001 to 0.005 Ω-cm. Then the silicon wafer was cleaned using the RCA cleaning method and the grid shape on the mask was printed on the front side of the silicon using photolithography. The 3.61 cm2 front face of the silicon was placed in a double-tank electrochemical cell designed by us and was anodized at various current densities for certain periods of time to allow the formation of a porous layer throughout the sample. Finally, the pore formation was completed by passing a high current through the rear surface of the silicon to ensure that the pore tips were opened. The thickness of the porous layer formed was observed by scanning electron microscopy. Electrochemical impedance spectroscopy was performed, with the help of a fuel passage test and with formic acid, to measure the usability of the porous silicon as a membrane. Ion passage was observed as a result of the experiments performed