Preliminary evaluation of an alkaline chitosan-based membrane fuel cell

New polymer electrolyte composite membranes were prepared by using chitosan as the matrices and incorporating potassium hydroxide for ionic functionality. These membranes had a three-layer structure, which consisted of a porous intermediate layer and two crosslinked solid surface layers. Their ionic-conductive properties were investigated using impedance spectroscopy. Some composite membranes showed a conductivity near 10−2 S cm−1 after hydration for 1 h at room temperature. Several composite membranes were preliminarily integrated into fuel cells for the assessment of their electrochemical performance using hydrogen as fuel, air as oxidant and platinum as the electrode catalysts. A membrane electrode assembly was fabricated by directly pressing two gas-diffusion electrodes onto the two opposite surfaces of the composite membrane. All fuel cells showed an open-circuit potential around 1.0 V, and under appropriate running conditions, a current density of about 30 mA cm−2 was achieved. Some possible improvements on the performance of the resultant fuel cells are also suggested.