New solid polymer electrolyte membranes for alkaline fuel cells

New solid polymer electrolyte composite membranes have been prepared using chitosan as matrices and incorporating potassium hydroxide as the functional ionic source. These membranes were featured as a three‐layer structure having a porous intermediate layer while the two crosslinked surface layers are dense. Results from impedance spectroscopy analysis showed that the conductivity of some hydrated composite membranes, after hydration for 1 h at room temperature, reached about 10−2 S cm−1. Several composite membranes were then tested in alkaline fuel cells, using hydrogen as fuel, air as oxidant and platinum as the electrode catalyst. A current density of 35 mA cm−2 has been achieved at 60 °C with a flow rate of hydrogen at 50 ml min−1 and air at 200 ml min−1. Copyright © 2004 Society of Chemical Industry