Performance of an alkaline fuel cell with single or double layer electrodes

Abstract

In the present research, the improvement of an alkaline fuel cell performance by changing the electrode structure and manufacturing method has been achieved by employing multilayer, Teflon-bonded gas diffusion type electrodes which were prepared by the rolling method. Active carbon or carbon black was used as the support material, platinum as the catalyst and nickel screen as the backing material. Double layer electrodes possessed the active and the diffusion layers on the backing layer. However, the single layer electrodes only had the active layer on the backing layer. The electrode manufacturing method was ameliorated by applying different compaction loads and altering the sintering conditions. The electrodes were prepared by using different PTFE contents and platinum loadings. The voltage-current density characteristics of the fuel cell were measured at different temperatures (25–70°C) in a test module. The specific power density (mW/mg Pt) and the fuel cell efficiency obtained by using the double layer electrodes were higher compared to the single layer electrodes. The minimum initial cost per kilowatt electricity produced was obtained with double layer electrodes having 0.3 mg/cm 2 platinum load. The fuel cell assembled with these electrodes delivered a current density of 129 mA/cm 2 at a cell voltage of 0.6 V. The current density increased to 225 mA/cm 2 at the same voltage when the platinum load was increased to 2 mg/cm 2.