Development of Improved Passive Configurations of DMFC with Reduced Contact Resistance

Abstract The Direct Methanol Fuel Cell (DMFC) represents today an appropriate solution for powering portable applications and small electronic devices, due to: 1) its compactness, 2) the high power density when compared with batteries and 3) the facility in transporting proper quantities of fuel (generally a liquid mixture of methanol and water). In order to further reduce the DMFCs size, passive configurations without external pumps and auxiliary devices are actively studied. Oxygen is supplied from the surrounding air while methanol-water solution is stored into a built-in tank in contact with the gas diffusion layer (GDL) that is constantly kept wet. Such configurations have a lower current density, roughly around 10÷30 mA/cm2, when compared with active configuration (40÷80 mA/cm2). It is then important to improve the baseline performance (power and efficiency) of such cells by optimizing all system components. Here we aim at reducing the effects of the contact resistance between GDL and current collectors by carrying out a sensitivity analysis on a number of relevant cells parameters such as:. assembly shape, gaskets, current collectors materials and open ratios. Analysis will be carried out at different molar concentrations (1 to 4 M) of the water-methanol solution used as fuel.