Design and testing of a monopolar configuration direct methanol fuel cell stack for portable applications

- In this work, a simple and functional stack design was developed for direct methanol fuel cells (DMFCs) with the aim of reducing capital costs. A simplified planar ministack, with a reduced number of components, was designed for portable applications. This planar design facilitated the manufacturing of a compact passive mode operation ministack. The ministack provided an output power of 1.30 W under air-breathing mode operation, at room pressure and temperature without any auxiliary. The device consisted of 10 cells, two circuit boards were used to clamp and support MEAs and to electrically connect the electrodes. The ministack, for the passive mode operation, achieved a normalized power density of 30 mW cm -2 with 5 M methanol feed. The tests were carried out using membrane-electrode assemblies (MEAs) with different membranes as electrolytes. These results favorably compare with the best performance reported in the literature for passive-mode DMFC mini-stacks based on Nafion 115 membrane. Passive DMFCs can potentially result in high reliability, low cost, high fuel utilization and high energy density (using a concentrated methanol solution), which are in favour of portable equipment in future electronic devices.