A membrane electrode assembly (MEA) with a novel trilaminar-catalytic layered structure was designed and fabricated for a micro-direct methanol fuel cell (μ-DMFC). The trilaminar-catalytic layer comprises three porous layers. The medial layer has a lower porosity than the inner and outer layers. The simulation results predicted a lower water content and a higher oxygen concentration in the trilaminar-catalytic layer. The novel trilaminar-catalytic layer enhanced the back diffusion of water from the cathode to the anode, which reduces methanol crossover and improves oxygen mass transportation. The electrochemical results of the half-cell test indicate that the novel MEA has a greatly increased cathode polarization and a slightly increased anode polarization. Thus, this novel μ-DMFC structure has a higher power density and a longer discharging time, and hence may be used in portable systems.

The design of the anode flow field is critical for yielding better performance of micro direct methanol fuel cells (µDMFCs). In this work, the effect of different flow fields on cell performance was investigated by the simulation method. Compared with grid, parallel and double-serpentine flow fields, a single-serpentine flow field can better improve the mass transfer efficiency of methanol and the emission efficiency of the carbon dioxide by-product. The opening ratio and channel length also have important effects on the cell performance. The cells were manufactured using silicon-based micro-electro-mechanical system (MEMS) technologies and tested to verify the simulation results. The experimental results show that the single-serpentine flow field represents a higher peak power density (16.83 mWcm−2) than other flow fields. Moreover, the results show that an open ratio of 47.3% and a channel length of 63.5 mm are the optimal parameters for the single-serpentine flow field.

The open-cathode forced-convection proton exchange membrane fuel cell has emerged as a viable option for portable energy sources. The forced-convection open-cathode mode, however, makes the cell’s performance sensitive to changes in the cathode channel and fan parameters. In this study, small fuel cell stacks with varying cathode channel depths, widths, and width–rib ratios were assembled, and the effects of different cathode channel parameters and fan duty ratios on cell performance were investigated. The experimental results show that changing the cathode channel parameters has a significant impact on oxidant supply. When the channel width is increased, the cell performance increases first, then decreases. The cell performance decreases as the channel width–rib ratio increases. The performance of the cell improves as the cathode channel depth increases. Furthermore, the experimental results show that decreasing the duty ratio of the fan and using moderate heating improves cell performance.