Mass transport optimization in the anode diffusion layer of a micro direct methanol fuel cell

• The gradient anode gas diffusion layer is applied to enhance the power density.
• A 2D, two-phase model coupled with hydrophobic characteristic is established.
• A metal-based μDMFC with the effective area of 0.64 cm2 is fabricated.
• Detailed experiments are conducted to validate the simulation results.

In this paper, the gradient AGDL (anode gas diffusion layer) is applied to prompt the methanol/CO2 transport, and improve the performance of the μDMFC (micro direct methanol fuel cell). A two-dimensional, two-phase model coupled with mass/momentum transports and hydrophobic characteristic is first established, with the methanol concentration distribution, CO2 volume fraction, and the polarization curve simulated. In addition, a metal-based μDMFC with the effective area of 0.64 cm2 is fabricated, such that detailed experiments are conducted to validate the simulation results. The results reveal that when the AGDL is treated with 10 wt% of PTFE (Polytetrafluoroethylene), the best performance with a peak power density of 19 mW cm−2 is achieved at room temperature. Finally, a novel AGDL structure with gradient PTFE content is prepared to improve the two-phase convection transport and the power density.