Laser-perforated anode gas diffusion layers for direct methanol fuel cells

Novel anode gas diffusion layers (AGDLs) with both hydrophobic and hydrophilic pathways are created to enhance transfer of both methanol and CO₂. Such AGDLs are created by perforating PTFE-treated AGDLs with laser, so that the original pores/pathways in the AGDL are hydrophobic and the laser perforations are hydrophilic, thus providing easy transport paths for both the liquid methanol solution and CO₂. One of the novel AGDLs has increased the cell performance by 32% over the non-perforated AGDL. Results of electrochemical impedance spectroscopy (EIS) show that the main reason for the performance enhancement is due to the reduction in mass transfer resistance. Additionally, there is a reduction in charge transfer resistances due to the enhanced methanol transfer to the catalyst layer. The results of linear sweep voltammetry (LSV) show that the perforations increase methanol crossover, thus if perforation density of the AGDL is too high, the cell performances are lower than that of the virgin AGDL.