Less is More: A Comprehensive Study on the Effects of the Number of Gas Diffusion Layers on Air–Cathode Microbial Fuel Cells

Air-cathode microbial fuel cells (AC-MFC) use a gas-diffusion-layer (GDL) coating based on polytetrafluoroethylene applied to the cathode prevent electrolyte leakage. However, this type of GDL can also lead decrease in MFC performance due electron-transfer limitation, mass-transfer limitation or catalyst availability. This study provides comprehensive understanding significance coating, demonstrating interaction between number coatings and external resistance (Rext) used. An experimental design 28 mL AC-MFCs was prepared conducted using two different Rext (10 249 ?) four (1 4 layers). The effect not significant when operating with high Rext, where electron transfer limiting process. low, amount limited Pt availability catalytic surface. Thus, GDL-1 10 ? as reached 0.96 mA/cm2, 3-fold higher than that obtained (ca. 0.30 mA/cm2). Besides, current density did vary noticeably other cathodes Rext. Contrarily, decreased increased (0.74, 0.57 0.37 for GDL-2, GDL-3 GDL-4 respectively). These values agreed those polarization curve. Furthermore, limitations were observed electrochemical impedance spectroscopy measurements: charge GDL, related ease flow. were18 ?, 22 53 58 GDL-1, GDL-4, respectively, both cathodes.