PVDF layer as a separator on the solution-side of air-cathodes: the electricity generation, fouling and regeneration

Abstract

Cost effective air-cathodes are very important for application of Microbial Fuel Cells (MFCs). Carbon fiber cloth was used as the base for preparing air-cathodes with cheap polyvinylidene fluoride (PVDF) coating on the solution-side to replace expensive Nafion as a separator regardless of the ion exchange part. The separator on the solution-side was a vital part for stable electricity generation. Another PVDF layer was coated on the air-side via a thickness-controllable method as the diffusion layer. The comparisons between Nafion and PVDF on the solution-side of cathode in electricity generation and fouling/regeneration were tested in MFCs without any catalyst. The cell voltage of the Nafion air-cathode MFC (0.23 V) was slightly higher than the PVDF MFC (0.2 V). Biofouling and cation deposition on air-cathodes became more severe with time, negatively affecting electricity generation. Soaking the air-cathode with solution-side Nafion in HCl (maximum power density: 338.1 mW m⁻²) can regenerate the cathodes and enhance the electricity generation much more than that regenerated by ultraviolet light (UV) irradiation.