Air-cathode preparation with activated carbon as catalyst, PTFE as binder and nickel foam as current collector for microbial fuel cells

• Developed three-dimensional structure cathode with low internal resistance
• Decreasing the PTFE loading in the catalyst layer increased the cathode performance.
• The current collector structure and catalyst characteristics are the key factors to cathode performance.
• A nickel foam cathode has high performance and low cost, and is feasible for MFC scale-up.

A cathode is a critical factor that limits the practical application of microbial fuel cells (MFCs) in terms of cost and power generation. To develop a cost-effective cathode, we investigate a cathode preparation technique using nickel foam as a current collector, activated carbon as a catalyst and PTFE as a binder. The effects of the type and loading of conductive carbon, the type and loading of activated carbon, and PTFE loading on cathode performance are systematically studied by linear sweep voltammetry (LSV). The nickel foam cathode MFC produces a power density of 1190 ± 50 mW m− 2, comparable with 1320 mW m− 2 from a typical carbon cloth Pt cathode MFC. However, the cost of a nickel foam activated carbon cathode is 1/30 of that of carbon cloth Pt cathode. The results indicate that a nickel foam cathode could be used in scaling up the MFC system.