Abstract: In order to promote the energy output of microbial fuel cell (MFC), reduce the internal resistance of MFC and the cost of processing organics, a direct-air cathode single-chamber microbial fuel cell was constructed by using air electrode as cathode, foamed nickel (ferrumiron) as anode and glucose as the anode fed. The results demonstrated that the open circuit voltage reached 0.62 V, the internal resistance of the cell was 33.8 Ω, the maximum power density reached 700 mW·m-2 (4146 mW·m-3), and the electron recovery was 20%. The discharge curve and cyclic voltammetry tests revealed that the first discharge capacity and energy density were 263 mAh·g-1 COD (chemical oxygen demand) and 77.3 mWh·g-1 COD, respectively. The charge-discharge performance and stability of MFC were pretty good. The electrochemical impedance spectroscopy analysis demonstrated that the cell impedance increased with the increase of discharge time, which was one of the reasons resulting in the decrease of output voltage. The degradation rate of COD (chemical oxygen demand) reached 56.5% after it operating for 8 h. The degradation of COD followed the first order reaction model.

Key words: Microbial fuel cell, Air-cathode, Power density, Electrochemical property