The Modification And Application Of Cathode Materials In Microbial Fuel Cells

Microbial Fuel Cell (MFC) represents the newest electricity production device, using microorganisms as catalysts and bio-electrochemical reaction to generate electricity.At the same time, it can degradate the organic matter in wastewater. High cost and low power output are the two major hurdles of MFC development on a large scale. The cathode electrode and separating membrane account for the main effect parts of these problems. Therefore, This study prepared different modified amounts of PANI modified electrodes and α-MnO2. β-MnO2、γ-MnO2modified electrodes, then tested the electrochemical performances of modified electrodes, such as CW EIS and Tafel. Experimental results show that compared with the graphite felt electrode, the electrochemical response and corrosion resistance of polymer polyaniline and manganese dioxide modified electrodes is significantly increased. The modified electrodes possess higher oxygen reduction current, and the internal resistance was obviously decreased, thereby speeding up the rate of electron transfer. The modified electrodes as the cathodes to run MFC, output power and electrical performance of the battery were both significantly improved. Wherein, the open circuit voltage of β-MnO2electrode modified MFC reached676.7mV, the maximum power density of58mW/m2; The maximum power density of PANI-160modified electrode MFC reached262mW/m2, more than15times of non-modified electrode MFC(17mW/m2), better than MnO2modified MFC. The internal resistance of the battery system is also reduced from130Ω to75Ω.Based on the PAN I-160cathode materials, in composite anion exchange membranes MFC, dual chamber air cathode MFC were runned, and compared with commercial AMI-7001. The results indicated that:PANI-160modified air cathodes in MFC, composite membranes exhibited good producing electricity performance, under the same conditions, the output power is higher than the commercial membrane AMI-7001, the maximum power density reached up to172mW/m2, decreased the internal resistance and shorten the start-up cycle of the battery system. Among them, the composite membrane rQPES2/1-(7/3) in the MFC, the open circuit voltage (OCV) achieved593.9mV, the battery internal resistance was100Ω, less than the AMI-7001(130Q); at voltage398.5mV, current density265.7mA/cm2, the maximum power density of106mW/m2.The PANI-160modified electrodes as cathodes, in proton exchange membrane MFC. The experimental results show that:During two-chamber air cathode MFC operation, electrical performance improved with increasing the content of sulfonated polymer SDFDPS, moreover the maximum power density of SPAES membranes are superior to commercial AMI-7001. For example, the OCV of R5/5MFC reached up to587.6mV, the battery internal resistance was50Ω, at voltage281.2mV, current density1124.6mA/cm2, the peak power density reached316.2mW/m2. Modified cathode and SPAES proton exchange membrane has great prospects for development in the battery system.