Application of Modified Foam Graphite Anode with Low Potential in Marine Benthic Microbial Fuel Cell

Abstract

Foam graphite is a novel anode material and its modification is one important way to increase the performance of marine benthic microbial fuel cell.The electrochemical performance of mixed-acid modified foam graphite anode was investigated.The results showed that the hydroxyl and carboxyl groups were introduced on foam graphite surface after modification.The contact angle of modified anode decreased 24.5°,resulting in higher wettability and better attachment for bacteria.Its exchange current density reached 6760.8 mA/m2 and the kinetic activity was improved 53.7-fold higher than the original one.Additionally,the present study also found that the anode potential of modified decreased 100 mV,and its open circuit potential reached 865 mV(plain anode 750 mV).The power density of modified cell reached 358.1 mW/m2,2.4-fold higher than unmodified foam.Three months discharge showed that the modified anode and its cell have relatively stable performance.Meanwhile,the paper primarily analyzed the reasons why the anode potential was lower and kinetic activity was higher after modification.The results gave some enlightenments to constructing a novel marine benthic microbial fuel cell with higher output voltage and power.