Thermally Expanded Graphite Incorporated with PEDOT:PSS Based Anode for Microbial Fuel Cells with High Bioelectricity Production

Abstract

Modification of anodes with highly biocompatible materials could enhance bacterial adhesion, growth, and improve the rate of electron-transfer ability in microbial fuel cells (MFCs). As such, there has been increasing interest in the development of innovative anode materials to prepare high-performance MFCs. We report the synthesis of poly(3,4-ethylene dioxythiophene):poly(4-styrene sulfonate) (PEDOT:PSS) doped with thermally expanded graphite (TEG) composite coated carbon felt (CF) as anode for MFCs. For this purpose, as-synthesized PEDOT:PSS/TEG composite was characterized using high-resolution scanning electron microscopy (HR-SEM), Raman and Fourier transform infrared (FT-IR) spectroscopies which indicated successful incorporation of TEG within PEDOT:PSS film. Furthermore, the electrochemical activity of the PEDOT:PSS/TEG coated CF was employed as the anode in the MFCs with sewage water as an anolyte. PEDOT:PSS/TEG@CF anode exhibited higher ion-transfer ability, superior bio-electrochemical conductivity, and excellent capacitance. Using the PEDOT:PSS/TEG@CF anode, we have constructed MFCs which exhibited good power (68.7 mW m−2) and current (969.3 mA m−2) densities compared to the unmodified CF based anode. The reliability of the MFCs performance was also investigated by testing three independently prepared MFCs with PEDOT:PSS/TEG@CF anodes which all showed a constant voltage (∼540 mV) due to the higher stability and biocompatibility of PEDOT:PSS/TEG@CF.