title: Electrochemically exfoliated graphene anodes with enhanced biocurrent production in single-chamber air-breathing microbial fuel cells.
abstract: Microbial fuel cells (MFCs) present promising options for environmentally sustainable power generation especially in conjunction with waste water treatment. However, major challenges remain including low power density, difficult scale-up, and durability of the cell components. This study reports enhanced biocurrent production in a membrane-free MFC, using graphene microsheets (GNs) as anode and MnOx catalyzed air cathode. The GNs are produced by ionic liquid assisted simultaneous anodic and cathodic electrochemical exfoliation of iso-molded graphite electrodes. The GNs produced by anodic exfoliation increase the MFC peak power density by over 300% compared to plain carbon cloth (i.e., 2.85Wm(-2) vs 0.66Wm(-2), respectively), and by 90% compared to conventional carbon black (i.e., Vulcan XC-72) anode. These results exceed previously reported power densities for graphene-containing MFC anodes. The fuel cell polarization results are corroborated by electrochemical impedance spectroscopy indicating three times lower charge transfer resistance for the GN anode. Material characterizations suggest that the best performing GN samples were of relatively smaller size (~500nm), with higher levels of ionic liquid induced surface functionalization during the electrochemical exfoliation process.
authors.affiliation: Department of Chemical and Biological Engineering, Clean Energy Research Centre, The University of British Columbia, 2360 East Mall, Vancouver, BC, Canada V6T 1Z3.
authors.forename: Amin Taheri
authors.initials: AT
authors.lastname: Najafabadi
authors.affiliation: Department of Chemical and Biological Engineering, Clean Energy Research Centre, The University of British Columbia, 2360 East Mall, Vancouver, BC, Canada V6T 1Z3.
authors.forename: Norvin
authors.initials: N
authors.lastname: Ng
authors.affiliation: Department of Chemical and Biological Engineering, Clean Energy Research Centre, The University of British Columbia, 2360 East Mall, Vancouver, BC, Canada V6T 1Z3. Electronic address: egyenge@chbe.ubc.ca.
authors.forename: Előd
authors.initials: E
authors.lastname: Gyenge
mesh_terms: D001674:Bioelectric Energy Sources / Q000382:microbiology*; D004560:Electricity; D004566:Electrodes; D004867:Equipment Design; D004926:Escherichia coli / Q000254:growth & development; D006108:Graphite / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry
chemical_list: D052578:Ionic Liquids; D006108:Graphite
keywords: Electrochemical exfoliation of graphite; Graphene; Ionic liquid; Microbial fuel cell