Supercapacitive paper based microbial fuel cell: High current/power production within a low cost design

Microbial fuel cells (MFCs) with paper separators and liquid containing elements were investigated in super-capacitive mode. MFCs (15 mL) in a supercapacitive configuration, consisted of plain wrapped carbon veil anode(negative) and conductive latex cathode (positive). The internal supercapacitor is discharged galvanostaticallyand is self-recharged as red-ox reactions occur on both electrodes. MFCs were discharged at different currentpulses varying from 1 mA to 7 mA. The MFCs had an equivalent series resistance of 41.2 ± 3.5Ωcaused mainlyby the cathode. A maximum power of 1.380 ± 0.083 mW (0.092 ± 0.006 mW mL−1) was measured.Durability tests were conducted over 24 h collecting 1000 discharge cycles (0.5 s) and self-recharges (85 s) at acurrent of 1 mA. Over time the anode potential dropped causing a decline in performance perhaps due toevaporation of liquid from the pyramidal structure. Resistance and apparent capacitance measured during thedurability test remained approximately constant during the cycles.