Scaling effect on mems-based microbial fuel cells: Toward a carbon-neutral miniaturized power source

Abstract

We report the scaling effect on a μL-scale miniaturized microbial fuel cell (MFC), gearing toward a carbon-neutral miniaturized power source. MFCs have been studied for many years, yet the scaling effect on MFCs has not been addressed effectively in the past. This work studies the scaling effect on mass transfer to improve the power density of a μL-scale MFC. As scaling down the characteristic length, Reynolds number decreases and mass transfer coefficient rapidly increases, resulting in a higher power density. Areal and volumetric power densities of 83 μW/cm2 and 3.32 mW/cm3 are obtained, respectively; both of which the highest ever reported among all μL-scale MFCs to date. Columbic efficiency (CE) of 79.4 % is marked, more than 2.5 folds of the previously reported maximum CE in μL-scale MFCs.