Boosting power density of microfluidic biofuel cell with porous three-dimensional graphene@nickel foam as flow-through anode

Microfluidic microbial fuel cells (μMFC) combine the microfluidic technology and bio-catalysts anchored at the electrode, representing an emerging bio-power generator. However, a major challenge towards further development is their low bio-catalysts loading on the electrodes. Previous researches have revealed the bio-electrode structure and nutrient-feeding type play a significant role in the power generation of μMFC. In this study, we fabricate a membrane-free μMFC with a piece of graphene-decorated nickel mesh as bio-anode, which is fed in a flow-through manner. The scanning electron microscopy and pore-distribution variation analysis show the mixed bacteria grow densely on the surface of the electrode. Benefited from the enriched bacterial colonization and sufficient nutrient supply, the μMFC produces a remarkably high areal power density of 1.11 W m−2 at a current density of 2.15 A m−2. These values are substantially higher than those of conventional two-dimensional electrodes and flow-over architectures measured under the same condition.