Graphene electrodes enhance performance for microliter scale microbial fuel cells

Recently, microliter-scale microbial fuel cells (μMFCs) have garnered significant interest as effective energy harvesters for low power biological and electronic systems. Although researchers have attained high current densities and columbic efficiencies from such fuel cells, low power outputs and working potentials caused by the use of Au/Cr electrodes have limited the implementation of μMFCs in practical applications. To overcome these limitations, here we present a graphene-based μMFC (G-MFC) that utilizes laser synthesized graphene electrodes to generate open circuit potentials (OCPs) of 0.8 ± 0.05 V and power densities of 1820 ± 10 W/m³. Furthermore, the G-MFC produces a maximum power output of 364 μW. The stack-able and low cost design of our G-MFC allows for a wide range of applications and also serves as a platform for repeatable electrode and substrate based testing. These results suggest that our G-MFC methodology could offer an effective route to achieve viable energy harvesters for low power systems.