Improving microbial fuel cells power output using internal and external optimized, tailored and totally green supercapacitor

In this work, the external and internal integration of supercapacitive features in the electrodes of microbial fuel cells (MFCs) has been investigated to improve their power performance. The external integration relies on the direct parallel connection with a tailored green supercapacitor. The latter was assembled involving only sustainable components within the core of the circular economy. Instead, the integration of internal supercapacitive features is based on the decoration of the bacterial anode with high surface area activated carbon obtained from the pyrolysis of agricultural waste biomass. Both strategies are capable to improve the maximum power of MFCs by almost one order of magnitude (from 0.6 mW to 6.7 mW and 6.5 mW for the external and internal supercapacitive microbial fuel cell, respectively). The internal integration of supercapacitive features in MFCs, on the other hand, enables higher discharge energy at higher current pulses (from 1 μWh to 2.4 μWh to 42 μWh, for the internal, external supercapacitive and bare MFC, respectively). Overall, these two strategies are capable to improve the performance of MFCs without affecting the cell volume.