Development of Sustainable Hybrid Microbial Fuel Cell (MFC) System from Living Plants for Low-power Field Electronic Devices

Microbial Fuel Cells (MFCs) are a promising renewable and sustainable energy solution for low-power field electronic devices, but still remain in the research phase due to low power output efficiency. This research systematically studied three tubular MFC systems including standalone soil microbial fuel cells (S-MFCs), plant microbial fuel cells (P-MFCs), and a proposed hybrid MFC (H-MFC) system. All tubular MFC systems were carefully constructed using three types of soils (potting soil, yard soil, and river soil), four plants (Bonnie Curly Spider, Peace Lily, Lemongrass, and Tomato Plant), and two types of electrodes (zinc mesh as the cathode and copper spiral as the anode). Power density from each system was calculated as a function of the days during growth and was based on the experimental measurement of the open voltage of every setup. The results showed that a standalone S-MFC system had easy implementation and a higher power density initially than some P-MFCs but was not as sustainable as P-MFCs, whereas both P-MFC and hybrid systems could produce power densities for sustained periods of time. However, the difference in power density between P-MFC and hybrid systems was observed after 18 days for potting soil and 11 days for yard soil, and after 30 days, the power density of all hybrid systems was roughly 2 times that of all P-MFC setups. Furthermore, the hybrid systems displayed significant advantages over their S-MFC and P-MFC counterparts, especially in the sustained power output and ease of replaceability, meaning that future implementation of this technology in a scaled-up setting is more feasible. Therefore, it is suggested that hybrid MFC systems will be the future direction of S-MFC and P-MFC technology.