Self-contained and integral microbial fuel cells as portable and sustainable energy sources for low-power field devices

Abstract

Background: With a smaller environmental footprint and longer operation times, Microbial Fuel Cells (MFCs) are now preferred over other renewable technologies for powering small electronic devices in the field. Although with excellent performance in the laboratory, most of MFCs fail for not considering the real field conditions. The purpose of this study is the development of a compact, portable, and self-sustaining format of energy production based on MFC technologies. For this, three MFC configurations, soil MFC, plant MFC and a hybrid-MFC, where a plant and a soil MFC are combined, are assembled in portable power devices and compared.

Results: Plant MFCs provided lower performances (maximum power of 0.6 ± 0.4 µW·cm⁻²) resulting from a fast and sharp decrease in the anode potential by the flowing of oxygen from the aerenchyma of the plant roots. The performance of soil MFCs was much better (maximum power of 2.0 ± 0.02 µW·cm⁻²), but not sustained over time (20 days) by the depletion of organic matter. The combination of a soil MFC and a plant in separate compartments of a single container results in a hybrid-MFC with a good performance (maximum power of 2.7 µW·cm⁻²) which sustained over time for more than 1 month.

Conclusions: Therefore, the hybrid self-containing MFCs appears as an ideal alternative for the long-term power supply of low-power field electronic devices, from meteorological sensors or LED lights.