Assessing the effect of the electrode orientation on the performance of soil microbial fuel cells

¹ Department of Chemical Engineering, University of Bath, BA2 7AY, Bath, United Kingdom
² Centre for Biosensors, Bioelectronics and Biodevices, University of Bath, BA2 7AY, Bath, United Kingdom

^* Corresponding author: m.di.lorenzo@bath.ac.uk

Abstract

Soil microbial fuel cells (SMFCs) are a sub-class of the microbial fuel cells family, in which the soil acts as the electrolyte, and as the source of microorganisms and organic fuel. Given the great simplicity of the system design, SMFCs show a promising avenue for energy generation in remote areas. In this study, we investigate the influence that geometrical factors, such as the electrode orientation, have on the electrochemical performance of SMFCs. Two types of electrode orientations: horizontal and vertical, were tested. Additionally, the influence of anode and cathode immersion in soil was explored too. Our results demonstrate that vertical positioning of the cathode in soil is not a viable option. The increase in cathodic immersion leads to a more rapid performance decay, attributed to more anaerobic conditions along soil’s depth. The increase in anode immersion has a positive effect on the evolution of the negative electrode potential. However, with the increase in electrode spacing, the performance drops due to a greater internal resistance.