Improving power production in linear forms of microbial fuel cells

Benthic microbial fuel cells (BMFCs) are devices that generate persistent energy by coupling bioanodes and biocathodes through an external energy harvester. Advances in BMFC system design have increased feasibility for its use in ocean monitoring. Previous iterations of BMFCs designed by this same group have relied upon carpet like anodes to harvest energy from electrochemically active bacteria in the sediment at power densities of 10 - 20 mW/m-2. Although successful, these 2D anodes are difficult to deploy. In this paper, we evaluate linear cable anodes as an alternative scaling strategy. Commercially manufactured, these cable anodes are wound around insulated underwater cables and can be handled similar to linear hydrophone arrays. Used as delivered, cable anodes performed poorly and generated ~0.3 mW/m. To improve power production, we added a washing step to remove any chemical binders used in manufacturing and frayed the cable, exposing short strands of carbon yarn. Treated cable anodes generated 1-2 mW/m, which was comparable to and slightly improved over the performance of carpet like anodes.