Influence of hydrodynamics and depth on the performance of 3D-printed microbial fuel cells

Submersible devices, such as underwater monitoring systems and aquatic environmental sensors, represent a rapidly evolving research frontier driven by hydrodynamic challenges and the need for autonomous operations. Sustainable powering of these systems using Microbial Fuel Cells (MFCs) offers a viable and eco-friendly alternative. This study presents a comprehensive evaluation of 3D-printed MFCs fabricated via Fused Deposition Modeling (FDM), employing fiber-based electrodes as both anode and cathode materials. The devices were tested at varying depths within an acrylic tank under various hydrodynamic conditions (stagnant and aerated) in both lake and artificial seawater. Results revealed a moderate decline in power density with increasing submersion depth. However, aeration markedly enhanced performance in lake water, improving power retention from 62.88% to 68.06%, owing to increased oxygen availability that facilitated the oxygen reduction reaction (ORR) and microbial activity. In contrast, aerated artificial seawater exhibited a minor decline in performance (from 85.22% to 75.76%), likely due to ionic turbulence and bubble-induced disturbances within the electrolyte. Repeatability and operational stability tests confirmed consistent electrochemical performance, underscoring the reliability of these systems for long-term operation. Overall, this work advances the development of depth-adaptive, self-powered platforms for real-time underwater monitoring and environmental sensing applications.