Microbial fuel cells: Bright sparks and lingering shadows - a comprehensive review

Microbial Fuel Cells (MFCs) are a bioelectrochemical technology that is associated with innovation, as they utilize the metabolism of microorganisms to break down organic waste into electricity, offering two key benefits: clean energy and wastewater treatment (dual benefits). This review presents an overview of recent innovations in MFC design, materials, and microbial engineering that aim to address critical issues, including low power density, biofouling, and scalability. The power densities have been considerably enhanced to 600 mW/m², and COD removal efficiencies and Coulombic efficiency have increased to 92% and 65%, respectively, over the past five years. The most prominent trends in this development are the appearance of nanostructured electrodes, conductive polymers, well-designed microbial consortia, and innovative membrane materials. Artificial intelligence and hybrid renewables have created a new opportunity to improve performance and minimize cost. Nevertheless, commercial application is still hindered by the high cost of the material and its long-term stability issues. This review explores the potential of MFCs in the context of decentralised energy systems and the circular economy, critically appraising the existing research on the topic. By combining waste management with clean energy production, MFCs offer a promising approach to achieving environmental sustainability and energy resilience.