ABSTRACT

Microbial fuel cells (MFCs) can be considered as one of the most promising technologies to help address the challenge of climate change (Hernández-Fernández et al., 2015). These devices can convert the chemical energy present in a substrate, such as wastewater, into electricity, offering a twofold benefit, electricity generation and water treatment. Bacteria in the anode chamber degrade the substrate (oxidation) and transfer the electrons released to the anode through an external circuit. Protons pass through the proton exchange membrane to the cathode, where they react with oxygen (reduction) and the electrons from the anode to form water. MFCs can be set up in double-chamber or single-chamber configurations. Double-chamber designs include both an anodic and a cathodic chamber, commonly separated by a selective separator for ion exchange, while single-chamber MFCs only comprise an anodic chamber, with the cathode electrode exposed to the air (Du et al., 2007; Oliveira et al., 2013). The main components (anode, cathode, and separator) and the final design in which they are assembled play a key role in MFC performance and efficiency. In recent years, studies focused on MFCs have grown exponentially because this technology still shows certain limitations associated with their practical implementation. The high cost of some materials, such as proton exchange membranes or precious catalysts, and the complexity of MFC configurations have limited their commercial use. This chapter describes the most significant advances made in terms of materials and designs for MFC construction. The information covered ranges from the simplest and lowest cost materials to those more complex options that can even outperform noble metals. Furthermore, the chapter also includes the evolution of the MFC assemblies developed in recent years, including the discussion of operational parameters.