Studying the compatibility of hydrogels as a separator for microbial fuel cells developed by 3D-printed technology

Hydrogels have emerged as a promising sustainable alternative to proton exchange membranes (PEM) as components of microbial fuel cells (MFCs). This study investigates the feasibility of the replacement of the separator element by comparing the performance of air-breathing and bicompartmental cells consisting of Membrane Electrode Assemblies (MEAs) and Hydrogel Electrode Assemblies (HEAs) in terms of electrochemical efficiency, biocompatibility and chemical stability. Results demonstrate the feasibility of the replacement, which becomes especially important in terms of the necessary reduction of fluorinated membranes. However, the voltage generated by HEA-based configurations was slightly lower than that achieved by cells equipped with MEAs. In addition, they indicate that the two-compartment HEA configuration is more suitable than the air-breathing one to ensure proper acclimation of anaerobic electrogenic bacteria in the anode and prevent desiccation. This work highlights that hydrogels represent an encouraging, available and environmentally friendly solution for MFCs, which could accelerate the transition to energy independence and sustainable technological advances in a variety of applications.