3D-Printed Electrodes for Power-Producing Microbial Fuel Cells

• Michael Earley, Computer Engineering, University of Delaware

• Nathan Lazarus, Electrical and Computer Engineering, University of Delaware

Microbial Fuel Cells (MFCs) are a low source of clean, renewable energy that can be constructed using inexpensive materials, such as mud and plastic. Electricity can be derived from their metabolic process by using bacteria that can naturally or artificially be found within different substances. Microbial fuel cells can use various substances for bacteria to inhabitant or feed on. Many past studies have shown how different microbes and feeding fuels can improve the overall performance of individual MFCs. However, fewer studies have explored the potential of MFCs through other means. The purpose of this study begins with using additive manufacturing–also known as 3D-printing–to fabricate MFCS; specifically focusing on the electrodes. In this study, conductive polylactic acid, conductive PLA (ProtoPlant, USA), was the primary filament used for each experiment, with the exception of Electrifi (Multi3D, USA) for further testing. The standardized MFCs in this study were soil-based, and they were vesseled by a 32 oz., food-grade, plastic container. Each experiment was done in sets of 3 and then averaged afterward. The soil being used for the MFCs is commercially bought garden soil (Miracle-Gro). Water from a local creek was used to both inoculate and fuel the MFCs. Each MFC had two electrodes connected by an external load of approximately 10 kΩ. As a control, a standard wire mesh covered in epoxy glue and activated carbon was used as both the cathode and anode electrodes. The control group produced a maximum OCV of  225.1 mV and a maximum power of 1.27E-02 mW. Meanwhile, the 3D-printed electrodes, made up of carbon PLA filament, produced a maximum OCV of 66.9 mV with a maximum power of 1.42E-06 mW.