3D-Printed Conductive Polymers as Alternative for Bioelectrochemical Systems Electrodes: Abiotic Study and Biotic Start-Up

Despite over two decades of intense research into bioelectrochemical systems (BESs), their practical implementation remains unrealized, partly due to the low performance of bioelectrodes. With the introduction of additive manufacturing techniques, the development of a new generation of bioelectrodes with custom-shaped geometries using conductive composites has become feasible. This study examines the potential of using two conductive composites, Poly-lactic acid (PLA) and thermoplastic polyurethane (TPU), for 3D-printed electrodes. Electrochemical characterization reveals that TPU has a charge transfer resistance approximately two orders of magnitude higher than PLA, rendering it unsuitable for bioelectrodes. The presence of triangular patterns enhances the performance of planar electrodes, with optimal results observed for PLA-based electrodes with surface pattern depths between 0.6 and 1.4 mm. Additionally, electrodeposition (ED) of graphene oxide (GO) further improves performance across all cases. During the subsequent biotic start-up, patterned PLA electrodes with a depth of 1.4 mm exhibit higher current. However, these 3D-printed electrodes exhibit degradation after 56 days of operation.