Hybrid Manufacturing of Oxidation Resistant Cellulose Nanocrystals-Copper-Graphene Nanoplatelets Based Electrodes

Novel green electrodes were fabricated through the combination of cellulose nanocrystals (CNC), graphene nanoplatelets (GNP) and copper precursors. Electrodes were produced by a hybrid manufacturing process that included vacuum filtration, intensive pulsed light (IPL) sintering, mechanical hot pressing and heat treatment to reduce the number of junctions and flatten the components into a parallel arrangement. Copper provides excellent electrical conductivity and cost efficiency, but it can be easily oxidized. CNC is a renewable material that acts as a strong binder, allowing the compaction of the electrodes and providing a surface for copper ions to be adsorbed. GNP prevents copper oxidation and acts as conductive bridges. This combination of processes and materials yielded decreases in electrical resistance, even after 5 days of heat treatment at 175 °C that would typically cause oxidation. At this temperature, carbonization of CNC began to occur. After applying a two percent strain to the electrodes, high CNC concentration electrodes maintained a similar electrical performance, whereas low CNC concentration electrodes exhibited a significant reduction in electrical conductivity. The ability to withstand elevated temperatures for long durations and external strains make the nanocomposite electrodes attractive for various applications such as electrodes, electrical devices and sensors.