Printing of Graphene Nanoplatelets into Highly Electrically Conductive Three-Dimensional Porous Macrostructures

The manufacturing of three-dimensional (3D) graphene monoliths with remarkable electrical performance has become a challenging issue because their potential applications in the energy and electronic-based fields. Here we show the development of outstanding electrically conductive graphene patterned cellular structures combining a versatile and easily scalable filament printing method, such as Robocasting, with the use of highly crystalline graphene nanoplatelets (GNPs) as the graphene source. Robust 3D pure graphene-based monoliths have been manufactured by printing pseudoplastic aqueous-based GNPs inks with high graphene contents (36.6 wt %) and further thermal treatment by spark plasma sintering. Specific conductivities up to 385 S·cm –1 have been assessed along the longitudinal direction of the 3D structure, i.e., where the current mainly flowed along the struts, being more conductor than reported 3D synthesized graphene structures and up to 2 orders of magnitude higher than 3D printed graphene monoliths. The present findings could open a straightforward pathway for creating, in a controlled way, a wide range of graphene-based hierarchical structures with an excellent electrical performance and robustness that could be employed for energy storage systems.