Extrusion 3D printing of carbon nanotube-assembled carbon aerogel nanocomposites with high electrical conductivity

Abstract

Carbon nanotubes (CNTs) with high aspect ratio and excellent electrical conduction offer huge functional improvements for current carbon aerogels. However, there remains a major challenge for achieving the on-demand shaping of carbon aerogels with tailored micro-nano structural textures and geometric features. Herein, a facile extrusion 3D printing strategy has been proposed for fabricating CNT-assembled carbon (CNT/C) aerogel nanocomposites through the extrusion printing of pseudoplastic carbomer-based inks, in which the stable dispersion of CNT nanofibers has been achieved relying on the high viscosity of carbomer microgels. After extrusion printing, the chemical solidification through polymerizing RF sols enables 3D-printed aerogel nanocomposites to display high shape fidelity in macroscopic geometries. Benefiting from the micro-nano scale assembly of CNT nanofiber networks and carbon nanoparticle networks in composite phases, 3D-printed CNT/C aerogels exhibit enhanced mechanical strength (fracture strength, 0.79 ​MPa) and typical porous structure characteristics, including low density (0.220 ​g ​cm⁻³), high surface area (298.4 ​m² ​g⁻¹), and concentrated pore diameter distribution (∼32.8 ​nm). More importantly, CNT nanofibers provide an efficient electron transport pathway, imparting 3D-printed CNT/C aerogel composites with a high electrical conductivity of 1.49 ​S ​cm⁻¹. Our work would offer feasible guidelines for the design and fabrication of shape-dominated functional materials by additive manufacturing.