Large-scale preparation of electrically conducting cellulose nanofiber/carbon nanotube aerogels: Ambient-dried, recyclable, and 3D-Printable

Abstract

This work demonstrates an ambient-dried and non-chemical cross-linking way of preparing functional aerogels from cellulose nanofibrils (CNFs) and carbon nanotubes (CNTs), constructing aerogel pore walls with sufficient mechanical properties by cycling freeze-thawing to cross-linking CNFs and CNTs. During the process, a novel dual-networks interpenetrating strategy is constructed benefiting from the tubular dispersion of CNFs and CNTs, enabling the creation of hybrid dual-networks of hydrophobic and hydrophilic nanofibers. As a result, aerogels with tunable densities (0.0519 g cm−3), high specific surface area (157.24 m2 g−1), and good conductivity (30.95 S cm−1) can be prepared. Besides, the aerogels can be easily recyclable due to the absence of chemical crosslinking. Various shaped and structural characteristics of the aerogels can be adjusted through 3D printing or mold, behaving a large-scale production future (diameter of aerogel up to 8.68 cm). To demonstrate their use in various applications, the aerogels show high specific electromagnetic shielding properties (440.9 dB cm3 g−1) and can be used as a free-standing electrode for loading active materials (e.g., MnO2), exhibiting excellent energy storage properties (551 F g−1). More than that, this method can be applied to other nanofibers (ANF, PI, etc.), and even more diverse structures are expected to be obtained.