Compressible, superelastic and fatigue resistant carbon nanofiber aerogels derived from bacterial cellulose for multifunctional piezoresistive sensors

Abstract

Carbon aerogels have been widely exploited for wearable piezoresistive sensing thanks to their fascinating properties such as ultralow density, high electrical conductivity, superelasticity, and fatigue resistance, but to date, maintain high mechanical performances and high sensitivity in a wide pressure range still remains a huge challenge for carbon aerogels based piezoresistive sensors. Herein, we propose a simple but efficient morphology-maintained carbonization strategy by tailoring the pyrolysis chemistry of BC to fabricate superelastic and fatigue-resistant carbon nanofiber aerogels. Bacterial cellulose hydrogels are fabricated as nanofiber aerogels with a 3D-interconnected honeycomb-like structure by unidirectional freeze-drying technology, while the rational introduction of (NH 4 ) 2 SO 4 significantly inhibits the shrinkage and deformation of bacterial cellulose nanofiber aerogels during the carbonization process, enabling the retention of the 3D-interconnected honeycomb-like structure after carbonization. The as-prepared carbon nanofiber aerogels (CNFAs) exhibit exceptional mechanical performances of high compressibility (up to 99% strain), superelasticity (∼97.4%, 500 cycles at 90% compression), and fatigue resistance (up to 10 000 cycles). Moreover, the CNFAs derived sensor possesses a high sensitivity (5.66 kPa −1 ) at a wide pressure range (0–28 kPa), and a fast response time (∼100 ms), enabling the CNFAs-based sensor to monitor signals of the human body, spatial pressure, and voice recognition. These fascinating attributes make the CNFAs highly attractive for flexible wearable devices. • Biomass-based carbon nanofiber aerogels were designed for Multifunctional sensors. • The carbon nanofiber aerogel reveals a 3D-interconnected honeycomb-like structure. • Superior compressibility and fatigue resistance surpasses other carbon aerogels. • The carbon nanofiber aerogel possesses a high sensitivity at a wide pressure range.