Supramolecular Self-Assembly of 3D Conductive Cellulose Nanofiber Aerogels for Flexible Supercapacitors and Ultrasensitive Sensors

Abstract

Nature employs supramolecular self-assembly to organize many molecularly complex structures. Based on this, we now report for the first time the supramolecular self-assembly of 3D lightweight nanocellulose aerogels using carboxylated ginger cellulose nanofibers and polyaniline (PANI) in a green aqueous medium. A possible supramolecular self-assembly of the 3D conductive supramolecular aerogel (SA) was provided, which also possessed mechanical flexibility, shape recovery capabilities, and a porous networked microstructure to support the conductive PANI chains. The lightweight conductive SA with hierarchically porous 3D structures (porosity of 96.90%) exhibited a high conductivity of 0.372 mS/cm and a larger areanormalized capacitance (C s ) of 59.26 mF/cm 2 , which is 20 times higher than other 3D chemically cross-linked nanocellulose aerogels, fast charge−discharge performance, and excellent capacitance retention. Combining the flexible SA solid electrolyte with low-cost nonwoven polypropylene and PVA/H 2 SO 4 yielded a high normalized capacitance (C m ) of 291.01 F/g without the use of adhesive that was typically required for flexible energy storage devices. Furthermore, the supramolecular conductive aerogel could be used as a universal sensitive sensor for toxic gas, field sobriety tests, and health monitoring devices by utilizing the electrode material in lightweight supercapacitor and wearable flexible devices.

1D/2D Nanomaterials Synergistic, Compressible, and Response Rapidly 3D Graphene Aerogel for Piezoresistive Sensor

“…[ 1,2 ] In general, aerogels can be prepared by chemical vapor deposition (CVD), [ 3 ] hydrothermal methods, [ 4 ] and 3D printing, [ 5 ] while they can be prepared form silica, [ 6 ] carbon nanotubes, [ 7 ] graphene, [ 8,9 ] polyimide, [ 10,11 ] Kevlar, [ 12,13 ] and natural materials [ 14–16 ] to name a few. Due to the unique structure and properties of aerogels, they can be utilized for energy storage and conversion, [ 17–19 ] sensors, [ 20,21 ] catalyst support, [ 22,23 ] environmental remediation, [ 24,25 ] and many other diverse applications.…”

Ultrasensitive Physical, Bio, and Chemical Sensors Derived from 1‐, 2‐, and 3‐D Nanocellulosic Materials

“…As reported by Wang et al, a conductive supramolecular aerogel consisting of carboxylated ginger‐derived CNF and PANi was made into a vital sign sensor by pressing it with PVA/PP nonwoven fabric while the electrical signals were transmitted through a double‐sided conductive copper tape 18. The as‐prepared sensors can perform the detection of finger motion and human pulse at the wrist.…”

“…It has been well demonstrated that 3D structures are better able to enhance the gas sensing performance than their 2D counterparts, which can be attributed to higher specific surface area, more reactive sites and larger “space” for the transportation or storage of electrons/holes and gases 113a,142. Wang et al18 fabricated a conductive supramolecular aerogel (SA) with carboxylated ginger‐derived CNF and PANi, which has a porosity of 96.90% and a conductivity of 0.372 mS cm −1 . The SA was further adopted as a gas sensor to detect chloroform, ethanol, toluene, and formaldehyde, since its resistance varies upon contact with different gases, and the response curves have different shapes.…”

“…The CNF/TiO 2 nanoparticle composite film is an ideal substrate for redox protein immobilization,17 demonstrating that CNF can be a building block for sensor applications. Nanocellulose aerogels have excellent capacitance retention at high charge–discharge rates, since they possess a large number of channels for electronic and ionic diffusion of charges 18…”

Green Synthesis of Free Standing Cellulose/Graphene Oxide/Polyaniline Aerogel Electrode for High-Performance Flexible All-Solid-State Supercapacitors

“…For instance, a 3D CNFs/PANI aerogel electrode has been prepared by the supramolecular self-assembly method by mixing of CNFs and PANI nanocomposite suspension. Unfortunately, the maximum specific capacitance of CNF/PANI aerogel was only of 59.26 mF/cm 2 at 10 mV/s [30]. CNFs/rGO/PPy aerogel electrodes were reported to have 1.77 mg/cm 2 of the active materials and exhibited high areal capacitance of 400 mF/cm 2 at 0.25 mA/cm 2 , with the capacitor retention rate of only 75.6% [31].…”