4 research outputs found
Self-Assembled Multifunctional Hybrids: Toward Developing High-Performance Graphene-Based Architectures for Energy Storage Devices
The
prospect of developing multifunctional flexible three-dimensional
(3D) architectures based on integrative chemistry for lightweight,
foldable, yet robust, electronic components that can turn the many
promises of graphene-based devices into reality is an exciting direction
that has yet to be explored. Herein, inspired by nature, we demonstrate
that through a simple, yet novel solvophobic self-assembly processing
approach, nacre-mimicking, layer-by-layer grown, hybrid composite
materials (consisting of graphene oxide, carbon nanotubes, and conducting
polymers) can be made that can incorporate many of the exciting attributes
of graphene into real world materials. The as-produced, self-assembled
3D multifunctional architectures were found to be flexible, yet mechanically
robust and tough (Young’s modulus in excess of 26.1 GPa, tensile
strength of around 252 MPa, and toughness of 7.3 MJ m<sup>–3</sup>), and exhibited high native electrical conductivity (38700 S m<sup>–1</sup>) and unrivalled volumetric capacitance values (761
F cm<sup>–3</sup>) with excellent cyclability and rate performance
Organic Solvent-Based Graphene Oxide Liquid Crystals: A Facile Route toward the Next Generation of Self-Assembled Layer-by-Layer Multifunctional 3D Architectures
We introduce soft self-assembly of ultralarge liquid crystalline (LC) graphene oxide (GO) sheets in a wide range of organic solvents overcoming the practical limitations imposed on LC GO processing in water. This expands the number of known solvents which can support amphiphilic self-assembly to ethanol, acetone, tetrahydrofuran, <i>N</i>-dimethylformamide, <i>N</i>-cyclohexyl-2-pyrrolidone, and a number of other organic solvents, many of which were not known to afford solvophobic self-assembly prior to this report. The LC behavior of the as-prepared GO sheets in organic solvents has enabled us to disperse and organize substantial amounts of aggregate-free single-walled carbon nanotubes (SWNTs, up to 10 wt %) without compromise in LC properties. The as-prepared LC GO-SWNT dispersions were employed to achieve self-assembled layer-by-layer multifunctional 3D hybrid architectures comprising SWNTs and GO with unrivalled superior mechanical properties (Young’s modulus in excess of 50 GPa and tensile strength of more than 500 MPa)
Self-Assembled N/S Codoped Flexible Graphene Paper for High Performance Energy Storage and Oxygen Reduction Reaction
A novel flexible three-dimensional
(3D) architecture of nitrogen and sulfur codoped graphene has been
successfully synthesized via thermal treatment of a liquid crystalline
graphene oxide–doping agent composition, followed by a soft
self-assembly approach. The high temperature process turns the layer-by-layer
assembly into a high surface area macro- and nanoporous free-standing
material with different atomic configurations of graphene. The interconnected
3D network exhibits excellent charge capacitive performance of 305
F g<sup>–1</sup> (at 100 mV s<sup>–1</sup>), an unprecedented
volumetric capacitance of 188 F cm<sup>–3</sup> (at 1 A g<sup>–1</sup>), and outstanding energy density of 28.44 Wh kg<sup>–1</sup> as well as cycle life of 10 000 cycles as
a free-standing electrode for an aqueous electrolyte, symmetric supercapacitor
device. Moreover, the resulting nitrogen/sulfur doped graphene architecture
shows good electrocatalytic performance, long durability, and high
selectivity when they are used as metal-free catalyst for the oxygen
reduction reaction. This study demonstrates an efficient approach
for the development of multifunctional as well as flexible 3D architectures
for a series of heteroatom-doped graphene frameworks for modern energy
storage as well as energy source applications
High-Performance Multifunctional Graphene Yarns: Toward Wearable All-Carbon Energy Storage Textiles
The successful commercialization of smart wearable garments is hindered by the lack of fully integrated carbon-based energy storage devices into smart wearables. Since electrodes are the active components that determine the performance of energy storage systems, it is important to rationally design and engineer hierarchical architectures atboth the nano- and macroscale that can enjoy all of the necessary requirements for a perfect electrode. Here we demonstrate a large-scale flexible fabrication of highly porous high-performance multifunctional graphene oxide (GO) and rGO fibers and yarns by taking advantage of the intrinsic soft self-assembly behavior of ultralarge graphene oxide liquid crystalline dispersions. The produced yarns, which are the only practical form of these architectures for real-life device applications, were found to be mechanically robust (Young’s modulus in excess of 29 GPa) and exhibited high native electrical conductivity (2508 ± 632 S m<sup>–1</sup>) and exceptionally high specific surface area (2605 m<sup>2</sup> g<sup>–1</sup> before reduction and 2210 m<sup>2</sup> g<sup>–1</sup> after reduction). Furthermore, the highly porous nature of these architectures enabled us to translate the superior electrochemical properties of individual graphene sheets into practical everyday use devices with complex geometrical architectures. The as-prepared final architectures exhibited an open network structure with a continuous ion transport network, resulting in unrivaled charge storage capacity (409 F g<sup>–1</sup> at 1 A g<sup>–1</sup>) and rate capability (56 F g<sup>–1</sup> at 100 A g<sup>–1</sup>) while maintaining their strong flexible nature