Synergistic Effects from Graphene and Carbon Nanotubes Enable Flexible and Robust Electrodes for High-Performance Supercapacitors

Abstract

Flexible and lightweight energy storage systems have received tremendous interest recently due to their potential applications in wearable electronics, roll-up displays, and other devices. To manufacture such systems, flexible electrodes with desired mechanical and electrochemical properties are critical. Herein we present a novel method to fabricate conductive, highly flexible, and robust film supercapacitor electrodes based on graphene/MnO(2)/CNTs nanocomposites. The synergistic effects from graphene, CNTs, and MnO(2) deliver outstanding mechanical properties (tensile strength of 48 MPa) and superior electrochemical activity that were not achieved by any of these components alone. These flexible electrodes allow highly active material loading (71 wt % MnO(2)), areal density (8.80 mg/cm(2)), and high specific capacitance (372 F/g) with excellent rate capability for supercapacitors without the need of current collectors and binders. The film can also be wound around 0.5 mm diameter rods for fabricating full cells with high performance, showing significant potential in flexible energy storage devices.

MoS2-coated vertical graphene nanosheet for high-performance rechargeable lithium-ion batteries and hydrogen production

“…The structural rigidity of VGNS can prevent the restacking of graphene nanosheets, a commonly observed problem in horizontal graphene. [20][21][22] Using a simple solvothermal method, we further show that MoS 2 nano-leaves with a thickness of~3 nm can be directly grown on VGNS with a controllable mass loading and pore size distribution. This unique nanoarchitecture design offers several attributes for effective energy storage and conversion.…”

Bottom-up Design of Three-Dimensional Carbon-Honeycomb with Superb Specific Strength and High Thermal Conductivity

“…Such structures may find their applications in biomedical engineering like expanding blood vessels radically without exerting any axial stretch. One of the important feature of C-honeycomb is its ultra-light weight with tunable cell sizes that may be employed as electrodes for batteries with ultrafast charge and discharge rates 37 , flexible supercapacitor electrodes 38 , and storage media 39 . The density 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 15 of C-honeycombs with ܽ = 5.8Å to 29.7Å are only 1.31 g/cm 3 to 0.31 g/cm 3 , much lower than 3.52 g/cm 3 for diamond and 2.26 g/cm 3 for graphite 40 .The high specific strength of 3-D C-honeycomb render it extremely competitive for the use as an ultra-light weight architected functional material 41 .…”

A Review of Metal Oxide Composite Electrode Materials for Electrochemical Capacitors

“…In addition, PEDOT/PSS can act as an e®ective dispersant and binder for improving the adhesion to the substrate and the connection among MnO 2 / CNTs particles. Similarly, Cheng and co-workers 135 (2012) adopted novel approach of fabricating ternary nanocomposites of graphene-MnO 2 -CNTs via direct growth of MnO 2 nanoparticles and CNTs on graphene substrate. CNTs which provide electronic conductivity and mechanical reinforcement in combination with highly electrochemically active MnO 2 nanoparticles and high-surface-area graphene enable the synergetic e®ects for superior nanocomposite electrodes.…”

“…These°exible electrodes successfully deliver high speci¯c capacitance of 372 F/g without the need of current collectors and binders. 135 Another research group has reported on a novel PANI/TiO 2 /graphene oxide (GO) composite which demonstrated the highest speci¯c capacitance of 1020 F/g. 111 TiO 2 nanoparticles serve as avenue for electrode to penetrate to three-dimensional graphene oxide-PANI networks, facilitating the Faradaic reactions of PANI.…”