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2D reentrant auxetic structures of graphene/CNT networks for omnidirectionally stretchable supercapacitors.
- Source :
-
Nanoscale [Nanoscale] 2017 Sep 14; Vol. 9 (35), pp. 13272-13280. - Publication Year :
- 2017
-
Abstract
- Stretchable energy storage systems are essential for the realization of implantable and epidermal electronics. However, high-performance stretchable supercapacitors have received less attention because currently available processing techniques and material structures are too limited to overcome the trade-off relationship among electrical conductivity, ion-accessible surface area, and stretchability of electrodes. Herein, we introduce novel 2D reentrant cellular structures of porous graphene/CNT networks for omnidirectionally stretchable supercapacitor electrodes. Reentrant structures, with inwardly protruded frameworks in porous networks, were fabricated by the radial compression of vertically aligned honeycomb-like rGO/CNT networks, which were prepared by a directional crystallization method. Unlike typical porous graphene structures, the reentrant structure provided structure-assisted stretchability, such as accordion and origami structures, to otherwise unstretchable materials. The 2D reentrant structures of graphene/CNT networks maintained excellent electrical conductivities under biaxial stretching conditions and showed a slightly negative or near-zero Poisson's ratio over a wide strain range because of their structural uniqueness. For practical applications, we fabricated all-solid-state supercapacitors based on 2D auxetic structures. A radial compression process up to 1/10 <superscript>th</superscript> densified the electrode, significantly increasing the areal and volumetric capacitances of the electrodes. Additionally, vertically aligned graphene/CNT networks provided a plentiful surface area and induced sufficient ion transport pathways for the electrodes. Therefore, they exhibited high gravimetric and areal capacitance values of 152.4 F g <superscript>-1</superscript> and 2.9 F cm <superscript>-2</superscript> , respectively, and had an excellent retention ratio of 88% under a biaxial strain of 100%. Auxetic cellular and vertically aligned structures provide a new strategy for the preparation of robust platforms for stretchable energy storage electrodes.
Details
- Language :
- English
- ISSN :
- 2040-3372
- Volume :
- 9
- Issue :
- 35
- Database :
- MEDLINE
- Journal :
- Nanoscale
- Publication Type :
- Academic Journal
- Accession number :
- 28858356
- Full Text :
- https://doi.org/10.1039/c7nr02869e