Multifunctional microporous activated carbon nanotubes anchored on graphite fibers for high-strength and high-rate flexible all-solid-state supercapacitors

Abstract

Flexible all-solid-state supercapacitors (ASSSCs) based on stable gel electrolyte have attracted enormous attention due to their potential application for wearable and portable electronic devices, but usually suffer from lack of structural stability for integrated devices during the bending and folding process, mainly due to the weak interfacial interaction force between electrode materials and gel electrolyte. We report a novel high-strength ASSSC based on activated multiwalled carbon nanotubes anchored on graphite fibers (GF@aMWNTs) by electrostatic assembly and electrophoretic deposition (EPD). With high areal density of aMWNTs, the GF@aMWNTs fabricated by EPD technique exhibit the maximum tensile strength of 47.9 ± 2.0 MPa for the sandwich-type GF@aMWNT/PVA/GF@aMWNT films, mainly attributed to the microporous aMWNTs as an important “bridging” role in the combination of GF electrodes and PVA electrolyte. The assembled symmetric ASSSC based on the GF@aMWNT electrodes, can provide an outstanding specific capacitance of 177 F g−1 at 1 A g−1, a maximum power density of 25 kW kg−1 (13.1 Wh kg−1) as well as excellent capacitance stability in cycling test and bending state. This high-rate ASSSC is anticipated to open up an exciting route to enhance the structural strength of integrated devices for high-efficient energy storage.