Electrochemical fabrication of carbon nanotube/polyaniline hydrogel film for all-solid-state flexible supercapacitor with high areal capacitance

Abstract

Carbon nanotube (CNT) film is a favorable kind of substrate in flexible electric devices because of its superior flexibility, favorable mechanical strength and excellent electrical conductivity. Moreover, since conductive polymer polyaniline (PANI) owns high capacitance and easy manufacture method, it is always 10 in favor for the supercapacitors. In this research, CNT film synthesized via floating catalyst chemical vapor deposition method could be further activated by electrochemically re-expanding to achieve better porosity and higher specific area, in order to obtain all-solid-state flexible supercapacitor with higher area capacitance. Comparing with the pristine CNT film characterized by PANI, electrochemically fabricated CNT hydrogel film with PANI deposition had higher specific area capacitance, which was 680 mF cm -2 at 15 1 mA cm -2 . All-solid-state supercapacitor that was synthesized by this composite film exhibited high specific area capacitance of 184.6 mF cm -2 at 1 mA cm -2 , which was higher than many similar supercapacitors. The rolling test showed that this supercapacitor maintained its high capacitance even in the rolling condition. After 500 charge-discharge cycles, it also remained high Coulombic efficiency and specific area capacitance. This all-solid-state supercapacitor shows great potential for energy storage 20 device.CNT film prepared via floating catalyst CVD method was activated by electrochemical strategy for better PANI growth. Both of this CNT/PANI hydrogel film electrode and flexible symmetric supercapacitor based on this electrode material exhibited high areal capacitance.

Recent advances in flexible supercapacitors based on carbon nanotubes and graphene

“…Approaches including CVD/floating catalyst CVD [41][42][43][44][45][46][47], vacuum filtration [48][49][50][51][52], interfacial reaction [53,54], and printing [55] have been developed to fabricate CNT films for use in flexible supercapacitor applications.…”

“…When tested in biological media, the ink-coated hydrogel had a specific capacitance of approximately 30 F g −1 . To enhance the capacitive performance, a large number of materials including polymers [41,44,52,54], metal oxides [47,51], metal sulfides [46], MXenes [49], and layered double hydroxides [48] have been combined with CNTs film. A facile method has been reported to fabricate MWCNT/PDMS films via a water surface assisted synthesis [53].…”

“…Flexible supercapacitor based on the SWCNT/PANI films exhibited high energy and power densities of 131 W h kg −1 and 62.5 kW kg −1 , respectively. A CNT/PANI hydrogel film was fabricated by an electrochemical reexpansion method [44]. During the re-expansion process, the CNT films prepared by floating catalyst CVD growth were activated by cyclic voltammetry scanning in a H 2 SO 4 solution, leading to expansion of the film thickness from 0.01 to 1 mm.…”

Recent advances and challenges of stretchable supercapacitors based on carbon materials

“…They will facilitate the charge transfer by providing more channels for electrolyte access and reducing the ion diffusion distance even under mechanical strain. Developed to date, established methods for the preparation of CNTs include laser ablation, arc discharge, and chemical vapor deposition (CVD) [87]. CNTs can be put into mass production at relatively low cost and therefore have attracted widespread academic and industrial interest.…”

Nano nickel oxide coated graphene/polyaniline composite film with high electrochemical performance for flexible supercapacitor

“…The capacitance decays with increasing the scan rate, which is caused by the relatively slow diffusion of the ions in the electrolyte at higher scan rates. Comparing with different flexible supercapacitor materials, the areal capacitance is much higher, as shown in Table.1 [48][49][50][51][52].…”