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

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 the conductive polymer polyaniline (PANI) possesses a high capacitance and is easy to manufacture, it is always a favored material in the field of supercapacitors. In this research, CNT film synthesized via a floating catalyst chemical vapor deposition method could be further activated by its electrochemical re-expansion to achieve better porosity and higher specific area, in order to obtain an all-solid-state flexible supercapacitor with a higher area capacitance. In comparison with the pristine CNT film decorated with PANI, electrochemically fabricated CNT hydrogel film with PANI deposition had a higher specific area capacitance of 680 mF cm(-2) at 1 mA cm(-2). The all-solid-state supercapacitor that was synthesized from this composite film exhibited a 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 under conditions of rolling. After 500 charge-discharge cycles, it also retained its high coulombic efficiency and specific area capacitance. This all-solid-state supercapacitor shows great potential in the field of energy storage devices.