A Flexible Supercapacitor Prepared with Surface Modified Carbon Nanotube Film Electrode and Hydrogel Electrolyte

Abstract

As the demand for wearable devices increases, compatible energy storage systems have been explored. Energy systems integrated into wearable devices require mechanical robustness and stable electrochemical performance under mechanical deformations such as bending and folding. Herein, the flexible supercapacitor is fabricated with surface modified carbon nanotube (CNT) film and a cross-linked acrylamide@N', N'-methylenebisacrylamide (AAM@MBA) hydrogel to mount on wearable devices. CNT film is a promising candidate for the electrode of flexible supercapacitors owing to its high electrical conductivity, surface area, flexibility, and excellent mechanical properties. The high ionic conductivity, good viscoelasticity, and shock absorption of hydrogel polymers make them suitable electrolyte materials for flexible supercapacitors. The heat treatment under air atmosphere is conducted on CNT film to enhance the interfacial adhesion with hydrogel electrolyte. The flexible supercapacitor delivers 8.15 F g(-1) of specific capacitance and shows 93 % of good capacitance retention up to 400 cycles. Furthermore, it works normally when bending stress is applied. The flexible supercapacitor in this study is expected to be used in wearable devices, thanks to its good performance and high flexibility.