Polyaniline enhanced partially reduced graphene oxide/carbon nanotube composite films as free-standing electrodes for flexible solid-state supercapacitors
Min Jiang, Yuxuan Chen, Zhiyang Lin, Yulai Zhao, Linxi Hou
Abstract
Reduced graphene oxide (rGO) is a type of significant electrode material for flexible supercapacitor due to its outstanding mechanical and electrochemical properties . However, low oxidative activity of rGO remains a constraint in developing such devices. In this study, partially reduced graphene oxide (prGO) with enhanced oxidative activity was prepared, into which carbon nanotubes (CNTs) were incorporated to prepare CNT/prGO film with a loosened structure by filtration. Then, polyaniline (PANi) was deposited onto the surface of CNT/prGO composite through in-situ polymerization, resulting in CNT/prGO/PANi composite film . The morphology and structure were investigated via SEM, TEM, XPS , etc. The influences of CNT/prGO ratio and aniline polymerization time on the morphology and electrochemical performance were studied. The electrochemical test results indicated that the CNT/prGO/PANi composite exhibited the best electrochemical performance under the conditions of aniline polymerization for 4 h and CNT/prGO ratio of 3:10. Further increasing the polymerization time or CNT/prGO ratio resulted in short rods-like PANi coated CNTs which merge to form a large flake morphology. The optimized CNT/prGO/PANi demonstrated a specific capacitance of 706 mF cm −2 (∼353 F g −1 ) at 0.1 mA cm −2 , with the specific capacity retaining 78 % of its original value after 3000 charging/discharging cycles at 1 mA cm −2 . Flexible supercapacitors fabricated with CNT/prGO/PANi as electrode exhibited an energy density of 245 mW h cm −2 at 124 mW cm −2 . These results suggest that flexible solid-state supercapacitors based on CNT/prGO/PANi hold promising potential for energy storage applications.