TITLE:
Graphene/Polypyrrole Nanocomposite as Electrochemical Supercapacitor Electrode: Electrochemical Impedance Studies
AUTHORS:
Punya A. Basnayaka, Manoj K. Ram, Lee Stefanakos, Ashok Kumar
KEYWORDS:
Capacitance; Graphene; Conducting Polymers; Equivalent Circuit; Time Constant
JOURNAL NAME:
Graphene,
Vol.2 No.2,
April
30,
2013
ABSTRACT: Graphene-Polypyrrole (G/PPy) was synthesized by chemical oxidative polymerization method, and electrochemical impedance spectroscopy (EIS) analysis was employed to study the frequency response characteristics of supercapacitors based on G/PPy conducting polymer nanocomposite. It is found that a uniform G/PPy nanocomposite is formed with polypyrrole (PPy) being homogeneously surrounded by graphene nanosheets. The porous structure allowed electrolyte and ions diffusion in synthesized G/PPy nanocomposite. The metallic conductivity of Graphene-polypyrrole exhibited higher knee frequency at 125 Hz than the knee frequency of pristine PPy at 36 Hz. The high knee frequency of G/PPy supercapacitor is indicative of high power application and long cycle life. The G/PPy nanocomposite based supercapacitor with 1MH2SO4 as the electrolyte showed specific capacitances of 270 F/g at 0.1 Hz and112 F/g at 125 Hz.