Effect of reduced graphene oxide-silica composite in polyaniline: electrode material for high-performance supercapacitor

In order to improve the pseudocapacitance properties and cycle stability of polyaniline (PANI), reduced graphene oxide-silica (rGOS) is used to modify the polyaniline material. Ternary composites of reduced graphene oxide-silica-polyaniline (rGOSP) are prepared by chemical polymerization of aniline using ammonium persulfate oxidant with various amounts of rGOS in aq. 1 M H2SO4 solution. Morphology analysis of rGOSP composite revealed that the nano fibers form of polyaniline is intercalated in the graphene layers and also covered the rGOS. Symmetric supercapacitor cell is fabricated in CR2032 coin cell with rGOSP composite as electrode and its electrochemical performance is evaluated from cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy techniques. rGOSP composite yielded a higher capacitance and lower ESR value compared to that of its individual components, PANI and rGOS. The energy density of the composite is found to be 10 W h kg(-1) at a power density of 2310 W kg(-1). Furthermore, over 75.2 % of the original capacitance is retained after 6000 galvanostatic charge-discharge cycles at 0.8 A g(-1).