Ternary sulfonated graphene/polyaniline/carbon nanotubes nanocomposites for high performance of supercapacitor electrodes

Binary carbon nanotubes (CNTs)-reinforced conducting polyaniline (PANI) and ternary sulfonated graphene nanosheets (s-GN)-decorated CNT@PANI nanocomposites were prepared. The role of functionalized s-GNs with methanol and sulfuric acid on the structural characteristics of CNTs20%@PANI@s-GNs(20%) nanocomposites was evaluated by XRD, SEM, and FTIR spectroscopy. The s-GN nanopowders were observed to improve the intercalation with a less agglomeration and uniformly sandwiched CNT@PANI composites for the functional SO-3 groups. The cyclic voltammetry (CV) curves showed that the s-GNs have increased the electrochemical capacitance by 37% from 305 F/g for CNT20@PANI to 419 F/g for CNT20@PANI@s-GN(20) nanocomposites for the free mobility of the electronic carriers on the s-GN surface, larger surface area of graphene and presence of the functional groups. The electrochemical impedance spectroscopy (EIS) measurements of ternary s-GN@PANI@CNTs composites in 0.5 M H2SO4 electrolyte at scan rate of 5 mV/s exhibited a higher energy density of 209 Wh/kg with a power density of 381 W/kg. The s-GNs also enhanced the interfaces between the electrolyte and the capacitor's electrode and extra pseudo-capacitive. The conductivity (sigma) and the total resistivity (rho) of the ternary nanocomposites films increased due to the surface area, hydrophilic oxide surface SO-3 groups and thereof higher mobility of the electronic charge carriers and restricted volume expansion during the charge/discharge cycling of the capacitor's electrodes.