High performance nanostructured symmetric reduced graphene oxide/polyaniline supercapacitor electrode: effect of polyaniline morphology

The synergetic impact of reduced graphene oxide (rGO) with different morphologies of polyaniline (PANI) has been studied for the energy storage devices. The electrode materials are synthesized via in-situ polymerization method at a low molar concentration (0.1 M) of an aqueous H 2 SO 4 electrolyte medium in order to enhance the electrochemical capacitive behavior of rGO/PANI nanocomposites. The aim of this work is to enhance the overall capacitive behavior of rGO by incorporating different PANI morphologies (granular and flakes). The work aims at overcoming the limitations present in the PANI and rGO that deteriorates their electrochemical performances. The electrochemical analysis showed that the maximum specific capacitance of 681 F/g is for rGO/flakes PANI with a good retention rate of 63 %, high energy and power density (9 Wh Kg −1 and 1100 W Kg -1 ), high coulombic efficiency of 86 % as compared to the granular morphology with a maximum capacitance of 478 F/g at a scan rate of 10 mV/s. The large specific surface area is provided by rGO/f-PANI (41.96 m 2 /g) and rGO/g-PANI (33.10 m 2 /g) than their individual constituents. A low internal resistance provided by rGO/f-PANI (0.51 Ω) results in a large interfacial area for the enhancement of capacitive behavior of an electrode material. Considering the supercapacitor performance of rGO material with PANI morphologies and its ease of synthesis as well as affordability rGO/g-PANI and rGO/f-PANI, the nanocomposite seems to be a promising electrode material for next generation supercapacitors. Graphical Abstract for rGO with different PANI morphologies. • Chemical Synthesis of rGO with PANI morphologies (granular and Flakes) are synthesized via in-situ polymerization. • The rGO/f-PANI have specific capacitance of 681F/g higher than the rGO/g-PANI with 478F/g. • The increase in thermal stability and minimum mass loss is observed in rGO/f-PANI resulting in its higher efficiencies. • The enhanced capacitive performance for composites is observed due to change in various XRD parameters (d, R and D). • The decrease in the bandgap of rGO/f-PANI (2.72 eV) has resulted in higher conductivity of the hybrid materials.