Single step synthesis of rGO, copper oxide and polyaniline nanocomposites for high energy supercapacitors

Highlights: • Use of rGO/copper oxide/PANI composite for supercapacitor applications. • High specific capacitance of 684 F g⁻¹ and energy density of 136.98 W h kg⁻¹. • The energy density obtained is comparable to those of Li-ion batteries. • 45 s of energy backup on charged with EW high power 6F22 battery for 60 s. Reduced graphene oxide, copper oxide and polyaniline (GCP) nanocomposites possessing energy densities close to many of Li-ion batteries are synthesized by facile in-situ single step chemical method by varying the weight percentage of each of the constituent materials. Of all the composites synthesized, the one with weight percentage of G_12%: Cu₂O/CuO_40%: P_48% (G12CP) exhibits the maximum specific capacitance of 684.93 F g⁻¹, specific capacity of 821.91 C g⁻¹, energy density of 136.98 W h kg⁻¹, and power density of 1315.76 W kg⁻¹ at the current density of 0.25 A g⁻¹. The composite shows the retention of 84% of its initial capacitance up to 5000 cycles at a scan rate of 700 mV s⁻¹. The electrochemical performance of G12CP is superior to the performances of other ternary composites and those of binary composites synthesized with respective weight ratios as that of G12CP composite. The potential of G12CP to act as a secondary power backup device is successfully demonstrated and the performance obtained is comparable with some of the previously reported similar works, and even superior to some others.