Synthesis and characterization of electrospun reduced graphene oxide/nickel oxide/poly(caprolactone) nanofibers for enhanced corrosion resistance and energy storage performance

In this work, electrospun reduced graphene oxide (rGO)/nickel oxide (NiO)/poly(caprolactone) (PCL) nanofibers were prepared with different concentrations of rGO was synthesized using a chemical reduction route. X-ray diffraction peaks at 21.3° and 24.5° reveal (110) and (200) planes of PCL polymer with orthorhombic unit cell parameters. Broad peaks at 26.9° and 37.3° are the plane (002) and (111) respectively for rGO and NiO, respectively in the rGO/NiO/PCL nanofiber. The defect parameter in carbon, ID/IG, for pure rGO and rGO/NiO/PCL varied from 0.87 to 0.33, indicating an increase in the sp² domain as the rGO content increased from 5 % and 15 % of rGO/NiO/PCL nanofiber. The corrosion resistance of rGO/NiO/PCL nanofiber Ecorr and Icorr increases with increasing rGO content. In corrosion, analysis reveals the minimum values of Ecorr and Icorr are 0.04 V and 2.6 μA, respectively. The specific capacitance estimated from cyclic voltammetry, CV and Galvanic charging and discharging, GCD analysis is 381.9 Fg⁻¹ at a scan rate of 5mVs⁻¹ and 524 Fg⁻¹ respectively. The maximum energy density, E and power density, P are 72.7 W h kg⁻¹ of 499.9 k W kg⁻¹ for 15 wt% rGO/NiO/PCL nanofiber. Moreover, rGO/NiO/PCL nanocomposite exhibited good cycle stability of 65.5 % after 1000 charge–discharge cycles. NiO/rGO/PCL nanocomposite are one of the best candidates for supercapacitor application