Interwoven of γ-MnO2 and V2O5 nanostructures with polyindole grafted reduced graphene oxide nano-platform for high-efficient supercapacitors: A collaborated insight of experimental and surface morphological studies

Abstract

The continuous evolution toward high-yield electronic devices with green and mechanical robust properties offers an emerging demand for polymeric nanocomposite electrodes. Herein, an efficient in-situ electro-synthesized route was pursued in designing novel reduced graphene oxide/polyindole (rGO/PIND) nanocomposite electrodes decorated by γ-MnO2 and V2O5 nanostructures. A nanosecond fiber laser was applied to synthesize V2O5 nanoparticles through laser ablation in liquid (LAL) technique and γ-MnO2 nanostructure was constructed by a solid-state reaction method. The fabricated electrodes were characterized by physical and electrochemical methods. To investigate the effect of the surface morphological features on the electrochemical (EC) performance of nanocomposite electrodes the surface statistical, Areal Autocorrelation Function (AACF), and fractal studies were carried out by using AFM analysis. These studies revealed the presence of nanoparticles results in more compactness and well-developed surface morphology with more roughness and irregularity. The electrochemical study of the design electrodes was performed in three and two-electrode setups. Two asymmetric supercapacitors (ASCs) of rGO//rGO/PIND/V2O5, rGO//rGO/PIND/γ-MnO2 were fabricated and characterized by physical and electrochemical methods. The rGO//rGO/PIND/γ-MnO2 ASSC device provided a superior specific capacitance (CS) of 165F g−1, energy density of 51.5 Wh kg−1, and power density of 3.7 kW kg−1 at 5.0 A g−1 with 95.7% retention of CS after 10,000 cycles and with a broad 1.50 V potential window. Additionally, the rGO/PIND/γ-MnO2//rGO/PIND/γ-MnO2 symmetric supercapacitor (SSC) device exhibited 28.5 Wh kg−1 energy density, and 6.8 kW kg−1 power density at 5.0 A g−1 with 92.8% retention capacitance after 10,000 cycles.