▎ 摘　　要

A polyindole-MnO2 (PIn-MnO2)/reduced graphene oxide (RGO)-based ternary composite system has been assembled by an in-situ polymerization. In this system, the concentration of RGO has been varied by the interval of 0.25 wt.% in fixed quantity of PIn-MnO2 system. The mean crystallite size of RGO was observed to be 6.64 nm calculated by using Debye-Scherrer formula. This study demonstrates the dispersion of RGO nanoparticles in PIn-MnO2 system to optimize the supercapacitive properties. As expected, the supercapacitive properties of PIn-MnO2-RGO composites were influenced by the addition of RGO nanoparticles and it is optimized for 0.5 wt.% of RGO concentration. The 0.5 wt.% RGO-loaded PIn-MnO2-RGO composite shows specific capacitance of the order 1750 Fg(-1) at a scan rate of 50 mV s(-1). The main accomplishment of present work is that the 0.5 wt.% RGO-loaded composite shows long-term stability, which is capacitance retention up to 6000 cycles. Similarly, galvanostatic charge/discharge curves of 0.5 wt.% RGO-loaded composite show long and nearly symmetric behavior, which is suitable for range of practical applications.