Conducting co-polymer derived N, S co-doped metal-free hierarchical nanoporous carbon for robust electrochemical capacitor

Abstract

The present investigation reported metal-free hierarchical porous and robust Nitrogen (N), Sulphur (S) co-doped carbon (NS-CoP@C) electrode for supercapacitor application. The NS-CoP@C was synthesized by single-step carbonization and activation of thiourea co-doped aniline-pyrrole co-polymer (CoP). The thiourea acted as a doping as well as activating agent. The data of three different electrode materials PANI-PPy co-polymer (CoP), PANI-PPy co-polymer derived Carbon (CoP@C) and N, S co-doped carbon derived from PANI-PPy co-polymer (NS-CoP@C) are compared in the present report. The electrode materials were initially characterized by various spectroscopic techniques. It is observed that among the three electrode material, NS-CoP@C possess higher specific surface area (SSA), high pore volume and hierarchal porous structure with a better mesopore-to-micropore volume ratio. In a three-electrode system, NS-CoP@C possesses a high specific capacitance of 344.2 F/g @ 0.5A/g. Moreover, NS-CoP@C electrode was used to fabricate an all solid-state (PVA-1 M H2SO4 polymer gel electrolyte) and aqueous (1 M H2SO4 electrolyte) symmetrical supercapacitor devices in the two-electrode system. This NS-CoP@C electrode was used as both positive and negative electrode material in both types of devices. Among them, the solid-state device operates at a wide potential window of 2 V, as a consequence delivering an implausible energy and power density of 45.25 Wh/kg and 1025.64 W/kg while maintaining a capacity retention of 90.1 % even after 8500 charge-discharge cycles. Hence, the excellent performance of conducting PANI-PPy co-polymer-derived N, S co-doped carbon paved new ground for developing an alternative electrode for futuristic energy storage devices.