Synthesis of GNS-MnS hybrid nanocomposite for enhanced electrochemical energy storage applications

Abstract

With high power density and promising possibilities for high energy density, the electrochemical capacitor has become an indispensable energy storage device to satisfy the future energy demands. Here in, we report on synthesis of graphene nanosheets (GNS) supported manganese sulfide (MnS) hybrid (GNS-MnS) nanocomposite by a simple, facile hydrothermal process. The resultant GNS-MnS hybrid nanocomposite with robust electronic amalgamation facilitates swift transfer of both ions and electrons across the interface between electrode surface and electrolyte ions than pristine MnS. Benefiting from the better conduction along with improved active sites of the MnS in GNS-MnS hybrid nanocomposite, a high ratio surface/near-surface reactions is dominated by high specific capacity even at high current rate. As such, the GNS-MnS hybrid nanocomposite exhibited a maximum specific capacitance of 792 F g−1 at 2 A g−1 along with better retention rate of 58% at 15 A g−1, is significantly higher than that of pristine MnS (423 F g−1 at 2 A g−1 and 37% retention at 15 A g−1). In addition, the fabricated symmetric GNS-MnS hybrid nanocomposite cell delivered a high energy density of 25 W h kg−1 and power density of 7160 W kg−1. Moreover, specific capacitance of 91.1% is retained after 15000th cycles with columbic efficiency of ∼100% at 20 A g−1. The remarkable electrochemical performance of GNS-MnS hybrid nanocomposite electrode demonstrated its potential as a key material for developing high energy supercapacitors.