Tracking Pseudocapacitive Contribution to Superior Energy Storage of MnS Nanoparticles Grown on Carbon Textile

Abstract

Transition metal chalcogenides have emerged as a new class of electrode materials for energy storage devices with superior electrochemical performance. We have directly synthesized manganese sulfide nanoparticles on carbon textile substrate and used them as electrodes to fabricate flexible all-solid-state supercapacitors. By voltammetry analysis, we have studied the electrochemical properties of MnS-CT composites, which reveal that the Faradaic diffusion-controlled process dominates at low scan rates (82.85% at 5 mV s(-1)) and even at high scan rates (39% at 20 mV s(-1)). The MnS-CT electrode shows high capacitance of 710.6 F g(-1) in LiCl aqueous electrolyte, and the surface redox reactions on MnS nanoparticles are found to be responsible for the high pseudocapacity, which is further analyzed by XRD and HRTEM. Furthermore, MnS-CT supercapacitor exhibits excellent pseudocapacitive performance (465 Fg(-1) at 5 mV s(-1)), excellent stability, light weight (0.83 g as a whole device), and high flexibility. The device has also achieved high energy density and high power density (52 Wh kg(-1) at 308 W kg(-1) and 1233 W kg(-1) with 28 Wh kg(-1), respectively). In practice, three charged supercapacitors in series can power four red light-emitting diodes (LEDs) (2.0 V, 15 mA) for 2 min. All of the evidence shows that MnS nanoparticles combined with carbon textile is a promising electrode material for pseudocapacitors.