Publication

Abstract : Transition metal chalcogenides have been described as promising electrode materials for supercapacitors due to their low electronegativity, suitable electrical conductivity, comparatively higher specific capacitance, and favorable electrochemical redox regions. However, the poor electrical conductivity and substantial volume fluctuations provide a significant obstacle to industrial use. A new method to develop metal incorporated GO at the time of GO synthesis and subsequent conversion to metal sulfoselenides is proposed and demonstrated here. This novel process incorporates the advantages of both GO and the metal sulfoselenides for electrochemical energy storage applications. The average size of the nanoclusters was 52 nm as identified by Transmission electron microscopy. As pseudocapacitive electrode GO-MnSSe delivered a specific capacitance of 603 F/g at 0.1 A/g in 1 M KCl of aqueous electrolyte, because of their distinct and stable form. The fabricated 2-electrode device showed a specific capacitance of 98.5 mF/cm2 at 80 µA/cm2, showing good retention of 67 % at the end of the 9000 cycles. As Li-ion battery half-cells, at specific currents of 50, 100, 250, and 500 mA/g, GO-MnS delivered a capacity of 587, 378, 273, and 211 mA h/g respectively, reflecting a retention rate of 64 %, while the specific current was increased 10 times. The initial capacity of GO-MnS and GO-MnSSe at 100 mA/g was 494 and 495 mAh/g respectively, and for GO-MnS and GO-MnSSe at 250 mA/g the delivered capacity values were 376 and 363 mA h/g respectively. Coulombic efficiency (CE) for GO, GO-SW (single wash), GO-MnS, and GO-MnSSe were 99.52 %, 99.6 %, 98.7 %, and 99 % respectively at the end of the 100 cycles. Moreover, GO-MnS were cycled at a higher rate of 500 mA/g for 500 cycles which showed a decay initially nevertheless it stabilized after few cycles and showed a retention of 88 % at the end of 500 cycles from 20th cycle. The ex-situ morphological analysis of GO-MnS were conducted as well as the kinetic of the electrode were studied by before and after cycling EIS measurement. As part of this, as an anode for lithium-ion batteries, high Li-ion storage capacity and cyclic stability were observed.