Optimised electrochemical energy storage performance of MoS<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si71.svg" display="inline" id="d1e328"><mml:msub><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> anchored to carbon cloth for advanced asymmetric aqueous supercapacitors
Mian Muhammad Faisal, Oliver M Rigby, Stephen D. Campbell, Michael Hunt
Abstract
We explore the electrochemical energy storage performance of binder-free molybdenum disulphide decorated carbon cloth electrodes (MoS 2 @CC) in six aqueous electrolytes, selecting the most suitable combination for the construction of an asymmetric supercapacitor. The MoS 2 @CC electrodes were synthesised by a single-step hydrothermal method without the use of a binder. Our findings show that the capacitance performance and resilience of the MoS 2 @CC electrodes are strongly influenced by the electrolyte, particularly the overall conductivity. Optimal performance, balancing capacitance, equivalent series resistance and cycle life was achieved in 1.0 M Na 2 SO 4 in which MoS 2 @CC delivers a capacitance of 223 ± 2 F g −1 , retaining ≈ 94 % capacity after 5000 charge–discharge cycles. In comparison, 0.5 M H 2 SO 4 , and 5.0 M LiCl, although initially outperforming 1.0 M Na 2 SO 4 , produced rapid electrode degradation. An asymmetric supercapacitor using binder-free MoS 2 @CC and manganese oxide decorated carbon cloth (MnO 2 @CC) electrodes in 1.0 M Na 2 SO 4 electrolyte exhibited a capacitance of 110 ± 4 F g −1 , a specific energy density of 60 . 5 ± 0 . 7 W h kg −1 , and a power density of 1250 ± 50 W kg −1 over a 2.0 V voltage window, superior to similar devices reported in the literature. The asymmetric cell demonstrated excellent stability, retaining 82% capacitance after 5000 galvanostatic charge–discharge cycles and 80% after 15000 cycles.