High performance solid state flexible supercapacitor based on molybdenum sulfide hierarchical nanospheres

Abstract Molybdenum sulfide (MoS 2 ) hierarchical nanospheres are synthesized using a hydrothermal method and characterized by X-ray powder diffraction, Brunauer–Emmett–Teller, scanning electron microscopy and transmission electron microscopy. The prepared MoS 2 is used to fabricate solid state flexible supercapacitors which show excellent electrochemical performance such as high capacitance 368 F g −1 at a scan rate of 5 mV s −1 and high power density of 128 W kg −1 at energy density of 5.42 Wh kg −1 . The fabricated supercapacitor presents good characteristics such as lightweight, low cast, portability, high flexibility, and long term cycling stability by retaining 96.5% after 5000 cycles at constant discharge current of 0.8 mA. Electrochemical impedance spectroscopy (EIS) results reveal low resistance and suggest that MoS 2 nanospheres would be a promising candidate for supercapacitors. Three charged supercapacitors connected in series can light 8 red color commercial light emitting diodes (LEDs) for 2 min, demonstrating its capability as a good storage device.