▎ 摘　　要

Electrochemical supercapacitors are vital for the advancement of energy storage devices. Herein, we report the synthesis of molybdenum selenide (MoSe2), tungsten-doped molybdenum selenide (W-MoSe2) and their graphene (G) composites (W-MoSe2/G) via a facile hydrothermal method. Physiochemical properties of the as-synthesized samples are examined using X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller measurements, scanning electron microscopy, high resolution transmission electron microscopy and energy dispersive X-ray spectroscopy measurements. Used as working electrodes for supercapacitors, MoSe2 nanostructures could deliver the specific capacitance of 106 F g(-1) at 2 mV s(-1) scan rate. Further, doping with tungsten (W) demonstrates the variation of specific capacitances with 2 M % of tungsten as the optimum doping amount, delivering the maximum specific capacitance of 147 F g(-1). Furthermore, graphene composites of these nanostructures deliver the enhanced specific capacitances of 248 F g(-1) and complimented with excellent capacitance retention capability of 102% for 20000 cycles. (c) 2019 Elsevier Ltd. All rights reserved.