Abstract
Two-dimensional transition metal chalcogenides have gained much consideration as electrode materials
in electrochemical energy storage devices. In this work, we successfully prepared 2H-MoSe2 sheets and
investigated their charge-storage performance in organic electrolyte via fabrication of symmetric
supercapacitor (SSC). The formation of 2H-MoSe2 nanosheets was confirmed using X-ray diffraction, Xray
photoelectron spectroscopy, high-resolution transmission electron microscope, Raman spectrum and
mapping analyses, respectively. The cyclic voltammetric analysis revealed the presence of pseudocapacitive
nature of charge-storage in the MoSe2 SSC with a specific cell capacitance of 25.31 F g1 obtained at
a scan rate of 5 mV s1. The charge-discharge analysis revealed that the MoSe2 SSC possesses a high
specific cell capacitance of 16.25 F g1 (obtained at a current density of 0.75 A g1), an energy density of
20.31Wh kg1 and excellent cyclic stability with capacitance retention of about 87% over 10,000 cycles.
The MoSe2 SSC delivered an excellent power density of 7.5 kWkg1 obtained from the CD profiles
measured using a current density of 5 A g1. The energy/power density of the MoSe2 SSC device is
comparable or even higher with the reported SSCs using 2D materials such as graphene sheets, siloxene
sheets, and MXene sheets, respectively. Electrochemical impedance spectroscopic analysis (Nyquist and
Bode plots) were used to understand the capacitive nature and charge-transfer kinetics of the MoSe2 SSC
in organic electrolyte. Furthermore, we have also demonstrated the real-time application of the MoSe2
SSC as an indication of their candidature towards the development of next-generation energy storage
devices.
