This work describes the formation of two-dimensional molybdenum di-sulfide (MoS2) nanosheets via topochemical sulfurization of MoO3 microplates and its applications towards wide-temperature tolerant supercapacitors. Physico-chemical characterizations such as XRD, FE-SEM, HR-TEM, XPS and elemental mapping analysis revealed the formation of MoS2 nanosheets with lateral size in the range of 200 nm. The electrochemical properties of the MoS2 electrode using three-electrode configuration tests revealed the presence of pseudocapacitive mechanism of charge-storage with a high capacitance (119.38 F g−1) from cyclic voltammetry profiles and superior cyclic stability of 95.1% over 2000 cycles. The symmetric supercapacitor (SSC) fabricated using MoS2 electrodes delivered a high-energy density (6.56 Wh kg−1) and high-power density (2500 W kg−1) with long cycle life. The electrochemical performance of the MoS2 SSC exhibited ~121% improvement at 80 °C compared to that achieved at 20 °C and the mechanism of improved properties were examined with the use of electrochemical impedance spectroscopy. These experimental results indicate usefulness of topochemically synthesized MoS2 for construction of wide-temperature tolerant supercapacitors that can be useful in a variety of industrial sectors.