Structural-Morphological Insights into Optimization of Hydrothermally Synthesized MoSe2 Nanoflowers for Improving Supercapacitor Application

Abstract

The present work reported a lucid and improved hydrothermal methodology for synthesis of MoSe2 nanoflowers (MNF) at 210 °C. To observe the effect of temperature on fascinating properties, the process temperature was modified by ±10 °C. The as-prepared MNF were found to consist of 2D nanosheets which assembled into 3D flower-like hierarchical morphology via Van-der Waals force. The elemental-composition and -mapping of MNF reveals that the constituents are uniformly distributed throughout the material. Crystallography and structural analyses confirmed that the as-synthesized MNF were of highly crystalline nature with two-layer hexagonal (2H) phase of MoSe2 (2H-MoSe2). Additionally, microstructure and lattice scale features of MNF studied using HRTEM disclosed that ultrathin nanosheets having thickness  3 nm, which were few atomic layers thick. A plausible formation and growth mechanism of as-prepared MNF was also proposed. For the purpose of developing supercapacitors, the electrochemical energy-storage characteristic of synthesized MNF was examined. Maximum specific capacitance of 284.8 F g-1 at 5 mV s-1 scan rate was demonstrated by the three-electrode setup, and capacitance retention was about 88% even after 10,000 cycles. As an electrode material for supercapacitors, MNF has great potential due to its high specific capacitance and exceptional cycle stability.