Chemical Vapor Deposition-Grown Hierarchical SnS2 Nanostructures for High-Performance Supercapacitor Electrodes

초록

Transition metal sulfides and their composite materials have received considerable attention as electrode materials for electrochemical devices. In particular, tin(IV) disulfide (SnS2) nanoflowers have attracted significant interest because of their unique nanoscale architectures and layered crystalline structures. Herein, this study investigates the controlled synthesis of hierarchical SnS2 nanostructures via chemical vapor deposition (CVD) and their potential as advanced electrode materials for high-performance supercapacitors. X-ray diffraction (XRD) analysis confirmed the hexagonal crystalline phase of SnS2, while X-ray photoelectron spectroscopy (XPS) verified the chemical states and elemental composition of the synthesized material. Morphological analysis using scanning electron microscopy (SEM) revealed a consistent flower-like nanostructure, whereas stoichiometry of Sn and S elements was confirmed through energy-dispersive X-ray analysis. Cyclic voltammetry (CV) indicated pseudocapacitive behavior, with chronopotentiometry yielding a specific capacitance of 187 F/g at 0.5 A/g. Electrochemical impedance spectroscopy (EIS) analysis revealed a low charge-transfer resistance (Rct) of approximately 1.2 Omega. Additionally, long-duration stability assessments at a current density over 5000 cycles demonstrated outstanding cycling stability, retaining approximately 88% of the original capacitance. This improved electrochemical performance was primarily due to the SnS2 nanostructures featuring a flower-mimetic shape, which substantially increased the effective surface area and enhanced the accessibility of the electroactive sites, thus, significantly increasing the specific capacitance.