CVD-Grown Orthorhombic SnSe Nanorods for Enhanced Charge Storage in Coin Cell Supercapacitors
摘要
The novel fabrication of a tin selenide (SnSe) nanorod coin cell was performed where chemical vapor deposition (CVD) was utilized to synthesize Sn:Se samples from 1:1 to 1:4 by increasing the selenium content. X-ray diffraction (XRD) confirmed a highly crystalline orthorhombic SnSe phase, with average crystallite sizes ranging from 22.06 nm to 25.34 nm. Scanning electron microscopy (SEM) indicated a unique morphological transition from spherical nanoparticles in selenium-deficient samples to aligned nanorods in the selenium-rich (1:4) composition, with a consistent elemental distribution. High-resolution transmission electron microscopy (HRTEM) of the nanorods revealed distinct lattice fringes, confirming their high crystallinity, while X-ray photoelectron spectroscopy (XPS) confirmed the presence of Sn2+ and Se2+ without any surface oxidation. UV–Vis absorption near 290 nm indicated direct (1.70–1.68 eV) and indirect (1.60–1.58 eV) bandgaps with the addition of selenium, suggesting enhanced conductivity. Electrochemical analysis demonstrated excellent pseudocapacitive behavior for the 1:4 SnSe, achieving 759 F/g at 1 A/g with a coulombic efficiency of 98.11%. A coin cell based on the nanorods delivered a capacitance of 124.65 F/g and an energy density of 44.56 Wh/kg, showing exceptional performance for supercapacitor applications, which remains unexplored in the literature.