Comprehensive Structural, Morphological, and Electrochemical Investigation of CdO Nanoparticles Synthesized by a Low‐Concentration Hydrothermal Method

This work presents a straightforward and rapid one‐step hydrothermal method for creating concentration‐dependent nanostructures, demonstrating the promise of cadmium oxide (CdO) nanopowders as useful electrode materials for energy storage applications. Concentration‐dependent nanostructures were successfully synthesized via a hydrothermal method and systematically investigated for their electrochemical energy storage properties. Structural analysis confirmed phase formation corresponding to JCPDS card no. 65‐2908, with an average crystallite size of 13 nm, indicating the formation of well‐defined nanocrystalline material. FESEM analysis revealed a uniformly dispersed and tightly packed granular morphology, while EDX confirmed the elemental composition of 75.99% cadmium and 24.01% oxygen. Optical characterization using UV–visible spectroscopy showed a narrow band gap of 1.35 eV, suggesting enhanced electrical conductivity, and contact angle measurements indicated a hydrophobic surface with a value of 105°. Electrochemical performance evaluated through cyclic voltammetry (CV) and chronopotentiometry (CP) demonstrated a high specific capacitance of 315.6 F/g from CP and 622.12 F/g from CV measurements. Additionally, the electrode exhibited a remarkable specific energy of 438.36 Wh/kg and specific power of 20.31 kW/kg, confirming excellent supercapacitor behavior. The BET results confirm the mesoporous nature of the synthesized material with a Type IV isotherm, H3 hysteresis loop, and moderate surface characteristics.