Design and performance evaluation of 2D nickel oxide nanosheet thin film electrodes in energy storage devices

This research comprehensively investigates the structural, optical, and electrochemical properties of nickel oxide (NiO) nanoparticles, focusing on its potential applications in energy storage systems, particularly electrochemical double-layer capacitors (EDLCs). In a single-step hydrothermal process, two-dimensional (2D) NiO nanoparticles was synthesized using carbon templates. X-ray diffraction analysis confirmed NiO nanoparticle’s crystalline nature, revealing a crystallite size of approximately 35 nm. Optical characterization unveiled NiO nanoparticle’s distinctive absorption pattern in the UV region, with additional absorbance observed in the visible region, and a calculated band gap of 2.6 eV. Morphological studies depicted a unique 2D nanosheets structure for NiO nanoparticles, with microstructural images showing fringe patterns and selected area electron diffraction patterns indicating its polycrystalline nature. NiO nanoparticles exhibit excellent electrochemical performance, including high specific capacitance, which is crucial for efficient energy storage. Their unique 2D nanosheet structure enhances surface area and facilitates better charge transport, making them ideal for EDLCs. Additionally, the reduced band gap of NiO nanoparticles, as determined in this study, improves their conductivity and overall electrochemical behavior. These novel attributes position NiO nanoparticles as superior materials for advancing the performance and efficiency of energy storage devices. Crucially, NiO nanoparticles exhibited a high specific capacitance of 13 F/g, highlighting its suitability for EDLCs. This finding positions NiO nanoparticles as a promising candidate for energy storage applications, advancing the field of supercapacitors. Electrochemical analysis through cyclic voltammetry and Nyquist plots further elucidated the material's potential in energy storage applications. This interdisciplinary exploration enriches our understanding of NiO nanoparticles and underscores its utility in emerging energy storage technologies, guiding further advancements in supercapacitor systems for sustainable energy solutions.