Synthesis and characterization of zinc hydroxide Zn(OH)2 thin film for high-performance supercapacitors using SILAR method

Abstract

Zinc hydroxide [Zn(OH)₂] is a multifaceted substance with significant potential in diverse domains such as energy storage, catalysis, and environmental cleanup. Zn(OH)₂ is appropriate for pseudocapacitor applications because of its strong electrochemical activity, cost-effectiveness, and environmentally favorable features. In this investigation, we have effectively synthesized nanoflakes of zinc hydroxide [Zn(OH)₂] as electrode material on stainless steel substrates for supercapacitor applications using the successive ionic layer adsorption and reaction (SILAR) technique. The performance of the electrode material is enhanced by nanoflakes, which encourage electrolyte diffusion and provide more channels for ion migration. Optical absorption analysis unveiled a direct band transition, showcasing a band gap of 3.35 eV. The synthesized material underwent characterization through scanning electron microscopy (SEM) and X-ray diffraction (XRD), confirming their well-defined morphology and crystalline structure with uniform distribution. The cyclic voltammetry as well as galvanostatic charge–discharge experiments were performed in a three-electrode configuration using a 1 M KOH aqueous electrolyte. The electrochemical results demonstrated that the Zn(OH)₂ nanoflakes thin film electrode revealed a remarkable specific capacitance of 123 F g⁻¹ at a current density of 1 A g⁻¹. Additionally, it displayed an extended cycling lifespan, retaining 72% of its original capacitance even afterward undergoing 5000 cycles at a scan rate of 100 mV s⁻¹.