Binder-free tuberosa architectured barium hydroxide thin film for supercapacitor application

Abstract

In recent times, there has been a rising interest in utilizing alkaline earth metals for energy storage applications. Thin films of Ba(OH)₂ were deposited on stainless steel (SS) using the successive ionic layer adsorption and reaction (SILAR) method. The characterization of prepared films was carried out through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photo-electron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). The surface study of Ba(OH)₂ thin film on SS reveals the polianthes tuberosa morphology. The electrochemical properties of the prepared electrodes were examined using cyclic voltammetry (CV) in a 1 M Na₂SO₄ electrolyte solution. The electrode exhibited a maximum specific capacity (\({C}_{\text{s}}\)) of 402.8 C g⁻¹ at a current rate of 0.5 mA for 2 V potential window, having cyclic stability with a retention of 63.5% after 1000 CV cycles. This electrode demonstrated energy density of 112 Wh Kg⁻¹ and a power density of 3400 W Kg⁻¹ at a current rate of 0.5 mA. Furthermore, a solid-state symmetric supercapacitor device has been fabricated. The device exhibits energy and power densities of 0.32 Wh Kg⁻¹ and 251.08 W Kg⁻¹, respectively. The practical applicability of the device has been shown by illuminating blue-, green-, red- and white-coloured light emission diodes (LEDs) and flexibility test at different angles. These findings suggest the potential of Ba(OH)₂ thin films, deposited via SILAR, as promising materials for supercapacitive energy storage applications.