Tamarind shell-derived activated carbon composite with NiCo2O4 as a positive electrode for high-performance asymmetric supercapacitors

Abstract

This study presents the synthesis of a NiCo₂O₄/AC by hydrothermal technique. NiCo₂O₄ nanorods were decorated with tamarind shell-derived activated carbon to create a composite electrode with enhanced conductivity and high surface area. The NiCo₂O₄ improves pseudo capacitance, while the activated carbon provides a porous structure that facilitates fast ion and electron transport. The activated carbon’s sheet-like morphology acts as an ion buffer, shortening diffusion pathways. The composite electrode was characterized and exhibited excellent electrochemical performance in asymmetric capacitors. The NiCo₂O₄/AC composite electrode exhibits a specific capacitance of 1833 Fg⁻¹ at 1 Ag⁻¹. The constructed NiCo₂O₄/AC//AC device demonstrates an operating voltage window of 0 –1.6, providing a substantial energy density of 40.6 Whkg⁻¹ at a power density of 2244 W kg⁻¹. These outcomes highlight the promise of the NiCo₂O₄/AC composite for practical energy storage applications.