Enhanced capacitance of nickel ferrite decorated laser-induced graphene nanocomposite for symmetric supercapacitor device

Abstract

The demand for high-performance energy storage devices, such as supercapacitors, has driven the exploration of hybrid electrode materials with enhanced charge storage capabilities. This study investigates the development of a novel NiFe₂O₄ (NFO) decorated LIG nanocomposite as an advanced electrode material for supercapacitor applications. Firstly, the LIG was synthesized by direct laser-conversion of polyimide to graphene followed by in-situ decoration of NFO nanoparticles by the drop-casting method. This facile strategy resulted in NFO/LIG nanocomposite with well-dispersed NFO nanoparticles, as verified by Raman spectroscopy. Furthermore, the morphological and structural analysis of the nanocomposite was carried out by using FESEM, EDX, and HRTEM. Additionally, XPS analysis revealed the existence of Ni²⁺ and Fe³⁺ ions which create redox active sites within NFO/LIG and permit the diffusion of electrolyte ions to form redox species. The unique physicochemical properties of graphene, combined with the pseudocapacitive characteristics of NFO, are leveraged to enhance specific capacitance, energy density, and overall electrochemical performance. Electrochemical results showed a remarkable increase in the specific capacitance of NFO/LIG nanocomposite (198 mF/cm² at 1.5 mA/cm²), as compared to pure LIG (65 mF/cm² 1.5 mA/cm²). When utilized as a symmetric supercapacitor, the device offers areal specific capacitance of 44 mF/cm² at 1.5 mA/cm². In addition to this, a pouch cell assembly was designed on a flexible substrate using PVA/KOH gel electrolyte demonstrating 18.7 mF/cm² at 5 mV/s, highlighting the potential use of NFO/LIG electrodes in energy storage applications.