Hybrid NiO@TiO2 nano-architecture for improved electrochemical performance with simulation corroboration

Supercapacitors' effective short-term power delivery has garnered a lot of attention; however, they face challenges in terms of stability and capacity. Promising possibilities for enhancing supercapacitor performance are nanocomposites with reduced ion/electron diffusion routes and increased specific surface areas. Hence, this study focused on the fabrication and electrochemical performance of supercapacitor electrodes made of NiO@TiO2 nanocomposites, addressing a gap in the literature on NiO nanoparticles (NiO NPs) loaded with TiO2 nanofibers. The presence of Ni2+, Ni3+, and -OH functional groups was detected using X-ray photoelectron spectroscopy (XPS), and the elements presence was reiterated by energy-dispersive X-ray spectroscopy (EDS). Scanning electron microscopy (SEM) in addition to transmission electron microscopy (TEM) elucidated the morphological concepts, demonstrating width as 72 nm for NiO NPs and the length of the TiO2 nanofibers ranging between 300 and 500 nm. An exceptional specific capacitance of 750 F·g−1@3 A·g−1 was demonstrated by NiO@TiO2 electrodes, with reasonable cyclic reliability (94.6 %@15 A·g−1) post 10,000 galvanostatic charge–discharge (GCD) cycles. At 1.9 A·g−1 current density, NiO@TiO2 – two electrode arrangement generated a significant amount of energy density, 54.29 Wh·kg−1@ 4446 W·kg−1 power density along with a competent cyclic stability post 10,000 cycles. We also employed a self-analyzed monolayer (SAM) approach to assess cyclic voltammetric (CV) response by utilizing a coupled simulation of the Butler–Volmer and Nernst–Planck–Poisson (N-P-P) models through finite element modeling in COMSOL. The results obtained suggest that NiO@TiO2 electrodes have excellent electrochemical traits indicating that they are commendable nanocomponents for applications involving advanced energy storage.