Core/shell structured Ti/Si/C composite for high-performance zinc-ion hybrid capacitor

Abstract

Zinc-ion capacitors (ZnIC) have focused great attention due to high intrinsic safety and their advantages in terms of environmental protection and price. However, the increase in energy and power densities still remains a challenge. Therefore, this study aims to design and fabricate novel low-cost and environmentally-friendly nanocomposite based on titania/silica/carbon used as cathode in ZnIC. The fabrication procedure involves the functionalization of TiO2 nanoparticles with APTES and glucose, followed by a hydrothermal reaction and carbonization at 600, 700, and 800 °C (Ti/Si/C-Tx, where Tx is the temperature of carbonization) to result in carbon-coated titania/silica with a core/shell architecture. In-situ Raman and X-Ray Diffractometry (XRD) analyses were conducted to elucidate the electrochemical behaviour of the material during charge-discharge cycles. The nanocomposites were electrochemically tested using cyclic voltammetry (CV), galvanostatic cycling with potential limitation (GCPL), and potentio electrochemical impedance spectroscopy (PEIS). The designed nanocomposite showed improved performance in terms of specific capacity, power, and energy densities with values of 295 F/g, 160 W/kg, and 210 Wh/kg, respectively. Ti/Si/C-700 also demonstrated a high stability retention of 85% after 10′000 cycles, indicating its potential for use in energy storage devices. Despite these promising results, further research is required to improve capacity retention at increased current densities. The key implication of this study is the potential for the development of low-cost and high-performance energy storage devices for various applications, contributing to the growth of renewable energy sources.