Nanostructured TiO2-Coated Activated Carbon Composite as an Electrode Material for Asymmetric Hybrid Capacitors

Abstract

A nanostructured TiO2-coated activated carbon (TAC) composite was synthesized by a modified sol-gel reaction and employed it as a negative electrode active material for an asymmetric hybrid capacitor. The structural characterization showed that the TiO2 nano-layer was deposited on the surface of the activated carbon and the TAC composite has a highly mesoporous structure. The evaluation of electrochemical characteristics of the TAC electrode was carried out by galvanostatic charge/discharge cycling tests and electrochemical impedance spectroscopy. The obtained specific capacitance of the TAC composite was 42.87 F/g, which showed by 27.1% higher than that of the activated carbon (AC). The TAC composite also exhibited an excellent cycle performance and kept 95% of initial capacitance over 500 cycles.