TiO2/Carbon allotrope nanohybrids for supercapacitor application with theoretical insights from density functional theory

Abstract

TiO2/rGO and TiO2/MWCNT electrode materials have been synthesized by the hydrothermal method. The synergetic effect of TiO2/rGO electrode enhances the specific capacitance to a value of 558F/g at 1 A/g and having cyclic stability of 100% for up to 5000 cycles. The fabricated symmetrical supercapacitor device shows the maximum energy density of 14 W h/kg and power density of 9.6 kW/kg at 0.5 A/g and 32 A/g current density, respectively. TiO2/rGO electrode shows excellent cyclic stability leading to its claim as the potential electrode in the energy storage devices. From density functional theory calculations, we observed an enhanced density of states close to Fermi level for TiO2/rGO structure and charge transfer from 2p orbital of rGO to Ti 3d orbital of TiO2 signifying the enhancement in conductivity of the hybrid structure. Furthermore, the computed quantum capacitance has been increased for TiO2/rGO electrode which qualitatively supports our experimental findings.