Phase-dependent electrochemistry of TiO2 nanocrystals for supercapacitor applications

• Nanocrystals of TiO2 were prepared in pristine and composite forms.
• XRD results reveal the multiphase formation.
• Anatase phase of TiO2 shows higher BET surface area, pore size and pore volume.
• Low Rct and higher BET surface area exhibit enhanced capacitance for TiO2-A.

In the present work, we demonstrate the electrochemistry of nanocrystalline TiO2 in anatase (TiO2-A), anatase/rutile (TiO2-C) and rutile (TiO2-R) phases. Cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy were the techniques we employed to analyse the electrochemical properties of the electrodes. The observed results suggest that the electrode of TiO2-A possesses superior electrochemical properties due to its enhanced BET surface area, porous structure and low charge transfer resistance. At a low scan rate of 10 mV/s, CV analysis results imply a capacitance of 362 F/g for TiO2-A. Moreover, the galvanostatic charge-discharge study gives a specific capacitance of 312 F/g at a low scan rate of 10 A/g. Based on the higher energy density (882 W h kg− 1) and power density (1260 kW kg− 1), the TiO2-A electrode is a promising electrode material for fabricating supercapacitors.

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