Fabrication of Binder-free TiO2 Nanoparticle Electrodes for Supercapacitor in Low-Power Electronic Applications

In the present work, supercapacitor performance of binder-free TiO
2
nanoparticles electrodes, fabricated via a facile, cost effective electrophoretic deposition (EPD) technique has been analyzed. To enhance the electrical conductivity and adhesion of coated TiO
2
nanoparticles thin film over the graphite substrate, an optimized amount (2 wt. %) of multiwalled carbon nanotubes (MWCNTs) is added into the dispersion of TiO
2
nanoparticles. Uniform and smooth surface morphology of fabricated electrodes has been analyzed using field emission scanning electron microscope (FESEM). The electrochemical analysis of the electrodes is done in a three-electrode configuration cell with 2M KOH electrolyte through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). Electrochemical analysis reveals that the best optimized TiO
2
nanoparticles electrode having 2 wt.% MWCNTs displays an enhanced specific capacitance of
$320 \pm 5$
Fg
⁻¹
at 1 Ag
⁻¹
current density. The fabricated electrode displays a higher diffusion coefficient
$\sim 1.45\times 10^{-10}\text{cm}^{2}\mathrm{s}^{-1}$
and a small relaxation time constant
$(\tau_{\mathrm{o}}=89\ \text{ms})$
in 2M KOH. Moreover, fabricated TiO
2
nanoparticles electrode maintains 87 % capacity retention after 1000 charge/discharge cycles. We believe this study would be helpful in the designing of practical supercapacitor devices for low-power electronic applications.