Fabrication of tungsten decorated titania nanotube arrays as electrode materials for supercapacitor applications

• Tungsten decorated titania nano-arrays synthesized by anodizing and deposition.
• Amount of tungsten in nanotubes effects supercapacitive behavior of the electrodes.
• The maximum capacitance was 191 mF cm−2 in 1 M Na2SO4 aqueous electrolyte.

Tungsten decorated titania (WT) nanotube arrays was fabricated by electrochemical anodizing followed by chemical bath deposition in combination with a pyrolysis process. Resulting WT nanotube arrays were studied as potential electrode materials for electrochemical double layer capacitor (supercapacitor) applications. The structural, morphological, and compositional characteristics of the resulting electrode materials were evaluated by using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray (EDX) spectroscopy. Results showed that titania nanotube arrays (T) with an internal diameter of the tubes around 90–120 nm, an external diameter around 120–160 nm, wall thickness in the range of 30–60 nm and a length of 39 μm were grown on titanium substrate by electrochemical anodizing. Also tungsten particles are decorated mainly on the surface of the titania nanotube and to a less extent inside the nanotubes. The electrochemical behavior of WT electrodes was investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques in 1 M Na2SO4 aqueous electrolyte. The maximum capacitance obtained was 191 mF cm−2. The good electrochemical performance was attributed to the anchoring function of tungsten and support of titania nanotube arrays. Therefore this electrode material can be used as a promising material in supercapacitor applications.

Nyquist plots of different samples in a frequency of 100 kHz to 0.1 Hz at open circuit potential. The inset is equivalent circuit used tosimulate the EIS data.Figure optionsDownload as PowerPoint slide