Optical and Electrochemical Properties of Self-Organized TiO2 Nanotube Arrays From Anodized Ti-6Al-4V Alloy.

Henia Fraoucene,Marcel Pasquinelli,Thierry Djenizian,Mohammed Said Belkaid,Marielle Eyraud,Vinsensia Ade Sugiawati,Djedjiga Hatem,Florence Vacandio

doi:10.3389/fchem.2019.00066

Abstract

Due to their high specific surface area and advanced properties, TiO2 nanotubes (TiO2 NTs) have a great significance for production and storage of energy. In this paper, TiO2 NTs were synthesized from anodization of Ti-6Al-4V alloy at 60 V for 3 h in fluoride ethylene glycol electrolyte by varying the water content and further annealing treatment. The morphological, structural, optical and electrochemical performances of TiO2 NTs were investigated by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), UV-Visible spectroscopy and electrochemical characterization techniques. By varying the water content in the solution, a honeycomb and porous structure was obtained at low water content and the presence of (α + β) phase in Ti-6Al-4V alloy caused not uniform etching. With an additional increase in water content, a nanotubular structure is formed in the (α + β) phases with different morphological parameters. The anatase TiO2 NTs synthesized with 20 wt% H2O shows an improvement in absorption band that extends into the visible region due the presence of vanadium oxide in the structure and the effective band gap energy (Eg) value of 2.25 eV. The TiO2 NTs electrode also shows a good cycling performance, delivering a reversible capacity of 82 mAh.g−1 (34 μAh.cm−2.μm−1) at 1C rate over 50 cycles.

Highlights

Rechargeable batteries play an important role in powering the electronic devices and in storing energy due to their high energy and power density which are expected to be a solution for the future energy storage requirements (Li et al, 2017)
It should be noticed that the ternary titanium alloy studied in the present work consist of two metallurgical phases, the α phase being enriched in Al and the β phase in V (Macak et al, 2005)
Self-organized TiO2 NTs have been successfully synthesized via anodization of Ti−6Al−4V alloy at 60 V for 3 h in fluoride ethylene glycol electrolyte at various water contents (2 wt% up to 20 wt% H2O)

Summary

Introduction

Rechargeable batteries play an important role in powering the electronic devices and in storing energy due to their high energy and power density which are expected to be a solution for the future energy storage requirements (Li et al, 2017). Many researchers proposed to reduce the size of TiO2 anode material to the nanometer scale in order to increase the number of reaction sites, and gives new properties to the materials (Armstrong et al, 2005) Among these nanostructured materials, self-organized TiO2 nanotubes (TiO2 NTs) obtained by anodization of Ti foil can give a high porosity and larger specific area offering an enhancement in the cell capacity and cycle life (Ortiz et al, 2008, 2009; Fang et al, 2009; Panda et al, 2012; Kyeremateng et al, 2013b; Plylahan et al, 2014; Chang et al, 2015; Salian et al, 2017)

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