Energy storage ability and anti-corrosion properties of Bi-doped TiO2 nanotube arrays

• TiO2 and Bi-doped TiO2 nanotube arrays were obtained by anodisation of Ti and Bi-Ti alloys.
• The energy storage ability of TiO2 nanotube arrays was improved due to Bi-doping.
• TiO2-Bi (3%) had the best energy storage ability and anti-corrosion property.
• The properties of Bi-doped TiO2 samples could be explained well by the XPS results.

In this work, TiO2 and Bi-doped TiO2 nanotube arrays were obtained by anodisation of Ti and Bi-Ti alloys with different Bi contents. Electrochemical tests demonstrated that the energy storage ability of TiO2 nanotube arrays was significantly improved due to the Bi doping. The Bi-doped TiO2 nanotube arrays prepared from the Bi-Ti alloy with 3 at% Bi had the best energy storage performance and the potentials of the anodised samples were −0.13 V and −0.12 V after self-discharging for 20 h and 40 h respectively, therefore, Bi-doped TiO2 nanotube arrays could offer all-weather anti-corrosion protection for substrate metals. XPS analysis showed that the relative amount of Bi-O-Ti and Bi-O-Bi bonds was different and that defects in the oxides would also change due to different contents of Bi, which resulted in performance changes of the samples.