Enhanced performance of lithium ion batteries from self-doped TiO2 nanotube anodes via an adjustable electrochemical process

Abstract

In this work, we report on fabricating of self-doped TiO2 nanotube arrays via a facile electrochemical method by modify the electrochemical anodized amorphous TiO2 nanotube arrays with cathodic pulse doping. The self-doped TiO2 nanotube arrays is black appearance with abundant oxygen vacancy and hydroxyl groups in comparison with that of as-anodized ones. The initial discharge specific capacity of self-doped TiO2 nanotube anode is 1355 μA h/cm2 which is more than four times higher than 338 μA h/cm2 of the as-anodized TiO2 nanotube anode in lithium ion batteries. After 100 cycles, the specific capacity of the self-doped TiO2 nanotube electrodes still much higher than that of the as-anodized samples, which is attributed to good tubular morphology retention and secondary growth of the self-doped TiO2 nanotube arrays through the process of insertion/extraction Li+. The controllable regulation of the capacity of self-doped TiO2 anode is also achieved by adjusting electrochemical cathode pulse parameters. It is noteworthy that the cycled anode materials can be used as a catalyst for photocatalytic degradation of methylene blue which may shed light on the resource recovery and the environmental protection.