Electrochemically Self-Doped TiO2 Nanotube Arrays for Supercapacitors

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• 作者：He Zhou ; Yanrong Zhang
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：March 20, 2014
• 年：2014
• 卷：118
• 期：11
• 页码：5626-5636
• 全文大小：577K
• 年卷期：v.118,no.11(March 20, 2014)
• ISSN：1932-7455

文摘

The application of highly ordered TiO₂ nanotube arrays (NTAs) for energy storage devices such as supercapacitors has been attractive and of great interest owing to their large surface area and greatly improved charge-transfer pathways compared to those of nonoriented structures. Modification of the semiconductor nature of TiO₂ is important for its application in constructing high-performance supercapacitors. Hence, the present study demonstrates a novel method involving fabrication of self-doped TiO₂ NTAs by a simple cathodic polarization treatment on the pristine TiO₂ NTAs to achieve improved conductivity and capacitive properties of TiO₂. The self-doped TiO₂ NTAs at 鈭?.4 V (vs SCE) exhibited 5 orders of magnitude improvement on carrier density and 39 times enhancement in capacitance compared to those of the pristine TiO₂ NTAs. Impedance analysis based on a proposed simplified transmission line model proved that the enhanced capacitive behavior of the self-doped TiO₂ NTAs was due to a decrease of charge-transport resistance through the solid material. Moreover, the MnO₂ species was introduced onto the TiO₂ NTAs by an impregnation鈥揺lectrodeposition method, and the optimal specific capacitance achieved (1232 F g^鈥?) clearly confirmed the suitability of self-doped TiO₂ NTAs as effective current collector materials for supercapacitors.