Abstract
Carbon-doped TiO 2 nanotubes were synthesized through a sol–gel and subsequent hydrothermal process. Transmission electron microscopy and X-ray diffraction showed that the products are uniformly straight tubes with the diameter around 10 nm in anatase-type. The electrochemical performances of the nanotubes were tested by constant current discharge/charge, cyclic voltammetry, and electrochemical impedance spectroscopy. The initial discharge capacity reaches 291.7 mAh g −1 with a coulombic efficiency of 91.7% at a current density of 70 mA g −1. There is a distinct potential plateau near 1.75 and 1.89 V (versus Li +/Li) in the lithium intercalation and extraction processes, respectively, and the lithium insertion capacity is about 204 mAh g −1 over the plateau of 1.75 V region in the first cycle. From the 2nd to the 30th cycles, the average reversible capacity loss is less than 1.73 mAh g −1 per cycle. After 30 cycles, the reversible capacity still remains 211 mAh g −1 with a coulombic efficiency larger than 99.7%, implying a perfect reversibility and cycling stability.
Published Version
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