Abstract The triple-layered sandwich nanotube of carbon nanotube@TiO2 nanocrystalline@carbon is synthesized. TiO2 nanocrystalline stably adheres to carbon nanotubes. A layer of amorphous carbon shell derived by PPy tightly attaches on the surface of TiO2 nanocrystalline. Carbon nanotube@TiO2 nanocrystalline@carbon is of abundant mesopores, showing high pore volume of 0.92 cm3 g−1 and large specific surface area of 612 m2 g−1. As anode material of lithium ion batteries, it exhibits high discharge capacity, desirable cycling performance (236 mA h g−1 at 1C after 500 cycles) and excellent rate capability (187 mA h g−1 at 10C). The outstanding lithium storage performance comes from the supporting effect of the internal carbon nanotube and the protecting effect of the external carbon shell, which significantly increase cycling stability and electronic conductivity of TiO2. The large specific surface area brings about intense pseudocapacitive lithium storage effect, enhancing reversible capacity and rate performance of TiO2.

中文翻译：

---

具有优异储锂性能的碳纳米管@TiO2纳米晶@碳三层夹心纳米管

摘要 合成了碳纳米管@TiO2纳米晶@碳的三层夹心纳米管。TiO2 纳米晶稳定地粘附在碳纳米管上。一层由PPy衍生的无定形碳壳紧密附着在TiO2纳米晶表面。碳纳米管@TiO2纳米晶@碳具有丰富的介孔，孔体积高达0.92 cm3 g-1，比​​表面积高达612 m2 g-1。作为锂离子电池的负极材料，它具有高放电容量、理想的循环性能（500 次循环后 1C 下 236 mA hg-1）和优异的倍率性能（10C 下 187 mA hg-1）。出色的储锂性能来自于内部碳纳米管的支撑作用和外部碳壳的保护作用，显着提高了 TiO2 的循环稳定性和电子电导率。大的比表面积带来了强烈的赝电容储锂效应，提高了TiO2的可逆容量和倍率性能。