Organic macromolecule assisted synthesis of ultralong carbon@TiO2 nanotubes for high performance lithium-ion batteries

Abstract

Ultralong carbon coated TiO2 nanotube (500–1000nm) with well-crystallization has been synthesized via an efficient macromolecular-assisted method. Specifically, tubular TiO2 nanotube precursors synthesized via a hydrothermal method are firstly coated with polyvinylpyrrolidone (PVP). In the following crystallization heat-treatment process, PVP with a chain structure and suitable thickness restricts the stretching trend of inner TiO2 nanotube and carbonizes as high conductive substrate, finally helps nanotubes to avoid the collapse in heat-treatment. The conductive coating maintains the integrity of the electrode during the charge/discharge processes and promotes electron transport, the unique open channel structure of TiO2-B crystal gotten 400°C facilitates lithiation/delithiation paths of electrons and lithium ions, the tubular structure of TiO2 provides great electrode/electrolyte contact area. All of these factors are responsible for the remarkable rate capability (194mAhg−1 at 5C, 157mAhg−1 at 20C, 1C=334mAg−1) and high reversible charge/discharge capacity (154mAhg−1 after 100 cycles at 10C). The carbon coated TiO2 nanotube is superior to many reported TiO2 electrodes, which makes it hold great promise as an optional anode material for LIBs