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

Ultralong carbon coated TiO2 nanotube (500-1000 nm) 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 degrees 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 (194 mA h g (1) at 5C, 157 mA h g (1) at 20 C, 1 C = 334 mA g (1)) and high reversible charge/discharge capacity (154 mA h g (1) after 100 cycles at 10 C). 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 (C) 2016 Elsevier Ltd. All rights reserved.