Mesoporous TiO2-Sn/C Core-Shell Nanowire Arrays as High-Performance 3D Anodes for Li-Ion Batteries

Three-dimensional mesoporous TiO2-Sn/C core-shell nanowire arrays are prepared on Ti foil as anodes for lithium-ion batteries. Sn formed by a reduction of SnO2 is encapsulated into TiO2 nanowires and the carbon layer is coated onto it. For additive-free, self-supported anodes in Li-ion batteries, this unique core-shell composite structure can effectively buffer the volume change, suppress cracking, and improve the conductivity of the electrode during the discharge-charge process, thus resulting in superior rate capability and excellent long-term cycling stability. Specifically, the TiO2-Sn/C nanowire arrays display rechargeable discharge capacities of 769, 663, 365, 193, and 90 mA h g(-1) at 0.1C, 0.5C, 2C 10C, and 30C, respectively (1C = 335 mA g(-1)). Furthermore, the TiO2-Sn/C nanowire arrays exhibit a capacity retention rate of 84.8% with a discharge capacity of over 160 mA h g(-1), even after 100 cycles at a high current rate of 10C.