Kinetics-controlled growth of aligned mesocrystalline SnO2 nanorod arrays for lithium-ion batteries with superior rate performance

A general method for facile kinetics-controlled growth of aligned arrays of mesocrystalline SnO2 nanorods on arbitrary substrates has been developed by adjusting supersaturation in a unique ternary solvent system comprising acetic acid, ethanol, and water. The hydrolysis processes of Sn(IV) as well as the nucleation and growth of SnO2 crystals were carefully controlled in the mixed solvents, leading to an exclusively heterogeneous nucleation on a substrate and the subsequent growth into mesocrystalline nanorod arrays. In particular, aligned arrays of hierarchically structured, [001]-oriented mesocrystalline SnO2 nanorods with four {110} lateral facets can be readily grown on Ti foil, as well as many other inert substrates such as fluoride-doped tin oxide (FTO), Si, graphite, and polytetrafluoroethylene (Teflon). Due to the unique combination of the mesocrystalline structure and the one-dimensional nanoarray structure, the obtained mesocrystalline SnO2 nanorod arrays grown on metallic Ti substrate exhibited an excellent rate performance with a high initial Coulombic efficiency of 65.6% and a reversible capacity of 720 mA·h/g at a charge/discharge rate of 10 C (namely, 7,820 mA/g) when used as an anode material for lithium-ion batteries.