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.