TiO2 mesoporous single crystals (MSCs) with diverse constructions in a controllable fashion are successfully fabricated by a new template-free method for the first time, using oxalic acid (OA) as the pore-forming agent and morphological controller. Unlike the seeding-template based growth mechanism, the TiO2 MSCs in the present work may involve a process of oriented aggregation and crystallographic fusion of primary nanocrystals. The structural control of TiO2 MSCs can be easily realized by tailoring growth conditions, such as Ti-source concentration and OA dosages. Moreover, the TiO2 MSCs shows substantial improvement in lithium specific capacity from 0.2C to 10C in comparison to the reference TiO2 nanoparticle. The high-rate performance was further improved by fabricating MSCs/graphene oxide nanocomposites, and specific capacity of the composite at the rate of 20C is as high as 90 mA h g (1). This new template-free strategy may open up new and exciting opportunities for the preparation of other MSCs, and makes important applicatory significance for the structure design of high rate lithium ion battery anodes. (C) 2015 Elsevier Ltd. All rights reserved.