An architectured TiO 2 nanosheet with discrete integrated nanocrystalline subunits and its application in lithium batteries

An anatase TiO ₂ nanosheet with discrete integrated subunits was successfully synthesized via a rapid annealing treatment, which could be classified as non-equilibrium conditions on an as-prepared hydrogen titanate nanosheet. This unique TiO ₂ nano-object is uniform in length and width as a "sheet-like" shape which is integrated with numerous discrete nanocrystalline subunits. In contrast with the internal architecture of the TiO ₂ nanosheets produced under equilibrium and non-equilibrium conditions, the local structure collapse transformation mechanism from the hydrogen titanate nanosheet to the anatase TiO ₂ nanosheet with internal architecture is discussed. This unique anatase nano-object electrode exhibits high reversible lithium ion storage capacities and superior cyclic capacity retention at a high current rate. Such enhanced lithium storage performance could be attributed to the discrete subunits aggregation allowing efficient Li ⁺ ion diffusion and the interior anisotropy in the nanosheet can be more effective to buffer the volume variation during the lithium insertion/desertion cycle. © 2012 The Royal Society of Chemistry.