Epitaxial Li(4)Ti(5)O(12) thin-films were successfully synthesized on SrTiO(3) single-crystal substrates with (111), (110), and (100) lattice plane orientations using pulsed laser deposition (PLD). Thin-film X-ray diffraction (XRD) revealed that the Li(4)Ti(5)O(12) films had the same orientation as the SrTiO(3) substrates: Li(4)Ti(5)O(12) (111) on SrTiO(3) (111), Li(4)Ti(5)O(12) (110) on SrTiO(3) (110), and Li(4)Ti(5)O(12) (100) on SrTiO(3) (100). These epitaxial films contained island structures, and the morphology of the (111), (110), and (100) films, observed by field emission scanning electron microscopy (FE-SEM), exhibited angular, needle-like, and circular shapes, respectively. The electrochemical properties of 20 nm thick Li(4)Ti(5)O(12) (111) and (110) films were investigated by cyclic voltammetry. Reversible intercalation proceeded through both lattice planes due to the three-dimensional diffusion pathway of lithium in the spinel framework. Reduction peaks in the first cathodic scan appeared at different positions from those in subsequent scans, suggesting a surface reconstruction at the Li(4)Ti(5)O(12) surface due to interfacial reactions.

Electrochemical properties and structure changes of nano-sized Li 4 Ti 5 O 12 during lithium (de)intercalation were investigated using a two-dimensional thin film electrode. Li 4 Ti 5 O 12 thin films were deposited on a Nb:SrTiO 3 (110) substrate by a pulsed laser deposition technique. X-ray diffraction and reflectometry measurements confirmed the epitaxial growth of 27.6-nm-thick Li 4 Ti 5 O 12 (110) films. Galvanostatic charge-discharge curves showed a large discharge capacity of 217 mAh g −1 at the initial discharge cycle, although the reversible capacity decreased in subsequent cycles. In situ X-ray diffraction measurements clarified the drastic structural changes of the Li 4 Ti 5 O 12 film upon soaking in the electrolyte and during the first intercalation and deintercalation processes. The surface region of Li 4 Ti 5 O 12 had a different structure from the bulk during electrochemical cycling and could cause the nanosized Li 4 Ti 5 O 12 electrodes to have high capacities and poor stabilities.