Ultra-thin film electrodes of tetratitanate nanosheets

The lithium intercalation properties of ultra-thin films of tetratitanate nanosheets were examined to determine the intrinsic electrode performance and the influence of nanosheet layer lamination on the electrode properties. Ultra-thin films of tetratitanate nanosheets were prepared by layer-by-layer assembly directly onto a Pt current collector. The ultra-thin film of tetratitanate nanosheets prepared by single deposition operation exhibited a specific capacity of 0.13 mu Ah cm(-2), which is a large value corresponding to the reduction and oxidation of approximately 87% of the Ti ions. A change in the rate controlling process from a charge transfer reaction to diffusion was observed by cyclic voltammetry at 50 mV s(-1). The lithium ion diffusion coefficient was determined by analyzing the results computationally with a mathematical model, and it was found to be 3 x 10(-10) cm(2) s(-1). The nanosheets exhibited high reactivity in a thin film with an estimated thickness of 9.1 nm. Sufficient electronic conductivity of the electrode, whose thickness is below 10 nm, and sufficient lithium transportation through the electrode contribute to the high reactivity. (C) 2011 Elsevier B.V. All rights reserved.