Lithium Insertion into Vanadium Oxide Nanotubes: Electrochemical and Structural Aspects

The electrochemical and structural aspects of lithium insertion into vanadium oxide nanotubes have been studied. Structural changes, induced as lithium was inserted between the vanadium oxide layers, were followed by in situ synchrotron X-ray diffraction recorded during potential steps. Two separate processes were identified: a fast decrease of the interlayer distance followed by a slow two-dimensional relaxation of the intralayer vanadium oxide structure. The nanotubes were synthesized using crystalline V 2 O 5 as a precursor, instead of the normally used vanadium alkoxide, which produced a more cost-effective material with similar performance. Electrochemical measurements showed that surface processes, i.e., charge transfer and/or ohmic drop, were rate-controlling, as can be anticipated for the thin layer electrochemical conditions used in this study.