Studies on kinetics and diffusion characteristics of lithium ions in TiNb2O7

Abstract The diffusion coefficients and kinetics of lithium ion transport in TiNb2O7 nanocrystals at different charge-discharge potentials are determined by using Galvanostatic Intermittent Titration Technique (GITT), Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV). The chemical diffusion coefficient values ( D c h e m ) at different intercalation and de-intercalation potentials vary in a range of 10−15 - 10−16 cm2 s−1 and exhibit a ‘W’- type behavior. The differential intercalation capacity ( C i n t ) derived from various electrochemical techniques are compared, which showed maximum value at the lowest chemical diffusion coefficient. Cyclic voltammograms recorded at different scan rates are used to study the kinetics of Li-ions, which showed a capacitive behavior of 53% at 0.10 mV s−1 for TiNb2O7, demonstrating its suitability as high rate anode material in lithium ion batteries.