Studies on the Lithium Ion Diffusion Coefficients of Electrospun Nb2O5 Nanostructures Using Galvanostatic Intermittent Titration and Electrochemical Impedance Spectroscopy

• Main Authors: Rajan, Jose, Reddy, M. Venkatashamy, Le Viet, Anh, Ozoemenad, Kenneth I, Chowdary, B. V. R, Ramakrishna, S.
• Format: Article
• Language: English
• Published: Elsevier 2014
• Subjects: QD Chemistry
• Online Access: http://umpir.ump.edu.my/id/eprint/6248/1/fist-2014-rjose-Nb2O5Lidiffusion_abs_only.pdf; http://umpir.ump.edu.my/id/eprint/6248/; http://dx.doi.org/10.1016/j.electacta.2013.10.003
• Institution: Universiti Malaysia Pahang

We have studied the Li-diffusion coefficient values of electrospun Nb2O5 nanofibers and nanonuggets for lithium batteries. In brief, Nb2O5 nanofibers were prepared by electrospinning followed by sintering at temperatures range 500–1100 °C for 1 h in air to obtain pseudo-hexagonal, orthorhombic (O), and monoclinic (M) Nb2O5 phases. Electrochemical properties were evaluated by galvanostatic technique at room temperature. The H-, O- and M-Nb2O5 polymorphs delivered discharge capacities (at second cycle) of 152, 189 and 242 (±5) mA h g−1, respectively. The lithium diffusion coefficients (DLi) are calculated using galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) techniques carried at room temperature. The evaluated DLi values by GITT for H-, O-, and M-Nb2O5 phases are in the range 10−17–10−16, 10−15–10−14, and 10−13–10−12 cm2 s−1, respectively, in the voltage range 1.0–2.6 V vs. Li. DLi evaluated by EIS gave similar trend in the values but with a difference of one order higher magnitude.