Molecular dynamics simulation of ionic transport on molten Li–KCl interface

✍ Scribed by Xiao-Hui Duan; Jian-Feng Li; Wen-Jun Zhu

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 293 KB
• Volume: 111
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/qua.22905

✦ Synopsis

Abstract

A molecular dynamics study is performed to determine the dynamics and transport properties of the ions on the molten interface between anode metal Li and electrolyte KCl. Radial distribution function of the ionic pair and the behavior of the mean‐square displacement (MSD) as a function of time (t) indicate that KCl and metal Li are in the molten state at 2,200 K in the canonical ensemble. The dynamics of the ionic transport are characterized by studying MSD for the centers of mass of the ions at different temperatures. Diffusion coefficient is evaluated from the linear slope of the MSD (t) function in the range of 0–500 ps. The MSD and diffusion coefficient of the Li^+^ ions are much larger than those of the Cl^−^ and K^+^ ions due to the difference in ionic characteristic. The transport process has been dominated by the Li^+^ ions on the molten interface and the Li^+^ ions are main charge carriers. The energy barrier of the Li^+^ ions transporting into the molten KCl is fitted to be 5.28 kcal/mol in the light of the activation model. The electrical conductivity of the Li^+^ ions transporting into the molten KCl are calculated from the Nernst–Einstein formula to be in the range of 0.2–0.3 S cm^−1^. The current density resulted from the Li^+^ ions through the interface are estimated to be an order of 10^6^ A cm^−2^, which may be the value corresponding to a larger concentration gradient of the Li^+^ ions. Simulated results at different temperatures show that the diffusion coefficient, conductivity and current density have increased with the temperature. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011