Fersiynau electronig

Dangosydd eitem ddigidol (DOI)

  • T. R. Stechert
  • M. J. D. Rushton
    Grand Challenges in Ecosystem and the Environment Initiative, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY, UK alexander.papadopulos@plants.ox.ac.uk.
  • R. W. Grimes
  • A. C. Dillon
Materials with the LiAlF4 composition are of interest as protective electrode coatings in Li ion battery applications due to their high cationic conductivity. Here classical molecular dynamics calculations are used to produce amorphous model structures by simulating a quench from the molten state. These are analysed in terms of their individual pair correlation functions and atomic coordination environments. This indicates that amorphous LiAlF4 is formed of a network of corner sharing AlF6 octahedra. Li ions are distributed within this network, primarily associated with non-bridging fluorine atoms. The nature of the octahedral network is further analysed through intra- and interpolyhedral bond angle distributions and the relative populations of bridging and non-bridging fluorine ions are calculated. Network topology is considered through the use of ring statistics, which indicates that, although topologically well connected, LiAlF4 contains an appreciable number of corner-linked branch-like AlF6 chains. Thermal expansion values are determined above and below the predicted glass transition temperature of 1340 K. Finally, movement of Li ions within the network is examined with predictions of the mean squared displacements, diffusion coefficients and Li ion activation energy. Different regimes for lithium ion movement are identified, with both diffusive and sessile Li ions observed. For migrating ions, a typical trajectory is illustrated and discussed in terms of a hopping mechanism for Li transport. (C) 2012 Elsevier B.V. All rights reserved.
Iaith wreiddiolAnadnabyddus
Tudalennau (o-i)1917-1923
Nifer y tudalennau7
CyfnodolynJournal of Non-Crystalline Solids
Rhif y cyfnodolyn16
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - 15 Awst 2012
Cyhoeddwyd yn allanolIe
Gweld graff cysylltiadau