Molecular dynamics simulation of the effect of crystal orientation on lithium-ion diffusion at the V2O5/Li2SiO3 interface

The molecular dynamics computer simulation technique was used to determine the effect of the orientation of the V2O5 crystal (cathode) on Li-ion transport across the electrolyte/cathode interface for solid-state thin-film batteries and electrochromic devices. Simulations of the intercalation of lithium ions from a lithium metasilicate glass into V2O5 crystals oriented with the (001) and (010) planes parallel to the interface were performed. The simulations showed that lithium ions have better mobility into the (010) oriented interface than the (001) oriented interface. Energy barriers for Li motion in the <010> and <001> directions were determined to be 0.87 eV vs. 2.47 eV in V2O5 and 0.81 eV vs. 1.79 eV in delta-LiV2O5, respectively. The higher energy barrier in the <001> direction causes the accumulation of lithium ions between the crystal planes. For approximately the same amount of volume, the (010) V2O5/glass interface and an amorphous V2O5/glass interface contain 46 and 45% more Lithium ions, respectively, than the (001) V2O5/glass interface. (C) 1999 The Electrochemical Society. S0013-4651(98)06-077-7. All rights reserved.