科研之友
微信
新浪微博
Facebook
分享链接
摘要
Monte Carlo (MC) simulation has been performed to investigate the variation of chemical diffusion coefficient of Li ions in graphite as a function of applied voltage and its relation to the staging phenomenon. The interatomic potential between Li ions is parametrized using density functional theory and molecular statics to include interactions between Li ions through host-material elastic deformation. The present simulation in a bulk graphite system can simulate Li ion migration without uncertainties encountered in some experiments, and well reproduces not only root 3 x root 3 in-plane super lattice and stage structures observed in experiments, but also the decrease of chemical diffusion coefficient when two phases coexist reflecting the drop of thermodynamic factor. We have clearly shown that the stage structure and decrease of the chemical diffusion coefficient can be explained with only the interaction between Li ions through the deformation of host material. Furthermore we have found substages between stage-1 and -2 which may cause further uncertainties for the observation of the diffusion coefficient in the experiments.
- 出版日期2013-9
