Insights into Li+ Migration Pathways in 伪-Li3VF6: A First-Principles Investigation

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• 作者：Mazharul M. Islam ; Martin Wilkening ; Paul Heitjans ; Thomas Bredow
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2012
• 出版时间：November 1, 2012
• 年：2012
• 卷：3
• 期：21
• 页码：3120-3124
• 全文大小：326K
• 年卷期：v.3,no.21(November 1, 2012)
• ISSN：1948-7185

文摘

Magnetic, structural, and defect properties of lithium vanadium hexafluoride (伪-Li₃VF₆) are investigated theoretically with periodic quantum chemical methods. It is found that the ferromagnetic phase is more stable than the antiferromagnetic phase. The crystal structure contains three inequivalent Li sites (Li(1), Li(2), and Li(3)), where Li(1) occupies the middle position of the triplet Li(2)鈥揕i(1)鈥揕i(3). The calculated Li vacancy formation energies show that vacancy formation is preferred for the Li(1) and Li(3) sites compared to the Li(2) position. The Li exchange processes between Li(1) 鈫?Li(3), Li(1) 鈫?Li(2), and Li(2) 鈫?Li(3) are studied by calculating the Li⁺ migration between these sites using the climbing-image nudged elastic band approach. It is observed that Li exchange in 伪-Li₃VF₆ may take place in the following order: Li(1) 鈫?Li(3) > (Li(1) 鈫?Li(2) > Li(2) 鈫?Li(3). This is in agreement with recently published results obtained from 1D and 2D ⁶Li exchange nuclear magnetic resonance spectroscopy.

Keywords:

m+vanadium+fluoride&qsSearchArea=searchText">lithium vanadium fluoride; point defects; Li diffusion; migration+pathway&qsSearchArea=searchText">migration pathway; relaxation; activation energy