Topochemically De-Intercalated Phases of V2O5 as Cathode Materials for Multivalent Intercalation Batteries: A First-Principles Evaluation,Chemistry of Materials

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Topochemically De-Intercalated Phases of V2O5 as Cathode Materials for Multivalent Intercalation Batteries: A First-Principles Evaluation
Chemistry of Materials ( IF 7.2 ) Pub Date : 2016-08-05 00:00:00 , DOI: 10.1021/acs.chemmater.6b01006
Abhishek Parija ₁ , Yufeng Liang ₂ , Justin L. Andrews ₁ , Luis R. De Jesus ₁ , David Prendergast ₂ , Sarbajit Banerjee ₁

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The scarce inventory of compounds that allow for diffusion of multivalent cations at reasonable rates poses a major impediment to the development of multivalent intercalation batteries. Here, we contrast the thermodynamics and kinetics of the insertion of Li, Na, Mg, and Al ions in two synthetically accessible metastable phases of V₂O₅, ζ- and ε-V₂O₅, with the relevant parameters for the thermodynamically stable α-phase of V₂O₅ using density functional theory calculations. The metastability of the frameworks results in a higher open circuit voltage for multivalent ions, exceeding 3 V for Mg-ion intercalation. Multivalent ions inserted within these structures encounter suboptimal coordination environments and expanded transition states, which facilitate easier ion diffusion. Specifically, a nudged elastic band examination of ion diffusion pathways suggests that migration barriers are substantially diminished for Na- and Mg-ion diffusion in the metastable polymorphs: the predicted migration barriers for Mg ions in ζ-V₂O₅ and ε-V₂O₅ are 0.62–0.86 and 0.21–0.24 eV, respectively. More generally, the results indicate that topochemically derived metastable polymorphs represent an interesting class of compounds for realizing multivalent cation diffusion because many such compounds place cations in “frustrated” coordination environments that are known to be useful for realizing low diffusion barriers.

中文翻译：

V ₂ O _5的拓扑化学脱嵌相，作为多价插层电池的阴极材料：第一性原理评估

允许以合理速率扩散多价阳离子的稀有化合物库存严重阻碍了多价嵌入电池的开发。在这里，我们对比锂，钠，镁，和Al离子的嵌入的热力学和动力学两合成获得的亚稳相第V ₂ ø ₅，ζ-和ε-V ₂ ø ₅，与用于热力学的相关参数V ₂ O _5的稳定α相使用密度泛函理论计算。框架的亚稳定性导致多价离子的开路电压更高，而对于Mg离子的嵌入而言，其开路电压超过3V。插入这些结构中的多价离子会遇到次优的配位环境和扩展的跃迁状态，从而促进离子的扩散。具体地，离子扩散途径的轻推弹性带检查表明迁移屏障大大减少在亚稳态多晶型物NA-和Mg离子扩散：预测在ζ-V迁移障碍为Mg离子₂ ö ₅和ε-V ₂ Ø ₅分别为0.62-0.86和0.21-0.24 eV。更一般而言，结果表明，拓扑化学衍生的亚稳态多晶型物代表用于实现多价阳离子扩散的一类有趣的化合物，因为许多此类化合物将阳离子置于“受阻”的配位环境中，这些环境已知可用于实现低扩散势垒。

更新日期：2016-08-05

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