Evaluation of Multivalent Cation Insertion in Single- and Double-Layered Polymorphs of V2O5
Evaluation of Multivalent Cation Insertion in Single- and Double-Layered Polymorphs of V2O5
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DOI：
10.1021/acsami.7b05556
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发表时间：
2017-07-19
影响因子：
9.5
通讯作者：
Banerjee, Sarbajit
中科院分区：
文献类型：
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作者：
Parija, Abhishek;Prendergast, David;Banerjee, Sarbajit
多价嵌入式电池有可能规避统治锂离子技术的几个基本限制。这样的电池将有可能提供高体积能量密度，操作更安全，并且依赖于比地壳中的锂更丰富的材料。这种电池的嵌入阴极的设计需要考虑热力学方面，如结构畸变和能量学，以及动力学方面，如阳离子扩散的障碍。层状α-V2 O 5系统是锂离子的典型嵌入主体，但对于多价阳离子插入几乎没有表现得那么好。然而，丰富的V-O相图提供了许多亚稳多晶型物，这些多晶型物对多价阳离子插层具有更大的希望。在这篇文章中，我们探讨多价阳离子插入三个亚稳多晶型，γ '，δ'，和P'相的V2 O 5，使用密度泛函理论计算。的计算允许独特的结构基序介导的多价阳离子插入的影响进行评估。特别是，我们对比的影响，单与凝聚的双层，平面与起皱的单层，和特定的堆叠顺序的双层。我们证明，亚稳相提供了一些特定的优势，相对于化学稳定的多晶型物在较高的化学势差（引起较大的开路电压），并在提供访问的扩散途径，是高度依赖于特定的结构基序。这三种多晶型物被发现是特别有前途的钙离子嵌入，这是特别重要的考虑到非常稀疏的数量的可行的阴极材料，这种化学。这里的研究结果表明，通过改变堆叠顺序或层的厚度来定义层状亚稳多晶型物内的阳离子扩散途径的能力。
Multivalent intercalation batteries have the potential to circumvent several fundamental limitations of reigning Li-ion technologies. Such batteries will potentially deliver high volumetric energy densities, be safer to operate, and rely on materials that are much more abundant than Li in the Earth's crust. The design of intercalation cathodes for such batteries requires consideration of thermodynamic aspects such as structural distortions and energetics as well as kinetic aspects such as barriers to the diffusion of cations. The layered alpha-V2O5 system is a canonical intercalation host for Li-ions but does not perform nearly as well for multivalent cation insertion. However, the rich V-O phase diagram provides access to numerous metastable polymorphs that hold much greater promise for multivalent cation intercalation. In this article, we explore multivalent cation insertion in three metastable polymorphs, gamma', delta', and p' phases of V2O5, using density functional theory calculations. The calculations allow for evaluation of the influence of distinctive structural motifs in mediating multivalent cation insertion. In particular, we contrast the influence of single versus condensed double layers, planar versus puckered single layers, and the specific stacking sequence of the double layers. We demonstrate that metastable phases offer some specific advantages with respect to thermodynamically stable polymorphs in terms of a higher chemical potential difference (giving rise to a larger open-circuit voltage) and in providing access to diffusion pathways that are highly dependent on the specific structural motif. The three polymorphs are found to be especially promising for Ca-ion intercalation, which is particularly significant given the exceedingly sparse number of viable cathode materials for this chemistry. The findings here demonstrate the ability to define cation diffusion pathways within layered metastable polymorphs by alteration of the stacking sequence or the thickness of the layers.