Origin of Poor Cyclability in Li2MnSiO4 from First-Principles Calculations: Layer Exfoliation and Unstable Cycled Structure
Origin of Poor Cyclability in Li2MnSiO4 from First-Principles Calculations: Layer Exfoliation and Unstable Cycled Structure
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DOI：
10.1021/cm500803e
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发表时间：
2014-06
影响因子：
8.6
通讯作者：
Hosik Lee;Soon‐Dong Park;Janghyuk Moon;Hoonkyung Lee;Kyeongjae Cho;M. Cho;Sung Youb Kim
中科院分区：
文献类型：
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作者：
Hosik Lee;Soon‐Dong Park;Janghyuk Moon;Hoonkyung Lee;Kyeongjae Cho;M. Cho;Sung Youb Kim
良好的可循环性对于阴极材料的潜在应用是必不可少的。在这里，我们调查的二维（2D）锂层状和三维（3D）结构的多晶型的Li2FeSiO4和Li2MnSiO4使用密度泛函理论计算的结构稳定性。我们发现，这两种材料的所有2D锂层状多晶型物在完全脱锂后由于层剥离而不稳定，这可能导致无定形结构。然而，与可以通过形成能量稳定的3D循环结构来防止Li2FeSiO4的非晶化的事实相反，发现Li2MnSiO4的3D循环结构在脱锂化锂化循环期间不稳定。其结果是，Li2MnSiO4容易发生非晶化，循环性差。
Good cyclability is essential for the potential application of cathode materials. Here, we investigate the structural stability of two-dimensional (2D) Li-layered and three-dimensional (3D) structured polymorphs of Li2FeSiO4 and Li2MnSiO4 using the density functional theory calculations. We find that all 2D Li-layered polymorphs of both materials are unstable upon full delithiation owing to layer exfoliation, which can lead to an amorphous structure. However, in contrast to the fact that the amorphization of Li2FeSiO4 can be prevented by the formation of the 3D cycled structure that is energetically stable, the 3D cycled structure of Li2MnSiO4 is found to be unstable during delithiationlithiation cycling. As a result, Li2MnSiO4 easily undergoes amorphization and shows a poor cyclability.