材料科学
锂(药物)
元动力学
化学计量学
氧气
阴极
化学工程
曲面(拓扑)
插层(化学)
曲面重建
化学物理
粒子(生态学)
纳米技术
离子
物理化学
无机化学
分子动力学
计算化学
化学
几何学
有机化学
内分泌学
数学
工程类
地质学
海洋学
医学
作者
Yongwoo Shin,Kristin A. Persson
标识
DOI:10.1021/acsami.6b07259
摘要
There is a growing appreciation for the role of surface reactivity and subsequent reconstruction affecting the performance of high-voltage, high-capacity Li-ion cathode materials. In particular, the promising Li-excess materials are known to exhibit significant vulnerability toward oxygen release, which can cause surface densification and impede Li intercalation. Here we focus on the end member, Li2MnO3, as a Li-excess, Mn-rich representative of this class of materials and systematically elucidate all possible stoichiometric low Miller index surfaces with various cation ordering on each surface. We apply surface cation reconstruction rules that depend on the local environment, including target Mn–Li site exchanges, and optimize the resulting surface Li configurations using metadynamics. The equilibrium Wulff shape shows dominant (001), (010) surface facets, and almost all facets exhibit favorable Mn reconstruction. Most importantly, we find that while all equilibrium LixMnO3 surfaces become unstable toward oxygen release for x < 1.7, some facets are consistently more resistant than others which may provide a design metric for more stable particle morphologies and enhanced surface oxygen retention.
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