Interaction of Lithium with a Monolayer of Graphene Monoxide
Interaction of Lithium with a Monolayer of Graphene Monoxide
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DOI：
10.1021/acs.jpcc.1c01069
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发表时间：
2021-06
影响因子：
3.7
通讯作者：
D. Radevych;M. Gajdardziska-Josifovska;C. Hirschmugl;M. Weinert
中科院分区：
文献类型：
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作者：
D. Radevych;M. Gajdardziska-Josifovska;C. Hirschmugl;M. Weinert
研究了各种 LixCyOy 结构中锂原子与一氧化石墨烯 (GmO) 单层的相互作用，以确定单层 GmO 是否可以结合锂原子，并预测这种潜在的新型锂离子电池阳极材料的最大理论容量。密度泛函计算表明，Li 原子通过附着在氧原子上而吸附在 GmO 单层上，并且 Li 原子在锂化过程中倾向于排斥。孤立的锂原子更喜欢吸附在碳亚晶格的中空位点，尽管能量接近的氧亚晶格的中空位点可能更适合多层系统，因为它允许锂原子移动到更靠近单层的位置；在较高的Li浓度下，单层GmO的Li2C6O6构型是能量稳定的，而石墨烯（Li2C6）的等效构型则不然，并且Li2C2O2（理论容量为957 mAh/g）的形成能接近于零。能带结构和态密度的分析表明，尽管也形成了共价Li-O键，但Li将大部分价电子贡献给GmO，从而在离开GmO单层时促进Li+离子的形成。这些特性对于电池阳极材料来说是理想的，并且表明 GmO，尤其是多层形式的 GmO，是一种有前途的候选材料。
The interaction of Li atoms with a graphene monoxide (GmO) monolayer in various LixCyOystructures is investigated to determine if a monolayer of GmO can bind Li atoms and to predict the maximum theoretical capacity of this potentially new anode material for Li-ion batteries. Density functional calculations show that Li atoms are adsorbed on the GmO monolayer by attaching to the oxygen atoms and that Li atoms tend to repel during lithiation. An isolated Li atom prefers adsorption at the hollow site of the carbon sublattice although the hollow site of the oxygen sublattice, which is close in energy, may be preferable for multilayer systems since it allows Li atoms to move closer to the monolayer; at higher Li concentrations, the Li2C6O6configuration for monolayer GmO is energetically stable while an equivalent configuration for graphene (Li2C6) is not, and Li2C2O2(with a theoretical capacity of 957 mAh/g) has a formation energy near zero. Analysis of the band structure and density of states shows that Li donates a large fraction of its valence electron to the GmO although there is also the formation of covalent Li–O bonds, thus facilitating the formation of Li+ions when leaving the GmO monolayer. These characteristics are desirable for the battery anode material and suggest that GmO, especially in the multilayer form, is a promising candidate.