Department of Mining and Materials Engineering, McGill University , Montreal, Quebec, Canada.
ACS Appl Mater Interfaces. 2013 Dec 26;5(24):12968-74. doi: 10.1021/am403685w. Epub 2013 Dec 13.
In the present study, we investigate the irradiation-defects hybridized graphene scaffold as one potential building material for the anode of Li-ion batteries. Designating the Wigner V2(2) defect as a representative, we illustrate the interplay of Li atoms with the irradiation defects in graphene scaffolds. We examine the adsorption energetics and diffusion kinetics of Li in the vicinity of a Wigner V2(2) defect using density functional theory calculations. The equilibrium Li adsorption sites at the defect are identified and shown to be energetically preferable to the adsorption sites on pristine (bilayer) graphene. Meanwhile, the minimum energy paths and corresponding energy barriers for Li migration at the defect are determined and computed. We find that, while the defect is shown to exhibit certain trapping effects on Li motions on the graphene surface, it appears to facilitate the interlayer Li diffusion and enhance the charge capacity within its vicinity, because of the reduced interlayer spacing and characteristic symmetry associated with the defect. Our results provide critical assessment for the application of irradiated graphene scaffolds in Li-ion batteries.
在本研究中，我们研究了辐照缺陷杂化石墨烯支架作为锂离子电池阳极的潜在建筑材料。以 Wigner V2(2)缺陷为例，我们说明了锂离子与石墨烯支架中辐照缺陷的相互作用。我们使用密度泛函理论计算研究了 Li 在 Wigner V2(2)缺陷附近的吸附能和扩散动力学。确定了缺陷处 Li 的平衡吸附位置，表明它们在能量上优于原始（双层）石墨烯上的吸附位置。同时，确定并计算了缺陷处 Li 迁移的最小能量路径和相应的能量势垒。我们发现，尽管缺陷对石墨烯表面上 Li 运动表现出一定的捕获效应，但由于缺陷引起的层间间距减小和特征对称性，它似乎有利于层间 Li 扩散并提高其附近的电荷容量。我们的结果为辐照石墨烯支架在锂离子电池中的应用提供了重要评估。
