School of Materials Science and Engineering, The University of New South Wales, NSW 2052, Australia.
Phys Chem Chem Phys. 2018 Jul 11;20(27):18671-18677. doi: 10.1039/c8cp02740d.
The interactions between metals and two-dimensional materials, in particular, the adsorption energies, strongly determine the performances of rechargeable batteries. Previously, it has been demonstrated that heterostructures of two dimensional (2D) materials can lead to enhanced metal adsorptions, which were ascribed to the existence of 'synergistic' effects amongst metal atoms and two different 2D materials. However, further investigations are still required to reveal the physical mechanisms behind the contribution of these possible 'synergistic' effects for metal intercalations in 2D heterostructures. Here, we selected MoS2/graphene as a prototypical system, and we examined the adsorption and intercalation thermochemistry of monovalent atoms (Li, Na and K) and multivalent atoms (Mg, Ca and Al) using density-functional theory (DFT) calculations. The synergistic effects arising from charge polarizations in these systems were quantified using the three-body interaction energy terms. Our results show strong system dependencies whereby the interactions between the Mg or Ca atom with the MoS2/graphene heterostructures might exhibit cooperative bindings. Nevertheless, metal adsorptions on top of the graphene surface were all found to be anti-cooperative in this case. Our results suggest that enhancement of metal adsorptions using 2D heterostructures is predominantly driven by increasing dispersion interactions due to increases in the interaction surface areas.
金属与二维材料之间的相互作用，尤其是吸附能，强烈地决定了可充电电池的性能。以前已经证明，二维（2D）材料的异质结构可以导致金属吸附增强，这归因于金属原子和两种不同的 2D 材料之间存在“协同”效应。然而，仍需要进一步的研究来揭示这些可能的“协同”效应对 2D 异质结构中金属插层的贡献背后的物理机制。在这里，我们选择 MoS2/石墨烯作为一个典型的系统，并用密度泛函理论（DFT）计算研究了单价原子（Li、Na 和 K）和多价原子（Mg、Ca 和 Al）的吸附和嵌入热化学。使用三体相互作用能项来量化这些系统中电荷极化产生的协同效应。我们的结果显示出强烈的系统依赖性，其中 Mg 或 Ca 原子与 MoS2/石墨烯异质结构之间的相互作用可能表现出协同结合。然而，在这种情况下，在石墨烯表面上的金属吸附都被发现是反协同的。我们的结果表明，使用 2D 异质结构增强金属吸附主要是由于增加了相互作用表面积而导致的分散相互作用的增加。
