Although Li-ion batteries are extensively applied for different purposes, they suffer from safety problems, high cost, and short lifetime. Because of low cost, wide availability, and nontoxicity of magnesium, Mg-ion batteries (MIB) might be a good alternative to Li-ion batteries. Here, applying density functional theory calculations, we examined the potential application of zigzag (4,0), (5,0), (6,0), (7,0), and (8,0) carbon nanotubes in the anode of MIBs. We found that by increasing the tube diameter, the Mg 2+ adsorption energies are very slightly changed but the Mg adsorption sharply decreased indicating that the adsorption of Mg atom much more depends on the tube diameter and its adsorption energy is the key parameter for generating a cell voltage. We showed that by increasing the curvature of the CNT, the charge transfer is sharply increased upon Mg atom so that in the highest curvature, the interaction becomes ionic in nature with a Jahn-Teller distortion in the CNT structure. However, by increasing the CNT diameter, the cell voltage of MIB increased, from 4.0 V in the (4,0) to 5.3 V in the (8,0) CNT.

中文翻译：

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锯齿形碳纳米管在镁离子电池中潜在应用的计算研究

尽管锂离子电池被广泛应用于不同的用途，但它们存在安全问题、成本高和寿命短的问题。由于镁的低成本、广泛的可用性和无毒，镁离子电池 (MIB) 可能是锂离子电池的一个很好的替代品。在这里，应用密度泛函理论计算，我们研究了锯齿形 (4,0)、(5,0)、(6,0)、(7,0) 和 (8,0) 碳纳米管在阳极中的潜在应用MIB 的数量。我们发现，通过增加管径，Mg 2+ 吸附能变化很小，但 Mg 吸附量急剧下降，表明 Mg 原子的吸附更多地取决于管径，其吸附能是产生吸附量的关键参数。电池电压。我们表明，通过增加 CNT 的曲率，Mg 原子上的电荷转移急剧增加，因此在最高曲率下，相互作用在性质上变成离子，在 CNT 结构中出现 Jahn-Teller 畸变。然而，通过增加 CNT 直径，MIB 的电池电压增加，从 (4,0) 中的 4.0 V 增加到 (8,0) CNT 中的 5.3 V。