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arXiv 1810.02498cond-mat.mtrl-sci
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基于第一性原理计算预测锗石墨烯作为锂离子电池负极材料的前景

Germagraphene as promising anode material for Lithium-ion batteries predicted from first-principles calculations

Junping Hu, Chuying Ouyang, Shengyuan A. Yang, Hui Ying Yang

摘要:

寻找具有高容量的电极材料是开发锂离子电池(LIB)的关键挑战。石墨烯曾经被认为是一个有前途的候选者,但事实证明它太惰性,无法与Li相互作用。在此,通过第一性原理计算,我们预测锗掺杂的石墨烯(Germagraphene)是一种很有前途的锂离子电池负极材料。我们发现,在最佳Ge浓度下,对应于化学式C17 Ge,Germagraphene的比容量可高达1734 mAh/g,比石墨大四倍以上。我们表明,该材料是导电的锂吸附前后。我们还研究了Li在Germagraphene上的扩散过程,发现扩散势垒很低(~0.151 eV),这意味着Li的快速扩散。计算的平均嵌入电位很低(~ 0.03V),这有利于提高全电池的工作电压。此外,在锂嵌入过程中,材料的晶格变化相当小(~0.48%),这意味着良好的循环性能。这些结果表明,Germagraphene可能是一个有前途的高容量负极材料的LIB。

英文摘要:

Finding electrode materials with high capacity is a key challenge for developing Lithium-ion batteries (LIBs). Graphene was once expected to be a promising candidate, but it turns out to be too inert to interact with Li. Here, by using the first-principles calculations, we predict that Germanium doped graphene, termed as Germagraphene which has been achieved in recent experiment, is a promising LIB anode material. We find that at the optimal Ge concentration, which corresponds to the chemical formula C17Ge, the specific capacity for Germagraphene can be as high as 1734 mAh/g, over four times larger than graphite. We show that the material is conductive before and after Li adsorption. We also investigate the diffusion process of Li on Germagraphene, and find that the diffusion barrier is low (~0.151 eV), implying fast Li diffusion. The calculated average intercalation potential is very low (~0.03 V), which is beneficial for increasing the working voltage for the full-cells. In addition, during the process of Li intercalation, the lattice change for the material is quite small (~0.48%), implying good cycle performance. These results suggest that Germagraphene could be a promising high-capacity anode material for LIBs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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