Aluminum doping improves the energetics of lithium, sodium, and magnesium storage in silicon: A first-principles study

JOURNAL OF POWER SOURCES

卷:274

Article

Legrain, Fleur¹  Manzhos, Sergei¹ 

[1] Natl Univ Singapore, Dept Mech Engn, Singapore 117576, Singapore

关键词: Aluminum;    Lithium ion batteries;    Sodium ion batteries;    Magnesium ion batteries;    Silicon;    Negative electrode;   

DOI  :  10.1016/j.jpowsour.2014.10.037

来源: Elsevier

【 摘 要 】

While Si is an effective negative electrode material for Li-ion batteries, crystalline Si has been shown to be unsuitable for Na and Mg storage due, in particular, to insufficient binding strength. It has recently been reported that Si nanowires could be synthesized with high-concentration (several atomic %) and dispersed Al doping. Here we show based on density functional theory calculations that Al doping significantly improves the energetics for Na and Mg insertion, specifically, making it thermodynamically favored versus vacuum reference states. For high Al concentrations, the energy of Mg in Al-doped Si approaches the cohesive energy of Mg. However, the migration barriers for the diffusion of Li (0.57-0.70 eV), Na (1.07-1.19 eV) and Mg (0.97-1.18 eV) in Al-doped Si are found to remain about as high as in pure Si, likely preventing effective electrochemical sodiation and magnesiation. (C) 2014 Elsevier B.V. All rights reserved.

【 授权许可】

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