Li+ adsorption at prismatic graphite surfaces enhances interlayer cohesion

JOURNAL OF POWER SOURCES

卷:239

Article

Pastewka, Lars^1,2  Maiola, Sami³  Moseler, Michael^1,4,5  Koskinen, Pekka³ 

[1] Fraunhofer Inst Werkstoffmech IWM, D-79108 Freiburg, Germany

[2] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA

[3] Univ Jyvaskyla, NanoSci Ctr, Dept Phys, Jyvaskyla 40014, Finland

[4] Univ Freiburg, Freiburger Mat Forschungszentrum, D-79104 Freiburg, Germany

[5] Univ Freiburg, Inst Phys, D-79104 Freiburg, Germany

关键词: Graphite;    Lithium;    Surface chemistry;    Exfoliation;    Anode;    Density-functional calculation;   

DOI  :  10.1016/j.jpowsour.2013.03.110

来源: Elsevier

【 摘 要 】

We use density functional calculations to determine the binding sites and binding energies of Li+ at graphene edges and prismatic graphite surfaces. Binding is favorable at bare and carbonyl terminated surfaces, but not favorable at hydrogen terminated surfaces. These findings have implications for the exfoliation of graphitic anodes in lithium-ion batteries that happens if solute and solvent co-intercalate. First, specific adsorption facilitates desolvation of Li+. Second, chemisorption lowers the surface energy by about 1 J m(-2) prismatic surface area, and gives graphite additional stability against exfoliation. The results offer an explanation for experiments that consistently show exfoliation for hydrogenated graphite, but show no exfoliation for oxygenated graphite. (C) 2013 Elsevier B.V. All rights reserved.

【 授权许可】

Free