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Li+ adsorption at prismatic graphite surfaces enhances interlayer cohesion

: Pastewka, L.; Malola, S.; Moseler, M.; Koskinen, P.

Preprint urn:nbn:de:0011-n-2549369 (4.4 MByte PDF)
MD5 Fingerprint: 97912527858090fde62c51fb09023685
Erstellt am: 23.5.2014

Journal of power sources 239 (2013), S.321-325
ISSN: 0378-7753
European Commission EC
Bundesministerium für Bildung und Forschung BMBF
Bundesministerium für Bildung und Forschung BMBF
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IWM ()
graphite; lithium; surface chemistry; exfoliation; anode; density-functional calculation

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.