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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
Created on: 23.5.2014


Journal of power sources 239 (2013), pp.321-325
ISSN: 0378-7753
European Commission EC
FP7-INFRASTRUCTURES; 228398; HPC-EUROPA2
Bundesministerium für Bildung und Forschung BMBF
03SF0343G
Bundesministerium für Bildung und Forschung BMBF
13N10597
English
Journal Article, Electronic Publication
Fraunhofer IWM ()
graphite; lithium; surface chemistry; exfoliation; anode; density-functional calculation

Abstract
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.

: http://publica.fraunhofer.de/documents/N-254936.html