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Issue 63, 2016
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Stabilization of alkali metal ions interaction with OH-functionalized graphene via clustering of OH groups – implications in charge storage applications

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Abstract

Graphene synthesized by reduction of graphene oxide, depending on the degree of reduction, retains a certain amount of surface OH groups. Considering the surface OH groups/graphene layer system by means of density functional theory calculations, we evidenced the tendency of OH groups to cluster, resulting in enhanced system stability and no band gap opening. In the oxygen concentration range between 1.8 and 8.47 at%, with the addition of each new OH group, integral binding energy decreases, while differential binding energy shows the boost at even numbers of OH groups. Furthermore, we found that the clustering of OH groups over graphene basal plane plays a crucial role in enhancing the interactions with alkali metals. Namely, if alkali metal atoms interact with individual OH groups only, the interaction leads to an irreversible formation of MOH phase. When alkali atoms interact with clusters containing odd number of OH groups, a reversible transfer of an electron charge from the metal atom to the substrate takes place without OH removal. The strength of the interaction in general increases from Li to K. In an experimental investigation of a graphene sample which dominantly contains OH groups, we have shown that the trend in the specific interaction strength reflects to gravimetric capacitances measured in alkali metal chloride solutions. We propose that the charge stored in OH groups which interact with alkali metal cation and the π electronic system of the graphene basal plane presents the main part of its pseudocapacitance.

Graphical abstract: Stabilization of alkali metal ions interaction with OH-functionalized graphene via clustering of OH groups – implications in charge storage applications

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Publication details

The article was received on 24 May 2016, accepted on 09 Jun 2016 and first published on 10 Jun 2016


Article type: Paper
DOI: 10.1039/C6RA13509A
Citation: RSC Adv., 2016,6, 57910-57919
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    Stabilization of alkali metal ions interaction with OH-functionalized graphene via clustering of OH groups – implications in charge storage applications

    A. S. Dobrota, S. Gutić, A. Kalijadis, M. Baljozović, S. V. Mentus, N. V. Skorodumova and I. A. Pašti, RSC Adv., 2016, 6, 57910
    DOI: 10.1039/C6RA13509A

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