How much does size really matter? Exploring the limits of graphene as Li ion battery anode material. (February 2017)

• Record Type: Journal Article
• Authors: Sun, H.; Varzi, A.; Pellegrini, V.; Dinh, D.A.; Raccichini, R.; Del Rio-Castillo, A.E.; Prato, M.; Colombo, M.; Cingolani, R.; Scrosati, B.; Passerini, S.; Bonaccorso, F.
• Is Part Of: Solid state communications. Volume 251(2017)
• Page Start: 88
• Page End: 93
• Publication Date: 2017-02
• Subjects: Graphene -- Liquid phase exfoliation -- Lithium ion battery -- Electrodes; Solid state chemistry -- Periodicals; Solid state physics -- Periodicals; Chimie de l'état solide -- Périodiques; Physique de l'état solide -- Périodiques; 530.41
• DOI: 10.1016/j.ssc.2016.12.016
• Languages: English
• ISSNs: 0038-1098

Abstract

Abstract: We unravel the role of flake dimensionality on the lithiation/de-lithiation processes and electrochemical performance of anodes based on few-(FLG) and multi-layer graphene (MLG) flakes prepared by liquid phase exfoliation (LPE) of pristine graphite. The flakes are sorted by lateral size (from 380 to 75 nm) and thickness from 20 (MLG) to 2 nm (FLG) exploiting a sedimentation-based separation in centrifugal field and, finally, deposited onto Cu disks for the realization of four binder-free anodes. The electrochemical results show that decreasing lateral size and thickness leads to an increase of the initial specific capacity from ≈590 to ≈1270mAhg −1 . However, an increasing irreversible capacity is also associated to the reduction of flakes' size. We find, in addition, that the preferential Li ions storage by adsorption rather than intercalation in small lateral size (<100 nm) FLG flakes has a detrimental effect on the average de-lithiation voltage, resulting on low voltage efficiency of these anodes. We believe that the results reported in this work, provide the guidelines for the practical exploitation of graphene-based electrodes. Highlights: Solution processing. Sorting. Inexpensive. Environmentally-friendly.