Fluorinated Reduced Graphene Oxide as an Interlayer in Li-S Batteries

A. Vizintin (1, 2) , M. Lozinšek (3) , R.K. Chellappan (4) , Dominique Foix (5, 6, 4) , A. Krajnc (1) , G. Mali (7, 8) , G. Drazic (1) , B. Genorio (2) , Rémi Dedryvère (5, 6, 4) , R. Dominko (1)

1 KI - National Institute of Chemistry [Ljubljana]
2 University of Ljubljana
3 IJS - Jozef Stefan Institute [Ljubljana]
4 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
5 RS2E - Réseau sur le stockage électrochimique de l'énergie
6 ALISTORE-ERI - Advanced Lithium Energy Storage Systems - ALISTORE-ERI
7 National Institute of Chemistry
8 Centre of Excelence EN-FIST [Ljubljana]

We report on the synthesis of fluorinated reduced graphene oxide (F-rGO) by a direct fluorination of reduced graphene oxide (rGO) with F2 or XeF2/BF3 in anhydrous HF. Characterization performed by high-angle annular dark-field (HAADF)-scanning transmission electron microscopy (STEM) and NMR confirmed the formation of C-F bonds, which is also supported by the color change from graphite gray to light yellow. F-rGO has been used as an interlayer additive supported by a glass fiber separator in lithium-sulfur (Li-S) batteries in order to block the diffusion/migration of polysulfides from the porous positive electrode to the metallic lithium electrode and to prevent the redox shuttle effect. Electrochemical cycling of Li-S batteries has confirmed the beneficial role of F-rGO separators, with a more pronounced effect observed for high degrees of fluorination. X-ray photoelectron spectroscopy (XPS) studies have shown a direct effect on the amount of Li2S and polysulfides found on the lithium electrode and evidenced a better reversibility of reduction/oxidation mechanisms of sulfur at the positive electrode upon discharge/charge. © 2015 American Chemical Society.

Domaines: Matériaux; Autre

A. Vizintin, M. Lozinšek, R.K. Chellappan, Dominique Foix, A. Krajnc, et al.. Fluorinated Reduced Graphene Oxide as an Interlayer in Li-S Batteries. Chemistry of Materials, 2015, 27 (20), pp.7070-7081. ⟨10.1021/acs.chemmater.5b02906⟩. ⟨hal-01546715⟩