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Insights into the reversibility of aluminum graphite batteries

Elia, Giuseppe Antonio; Hasa, Ivana; Greco, Giorgia; Diemant, Thomas; Marquardt, Krystan; Hoeppner, Katrin; Behm, R. Jürgen; Hoell, Armin; Passerini, Stefano; Hahn, Robert

Herein we report a novel study on the reaction mechanism of non-aqueous aluminum/graphite cell chemistry employing 1-ethyl-3-methylimidazolium chloride:aluminum trichloride (EMIMCl:AlCl3) as the electrolyte. This work highlights new insights into the reversibility of the anion intercalation chemistry besides confirming its outstanding cycle life exceeding 2000 cycles, corresponding to more than 5 months of cycling test. The reaction mechanism, involving the intercalation of AlCl4− in graphite, has been fully characterized by means of ex situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure spectroscopy (XANES) and small-angle X-ray scattering (SAXS), evidencing the accumulation of anionic species into the cathode as the main factor responsible for the slight initial irreversibility of the electrochemical process.
Published in: Journal of Materials Chemistry A, 10.1039/c7ta01018d, Royal Society of Chemistry (RSC)