Elia, G.A.; Hasa, I.; Greco, G.; Diemant, T.; Marquardt, K.; Hoeppner, K.; Behm, R.J.; Hoell, A.; Passerini, S.; Hahn, R.: Insights into the reversibility of aluminum graphite batteries. Journal of Materials Chemistry A 5 (2017), p. 9682-9690
10.1039/c7ta01018d
Open Accesn Version

Abstract:
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.