Tetrafluoroborate Anion Intercalation into Graphite Electrode from Sulfolane

Electrolyte solutions of lithium tetrafluoroborate dissolved in sulfolane are applied in dual-ion batteries. A graphite positive electrode in this kind of solutions delivers a reversible anion storage capacity over 80 mAh g−1 at potentials over 4.5 V vs. Li/Li+. The structures of anion-graphite intercalation compounds are investigated in detail by the combination of in situ X-ray diffraction (XRD) and in situ Raman spectroscopic measurements.