FeCl3 intercalated few-layer graphene for high lithium-ion storage performance

Abstract

We report a facile and efficient approach to prepare graphene and FeCl₃-intercalated few-layer graphene (FeCl₃-FLG) with stage 1 FeCl₃-graphite intercalation compounds (GICs) as a precursor by a non-oxidation process. The enlarged interlayer spacing by the intercalation of FeCl₃ greatly weakens the interaction among graphite sheets and thus facilitates the exfoliation of FeCl₃-GICs. By ultrasonic treatment, FeCl₃-GICs are well exfoliated to graphene sheets (<2 nm) with a high yield of 100%, while the ultrasonication of pristine graphite is less efficient with a low yield (about 32%) of graphene sheets. By simply controlling the sonication time, FeCl₃-FLG consisting of graphene sheets and sandwiched FeCl₃ is also prepared, which exhibits a high capacity of 989 mA h g⁻¹ after 50 cycles, fairly higher than that of the sonicated graphite (503 mA h g⁻¹) and the theoretical value of graphite (372 mA h g⁻¹). Furthermore, FeCl₃-FLG still retains a reversible capacity as high as 539 mA h g⁻¹ even at a current density of 1000 mA g⁻¹. Therefore, the high reversible capacity, remarkable cycling stability and superior capability make FeCl₃-FLG promising as anode materials for large-scale and high-capacity lithium ion batteries.