One-pot synthesis of SnO2/reduced graphene oxide nanocomposite in ionic liquid-based solution and its application for lithium ion batteries

A facile and low-temperature method is developed for SnO2/graphene composite which involves an ultrasonic-assistant oxidation–reduction reaction between Sn2+ and graphene oxide in a choline chloride–ethylene glycol based ionic liquid under ambient conditions. The reaction solution is non-corrosive and environmental-friendly. Moreover, the proposed technique does not require complicated infrastructures and heat treatment. The SnO2/graphene composite consists of about 4 nm sized SnO2 nanoparticles with cassiterite structure mono-dispersed on the surface of reduced graphene oxide. As anode for lithium-ion batteries, the SnO2/graphene composite shows a satisfying cycling stability (535 mAh g−1 after 50 cycles @100 mA g−1), which is significantly prior to the bare 4 nm sized SnO2 nanocrsytals. The graphene sheets in the hybrid nanostructure could provide a segmentation effect to alleviate the volume expansion of the SnO2 and restrain the small and active Sn-based particles aggregating into larger and inactive clusters during cycling.