Microwave synthesis of SnO2 nanocrystals decorated on the layer-by-layer reduced graphene oxide for an application into lithium ion battery anode

Abstract

We demonstrate the microwave synthesis of tin oxide (SnO2) nanoparticles and direct deposition on the surface of restacking inhibited reduced graphene oxide (rGO) nanosheets for an application into lithium ion battery anodes. The mesoporous rGO-SnO2 nano-composite (G-SnO2), where the SnO2 nanoparticles are intercalated in the layer-by-layer structure of the restacking rGO nanosheets, can be synthesized within 10 min by microwave irradiation, simultaneously promoting the reduction of graphene oxides (GO). The size of SnO2 nanoparticles ranges from 5 to 10 nm and they are highly crystalline structure along with the change in the oxidation states from Sn2+ to Sn4+ in the process of the microwave synthesis. The G-SnO2 anodes show 1200 mAh g−1 at 50 mA g−1 and their specific capacity is preserved up to 1000 mAh g−1 during the 100 cycles. The coulombic efficiency keeps 97% after the 1st cycle and the high specific capacity of 747 mAh g−1 is maintained with 66.3% of capacity retention even when the current density increases from 50 mA g−1 to 300 mA g−1. These results indicate that the improvement of specific capacity, rate capability and cycle stability is attributed to the mesoporous layer-by-layer structure of G-SnO2, where the well-defined SnO2 nanoparticles are deposited on the restacking inhibited rGO nanosheets.