Microwave synthesis of SnO₂nanocrystals decorated on the layer-by-layer reduced graphene oxide for an application into lithium ion battery anode

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-SnO₂nano-composite (G-SnO₂), where the SnO₂nanoparticles 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 SnO₂nanoparticles 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-SnO₂anodes show 1200 mAh g⁻¹at 50 mA g⁻¹and their specific capacity is preserved up to 1000 mAh g⁻¹during the 100 cycles. The coulombic efficiency keeps 97% after the 1st cycle and the high specific capacity of 747 mAh g⁻¹is maintained with 66.3% of capacity retention even when the current density increases from 50 mA g⁻¹to 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 SnO₂nanoparticles are deposited on the restacking inhibited rGO nanosheets.