Microwave-assisted hydrothermal synthesis of SnO₂/reduced graphene-oxide nanocomposite as anode material for high performance lithium-ion batteries

Surfactant and organic solvents free SnO₂ nanospheres and SnO₂/reduced graphene oxide (SnO₂/rGO) nanocomposite were prepared by microwave assisted hydrothermal method. X-ray diffraction (XRD) and Raman spectroscopy results confirm the formation of pure nanocrystalline rutile phase of SnO₂ and nanostructured rutile phase of SnO₂ over the amorphous structured rGO. FE-SEM, EDX and HR-TEM results showed the formation of spherical shape SnO₂ nanoparticles and the formation of spherical shape SnO₂ nanoparticles over the crumpled nanosheets like morphology of rGO. The electrochemical measurements of lithium-ion batteries fabricated using pure spherical shape SnO₂ nanoparticles and crumpled nanosheets like morphology of SnO₂/rGO nanocomposite as an anode material showed the good initial discharge–charge capacity of 2128 and 1718 mA h g⁻¹ respectively. The capacity retention after 50 cycles is found to be 349 mAh g⁻¹ at a current density of 500 mA g⁻¹ for the lithium-ion battery fabricated using pure spherical shape SnO₂ nanoparticles and the capacity retention after 300 cycles is found to be 318 mAh g⁻¹ at a current density of 500 mA g⁻¹ for the lithium-ion battery fabricated using SnO₂/rGO nanocomposite, which is much better than the reported values. The observed better electrochemical performance of the lithium-ion battery is attributed to the formation of spherical shape SnO₂ nanoparticles over the crumpled nanosheets like morphology of highly porous graphene and also increased electronic conductivity of SnO₂/rGO nanocomposite. Hence, the crumpled nanosheets like morphology of highly porous of SnO₂/rGO nanocomposite prepared by microwave hydrothermal method can be a high-performance anode material for a lithium-ion battery application.