Reduced graphene oxide (RGO)-SnO_x (x=0,1,2) nanocomposite as high performance anode material for lithium-ion batteries

Although, metal oxide-graphene nanocomposites and their applications in Li ion battery is a subject of intense investigation over the years, the synthesis of the composite that often needs high temperature processing along with expensive equipment are the major issues to overcome. We demonstrate a facile, low cost and room temperature synthesis of SnO_X (x = 0,1,2) - reduced graphene oxide (RGO) nanocomposite where concurrent formation of SnO₂, reduction of SnO₂ to SnO_x nanoparticles and graphene oxide to reduced graphene oxide takes place in one pot in-situ chemical reduction process. Concentration of the reducing agent (NaBH₄, 0 mol–0.06 mol) is varied to examine the effect on the formation of the nanocomposite as well as their electrochemical performance. The RGO-SnO_x nanocomposite prepared by using 0.04 mol of reducing agent reveal better Li storage performance, stable capacitance (833 mAh g⁻¹ after 50 cycles, 767 mAh g⁻¹ after 100 cycles, current rate = 100 mA g⁻¹), and good rate capability (481 mAh g⁻¹ at ∼1 A g⁻¹). The lithium ion diffusion coefficient of RGO-SnO_x (0.04 mol) nanocomposite is estimated as 2.4 × 10⁻¹⁰ m²s⁻¹ that is one/two order higher than other RGO-SnO_x nanocomposites which promotes the Li ion transport in the composite. The synthesis procedure has a strong potential to be one of the universal method for the preparation of a variety of composites by the suitable variant in the synthesis protocol.