Preparation and Li-storage properties of SnSb/graphene hybrid nanostructure by a facile one-step solvothermal route

A SnSb nanocrystal/graphene hybrid nanocomposite was synthesized by a facile one-step solvothermal route using graphite oxide, SnCl2.2H2O and SbCl3 as the starting materials, absolute ethanol as the solvent, and NaBH4 as the reductant. The formation of SnSb alloy and the reduction of the graphene oxide occur simultaneously. SnSb nanoparticles with a size of 30–40 nm were uniformly anchored and confined by the graphene sheets, forming a unique SnSb/graphene hybrid nanostructure. The electrostatic attraction between the positively charged ions (Sn2+ and Sb3+) and the negatively charged graphene oxide plays an important role in the uniform distribution of the SnSb particles on the graphene sheets. The electrochemical Li-storage properties of the nanocomposite were investigated as a potential high-capacity anode material for Li-ion batteries. The results show that the nanocomposite exhibits an obvious enhanced Li-storage performance compared with bare SnSb. The improvement of the electrochemical performance could be attributed to the formation of two-dimensional conductive networks, homogeneous dispersion and confinement of SnSb nanoparticles and the enhanced wetting of active material with the electrolyte for increased specific surface area by the introduction of graphene into SnSb nanoparticles. Li-ion chemical diffusion coefficient and ac impedance were measured to understand the underlying mechanism for the improved electrochemical performance.