Intergrown SnO₂–TiO₂@graphene ternary composite as high-performance lithium-ion battery anodes

In recent years, a lot of metal oxides with high theoretical capacity have widely investigated as the high-performance anode materials for lithium-ion batteries (LIBs). In this work, a simple, facile and effective one-pot hydrothermal strategy toward ternary SnO₂–TiO₂@graphene composite has been developed by using SnCl₂ and TiOSO₄ as the starting materials. The obtained composite demonstrates a unique structure and high surface areas, in which both SnO₂ and TiO₂ nanoparticles are well grown on the surface of graphene. More interestingly, the SnO₂ and TiO₂ nanoparticles are intergrowth together, totally different with the traditional ternary hybrids. When used as anode material for LIBs, the introduction of TiO₂ plays a crucial role in maintaining the structural stability of the electrode during Li⁺ insertion/extraction, which can effectively prevent the aggregation of SnO₂ nanoparticles. The electrochemical tests indicate that as-prepared SnO₂–TiO₂@graphene composite exhibits a high capacity of 1276 mA h g⁻¹ after 200 cycles at the current density of 200 mA g⁻¹. Furthermore, the composite also maintains the specific capacity of 611 mA h g⁻¹ at an ultrahigh current density of 2000 mA g⁻¹, which is superior to those of the reported SnO₂ and SnO₂/graphene hybrids. Accordingly, the remarkable electrochemical performance of ternary SnO₂–TiO₂@graphene composites is mainly attributed to their unique nanostructure, high surface areas, and the synergistic effect not only between graphene and metal oxides but also between the intergrown SnO₂ and TiO₂ nanoparticles.

Intergrown SnO₂ and TiO₂ nanoparticles have been successfully anchored onto the graphene nanosheets as high-performance lithium-ion battery anodes.