Controllable synthesis of rod-like SnO2 nanoparticles with tunable length anchored onto graphene nanosheets for improved lithium storage capability

Abstract

In our work, rod-like SnO₂ nanoparticles with tunable length have been successfully anchored onto graphene nanosheets through a simple and in situ hydrothermal strategy under acidic conditions. The SEM and TEM images demonstrate that the unique rod-like SnO₂ nanoparticles with a diameter of 10–15 nm and length of 18–34 nm are uniformly anchored onto the surface of graphene nanosheets. Moreover, the particle sizes of rod-like SnO₂ nanoparticles can be readily adjusted by simply varying the reaction temperature. Interestingly, with the increase of reaction temperature from 120 to 160 °C, the rod length of SnO₂ nanoparticles significantly increased. More importantly, the SnO₂@graphene products exhibit a very high specific surface area, which played a key role in maintaining the structural stability against the irreversible volume change during Li⁺ insertion/extraction. The nanocomposites show an extremely high lithium storage capability and an excellent cycling performance. The initial discharge capacities are 1284 mA h g⁻¹ at current densities of 200 mA g⁻¹. After 100 cycles, the discharge capacity still remains as high as 981 mA h g⁻¹, indicating a superior retention capacity.