SnO2 is an attractive material due to high theoretical capacity (for both LIBs and NIBs), low cost, abundance and ease of synthesis. But there are many drawbacks that need to be overcome for SnO2 to be applied to actual batteries. Various technical issues include the large volume expansion during discharge/charge process in batteries, the formation of unstable solid electrolyte interface (SEI), and the aggregation of Sn particles during battery operation, all of which can lead to the rapid capacity fading of batteries.
In this work, ultra-fine SnO2 nanoparticles dispersed within unique 3D-graphene structure (SnO2/3D GS) were synthesized by easy and simple hydrothermal process. These 3D-graphene structure could accommodate large volume change, prevent aggregation of Sn, and provide much facile electron transfer during battery operation. The SnO2/3D GS material exhibited outstanding electrochemical performances as anodes for both LIBs and NIBs. The structure-property-performance relation was investigated by various methods including SEM, TEM, EIS, CV, and XRD. The focus was on comparative studies of the internal resistance and diffusivity of Li-ions and Na-ions in SnO2/3D GS composites. Furthermore, the direct conversion from SnO2 to amorphous Sn during discharge/charge of 1st cycle in LIBs and NIBs was monitored by in-situ XRD.