Optimization of SnO2 Nanoparticles Confined in a Carbon Matrix towards Applications as High-Capacity Anodes in Sodium-Ion Batteries

SnO2/carbon composites including amorphous carbon and graphene or carbon nanotubes are synthesized by a gas-liquid interfacial approach and subsequent annealing process. The effect of the carbon source and the conductive additive on the electrochemical performance is investigated by galvanostatic charge-discharge tests. SnO2@Glucose/Graphene (SnO2@Glu/G) composites as anodes of sodium-ion batteries show the best electrochemical performance, delivering 306 mA h g(-1) after 100 cycles at 0.1 A g(-1) between 0.01-3V, while exhibiting 278 and 226 mA h g(-1) at 1 and 2 A g(-1), respectively. The mechanism of improved electrochemical performance for graphene is researched in detail. The results reveal a porous structure with fine SnO2 particles due to the introduction of graphene oxide, and an effective electron charge transfer network from the graphene increases its reversible capacity, rate performance and cycling performance.