SnO2@C core-shell spheres: synthesis, characterization, and performance in reversible Li-ion storage

The nanostructured SnO2@C spheres with tin oxide cores and carbon shells were prepared by a facile onepot solvothermal method followed by a subsequent calcination at 600 C in a high-purity nitrogen atmosphere. The resulting samples were characterized with thermogravimetric analysis (TGA), X-ray diffraction (XRD), energydispersive spectroscopy (EDS), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and charge-discharge test. Electrochemical performance test showed that these SnO2@C core-shell spheres exhibited an initial discharge specific capacity of 667.4 mAh/g in the potential range of 1.2–0.01 V. After 18 cycles, the capacity of the SnO2@C core-shell spheres anode stabilized reversibly at about 370 mAh/g. This improved cycling performance could be attributed to the carbon shells, which can enhance the conductivity of SnO2 and suppress the aggregation of active particles to increase their structure stability during cycling. These SnO2@C core-shell spheres are promising anodes for lithium ion batteries. This study provides a facile way to improve the cycle ability of transition oxides for reversible lithium-ion storage.