Monodisperse SnO2/Co3O4 nanocubes synthesized via phase separation and their advantages in electrochemical Li-ion storage

Monodisperse SnO2/Co3O4 nanocubes are designed and prepared via a thermally induced phase separation. X-ray diffraction measurement reveals that the composite is composed of SnO2 and Co3O4 phases. Scanning electron microscopy and transmission electron microscopy bring insight into the morphology of the nanocubes, which have a size of 100–200 nm and consist of tightly contacted SnO2 and Co3O4 grains with a size of 20–30 nm. X-ray photoelectron spectroscopy indicates that the SnO2 and Co3O4 are chemically bound with each other. Comparative study in electrochemical properties is implemented among the SnO2/Co3O4 nanocubes, pure SnO2, Co3O4, and physical mixture of SnO2 and Co3O4. Electrochemical characterizations suggest that the SnO2/Co3O4 nanocomposite has remarkably enhanced electrochemical reversibility, cycling stability, rate capability, and faster charge-transfer than the others. The results highlight the synergistic effect derived from the Sn–Co binding in electrochemical Li-ion storage. In addition, the phase separation method is considered as an effective way to produce heterojunctions within binary or ternary composites.