Facile synthesis and lithium storage performance of SnO2–Co3O4 core–shell nanoneedle arrays on copper foil

• SnO2–Co3O4 core–shell nanoneedle arrays on copper foils were synthesized by a facile method.
• The reversible capacity of SnO2–Co3O4 is higher than them of pure Co3O4 and SnO2.
• Such high performances can be attributed to the synergistic effect between Co3O4 and SnO2.

SnO2–Co3O4 core–shell nanoneedle arrays are vertically aligned on copper foil by a facile template-free method. Without using any binder, conductive carbon or other ancillary materials, SnO2–Co3O4 core–shell nanoneedle arrays on copper foil are directly used as the anodes of lithium battery. At 0.5C rate (2 h per charging cycle), their reversible capacity maintains at ∼985 mA h g−1 after 20 cycles, higher than that of bare Co3O4 nanoneedle arrays (∼813 mA h g−1) and pure SnO2 nanostructures (∼582 mA h g−1). Such a high lithium storage capacity can be attributed to the synergistic effect between nanostructured SnO2 and Co3O4. Co3O4 nanostructures with high electrochemical activity can activate the irreversible capacity of SnO2, and the nanoarray structures can provide good contact, short electron transporting paths, high surface-to-volume ratio and open space in the system. These results indicate that one-dimensional nanocomposite arrays on copper foils are good candidates for the anode of lithium ion battery.