Monodispersed hierarchical Co 3 O 4 spheres intertwined with carbon nanotubes for use as anode materials in sodium-ion batteries

Monodispersed hierarchical Co3O4 spheres with a uniform particle size distribution were intertwined with carbon nanotubes to form a (Co3O4@CNTs) composite. The composite shows excellent cycling and rate performance with a capacity of up to 230 and 184 mA h g−1 at currents of 1600 and 3200 mA g−1, respectively, which is likely attributed to the formation of mixed conducting networks of both Na+ ions and electrons.