Hierarchical Co₃O₄@multiwalled carbon nanotube nanocable filmswith superior cyclability and high lithium storage capacity

Hierarchical Co₃O₄@multiwalled carbon nanotube (MWCNT) nanocable films are deposited on cop-per foils via a facile one-step electrophoretic deposition (EPD) from MWCNT suspension containing Co(NO ₃)₂·6H₂O and the subsequent heat treatment. The obtained films show network morphologies, withmicro-/mesoporous Co₃O₄sheath uniformly coated on the interconnected MWCNT core. By varying themass ratios of Co(NO₃)₂·6H ₂O to MWCNTs in the suspension, a series of nanocable films are obtained withdifferent Co₃O₄sheath thickness, morphology, and mass content. Among them, the Co₃O₄@MWCNT-4nanocable film, with a high surface area of 156 m² g^-1 and optimally hierarchical pore size distribution,proves to be a qualified candidate anode for lithium-ion batteries. The reversible capacity can reach ashigh as 1109 mAh g^-1 at a relatively high current of 0.2 C (1 C = 890 mA g ^-1). At a higher current of 1 C, thereversible capacity can retain as high as 860 mAh g^-1 and shows no obvious decay after 250 cycles.