Synthesis of porous CoO nanorods @ N-doped carbon as high-performance lithium ion battery anode

Abstract

Construction of porous-structure and carbon coated transition metal oxides is essential for their use as lithium ion battery anodes. In this study, CoO nanorods @ N-doped carbon have been prepared via a synchronous carbonization/reduction of Co3O4 nanorods @ polypyrrole composite. XRD patterns suggest the pure-phase CoO can be obtained when the added amount of pyrrole reaches an amount of 180 μL. SEM and TEM images show CoO with surface carbon layer can well inherit the porous nanorod structure of Co3O4 template, and partial nitrogen is doped into carbon backbone. As lithium ion battery anode, the optimal sample obtained at a pyrrole content of 270 μL can deliver an initial discharge capacity of 923.9 mAh g-1 with high Coulombic efficiency of 75.6% at 200 mAg-1, and a capacity value of 841.6 mAh g-1 can be kept after 100 cycles. Even at a high rate of 1000 mAg-1, a stable discharge capacity of 570 mAh g-1 can also be reached. These promising electrochemical performances may be attributed to the synergistic effect of porous structure and carbon coating.