Flower-like Co3O4 As an Anode Material for High Performance Li-Ion Batteries

The development of anode material with high specific capacity is the key issue in present   lithium ion batteries (LIBs) technology. Recently, transition metal oxides have attracted much attention as an anode material for LIBs due to its high theoretical capacity (~700 mA h/g), long cycle life and high rate performances. Among various metal oxides, cobalt oxide (Co₃O₄) has been intensively investigated as a promising anode material for LIBs owing to its high theoretical capacity (890 mAh g^-1), which is nearly two times higher than that delivered by conventional carbonaceous anodes. However, Co₃O₄ can suffer from poor cyclability and low rate capability, due to a large volume change and serious aggregation during charge/discharge cycling. Different proposals have been suggested to address this issue based on the tailored morphology, formation of nanocomposites with conductive additives and nano-size fabrication of Co₃O₄ electrode materials. In addition, various Co₃O₄ materials including nanotubes, nanorods, nanoneedles, nanospheres, platelets and nanowires have been synthesized and showed significantly improved lithium ion storage properties compared to their bulk counterparts. In this study, the electrochemical properties of flower-like Co₃O₄ synthesized by simple urea-assisted chemical co-precipitation strategy with porous structure were investigated.

A facile urea-assisted template free, surfactant less chemical co-precipitation method and subsequent calcination (400-600 ^oC) for 2 h was pursued to obtain pure cobalt oxide (Co₃O₄) sample. The synthesized sample exhibited the cubic spinel structure and flower-like morphology. The obtained morphology is assembled by nanorods rising from common center, and the nanorods were comprised of interconnected particles with porous structure. The changes in the surface area and porosity of the flower like structure have been induced by manipulating the calcination temperature, resulting in significant impact on the electrochemical properties. Electrochemical investigation showed that the flower-like Co₃O₄ exhibited excellent cycling stability (1452 mA h g^-1 at 0.5 C up to 300 cycles) and superior rate capability (reversible specific capacity of 880 mA h g^-1 at 10 C). The obtained flower-like Co₃O₄ materials showed excellent cycle life and high rate capability, making it promising for applications in high-power LIBs.