(217di) Controlling Morphology and Enhancing Electrochemical Performance of Cobalt Oxide By Addition of Graphite | AIChE

(217di) Controlling Morphology and Enhancing Electrochemical Performance of Cobalt Oxide By Addition of Graphite


Fei, L. - Presenter, New Mexico State University
Luo, H., New Mexico State University

Co3O4 has been intensively studied as battery anode materials due to its high theoretical capacity of 890 mAh/g. However, Co3O4 suffers from poor conductivity and large volume change during the insertion and extraction of Li ions. It has been well proven that introduction of carbon material to metal oxide is very helpful on improving conductivity and remaining structure stability. Among those widely studied carbon additives (e.g. graphene, carbon nanotubes/ fibers), the currently applied commercial anode material—graphite, not only possesses merits of other carbon materials like  high electronic conductivity, superior mechanical properties, excellent chemical tolerance, but also are naturally abundant.  Therefore, it is promising and economic to make Co3O4/graphite composite as anode material. This strategy combines the properties of two individual materials and avoids steps necessary for modification or preparation of other carbon-based materials. For example, the Hummer method, one of the most popular methods for the preparation of graphene, involves strong oxidant and acid, while catalysts and chemical vapor deposition are often required for making CNTs or CNFs.

Here, we synthesized Co3O4 nanowire, Co3O4 nanoparticle network, and Co3O4/graphite nanocomposite via a simple hydrothermal route and compared their electrochemical performance. We found the addition of graphite not only influenced the morphology of Co3O4, but also enhanced its electrochemical performance. In detail, the Co3O4 nanowire was formed without adding graphite; after introducing graphite, the morphology of the Co3O4 nanocomposite changed to a network through the partial overlapping of nanoparticles. When studied as anode material in lithium-ion batteries, the Co3O4/graphite nanocomposite outperforms two different pure Co3O4 samples by showing superior Li-ion battery performance with dramatically enhanced cyclic stability and excellent rate performance. Its reversible capacity remains as high as 551 mAh/g after 50th cycle at a current density of 500 mA/g while that of  the other two pure Co3O4 samples drops below 400 mAh/g.