Comparison of Co3O4 and CoO Nanoparticles as Anodes for Lithium-ion Batteries

Abstract

The development of portable electronic devices demands improvements in rechargeable batteries that will lead to high energy and power density, low cost and long cycle life.Among of the available kinds of batteries, lithium-ion batteries have attracted extensive attention because of their high energy density.Because the graphite anodes conventionally used in commercial lithium-ion batteries have a limited specific capacity (372mAh g -1 ), other anode materials are being investigated, e.g.transition metal oxides which have much higher specific capacity.Cobalt based oxide materials have attracted significant attention due to their high theoretical capacity (890mAh g -1 ) and good capacity retention [1,2].While the electrochemical performance of Co 3 O 4 and CoO has been widely studied, the reaction mechanisms that occur during lithiation in these materials remain unclear.Early studies suggested that the lithiation of Co 3 O 4 is a two-step reaction (first proceeding by intercalation then by conversion), other studies have shown that decomposition occurs at the initiation of the process [3].Because Co 3 O 4 and CoO have both different cycling performance and different crystal structures, an understanding of their reaction mechanisms and kinetics and the relation of these to their structures is of fundamental interest.