Tuning lithium storage properties of cubic Co3O4 crystallites: The effect of oxygen vacancies

Transition metal oxides show unique physical and chemical properties, and thus have a wide range of applications, including the electrodes for batteries, supercapacitors, and catalysts. However, poor electrical conductivity of the metal oxides hinder the above applications. In this work, we report a facile method to generate oxygen vacancies in cubic Co3O4 particles by thermal annealing in Ar atmosphere. By carefully controlling annealing condition, the oxygen vacancies can be well modulated while the formation of any other phases is avoided. The microstructure and chemical composition of the Co3O4 particles are studied by different methods. Lithium storage measurements show that the Co3O4 anodes with optimized oxygen vacancies (Co3O4-250) show a specific capacity of 904.2 mAhg(-1) at a current density of 0.1 Ag-1, and charge/discharge rate capability of 530.5 mAhg(-1) at 5.0 Ag-1. Well controlled oxygen vacancies together with sub-micrometer scale morphology in the annealed Co3O4 electrodes are responsible for the enhanced lithium storage properties. The current oxygen vacancy modulation strategy can also be used for other energy related applications, such as sodium ion batteries and electrocatalysts, with improved performance. (C) 2019 Elsevier B.V. All rights reserved.