Facet-Dependent Electrocatalytic Performance of Co3O4 for Rechargeable Li–O2 Battery

The facet-dependent performance has aroused great interest in the fields of catalyst, lithium ion battery and electrochemical sensor. In this study, the well-defined Co3O4 cubes with exposed (001) plane and octahedrons with exposed (111) plane have been successfully synthesized and the facet-dependent electrocatalytic performance of Co3O4 for rechargeable Li–O2 battery has been comprehensively investigated by the combination of experiments and theoretical calculations. The Li–O2 battery cathode catalyzed by Co3O4 octahedron with exposed (111) plane shows much higher specific capacity, cycling performance, and rate capability than Co3O4 cube with exposed (001) plane, which may be largely attributed to the richer Co2+ and more active sites on (111) plane of Co3O4 octahedrons. The DFT-based first-principles calculations further indicate that Co3O4 (111) has a lower activation barrier of O2 desorption in oxygen evolution reaction (OER) than Co3O4 (001), which is very important to refresh active sites of catalyst and generate a better cyclic performance. Also, our calculations indicate that Co3O4 (111) surface has a stronger absorption ability for Li2O2 than Co3O4 (001), which may be an explanation for a larger initial capacity in Co3O4 (111) plane by experimental observation.