Facet-Dependent Electrocatalytic Performance of Co 3 O 4 for Rechargeable Li–O 2 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 Co 3 O 4 cubes with exposed (001) plane and octahedrons with exposed (111) plane have been successfully synthesized and the facet-dependent electrocatalytic performance of Co 3 O 4 for rechargeable Li–O 2 battery has been comprehensively investigated by the combination of experiments and theoretical calculations. The Li–O 2 battery cathode catalyzed by Co 3 O 4 octahedron with exposed (111) plane shows much higher specific capacity, cycling performance, and rate capability than Co 3 O 4 cube with exposed (001) plane, which may be largely attributed to the richer Co 2+ and more active sites on (111) plane of Co 3 O 4 octahedrons. The DFT-based first-principles calculations further indicate that Co 3 O 4 (111) has a lower activation barrier of O 2 desorption in oxygen evolution reaction (OER) than Co 3 O 4 (001), which is very important to refresh active sites of catalyst and generate a better cyclic performance. Also, our calculations indicate that Co 3 O 4 (111) surface has a stronger absorption ability for Li 2 O 2 than Co 3 O 4 (001), which may be an explanation for a larger initial capacity in Co 3 O 4 (111) plane by experimental observation.