Unraveling the Catalytic Mechanism of Co3O4 for the Oxygen Evolution Reaction in a Li–O2 Battery

Abstract

Unraveling the catalytic mechanism of transition-metal oxides (TMOs) for the charging reaction in a Li–O 2 battery and characterizing their surface structures and electronic structure properties of active sites are of great importance for the development of an effective catalyst to improve low round-trip efficiency and power density. In the current study, an interfacial model is first constructed to study the decomposition reaction mechanism of Li 2 O 2 supported on Co 3 O 4 surfaces. The computational results indicate that the O-rich Co 3 O 4 (111)C with a relatively low surface energy in high O 2 concentration has a high catalytic activity in reducing overpotential and O 2 desorption barrier due to the electron transfer from the Li 2 O 2 layer to the underlying surface. Meanwhile, the basic sites of Co 3 O 4 (110)B surface induce Li 2 O 2 decomposition into Li 2 O and a dangling Co–O bond, which further leads to a high charging voltage in the subsequent cycles. The calculations for transition-metal (TM)-doped Co 3 O 4 (111) indicate that P-type doping of Co 3 O 4 (111) exhibits significant catalysis in decreasing both charging overpotential and O 2 desorption barrier. The ionization potential of doped TM is determined as an important parameter to regulate the catalytic activity of metal oxides.