First-principles study on oxygen reduction reaction over La_1-xSr_xCoO_3-δ

Understanding the electrode kinetics in solid oxide fuel cells is important to realize the highly efficient system. Doped lanthanum cobaltite and its derivatives are used as cathode materials in solid oxide fuel cell. As results of considerable number of studies, it is generally accepted that the dissociative adsorption of oxygen at the cathode surface is one of the rate-determining steps. Toward the rational design of cathode materials, we discuss how the electronic structure affects the surface kinetics of doped cobaltite in this study. We focus on La_0.5Sr_0.5CoO_3-δ (LSC) as cathode material and discuss the properties (001) surface with LaO termination based on density functional theory method. We investigated the oxygen adsorption energy and vacancy formation energy by changing the spin states of Co in LSC. The calculated properties are discussed in the context of the kinetic process of oxygen reduction at LSC surface together with future perspectives.