| Abstract Scope |
Room-temperature oxygen transport is believed to be negligible in lithium-ion battery electrode materials such as lithium transition-metal layered oxides. However, the short diffusion lengths (typically sub-microns) and long time (typically years) make oxygen transport an important consideration in the functionality of lithium-ion/electron mixed conductors. In this talk, I will discuss the thermodynamic and kinetic underpinnings of oxygen transport in layered oxides. Specifically, we consider the relationship between the lithium chemical potential and the oxygen chemical potential, which makes the thermodynamic activity of oxygen explicitly dependent on the electrical potential. In addition, we also discuss the interaction between oxygen defects and cation defects, namely the Schottky defect pairs. These defect interactions have substantial implications for disordering of the layered structure. Finally, we discuss the kinetics of oxygen transport at the nanoscale at room temperature far from equilibrium. Overall, oxygen defects are critical participants in the lithiation and delithiation of layered oxides must be carefully considered (and controlled) in applications such as lithium-ion batteries. |