Origin of surface segregation in LiCoO2: A DFT+U study

A Boev, M Arsentev, S Fedotov, A Abakumov, D Aksyonov


To explain the behavior of commercially important doping elements, such as Mg, Al, Ti, V, Cr, Mn, Fe, and Ni, we performed a DFT study of their segregation at the (104) low-energy surface of LiCoO2. By careful control of local oxidation states and magnetic moments of surface atoms, we find their most stable configurations. We discover that all elements, except Al and Cr, are prone to segregation that is primarily driven by the surface energies' difference between the host and solute lattices, which is explained through crystal-field stabilization energies. An additional contribution to segregation is caused by the elastic energy penalty to the ionic size mismatch effect. Finally, we rationalize the available experimental results and provide several predictions of highly segregating and nonsegregating dopants.

segregation surf en diff