Electronic structure and magnetism of Lix(Ni-Co-Mn)O2 in view of KKR-CPA calculations

The Korringa-Kohn-Rostoker method with the coherent potential approximation (KKR-CPA) has been applied to study the electronic structure of Li-x(Co-Ni-Mn)O-2 cathode material. The influence of chemical disorder, such as vacancy defects on Li and O as well as Co/Ni/Mn alloying, on electronic density of states has been analyzed focusing on the magnetic properties onset in the aforementioned materials. It is found that local magnetic moments on transition metal atoms appear in Li-x(Co-Ni-Mn)O-2 when decreasing Li content. The largest moment was calculated on Mn atom (similar to 1.5 mu(B)), while smaller magnetic moment was found on Co atoms (similar to 0.20 mu(B)). On the whole, the KKR-CPA density of states of Li-x(Co-Ni-Mn)O-2 recall either strongly doped semiconducting-like behaviour or half-metallic character in non-magnetic and magnetic states, respectively, with the band gap markedly reduced when accounting for O vacancy defects in calculations.