Lithium-rich complex transition-metal oxides Li2MoO3, Li2RuO3, Li3RuO4, Li3NbO4, Li5FeO4, Li5MnO4 and their derivatives are of interest for high-capacity battery electrodes. Here, we report a first-principles density-functional theory study of the atomic and electronic structure of these materials using the Heyd-Scuseria-Ernzerhof (HSE) screened hybrid functional which treats all orbitals in the materials on equal footing. Dimerization of the transition-metal ions is found to occur in layered Li2MoO3, in both fully lithiated and partially delithiated compounds. The Ru--Ru dimerization does not occur in fully lithiated Li2RuO3, in contrast to what is commonly believed; Ru--Ru dimers are, however, found to occur in the presence of lithium vacancies caused by lithium loss during synthesis and/or lithium removal during use. We also analyze the electronic structure of the complex oxides and discuss the delithiation mechanism in these battery electrode materials.
@article{arxiv.1810.02039,
title = {Electronic structure and properties of lithium-rich complex oxides},
author = {Khang Hoang and Myungkeun Oh and Yongki Choi},
journal= {arXiv preprint arXiv:1810.02039},
year = {2019}
}