Understanding the role of Li in strongly correlated cathode material LiMnO₂: Density functional and dynamical mean-field theory calculations

Layered lithium intercalating transition metal (TM) oxides are promising cathode materials for Li-ion batteries. LiNiO₂ doped with Co, LiNi_1-xCo_xO₂, are widely used as cathode materials for rechargeable lithium-ion batteries. However, the high cost and the potential toxicity of Co make it imperative to search for alternative cathode materials. In this regard, LiMnO₂, equivalent in a chemical formula to LiCoO₂, has drawn much attention because of the lower cost and the more environmentally benign nature of Mn as opposed to Co. In this talk, combining density functional theory with dynamical mean-field theory (DFT+DMFT), we will discuss the electronic structure properties of strongly correlated LiMnO₂ at different delithiation levels, specifically in their paramagnetic state. Interestingly, an insulating solution with an energy gap value was obtained in agreement with experimental data. We will also discuss the role of Li-2s in understanding the hidden correlation effects in these materials. In order to understand the role of Li to apprehend the strong correlation in LiMnO₂, we apply the crystal orbital Hamilton population method where chemical bond analysis dissects the effects of Li in LiMnO₂. Coupling between Mn-3d and Li-2s orbital hybridization will also be discussed.