The over-lithiated-oxides (OLOs) are a composite of layered structures of Li2MnO3 and LiMO2 (M = Mn, Fe, Co, Ni), and shown to have much higher storage capacity than traditional layered oxides as Li ion battery cathode, due to the presence of Li2MnO3 phase. However, experimental results indicate Li2MnO3 is not stable after the 1st charge-discharge cycle and would partly transform into layered LiMnO2, which would form a practically used phase as a mixture of both Li2MnO3 and LiMnO2. Experimentally, the effective dopants which would satisfy multiple cathode materials requirement of thermodynamic stability, optimized voltage, and improve kinetics based on ionic and electronic conductivities are under research. We therefore conduct the present DFT simulation work in order to provide such conceptual guidance. In the present work, redox potential, lithium ion diffusion behaviors of both phases are looked into details and we also reveal the electronic conduction mechanism in both phases, based on which influences of 10 cationic (Mg, Ti, V, Nb, Fe, Ru, Co, Ni, Cu, Al) and 2 anionic (N, F) dopants on the redox potential, ionic and electric conductivity are discussed. This work was supported by Samsung GRO project.

Ab initio study of doping effects on LiMnO2 and Li2MnO3 in OLO cathode for Li ion batteries

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.