Visualizing lithium-ion migration pathways in battery materials.

The understanding of lithium-ion migration through the bulk crystal structure is crucial in the search for novel battery materials with improved properties for lithium-ion conduction. In this paper, procrystal calculations are introduced as a fast, intuitive way of mapping possible migration pathways, and the method is applied to a broad range of lithium-containing materials, including the well-known battery cathode materials LiCoO2 , LiMn2 O4 , and LiFePO4 . The outcome is compared with both experimental and theoretical studies, as well as the bond valence site energy approach, and the results show that the method is not only a strong, qualitative visualization tool, but also provides a quantitative measure of electron-density thresholds for migration, which are correlated with theoretically obtained activation energies. In the future, the method may be used to guide experimental and theoretical research towards materials with potentially high ionic conductivity, reducing the time spent investigating nonpromising materials with advanced theoretical methods.