Design Principles for Fast Oxide Lithium-Ion Conductors

Inorganic lithium superionic conductors are one of the key components for the realization of all-solid-state batteries [1]. In this presentation, we will identify some of the structural features that enable very high Li-ion conductivity and demonstrate how they can be used to find novel Li-ion conductors. We will discuss two patterns that are commonly found in the best oxide-based lithium-ion conductors: activated local environment and corner-sharing frameworks. By embedding the lithium diffusion network into graph representations, we discover that the activated local environment of lithium sites allows fast diffusion [2]. In addition, by observing the crystal framework of known oxide lithium superionic conductors, we discover that they share a unique structural feature of corner-sharing frameworks. We find that in such frameworks, fast lithium-ion diffusion is allowed by severe distortion of the lithium-ion sites as well as reduced electrostatic interaction from the non-lithium cations. Using each of these patterns respectively, we performed high-throughput screening on the Materials Project [3] database and discover a total of 16 novel oxide frameworks that allow superionic lithium conductivity at room temperature, vastly expanding the currently limited structural types of superionic conductors. This study provides new insights on the structural origin of fast lithium-ion diffusion in oxides and allows much more diverse structural and chemical space to be considered as solid electrolytes for all-solid-state batteries.<br/><b>References:</b><br/>[1]Janek, J. & Zeier, W. G. A solid future for battery development. <i>Nat Energy</i> 1, 16141 (2016).<br/>[2]Xiao, Y., Jun, K, Ceder, G. <i>et al.</i> Lithium Oxide Superionic Conductors Inspired by Garnet and NASICON Structures. <i>Adv Energy Mater</i> (2021) doi:10.1002/aenm.202101437.<br/>[3]Jain, A., Persson, K. <i>et al.</i> Commentary: The Materials Project: A materials genome approach to accelerating materials innovation. <i>Apl Mater</i> 1, 011002 (2013).