Li-Metal Alloys and Their Unique Thermodynamic and Kinetic Properties

All-solid-state batteries will enable significant increases in energy density as they will allow the use of metallic Li anodes instead of graphite intercalation compounds. However, before metallic Li can be used as an anode, major metallurgical challenges must be overcome. Alloying of Li is a promising path with which to modify the intrinsic thermodynamic, mechanical and kinetic properties of metallic Li to enable the uniform deposition and stripping of Li at the anode/solid-electrolyte interface. Li forms a rich variety of intermetallic compounds when alloyed with different elements. Li diffusion within these intermetallic compounds can be complex due to the nature of anti-site defects and the relative mobilities between Li and the alloying elements. The unique thermodynamic and kinetic properties of different Li-metal alloys have important consequences for morphological evolution during Li deposition and stripping. In this talk, we will describe our first-principles statistical mechanics studies of non-dilute diffusion in Li-metal alloys such as Li-Sb, Li-Al, Li-Mg and Li-In and elucidate how strain and varying degrees of long and short-range order affect the kinetics of Li anodes.