Elucidating the mobility of H+ and Li+ ions in (Li6.25−xHxAl0.25)La3Zr2O12via correlative neutron and electron spectroscopy

Abstract

A major challenge toward realizing high-performance aqueous lithium batteries (ALBs) is the utilization of a metallic lithium anode. However, an ideal solid electrolyte that can protect metallic lithium from reacting with aqueous solutions while still maintaining a high lithium ion conduction is not currently available. One obstacle is the lack of a reliable experimental tool to differentiate the conduction behaviour of H⁺ and Li⁺ ions in a solid electrolyte. Here, by correlating neutron and electron spectroscopy, we quantitatively reveal the mobility and lattice occupancy of the two ions individually in protonated cubic Li_6.25Al_0.25La₃Zr₂O₁₂ (LLZO). Our results not only highlight LLZO as a potential effective separation layer for ALBs but also present a robust method to quantify the mobility of individual mobile ions in solid-state ion conductors.