Thermal evolution of lithium-ion distribution and local structure in Hf doped LiTa2PO8 electrolytes

There is increasing interest in lithium-ion-conducting solid electrolytes for their potential use in all-solid-state batteries addressing safety concerns associated with flammable liquid electrolytes currently used in Li-ion batteries. Recently, LiTa2PO8 (LTP) has been shown to exhibit high room temperature conductivity which can be increased significantly by Hf doping. This is not only due to the increase in the number of charge carriers, but also by preserving a “high-temperature” state where the Li+ ion distribution is more diffuse. Changes in the dimensionality of the ionic density and the associated conduction pathways seen in the parent compound are also thought to occur in the Hf doped system at low temperatures. This study aims to prove this using a combination of average and local structure analyses on heating from 4 K.