Li+ diffusion mechanism in solid-state superionic conductors by QENS

Li7-xLa3Zr2-xAxO12 (A=Al, Ga, Nb, Ta; LLZO) is one of the premier electrolyte materials for all solid-state batteries, combining high ionic conductivity, good chemical stability, and a wide electrochemical window. To these days, a conclusive description of the lithium diffusion mechanism that leads to the high conductivity is absent in the literature, with the role of collective motions and ion correlation not fully investigated. We have recently begun a systematic study of LLZO with A = Nb and x = 0.5 to fully elucidate its structure and dynamics, aiming to fill this knowledge gap by focusing our attention on the role of collective motions and phonons in the diffusion. We have so far carried out inelastic neutron scattering measurements of the phonons using the MERLIN and MARI instruments, as well as a preliminary polarized QENS experiment on LET instrument a using powder sample with a slightly different composition. Now we wish to better understand the effect of temperature on the quasi-elastic diffuse scattering by performing a Rapid access measurement on powder sample of LLZO;Nb 0.5 on the IRIS instrument. We have prepared a large (20g) powder sample, and plan to measure the system at approximately 4 temperatures for 16 hours each.