NMR studies on lithium ion migration in sulfide-based conductors, amorphous and crystalline Li3PS4

7Li spectra were observed for amorphous and crystalline Li3PS4 to study the structure of lithium ions. Lithium migration was studied using pulsed-gradient spin-echo 7Li NMR between 30 °C and 120 °C. The lithium diffusion behavior depended on the observation time and the pulsed-field gradient strength, and was quite different from the lithium diffusion in liquid electrolytes. Amorphous Li3PS4 showed higher ionic conductivity than crystalline Li3PS4, and similarly, the lithium diffusion rate was faster in amorphous samples. The lithium diffusion behavior in both conductors was not uniform and was distributed widely in time and space.