Quantifying the Extent of Improved Li-ion Motion using Quasi-Elastic Neutron Scattering

Sulphide superionic materials are candidate electrolytes for all-solid-state batteries. Quasi-elastic neutron scattering (QENS) is sought to obtain bulk diffusion rates and activation energies for two Li5.5PS4.5Cl1.5 electrolytes prepared by different methods; a standard cold pressed electrolyte, and a spark plasma sintered version. The ionic conductivity of the plasma sintered Li5.5PS4.5Cl1.5 samples is substantially greater than that of the commercial cold pressed material. The SPS post-processing, typically promotes grain growth which leads to enhanced conductivities, however structural modifications when using this SPS method have also been observed. QENS will allow us to determine the true bulk diffusion, which can then be compared to macroscopic diffusion (which considers bulk, grain boundary, and particle interface diffusion) determined by pulsed field gradient nuclear magnetic resonance allowing us to elucidate which of these factors is rate limiting for effective ion diffusion.