Investigating Changes in Lattice Dynamics from Post-Synthesis Treatment Processes using Inelastic Neutron Scattering

Sulphide superionic materials are candidate electrolytes for all-solid-state batteries. Inelastic neutron scattering (INS) is sought to investigate changes to the phonon band structure in three Li6PS5Cl electrolytes prepared by different methods; a standard cold pressed electrolyte, a heat-treated electrolyte and a spark plasma sintered version. Changes to the vibrational landscape of solid electrolytes can drastically change the prefactors which govern ionic conductivity. The ionic conductivity of the heat treated and plasma sintered Li6PS5Cl samples are substantially greater than that of the commercial cold pressed material. All other terms in the prefactor for conduction have been measured before and after processing. INS will allow us to collect the final prefactor term, giving us an insight into the lattice dynamics and thus material performance.