Measurement of the Average Kinetic Energy of Li in Li2S and the Solid State Electrolyte Li7P3S11

Solid-state electrolytes (SSE) demonstrate thermal and chemical stability in the presence of lithium-metal anode systems, and are of particular importance as the world moves towards higher energy density, higher operating voltage battery cells. This proposal aims to demonstrate the use of deep inelastic neutron scattering (DINS) for providing unique information of the lithium ions in solid electrolyte materials, namely the average kinetic energy of the ions as it varies with temperature. We will first measure Li2S in the temperature range 4K-350K in order to benchmark the simple, binary lithium-sulphur compound against previous DINS data for lithium. We will then measure the superionic conductor Li7P3S11 across the same temperature range to determine the difference in average kinetic energy of lithium in this commercially relevant SSE system