In situ structural characterization of Li3PS4 solid electrolytes under high pressure

All-solid-state batteries are typically manufactured under high pressure to decrease the resistance of the solid interface. However, until now, there has been a lack of research concerning changes in the structure of solid electrolytes owing to pressurization. Our study addresses this gap by exploring the structural modifications of the sulfide solid electrolyte Li 3 PS 4 under high-pressure conditions. We observed a tendency for PS 4 molecules to converge upon each other in both β -Li 3 PS 4 and g -Li 3 PS 4 crystals when subjected to a pressure of 100 MPa. In g -Li 3 PS 4 , X-ray scattering and pair distribution function analyses following pressure application and subsequent return to ambient conditions remained consistent with pre-compression measurements. Conversely, in β -Li 3 PS 4 crystals, post-pressure X-ray scattering differed from pre-compression measurements, suggesting pressure-induced atomic rearrangement within the crystal lattice. This underscores the importance of accounting for pressure-induced structural changes, especially in computational simulation studies where crystal structures are often assumed to remain static pre- and post-pressurization. Our findings demonstrate that under high pressure, the crystal structure of Li 3 PS 4 slightly changes by approximately 1~2%, rendering it a viable candidate for utilization as a solid electrolyte in all-solid-state batteries.