Science Daily January 11, 2022
Identifying and controlling the pertinent phonon modes coupled most strongly with ionic conductivity, and assessing the role of anharmonicity, could pave the way for discovering and designing new solid electrolyted (SEs) via phonon engineering. A team of researchers in the US (Duke University, University of Louisville, Oak Ridge National Laboratory, Argonne National Laboratory) investigated phonons in sodium thiophosphate (Na3PS4) and their coupling to fast Na diffusion and identified that anharmonic soft modes at the Brillouin zone boundary of the anharmonically stabilized cubic phase constitute key phonon modes that control the Na diffusion process in Na3PS4. They demonstrated how these strongly anharmonic phonon modes enable Na-ions to hop along the minimum energy pathways. Further, the quasi-elastic neutron scattering measurements probe the Na diffusivity and diffusion mechanism. These results offer detailed microscopic insights into the dynamic mechanism of fast Na diffusion and provide an avenue to search for further Na solid electrolytes…read more. TECHNICAL ARTICLEÂ
Graphical abstract. Credit: Energy Environ. Sci., 2021,14, 6554-6563Â