With a Little Help from 31P: Localized Hopping and Long-Range Li+ Transport in Argyrodite-Type Li6PS5I

Activity: Talk or presentationTalk at conference or symposiumScience to science

Description

Site-disordered thiophosphates of the formula Li6PS5X (X = Br, Cl) are considered as the most promising solid electrolytes for all-solid-state lithium batteries with respect to their superior Li+ diffusion properties [1]. Also, for Li6PS5I, with its ordered anion and cation sublattices, 7Li (and 31P) nuclear magnetic resonance (NMR) measurements suggest rapid localized Li+ exchange processes. However, the missing site disorder in Li6PS5I prevents fast long-range ion transport as verified by conductivity spectroscopy [1]. We compare results from 31P spin-lock NMR measurements with recent results from 1/T1ρ 7Li NMR experiments [1] to shed light on the pronounced bimodal diffusion behaviour seen in Li6PS5I. The observation of 31P via NMR offers a new perspective to look at ion diffusion within solids. The influence of rotational jump processes of the PS43- polyanions on Li+ dynamics (and vice versa) is discussed as well [2,3]. In conclusion, site disorder in the Li6PS5X family is the key property necessary to understand the extraordinarily high ionic conductivities seen in the samples with X = Br, Cl [4].

References
[1] I. Hanghofer, M. Brinek, S. L. Eisbacher, B. Bitschnau, M. Volck, V. Hennige, I. Hanzu, D. Rettenwander, H. M. R. Wilkening, Phys. Chem. Chem. Phys. 21 (2019) 8489.
[2] I. Hanghofer, B. Gadermaier, and H. M. R. Wilkening, Chem. Mater. 31 (2019) 4591.
[3] M. Brinek, C. Hiebl, K. Hogrefe, I. Hanghofer, and H. M. R. Wilkening, J. Phys. Chem. C 124 (2020) 22934.
[4] M. Gombotz, K. Hogrefe, R. Zettl, B. Gadermaier, and H. M. R. Wilkening, Phil. Trans. A, 2021, in press.
Period5 Jul 2021
Event title11th International Conference on Diffusion in Materials: DIMAT 2021
Event typeConference
LocationVirtual, Hungary
Degree of RecognitionInternational