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Four-Dimensional Quasielastic Neutron Scattering (4D-QENS) Analysis of Correlated Ionic Conduction in SrCl2

Jared Coles1,2, Omar Chmaissem1,2, Matthew Krogstad3, Daniel M. Pajerowski4, Feng Ye4, Duck Young Chung1, Mercouri G. Kanatzidis1,5, Stephan Rosenkranz1, and Raymond Osborn1,*

  • *Contact author: rosborn@anl.gov
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PRX Energy 5, 023002 – Published 14 April, 2026

DOI: https://doi.org/10.1103/b93d-755s

Abstract

Methods of elucidating the mechanisms of fast-ion conduction in solid-state materials are pivotal for advancements in energy technologies such as batteries, fuel cells, sensors, and supercapacitors. In this study, we examine the ionic conduction pathways in single crystal SrCl2, which is a fast-ion conductor above 900 K, using four-dimensional quasielastic neutron scattering (4D-QENS). We explore both coherent and incoherent neutron scattering at temperatures above the transition temperature into the superionic phase to explore the correlated motion of hopping anions. Refinements of the incoherent QENS yield residence times and jump probabilities between lattice sites in good agreement with previous studies, confirming that ionic hopping along nearest-neighbor directions is the most probable conduction pathway. However, the coherent QENS reveals evidence of de Gennes narrowing, indicating the importance of ionic correlations in the conduction mechanism. This highlights the need for improvements both in the theory of ionic transport in fluorite compounds and the modeling of coherent 4D-QENS in single crystals.

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Popular Summary

State-of-the-art experimental techniques can enable a deeper understanding of energy materials’ structure and properties. Advances in time-of-flight neutron scattering from single crystals now allow the energy broadening of ionic conductors to be measured over large volumes of momentum transfer, a technique known as four-dimensional quasielastic neutron scattering (4D-QENS). Experiments in the superionic phase of SrCl2 reveal the enhanced lifetime of ionic correlations from trapped interstitials during the conduction process. The results show that 4D-QENS can be a powerful probe of the mechanism of ionic diffusion in energy storage and transport materials.

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PRX Energy 5, 023002– Published 14 April, 2026
  • Received 18 September 2025
  • Revised 22 January 2026
  • Accepted 10 March 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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