The intercalation of alkali ions into layered materials has played an essential role in battery technology since the development of the first lithium-ion electrodes. Coulomb repulsion between the intercalants leads to ordering of the intercalant sublattice, which hinders ionic diffusion and impacts battery performance. While conventional diffraction can identify the long-range order that can occur at discrete intercalant concentrations during the charging cycle, it cannot determine short-range order at other concentrations that also disrupt ionic mobility. In this article, we show that the use of real-space transforms of single crystal diffuse scattering, measured with high-energy synchrotron x-rays, allows a model-independent measurement of the temperature dependence of the length scale of ionic correlations along each of the crystallographic axes in a sodium-intercalated V2O5. The techniques described here provide a new way of probing the evolution of structural ordering in crystalline materials.
@article{arxiv.1902.03318,
title = {Reciprocal Space Imaging of Ionic Correlations in Intercalation Compounds},
author = {Matthew J. Krogstad and Stephan Rosenkranz and Justin M. Wozniak and Guy Jennings and Jacob P. C. Ruff and John T. Vaughey and Raymond Osborn},
journal= {arXiv preprint arXiv:1902.03318},
year = {2022}
}