Superstructure and Correlated Na + Hopping in a Layered Mg-Substituted Sodium Manganate Battery Cathode are Driven by Local Electroneutrality.

Autor: Bassey EN; Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., Seymour ID; Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K., Bocarsly JD; Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K., Keen DA; ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford Campus, Didcot OX11 0QX, U.K., Pintacuda G; Centre de RMN à Très Hauts Champs, UMR 5082 (CNRS/Université Claude Bernard Lyon 1/Ecole Normale Supérieure de Lyon), University of Lyon, 69100 Villeurbanne, France., Grey CP; Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
Jazyk: angličtina
Zdroj: Chemistry of materials : a publication of the American Chemical Society [Chem Mater] 2023 Dec 07; Vol. 35 (24), pp. 10564-10583. Date of Electronic Publication: 2023 Dec 07 (Print Publication: 2023).
DOI: 10.1021/acs.chemmater.3c02180
Abstrakt: In this work, we present a variable-temperature 23 Na NMR and variable-temperature and variable-frequency electron paramagnetic resonance (EPR) analysis of the local structure of a layered P2 Na-ion battery cathode material, Na 0.67 [Mg 0.28 Mn 0.72 ]O 2 (NMMO). For the first time, we elucidate the superstructure in this material by using synchrotron X-ray diffraction and total neutron scattering and show that this superstructure is consistent with NMR and EPR spectra. To complement our experimental data, we carry out ab initio calculations of the quadrupolar and hyperfine 23 Na NMR shifts, the Na + ion hopping energy barriers, and the EPR g -tensors. We also describe an in-house simulation script for modeling the effects of ionic mobility on variable-temperature NMR spectra and use our simulations to interpret the experimental spectra, available upon request. We find long-zigzag-type Na ordering with two different types of Na sites, one with high mobility and the other with low mobility, and reconcile the tendency toward Na + /vacancy ordering to the preservation of local electroneutrality. The combined magnetic resonance methodology for studying local paramagnetic environments from the perspective of electron and nuclear spins will be useful for examining the local structures of materials for devices.
Competing Interests: The authors declare no competing financial interest.
(© 2023 The Authors. Published by American Chemical Society.)
Databáze: MEDLINE
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