Eric McCalla (Author), Bojan Budič (Author), Robert Dominko (Author)

Abstract

As part of a broad project to explore Li4MM′O6 materials (with M and M′ being selected from a wide variety of metals) as positive electrode materials for Li-ion batteries, the structures of Li4FeSbO6 materials with both stoichiometric and slightly deficient lithium contents are studied here. For lithium content varying from 3.8 to 4.0, the color changes from yellow to black and extra superstructure peaks are seen in the XRD patterns. These extra peaks appear as satellites around the four superstructure peaks affected by the stacking of the transition metal atoms. Refinements of both XRD and neutron scattering patterns show a nearly perfect ordering of Li, Fe, and Sb in the transition metal layers of all samples, although these refinements must take the stacking faults into account in order to extract information about the structure of the TM layers. The structure of the most lithium rich sample, where the satellite superstructure peaks are seen, was determined with the help of HRTEM, XRD, and neutron scattering. The satellites arise due to a new stacking sequence where not all transition metal layers are identical but instead two slightly different compositions stack in an AABB sequence giving a unit cell that is four times larger than normal for such monoclinic layered materials. The more lithium deficient samples are found to contain metal site vacancies based on elemental analysis and Mössbauer spectroscopy results. The significant changes in physical properties are attributed to the presence of these vacancies. This study illustrates the great importance of carefully determining the final compositions in these materials, as very small differences in compositions may have large impacts on structures and properties.

Keywords

materiali;elektrokemija;spektrografija;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: KI - National Institute of Chemistry
UDC: 620.1/.2
COBISS: 37872133 Link will open in a new window
ISSN: 0897-4756
Views: 4125
Downloads: 544
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Other data

Secondary keywords: materiali;elektrokemija;spektrografija;
Source comment: Soavtorji: Artem Abakumov, Gwenaelle Rousse, Marine Reynaud, Moulay Tahar Sougrati, Bojan Budic, Abdelfattah Mahmoud, Robert Dominko, Gustaaf Van Tendeloo, Raphael P. Hermann, Jean-Marie Tarascon;
Pages: str. 1699-1708
Volume: ǂVol. ǂ27
Issue: ǂiss. ǂ5
Chronology: Mar. 2015
DOI: 10.1021/cm504500a
ID: 10883515