Structural polymorphism in Li2CoSiO4 intercalation electrodes: a combined diffraction and NMR study
| Autor: | Christopher Lyness, A. Robert Armstrong, Peter G. Bruce, Michel Ménétrier |
|---|---|
| Přispěvatelé: | EaStCHEM, School of Chemistry, University of St Andrews [Scotland], Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB) |
| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Diffraction
Fermi contact interaction Chemistry Rietveld refinement General Chemical Engineering Intercalation (chemistry) 02 engineering and technology General Chemistry [CHIM.MATE]Chemical Sciences/Material chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Spectral line 0104 chemical sciences Crystallography Polymorphism (materials science) Electrode Materials Chemistry Hydrothermal synthesis 0210 nano-technology |
| Zdroj: | Chemistry of Materials Chemistry of Materials, American Chemical Society, 2010, 22 (5), pp.1892-1900. ⟨10.1021/cm9034374⟩ |
| ISSN: | 0897-4756 1520-5002 |
| DOI: | 10.1021/cm9034374⟩ |
| Popis: | International audience; Li2CoSiO4 was prepared in three polymorphic forms. The βII (Pmn21) polymorph was obtained by hydrothermal synthesis (150 °C), and subsequent heat treatments yielded the βI (Pbn21) form (700 °C) and the γ0 (P21/n) form (1100° then quenching from 850 °C). Rietveld refinement of X-ray and neutron powder diffraction patterns reveal considerable Li/Co mixing for βII, very moderate mixing for βI, and no mixing for γ0. 7Li MAS NMR spectra have been recorded for the three forms. The mechanism of the Fermi contact interaction that leads to negatively shifted signals is as yet unexplained, but the nature and the number of signals were analyzed in relation to the site occupancies for each compound. The agreement is good for βII, although the extent of disorder leads to very poorly defined NMR signals; it is reasonable (although not fully quantitative) for βI, where well-defined NMR signals can be assigned to definite environments; finally, the γ0 sample surprisingly leads to a single rather broad NMR signal, whereas two well-defined and rather different environments are present in the structure deduced from diffraction. |
| Databáze: | OpenAIRE |
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