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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Structure of crystalline and amorphous materials in the NASICON system Na1+xAlxGe2-x(PO4)(3)

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Gammond, Lawrence V. D. [1] ; Auer, Henry [2] ; Da Silva, Rita Mendes [1] ; Zeidler, Anita [1] ; Ortiz-Mosquera, Jairo F. [3] ; Nieto-Munoz, Adriana M. [3] ; Rodrigues, Ana Candida M. [4] ; Almeida Silva, Igor D'Anciaes [5] ; Eckert, Hellmut [6, 5] ; Benmore, Chris J. [7] ; Salmon, Philip S. [1]
Total Authors: 11
[1] Univ Bath, Dept Phys, Bath BA2 7AY, Avon - England
[2] Fraunhofer Inst Ceram Technol & Syst IKTS, Winterbergstr 28, D-01277 Dresden - Germany
[3] Univ Fed Sao Carlos, Programa Posgrad Cincia & Engn Mat, CP 676, BR-13565905 Sao Carlos, SP - Brazil
[4] Univ Fed Sao Carlos, Dept Engn Mat, CP 676, BR-13565905 Sao Carlos, SP - Brazil
[5] Univ Sao Paulo, Inst Fis Sao Carlos, CP 369, BR-13566590 Sao Carlos, SP - Brazil
[6] WWU Munster, Inst Phys Chem, Corrensstr 30, D-48149 Munster - Germany
[7] Argonne Natl Lab, Xray Sci Div, Adv Photon Source, 9700 South Cass Ave, Lemont, IL 60439 - USA
Total Affiliations: 7
Document type: Journal article
Source: Journal of Chemical Physics; v. 155, n. 7 AUG 21 2021.
Web of Science Citations: 0

The structure of crystalline and amorphous materials in the sodium (Na) super-ionic conductor system Na1+xAlxGe2-x(PO4)(3) with x = 0, 0.4, and 0.8 was investigated by combining (i) neutron and x-ray powder diffraction and pair-distribution function analysis with (ii) Al-27 and P-31 magic angle spinning (MAS) and P-31/Na-23 double-resonance nuclear magnetic resonance (NMR) spectroscopy. A Rietveld analysis of the powder diffraction patterns shows that the x = 0 and x = 0.4 compositions crystallize into space group-type R3, whereas the x = 0.8 composition crystallizes into space group-type R3c. For the as-prepared glass, the pair-distribution functions and Al-27 MAS NMR spectra show the formation of sub-octahedral Ge and Al centered units, which leads to the creation of non-bridging oxygen (NBO) atoms. The influence of these atoms on the ion mobility is discussed. When the as-prepared glass is relaxed by thermal annealing, there is an increase in the Ge and Al coordination numbers that leads to a decrease in the fraction of NBO atoms. A model is proposed for the x = 0 glass in which super-structural units containing octahedral Ge-(6) and tetrahedral P-(3) motifs are embedded in a matrix of tetrahedral Ge-(4) units, where superscripts denote the number of bridging oxygen atoms. The super-structural units can grow in size by a reaction in which NBO atoms on the P-(3) motifs are used to convert Ge-(4) to Ge-(6) units. The resultant P-(4) motifs thereby provide the nucleation sites for crystal growth via a homogeneous nucleation mechanism. Published under an exclusive license by AIP Publishing. (AU)

FAPESP's process: 17/17800-0 - Solid State NMR for the study of structure/property correlations in glassy and glass ceramic materials for energy storage applications
Grantee:Igor d'Anciães Almeida Silva
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass
Grantee:Edgar Dutra Zanotto
Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC