Glass-to-Crystal Transition in Li1+xAlxGe2-x(PO4)(3): Structural Aspects Studied by Solid State

Autor(es)

Schroeder, Cornelia ^[1] ; Ren, Jinjun ^[1] ; Rodrigues, Ana Candida M. ^[2] ; Eckert, Hellmut ^{[1, 3]}

Afiliação do(s) autor(es)

^[1] WWU Munster, Inst Phys Chem, D-48149 Munster - Germany

^[2] Univ Fed Sao Carlos, Lab Mat Vitreos LaMaV, BR-13560 Sao Carlos, SP - Brazil

^[3] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13590 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 118, n. 18, p. 9400-9411, MAY 8 2014.
• Citações Web of Science: 17

Resumo

The structural aspects of the glass-to-crystal transition in the technologically important ion conducting glass ceramic system L1+xAlxGe2-x(PO4)(3) (0 <= x <= 0.75) have been examined by complementary multinuclear solid state nuclear magnetic single and double-resonance experiments. In the crystalline state, the materials form solid solutions in the NASICON structure, with additional nanocrystalline AIPO(4) present at x values >= 0.5. Substitution of Al in the octahedral Ge sites results in a binomial distribution of multiple phosphate species, which differ in the number P-O-Al and P-O-Ge linkages and can be differentiated by P-31 chemical shift and P-31[Al-27] rotational echo adiabatic passage double resonance (REAPDOR) spectroscopies. The detailed quantitative analysis of these data, of complementary Al-27[P-31] rotational echo double resonance (REDOR) and of homonuclear P-31-P-31 double quantum NMR studies suggest that the AlO6 coordination polyhedra are noticeably expanded compared to the GeO6 sites in the NASICON-type LiGe2(PO4)(3) (LGP) structure. While the glassy state is characterized by a significantly larger degree of disorder concerning the local coordination of germanium and aluminum, dipolar solid state NMR studies clearly indicate that their medium range structure is comparable to that in NASICON, indicating the dominance of P-O-Al and P-O-Ge over P-O-P and Al-O-Ge connectivities. (AU)

• Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs