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Insights from Local Network Structures and Localized Diffusion on the Ease of Lithium Ion Transport in Two Mixed Glass-Former Systems
Autoři: Sklepic Kristina | Banhatti Radha D. | Tricot Gregory | Mošner Petr | Koudelka Ladislav | Mogus-Milankovic Andrea
Rok: 2017
Druh publikace: článek v odborném periodiku
Název zdroje: Journal of Physical Chemistry C
Název nakladatele: American Chemical Society
Místo vydání: Washington
Strana od-do: 17641-17657
Tituly:
Jazyk Název Abstrakt Klíčová slova
cze Vliv lokální struktury na difuzi a transport lithiových iontů ve skelných systémech se dvěma síťotvornými oxidy Práce je zaměřena na studium vlivu záměny P2O5 za GeO2 na strukturu (NMR spektroskopie, Ramanova spektroskopie) a elektrické vlastnosti (impedanční spektroskopie) lithných fosforečnanových a borofosforečnanových skel připravených v kompozičních řadách 40Li2O–(60–x)P2O5–xGeO2) a 40Li2O–10B2O3–(50–x)P2O5–xGeO2. fosforečnanová skla; borofosforečnanová skla; elektrické vlastnosti; struktura
eng Insights from Local Network Structures and Localized Diffusion on the Ease of Lithium Ion Transport in Two Mixed Glass-Former Systems The conductivity enhancement observed in the two glass systems A (40Li2O–(60–x)P2O5–xGeO2) and B (40Li2O–10B2O3–(50–x)P2O5–xGeO2) as the germanate content is increased from 0 to 25 mol % confirms the positive mixed glass-former effect (MGFE) in these systems. In this study, we further employ state-of-the-art NMR techniques along with Raman spectroscopy to probe the local network structures. We use the MIGRATION concept to model the experimental conductivity and permittivity spectra obtained from impedance spectroscopy to understand the scaling features of the spectra and to calculate the value of the spatial extent of the localized diffusion of the lithium ion. As x increases from 0 to 25 mol %, for system A, a continuous increase of the POGe cross-linkages as well as a continuous and strong modification of the phosphate network is observed. In system B, deeper analysis of the 31P magic-angle spinning NMR experiments done using 2D 11B/11B homonuclear and 11B/31P heteronuclear NMR is used to determine the nature of the BOB linkages as well as that of the POB linkages. Modeling of the conductivity spectra shows that the shape parameter of the spectra remains the same for both systems and for all compositions, a feature typical for MGFE. Furthermore, correlating the trends of the spatial extent of localized diffusion with that gleaned from the local structures, we infer that, as the relative germanate content increases, in the ternary glass (system A) the ease of mobility of the Li+ ion is enhanced while in the quaternary glass (system B, x > 0 mol %) it is somewhat hindered. phosphate glasses; borophosphate glasses; electrical properties; structure