Role of vanadium oxide on the lithium silicate glass structure and properties |
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| Authors: | Anuraag Gaddam Amarnath R. Allu Hugo R. Fernandes George E. Stan Catalin C. Negrila Atul P. Jamale François O. Méar Lionel Montagne José M.F. Ferreira |
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| Affiliation: | 1. CICECO –Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, Santiago University Campus, Aveiro, Portugal;2. Glass Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata, India;3. National Institute of Materials Physics, Magurele, Romania;4. Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181 – UCCS – Unité de Catalyse et Chimie du Solide, Lille, France |
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| Abstract: | The structural role of V in 28Li2O–72SiO2 (in mol%) lithium silicate glass doped with 0.5 mol% V2O5 was assessed using 29Si and 51V Nuclear Magnetic Resonance (NMR), Fourier-transform infrared (FTIR), and X-ray photoelectron (XPS) spectroscopy techniques. Despite the low amount of V2O5 used, the structural information obtained or deduced from the statistical analysis of the NMR data could explain the evolution of glass properties after V2O5 addition. The XPS results indicated that all vanadium exists in 5+ oxidation state. Both the 29Si NMR and FTIR data point toward an increase in the polymerization of the silicate network, caused by the V2O5 acting as network former, capable to form various  tetrahedral units (for n = 0, 1, and 2) in the glasses. These  units, which are similar to phosphate units, scavenge the Li+ ions and cause the silicate network to polymerize. However, in an overall balance, the entire glass network is depolymerized due to the additional nonbridging oxygens contributed by the vanadium polyhedra. The addition of vanadium causes the network to expand and increases the ionic conductivity. |
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| Keywords: | glass ionic conductivity lithium silicate structure vanadium/vanadium compounds |
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