Role of vanadium oxide on the lithium silicate glass structure and properties

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 QVn tetrahedral units (for n = 0, 1, and 2) in the glasses. These QVn 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.

Effect of Vanadium Oxide on the Crystallization of CaO–Al2O3–SiO2 Glass

“…In previous studies, both vanadium (V 5+ and V 4+ ) and molybdenum oxides were present in the glass network forming region [12][13][14][15][16]28 and were less rigid compared with alumina and silica. 13,29 Although V 3+ acting as a network modifier was proposed in the previous studies, 15,16 on the basis of vanadium structural units surrounded by oxygens 27 and the presence of tetragonal molybdenum oxide near glass network modifiers, 13 V 3+ units might be present near glass network modifiers similar to molybdenum oxide units.…”

Molecular Dynamics Simulation of Amorphous Vanadium Pentoxide

“…The average bonding distance O-O differs from the experimental one by about 7% due to the high degree of structural disorder of the constructed model by numerical method. Experimental studies in [6] also show that the structural order and properties of V2O5 is affected by the fabrication conditions and methods. The Figure 2 shows that V atoms are coordinated 5 and 6 by O atoms in which 5 coordination is the highest percentage (75.2%), number of coordinates 6 accounts for 19.2%.…”

“…For a long time, V2O5 materials have been manufactured and applied in science, technology and life. Many scientific publications [1][2][3][4][5][6] show that V2O5 materials exist in many different structures such as thin films, nanoparticles, nanorods, porous structure, and some polycrystalline. Because of these diverse structural morphologies, most studies focus on the characteristics and properties such as electronic, magnetic, electrical, electrochemical, optical, mechanical, and catalytic.…”

“…Because of these diverse structural morphologies, most studies focus on the characteristics and properties such as electronic, magnetic, electrical, electrochemical, optical, mechanical, and catalytic. Nanostructured V2O5 materials exhibit high energy density, high capacitance, good cyclic stability, and rapid electron transfer, so they can be used as supercapacitors and electrodes in batteries [2,3,[6][7][8][9]. It is also used as gas sensing materials, biosensors, and electrochromic materials.…”

An EPR investigation of defect structure and electron transfer mechanism in mixed-conductive LiBO2–V2O5glasses

“…It is important to note that in the glassy materials, two distinctly different and observable V 4+ environments can be expected, with the vanadium acting as a network forming or network modifying phase. [30][31][32] At low contents, in the network modifying phase, V 4+ defects are formed via charge compensation for Li and B, and can be considered well isolated in the bulk LiBO 2 network compared to other substitutional vanadium sites. On the other hand, in network forming phases, the structure is akin to defective V 2 O 5 (to short range order), whereby V 4+ sites are formed via incorporation of Li, B and oxygen vacancy defects.…”