2020 Volume 128 Issue 5 Pages 273-278
Understanding the mechanism behind the water durability improvement of phospho-vanadate glass is crucial for enabling the practical use of low-melting glass in lead-free sealing and secondary ion batteries. We demonstrate that Fe2O3 additive is a key component for improving the water durability while suppressing the rise of the glass transition temperature of V2O5–P2O5 (VP) glass, and characterize the local structural change by X-ray absorption fine structure measurements. In VP glass, the addition of Fe2O3 increases the coordination number of vanadium ion without changing the oxidation state. The water durability is relatively sensitive to the vanadium valence and coordination environment compared to the glass transition temperature and hardness. Minimizing V5+O4 units in phospho-vanadate glass is the key to improving the water durability.