Structure and properties of ZnO-containing lithium–iron–phosphate glasses

► Lithium–iron–phosphate glasses. ► Substitution of Li 2O with ZnO. ► Variation in structure and properties with ZnO substitutions. ► Crystallization of LiFeP 2O 7. Lithium–iron–phosphate glasses with compositions of (20 − x)Li 2O· xZnO·30Fe 2O 3·50P 2O 5 ( x = 0–7.2) have been prepared. The influences of the amount of ZnO on the structure, physical and chemical properties, and crystallization behavior of the glasses were investigated using Fourier transform infrared spectroscopy, differential thermal analysis and X-ray diffraction techniques. The density of glass was measured according to the Archimedes principle. The chemical stability was evaluated based on the weight loss after the glass particles were boiled in water. The results indicate that Zn 2+ ions cross-linked the phosphate chains by forming P–O–Zn bridges when 2 mol% of ZnO was added. When the amount of ZnO was further increased, [ZnO 4] tetrahedra were formed and ZnO acted as a glass network former, integrating the phosphate glass network. The density, chemical stability and the activation energy of crystallization of the glasses increased with the amount of ZnO, whereas the glass transition temperature decreased. All thermally treated glasses showed surface crystallization with LiFeP 2O 7 as the crystalline phase.