Improvement in structural, dielectric and energy-storage properties of lead-free niobate glass-ceramic with Sm2O3

Phase evolution, microstructure, dielectric performance, polarization, breakdown strength as well as energy-storage behaviors for the lead-free niobates glass-ceramics with Sm2O3 were systematically investigated. Two crystallographic structures of tetragonal tungsten bronze and orthorhombic perovskite complex phases were obtained and Sm3+ entered into the crystalline phases. The optimal microstructure of the glass-ceramic was obtained with Sm2O3 of 2 mol%. Both dielectric constant and polarizability were enhanced with increasing Sm2O3. The breakdown strength and energy-storage behaviors of the glass-ceramics were also improved by increased Sm2O3. The highest breakdown field of 21.2 kV/mm, the highest charged (0.74 J/cm3) and discharged energy density (0.45 J/cm3) were obtained in the glass-ceramic with 2 mol% Sm2O3. It is due to the reduced interfacial polarization in this particular composition.