Crystallization and Properties of Strontium Barium Niobate-Based Glass–Ceramics for Energy-Storage Applications

The crystallization kinetics, phase development, and electric properties of Al2O3–SiO2–SrO–BaO–Nb2O5–ZnO glass–ceramics were investigated for potential application of the materials for energy storage. Strontium barium niobate (Ba x Sr1−x Nb2O6) with the tetragonal tungsten-bronze structure was the major crystalline phase formed by both surface and bulk crystallization. The presence of ZnO made the glasses less stable, and thus promoted their crystallization, but had no significant effect on the microstructure of the resulting glass–ceramics. All glass–ceramic samples had a uniform microstructure, with a crystal size of approximately 50 nm. Optimized energy storage density of approximately 6.0 J/cm3 was achieved for the sample containing 0.5% ZnO; the average dielectric constant was 150–180 and the breakdown strength was 950–870 kV/cm over the temperature range 850–950°C.