High energy density ferroelectric glass-ceramics

In this study we examined the feasibility of using glass-ceramics with ferroelectric precipitates as high energy density dielectric materials. Specific goals were to demonstrate: 1) the formability of ferroelectric particles inside a glass matrix, 2) high dielectric constant and breakdown strength of glass-ceramics, and 3) improved energy density. Three glasses with network former (Si, Al, and B) content as low as 20 wt% was successfully formed using splash-quenching. After the crystallization temperature of each composition was determined by differential thermal analysis, a series of heat treatment were performed. X-ray diffraction results confirmed the formation of the appropriate ferroelectric phase (barium titanate for two compositions and barium strontium niobate for the third). The dielectric constant of the heat-treated samples can be up to 300 and the dielectric breakdown strength up to 800 kV/cm. Correspondingly, the projected energy density is 6-8 joules/c.c., an order of magnitude higher than commercial ceramic dielectrics.