Dielectric characterization and energy-storage performance of lead-free niobate glass–ceramics added with La 2 O 3

Abstract Lead-free niobate glass–ceramics added with La2O3 were synthesized through melt-quenching followed by controlled crystallization techniques. X-ray diffraction showed that a main phase determined as Sr0.5Ba0.5Nb2O6 was formed for all glass–ceramics. Analyses of the complex impedance indicated that the dielectric breakdown strength (BDS) strongly depended on the interface activity energy. Although the dielectric constant was decreased continuously, the dielectric loss tangent was well controlled below 0.01, and the BDS increased from 608 to 1127 kV/cm for the glass–ceramics with increasing La2O3 addition, which resulted in improvement of the energy density. The maximum theoretical energy-storage density of 7.1 J/cm3 was achieved in the glass–ceramic with 0.5 mol% La2O3 addition, which was improved by 2.7 times as compared with that of the pure glass–ceramic. This study provided the La2O3 added lead-free niobate glass–ceramic as an attractive candidate for making high-energy density capacitors.