Improvement of dielectric breakdown strength and energy storage performance in Er2O3–modified 0.95Sr0.7Ba0.3Nb2O6-0.05CaTiO3 lead-free ceramics

Abstract In this study, 0.95 Sr0.7Ba0.3Nb2O6-0.05CaTiO3-x wt% Er2O3 ceramics (SBNCTEx; x = 0–5) were synthesized using traditional solid-state method, and we investigated the microstructure, energy storage properties as well as the relationship between dielectric breakdown strength and interfacial polarization. As compared with pure 0.95 Sr0.7Ba0.3Nb2O6-0.05CaTiO3 ceramics, the Er2O3 dopants suppressed the grain growth of SBNCTEx, and the doped ones showed the dense microstructure. The secondary phase was found for x ≥ 1 according to the EDS results, and the influence of the secondary phase on relative dielectric breakdown strength has also been studied. The dielectric breakdown strength increased from 18.1 kV/mm to 34.4 kV/mm, which is good for energy storage. The energy storage density of 0.28 J/cm3 and the energy storage efficiency of 91.4% were obtained in the SBNCTE5 ceramics. The results indicate that SBNCTE ceramics can be used as energy storage capacitors.