Thermally and electrically induced antiferroelectric ↔ ferroelectric transition in perovskite ceramics for use in high energy density capacitors

摘要: Dielectric capacitors traditionally have very high power and short response time but low energy storage capability compared to batteries electrochemical capacitors. For efficient reliable of intermittent sources such as wind solar, devices would ideally both densities. The studies density capacitor dielectrics presented in this thesis are part the effort move toward paradigm. Ceramic antiferroelectric compositions Pb0.99Nb0.02[(Zr0.57Sn0.43)1-yTiy]0.98O3 (PNZST 43/100y/2) show promise due a sharp highly tunable phase transition from (AFE) ferroelectric (FE). This results significant increase polarization at critical electric field, storing large amount electrical that can be released during unloading if material undergoes reverse relatively field. These also display thermally induced transitions, which must understood order more fully understand how properties develop. Several thermal characterization methods (dielectric constant loss tangent, modulus mechanical expansion, calorimetry) been utilized uncover nature complex transitions lead-free pseudo-antiferroelectric composition (Bi1/2Na1/2)0.93Ba0.07TiO3 (BNT-7BT) lead-containing PNZST 43/8/2 composition. experiments reveal first multi-cell cubic second for