Ultrahigh energy storage density lead-free multilayers by controlled electrical homogeneity

Abstract

Introducing controlled electrical homogeneity can be an effective way to obtain ultrahigh energy storage density in lead-free multilayers.

Superior Energy‐Storage Capacitors with Simultaneously Giant Energy Density and Efficiency Using Nanodomain Engineered BiFeO3‐BaTiO3‐NaNbO3 Lead‐Free Bulk Ferroelectrics

“…Therefore, to obtain excellent energy‐storage properties, both a large ( P max − P r ) value and a high dielectric breakdown strength ( E B ) should be required. Even though some intrinsic dielectric breakdown mechanisms are closely correlated with the material component, the E B value can still be improved by optimizing the preparation process, doping technology, and so on . It is known that P r can be easily modulated by changing phase structure, improving dielectric relaxation behavior, or introducing defect engineering .…”

High‐temperature multilayer actuators based on CuO added BiScO3–PbTiO3 piezoceramics and Ag electrodes

“…This proves that the large strain of actuator at 200°C comes from the intrinsic properties of BS‐PT:0.3wt%CuO piezoelectric layer in deed. Although extensive studies focused on the Pb‐free piezoelectric ceramics and their multilayer actuators recently and some of them showed a strain as high as ≥0.4% at room temperature, there is still a long way for them to be applied in industries mainly because the ceramic MPBs and piezoelectric properties are not stable enough with the ambient temperature changing or the ceramic sintering temperature (eg, above 930°C) is too high to use pure Ag electrodes. As a comparison, the BS‐PT:0.3wt%CuO ceramic shows good temperature stability of MPBs, piezoelectric and mechanical properties at 20‐200°C.…”

Grain boundary engineering that induces ultrahigh permittivity and decreased dielectric loss in CdCu3Ti4O12 ceramics

“…Moreover, the average grain size was estimated by statistically analyzing the grain sizes in the SEM image, and the analysis was carried out using SEM image analysis software (Nano Measurer System, 1.2.5). The density of the samples was detected using the drainage method with the Archimedes principle . The silver electrodes for characterization of electrical property were prepared by covering the top and bottom of polished CdCu 3− x Zn x Ti 4 O 12 ceramics with silver paint and heating them at 840°C for 0.5 hour.…”

“…The search for ultrahigh permittivity ( ε r > 10 3 ) materials is one of the most popular research topics in the fields of microelectronics and energy storage devices . CaCu 3 Ti 4 O 12 (CCTO), a typical ACu 3 Ti 4 O 12 (ACTO, where A = Ca, Cd, La 2/3 , Y 2/3 , Bi 2/3 , Na 1/2 La 1/2 , Na 1/2 Y 1/2 , or Na 1/2 Bi 1/2 , for example) ceramic, has been widely studied due to its ultrahigh dielectric permittivity and good frequency/thermal stability.…”