Enhanced energy storage density in Ca and Ta co‐doped AgNbO3 antiferroelectric ceramics

Abstract

AbstractCa and Ta co‐doped AgNbO3 antiferroelectric lead‐free ceramics were fabricated by rolling process technique, and improved energy storage properties were obtained. X‐ray diffraction and Raman spectra indicate a single perovskite structure for (Ag1‐2xCax)(Nb1‐xTax)O3 ceramics. The dielectric performances were also investigated, showing that increasing the content of Ca and Ta from 0.1 to 5 mol% gradually decreased the temperatures of the phase transition of monoclinic M1‐M2 and M2‐M3. This proved the enhanced antiferroelectricity stability associated with the enlarged low temperature phase transition region. The obtained (Ag0.90Ca0.05)(Nb0.95Ta0.05)O3 ceramics exhibit an enhanced recoverable energy storage density (3.36 J/cm3) and efficiency (58.3%) with good temperature and frequency stability. The same composition shows excellent charge and discharge properties with a discharge current as high as 91.5 A and fast discharge speed (150 ns discharge period). All these merits demonstrate that AgNbO3‐based antiferroelectric ceramics are competitive with other lead‐based and lead‐free dielectric capacitors, which are promising candidates for dielectric energy storage applications.