Enhanced energy storage density in Ca and Ta co‐doped AgNbO 3 antiferroelectric ceramics

Abstract Ca and Ta co‐doped AgNbO 3 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 (Ag 1‐2 x Ca x )(Nb 1‐ x Ta x )O 3 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 M 1 ‐M 2 and M 2 ‐M 3 . This proved the enhanced antiferroelectricity stability associated with the enlarged low temperature phase transition region. The obtained (Ag 0.90 Ca 0.05 )(Nb 0.95 Ta 0.05 )O 3 ceramics exhibit an enhanced recoverable energy storage density (3.36 J/cm 3 ) 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 AgNbO 3 ‐based antiferroelectric ceramics are competitive with other lead‐based and lead‐free dielectric capacitors, which are promising candidates for dielectric energy storage applications.