Enhanced energy storage properties in (Bi 0.5 Na 0.5 ) 0.5 Sr 0.5 TiO 3-modified lead-free NaNbO3 3 antiferroelectric ceramics

The lead-free antiferroelectric material NaNbO3 3 (NN) is highly regarded for its exceptional breakdown electric field strength (Eb) b ) and substantial recoverable energy storage density (Wrec). rec ). However, the significant energy loss of NN reduces its W rec and tl under a strong electric field, constraining its application in energy storage domains. This study explores a novel approach by integrating the relaxation ferroelectric (Bi 1/2 Na 1/2 ) 1/2 Sr 1/2 TiO 3 (BNST) into NN to create NN-BNST relaxation anti-ferroelectrics, aiming to enhance their energy storage capabilities. The incorporation of BNST not only effectively reduces the grain size of NN but also disrupts its long-range ordered structure, forming polar nanoregions (PNRs) that mitigate energy density loss. Both W rec and tl of NN ceramic are significantly improved with increasing the concentration of BNST. Optimal results are achieved with the 0.75NN-0.25BNST ceramics, which demonstrate a high energy storage density (W rec = 3.83 J/cm3) 3 ) and conversion efficiency (tl = 76 %) while achieving an Eb b of 236 kV/cm. The analysis of Eb b enhancement in NNBNST ceramics is conducted through considerations of grain size, band-gap width, and activation energy, offering a robust framework for developing new NN-based antiferroelectrics for energy storage applications.