High breakdown strength and energy density in antiferroelectric PLZST ceramics with Al2O3 buffer

In this work, a new core-shell structure of antiferroelectric ceramic powder (Pb0.97La0.02Zr0.85Sn0.12Ti0.03O3-PLZST) coated with linear dielectric (Al2O3) has been successfully prepared to realize high energy density through tape-casting process. According to the experimental results of electron microscope, the sol-gel derived Al2O3 layer was uniformly coated on the PLZST particles and the Al2O3 layer can be taken as the buffer layer to effectively refine the grain growth as well. Therefore, the modified PLZST particles were fine and uniform compared with the pure PLZST. It was found that the buffer layer could undertake higher electric field and the electric field applied to PLZST particles was weakened based on finite element analysis, which can avoid the premature breakdown of PLZST. And the actual measured breakdown strength was significantly enhanced from 22.2 kV/mm to 35.5 kV/mm. Correspondingly, an extremely high recoverable energy storage density of 5.3 J/cm3 was obtained for PLZST with 0.5%wt Al2O3, an 204% enhancement over the pure PLZST ceramics (2.6 J/cm3), and the corresponding efficiency was up to 88.3%. In addition, impedance spectroscopy measurement was carried out to further confirm the better insulation of the ceramic with Al2O3 buffer.