Realizing high-performance capacitive energy storage in lead-free relaxor ferroelectrics via synergistic effect design

Abstract Developing lead-free dielectric ceramics with outstanding energy storage properties has become urgent for dielectric capacitors. Herein, a synergistic effect design strategy has been proposed that combined the merits of relaxor ferroelectrics with high polarization/low remanent polarization and enhanced linear materials with relatively high polarization/ultrahigh dielectric breakdown strength. Hence, a novel lead-free 0.955Bi0.5Na0.5TiO3-0.045Ba(Al0.5Ta0.5)O3-based ceramics are engineered though introducing the enhanced linear dielectrics of 0.9CaTiO3-0.1BiScO3. A large recoverable energy density (Wrec∼3.13 J/cm3) and high efficiency (η∼88.4 %) as well as excellent power density (PD∼95.1 MW/cm3) and discharge speed (t0.9∼36 ns), along with superior stabilities, have been simultaneously realized. The piezoelectric force microscope measurements reveals that incorporating CT-BS generates more highly-dynamic polar nanoregions (PNRs), giving rise to rapid reversibility of PNRs with concurrently tailored energy storage performance. This study demonstrates synergistic effect design is a feasible and paradigmatic way to explore high-efficiency dielectrics for high-power energy storage applications.