Improved capacitive energy storage in sodium niobate-based relaxor antiferroelectric ceramics

Ceramic-based dielectric capacitors have become an attractive issue due to their wide applications in current pulsed-/high-power electronic devices. Antiferroelectric ceramics generally exhibit ultrahigh energy density owing to their giant polarization activated by antiferroelectric–ferroelectric phase transition under a high electric field but suffer from large hysteresis, meanwhile giving rise to low efficiency. Herein, by introducing perovskite compound Sr(Fe0.5Ta0.5)O3 into an antiferroelectric NaNbO3 matrix, a stabilized antiferroelectric phase and an improved relaxor behavior are observed. That is, relaxor antiferroelectric ceramics are constructed. Accordingly, a double polarization–electric field (P–E) loop becomes slimmer with increasing incorporation of dopants, leading to an ultrahigh recoverable energy density of 11.5 J/cm3, an energy storage efficiency of 86.2%, outstanding frequency/cycling/thermal reliability, and charge–discharge properties in 0.90NaNbO3-0.10Sr(Fe0.5Ta0.5)O3 ceramics. This work reveals that inducing the relaxor behavior in antiferroelectric materials is an effective route to improve their capacitive energy storage.