Tailoring high energy density with superior stability under low electric field in novel (Bi0.5Na0.5)TiO3-based relaxor ferroelectric ceramics

Large energy storage density in relaxor ferroelectrics is commonly accompanied with high breakdown strength, which is adverse to the actual dielectric capacitor applications. We demonstrate that such drawback can be effectively resolved by using Sr0.7Bi0.2TiO3 (SBT) to partially replace relaxor ferroelectric 0.76(Bi0.5Na0.5)TiO3-0.24NaNbO(3) (BNT-NN-xSBT). In this study, a high recoverable energy storage density (W-rec similar to 3.12 J/cm(3) ) and favorable efficiency (eta similar to 75.3 %) are achieved in the BNT-NN-0.1SBT ceramic under a low electric field of 200 kV/cm, which is superior to that of most previously reported dielectric ceramics under the same electric field level. Good temperature stability (25 - 120 degrees C), moderate frequency dependence (1 -500 Hz), and excellent fatigue resistance (up to 10(5) cycles) are also realized. More interestingly, the indicated ceramics perform high power density (P-D similar to 36.40 MW/cm(3)) and fast discharge time (t(0.9) similar to 0.149 mu s) with remarkable temperature endurance. Moreover, of particular significance is that this study offers a feasible guideline to design comprehensive energy storage performance dielectric ceramics for practical applications.