NaNbO3-(Bi0.5La0.5)(Mg2/3Ta1/3)O3 lead-free ceramics achieve ultrafast discharge rate and excellent energy storage performance

Advanced energy storage ceramics are specially beneficial to pulsed power technologies on account of first-class reliability and ultrafast discharge rate. However, the inferior energy storage performance hinders their further applications in the field of energy storage. In this work, a comprehensive strategy was adopted to synthesize the (1 − x)NaNbO3-x(Bi0.5La0.5)(Mg2/3Ta1/3)O3 ((1 − x)NN-xBLMT) lead-free ceramics by traditional solid-state method. Polar nano-regions are generated and the grain size is reduced to the microscale by introducing complex ions of (Bi0.5La0.5)(Mg2/3Ta1/3)6+ into the NN ceramic. The enhanced recoverable energy storage density (Wr = 3.69 J/cm3) and a high efficiency (η = 78%) can be realized simultaneously in 0.90NN-0.10BLMT ceramic at 440 kV/cm. Moreover, the ceramic presents excellent thermal and frequency stability within the range of 20–100 °C and 1–100 Hz at 200 kV/cm, respectively. More noteworthy, an ultrafast discharge rate (t0.9 = 23.6 ns) can be achieved in 0.90NN-0.10BLMT ceramic at 120 kV/cm, which is better than that of other lead-free energy storage ceramics. These results show that 0.90NN-0.10BLMT ceramic has broad application prospects in lead-free dielectric ceramic capacitors.