High energy storage and ultrafast discharge in NaNbO3-based lead-free dielectric capacitors via a relaxor strategy

Dielectric capacitors with decent energy storage and fast charge-discharge performances are essential in advanced pulsed power systems. In this study, novel ceramics (1-x)NaNbO3-xBi(Ni2/3Nb1/3)O-3(xBNN, x = 0.05, 0.1, 0.15 and 0.20) with high energy storage capability, large power density and ultrafast discharge speed were designed and prepared. The impedance analysis proves that the introducing an appropriate amount of Bi (Ni0.5Nb0.5)O-3 boosts the insulation ability, thus obtaining a high breakdown strength (E-b) of 440 kV/cm in xBNN ceramics. A high energy storage density (W-total) of 4.09 J/cm(3), recoverable energy storage density (W-rec) of 3.31 J/cm(3), and efficiency (eta) of 80.9% were attained in the 0.15BNN ceramics. Furthermore, frequency and temperature stability (fluctuations of W-rec <= 0.4% over 5-100 Hz and W-rec <= 12.3% over 20-120 degrees C) were also observed. The 0.15BNN ceramics exhibited a large power density (19 MW/cm(3)) and ultrafast discharge time (similar to 37 ns) over the range of ambient temperature to 120 degrees C. These enhanced performances may be attributed to the improved breakdown strength and relaxor behavior through the incorporation of BNN. In conclusion, these findings indicate that 0.15BNN ceramics may serve as promising materials for pulsed power systems.

Automated summary

In this study, novel ceramics (1-x)NaNbO3-xBi(Ni2/3Nb1/3)O-3(xBNN) with high energy storage capability, large power density, and ultrafast discharge speed were designed and prepared. The 0.15BNN ceramics exhibited a high energy storage density, recoverable energy storage density, efficiency, large power density, and ultrafast discharge time, making them promising materials for pulsed power systems.