Improved energy-storage and charge–discharge properties achieved in NaNbO₃-Bi(Mg_0.5Zr_0.5)O₃ ceramics

Herein, the energy-storage performance of NaNbO₃-based lead-free ceramics has been successfully reinforced by introducing Bi(Mg_0.5Zr_0.5)O₃ to improve the breakdown strength (BDS) and suppress the remnant polarization (P_r). A superior discharge energy density (W_d) of 3.01 J cm⁻³ and an outstanding energy efficiency (η) of 90.2%, accompanied with high thermal stability of energy-storage performance ranging from 30 °C to 150 °C, have been concurrently recorded in 0.88NaNbO₃-0.12Bi(Mg_0.5Zr_0.5)O₃ ceramic at 320 kV cm⁻¹. The results show that the introduction of Bi(Mg_0.5Zr_0.5)O₃ can enhance BDS due to its considerable insulation, which is confirmed by the calculation of the band structure and the projected density of states. In addition, the remarkable current density (C_D) of 644.51 A cm⁻², preeminent power density (P_D) of 38.68 MW·cm⁻³ and transient energy release times (t_0.9) of 41.2 ns were also obtained in 0.88NaNbO₃-0.12Bi(Mg_0.5Zr_0.5)O₃ ceramic. Therefore, this study can significantly contribute to the application of NaNbO₃-based ferroelectrics in advanced pulsed power systems.