Bi(Mg0.5Sn0.5)O3-Doped NaNbO3 Lead-free Ceramics Achieve Excellent Energy-Storage and Charge/Discharge Performances

It is difficult for dielectric capacitors to achieve high recoverable energy density and energy efficiency simultaneously. The introduction of heterovalent ions into the A- and B-sites of NaNbO3 produces a local random field that improves the relaxor and the energy-storage performances. According to this strategy, (1 – x)NaNbO3–xBi(Mg0.5Sn0.5)O3(xBMS, x = 0.03, 0.05, 0.07, and 0.09) ceramics with high-energy-storage and excellent charge/discharge performances were prepared. Among them, the 0.09BMS ceramic achieved a large and recoverable energy-storage density (Wrec = 4.93 J/cm3) and high energy-storage efficiency (η = 81.5%). Furthermore, this energy-storage performance yielded excellent frequency and temperature stability (Wrec fluctuated by 6% in the temperature range of 20–180 °C and by 4.5% in the frequency range of 2–100 Hz). In addition, 0.09BMS ceramics have a high current density (CD = 971.93 A/cm2) and power density (PD = 87.47 MW/cm3) and an ultrafast discharge time (t0.9 = 25 ns). The abovementioned results show that the 0.09BMS ceramics are materials that exhibit promise for use in pulsed-power systems.