Designing novel lead-free NaNbO3-based ceramic with superior comprehensive energy storage and discharge properties for dielectric capacitor applications via relaxor strategy

Abstract

There are urgent demands for high performance capacitors with superior energy storage density and discharge performances. In this work, novel NaNbO3-based lead-free ceramics (0.91NaNbO3-0.09Bi(Zn0.5Ti0.5)O3) with high energy storage capability, high power density and fast discharge speed were designed and prepared. Bi(Zn0.5Ti0.5)O3 was chosen for the purpose to reduce the remnant polarization and improve the induced polarization. Consequently, a large stored energy storage density (Ws˜ 3.51 J/cm3) and high recoverable energy storage density (Wrec˜ 2.20 J/cm3) were obtained in 0.91NaNbO3-0.09Bi(Zn0.5Ti0.5)O3 ceramic under a high breakdown strength of 250 kV/cm, with excellent thermal stability in the range of 20–120 °C. More importantly, the investigated ceramics exhibited high power density (PD˜ 20 MW/cm3) and ultrafast discharge rate (t0.9˜ 0.25 μs), demonstrating potential application in pulse powehr systems. This work provides an effective means of achieving excellent energy storage and discharge performances in NaNbO3-based ceramics for application in dielectric capacitors.