Improved dielectric and energy storage properties of lead-free NaNbO₃-based ceramics by relaxation strategy

NaNbO₃-based lead-free ceramics have attracted much attention in high-power pulse electronic systems owing to their non-toxicity, low cost, and superior energy storage properties. However, due to the high remnant polarization and limited breakdown electric field, recoverable energy density as well as energy efficiency of NaNbO₃ ceramics were greatly limited. Thus, a strategy of introducing relaxor component to improve the energy storage performance of NaNbO₃ was proposed. Lead-free relaxor ferroelectric ceramics in system of (1 − x)NaNbO₃-xBi(Zn_1/2Zr_1/2)O₃ were prepared by a conventional solid-state reaction method. Effect of Bi(Zn_1/2Zr_1/2)O₃ content on the structural, dielectric, ferroelectric, and energy storage properties of NaNbO₃ ceramics was systematically investigated. The addition of Bi(Zn_1/2Zr_1/2)O₃ significantly enhanced the relaxation characteristics of the NaNbO₃ ceramics. The recoverable energy density and energy efficiency of the NaNbO₃-based ceramics were effectively improved. The 0.9NaNbO₃-0.1Bi(Zn_1/2Zr_1/2)O₃ ceramics obtained a maximum recoverable energy density of 1.19 J/cm³ and a high energy efficiency of 89.43% under 178 kV/cm.