Ultrahigh phase-transition electric field and giant energy density in NaNbO3–Bi(Zn0.5Sn0.5)O3 lead-free antiferroelectric ceramics

Abstract

Antiferroelectric (AFE) materials demonstrate great potential for dielectric energy-storage applications owing to the field-induced AFE–ferroelectric phase transition. The adjustment of the driving electric field for the phase transition (E_AF) is critical for achieving high energy-storage properties in AFEs. In this work, a complex perovskite Bi(Zr_0.5Sn_0.5)O₃ (BZS) with simultaneously small tolerance factor and B-site ion polarizability was introduced into NaNbO₃ (NN) to form (1–x)NN–xBZS solid solutions. The results of X-ray diffraction, transmission electron microscopy and Raman spectra indicate that the room-temperature AFE orthorhombic P phase of NN can be effectively stabilized by increasing the BZS content, which is closely related to the reduced off-centering displacements of B-site cations and enhanced antiferrodistortive degree. This process is also accompanied by a reduced AFE domain size owing to the disrupted long-range AFE order. As a result, a significantly enhanced E_AF of ≥45 kV mm⁻¹ was realized at x = 0.06, strikingly leading to a giant recoverable energy-storage density of ∼5.5 J cm⁻³. This work makes a breakthrough progress in energy-storage performances of NN-based AFE P-phase ceramics by controlling the E_AF, which might provide a new strategy for developing AFE energy-storage materials.