Excellent energy storage properties in NaNbO3-based lead-free ceramics by modulating antiferrodistortive of P phase

The adjustment of the antiferroelectricity of a perovskite cell and the reversibility of antiferroelectric (AFE) -ferroelectric (FE) phase transition under electric field is very important for achieving excellent energy storage properties in AFEs. In this work, obvious change of antiferroelectricity was found in novel Na(Nb1−xSbx)O3 lead-free ceramics fabricated via a conventional solid-state reaction method. Repeatable double P-E loops with large EA-F ~28 kV/mm and large EF-A ~10 kV/mm were obtained in the x = 0.1 ceramic with AFE P phase at room temperature, resulting in excellent energy storage properties with Wrec ~3.4 J/cm3, large CD ~366 A/cm2, high PD ~26 MW/cm3 as well as fast discharge rate t0.9 ~75 ns. The multiscale structure analysis results indicate that the increased antiferrodistortive (oxygen octahedral tilting) degree and the decreased off-centering displacements of B-site cations after the substitution of Sb for Nb make the main contributions to the achievement of stable AFE phase and reversible AFE-FE phase transition in this work. The Na(Nb1−xSbx)O3 ceramics with excellent energy storage properties show large potential for the next-generation pulse power capacitor applications, and the mechanism for modulating antiferroelectricity found in this work would provide guidance for designing high-performance AFEs.