Novel NaNbO3-based relaxors featuring ultrahigh energy storage performance

Abstract

Ferroelectric ceramics with ultrahigh power density and fast charging/discharging are attracting increasing attention. The practical application of most antiferroelectric ceramics in current electronics is significantly limited by their poor recoverable energy storage density. Here, a novel system ceramic of (1-x) Na0.84Ca0.16Nb0.84Ti0.16O3-xBiZn2/3Nb1/3O3 (NCNT-xBZN) solid solutions, possessing a giant Wrec∼7.05 J cm−3 and excellent conversion efficiency (η)∼83.7% under 53 kV mm−1, was synthesized to exhibit superior stability with changing temperature, frequency and fatigue behavior, together with the large current density (CD=571.8 A cm−2), ultrahigh power density (PD=85.7 MW cm−3) and ultrafast discharge rate (∼200 ns). These outstanding properties are attributed to the phase transformation from the AFE R to the FE Q phase, accompanied by the smashing of sub-microdomains into polar nanoregions, as the BZN content raises. The experimental results disclose that the synergistic effect of the highly dynamic response of polar nanoregions and the local lattice distortion arising from the disruption of long-range polar ordering by heterovalent ion filling generates a delayed saturation polarization with a strong relaxor behavior, thereby optimizing the energy storage density. The unique combination, together with a simple synthesis strategy, offers a refreshing strategy for the development of dielectric materials.