Compromise Optimized Superior Energy Storage Performance in Lead-Free Antiferroelectrics by Antiferroelectricity Modulation and Nanodomain Engineering

Lead-free antiferroelectrics with excellent energy storage performance can become the core components of the next-generation advanced pulse power capacitors. However, the low energy storage efficiency caused by the hysteresis of antiferroelectric-ferroelectric transition largely limits their development toward miniaturization, lightweight, and integration. In this work, an ultrahigh recoverable energy storage density of approximate to 11.4 J cm-3 with a high efficiency of approximate to 80% can be realized in La-modified Ag0.5Na0.5NbO3 antiferroelectric ceramics at an ultrahigh breakdown electric field of approximate to 67 kV mm-1 by the compromise optimization between antiferroelectricity enhancement and nanodomain engineering, resulting in the transformation of large-size ferrielectric antipolar stripe domains into ultrasmall antiferroelectric nanodomains or polarization nanoregions revealing as Moire fringe structures. In addition, the enhanced transparency with increasing La content can also be clearly observed. This work not only develops new lead-free antiferroelectric energy storage materials with high application potential but also demonstrates that the strategy of compromise optimization between antiferroelectricity modulation and nanodomain engineering is an effective avenue to enhance the energy storage performance of antiferroelectrics. An effective strategy of compromise optimization between antiferroelectricity modulation and nanodomain engineering is proposed in lead-free relaxor antiferroelectrics to realize an ultrahigh energy storage density of approximate to 11.4 J cm-3 and a large efficiency of approximate to 80%, which are mainly attributed to the enhanced antiferroelectric phase and relaxation behaviors, decreased domain size, large maximum polarization, and improved breakdown strength.image