High energy storage density in AgNbO3-based lead-free antiferroelectrics using A/B-site co-doping strategy

Lead-free antiferroelectric AgNbO3 ceramics have garnered extensive attention due to their rapid charge/discharge capabilities and environmentally friendly nature, holding immense potential for energy storage applications. However, the practical utilization of AgNbO3 has been hindered by its low energy storage density. This study employed an A/B-site co-doping strategy, which yielded positive effects on the energy performance of AgNbO3 ceramics. By modifying the A/B-sites with equivalent amounts of Bi3+ and Y3+ ions, enhanced maximum polarization, improved breakdown field, and slimmer hysteresis loops were simultaneously achieved, as the combined effects of refined grain size, wider optical bandgap, and randomly distributed antiferroelectric nanodomains, which were verified through the scanning electron microscope, transmission electron microscope, and ultraviolet–visible spectrum. As a consequence, a high energy storage density of 5.40 J/cm3 accompanied by an energy storage efficiency of 56.5% was achieved in the Ag0.97Bi0.01Nb0.994Y0.01O3 ceramic under a relatively low electric field of 190 kV/cm. This study underscores the effectiveness of A/B-site aliovalent co-doping as a viable strategy for developing high-performance ceramic capacitors for energy storage applications.