Enhanced energy-storage performances in lead-free ceramics via the Co-modulation by conduction effect and domain engineering

The main factors that limit the practical application of bismuth ferrite-based energy storage ceramics are their low breakdown electric field strength and large remnant polarization. Here, we achieve high energy storage behavior in (0.72-x)BiFeO3-0.28BaTiO3-xLa(Mg1/2Zr1/2)O3 (BF-BT-xLMZ) ferroelectric ceramics through directional defect modulation based on a transformation of the conductance mechanisms. The systematic experimental analysis coupled with the vacancy sink model suggests that the introduction of LMZ changes the trap-filled-limit conduction mode dominated by oxygen vacancy, leading to 4 times enhancement of the breakdown electric field in BF-BT-0.2LMZ. Meanwhile, the induced nanodomains create a size effect that effectively reduces the remnant polarization, resulting in an increase in efficiency by 3.5 times. As a result, the recoverable energy storage density of the ceramic reaches an outstanding 4.2 J/cm3, together with a high efficiency of 75.2 %. This work provides a feasible strategy for the development of ferroelectric family in the field of high-energy storage.