Dielectric materials have drawn increasing attention due to their high power density and fast charge-discharge speed. Although satisfactory energy storage performance has been achieved in lead-based ceramics, the exploration of suitable lead-free substitutions is highly desired since the rising environmental concerns caused by lead-based compounds. Herein, we demonstrate that a giant recoverable energy density of 7.01 J cm⁻³ together with high energy efficiency under 476 kV cm⁻¹, as well as impressive frequency stability (maximum variation of recoverable energy density < ±3% at 1 − 100 Hz) and thermal stability (maximum variation < ±10% over 25−120 °C) under 320 kV cm⁻¹, can be obtained in Lanthanum (La)-modified AgNbO₃ ceramics. It is revealed that the long-range antiferroelectric order in AgNbO₃ is interrupted by the incorporation of La, resulting in the transformation of micron-scale antiferroelectric domains into antiferroelectric nanodomains with concurrently improved energy density and efficiency. Additionally, the introduction of La content greatly suppresses the ferrielectricity of AgNbO₃ and enhances the dielectric breakdown strength up to 494 kV cm⁻¹ versus 178 kV cm⁻¹ for the pure AgNbO₃ ceramics. These results not only reveal the high potential of La-modified AgNbO₃ ceramics for energy storage applications but also open up a feasible approach of domain engineering to develop new lead-free energy-storage dielectric materials.

介电材料因其高功率密度和快速的充放电速度而受到越来越多的关注。尽管在铅基陶瓷中已经实现了令人满意的储能性能，但是由于铅基化合物引起的环境问题的日益增加，人们迫切希望探索合适的无铅替代品。在此，我们证明了7.01 J cm ^-3的巨大可恢复能量密度，以及在476 kV cm ^-1下的高能量效率以及令人印象深刻的频率稳定性（在1 − 100 Hz时可恢复能量密度的最大变化<±3％ ）和热稳定性（在25到120°C时最大变化<±10％）在320 kV cm ^-1下可以在镧（La）改性的AgNbO _3中获得陶瓷。揭示了通过掺入La而中断了AgNbO _3中的远距离反铁电有序，从而导致微米级反铁电畴转变为反铁电纳米畴，同时提高了能量密度和效率。另外，La含量的引入极大地抑制了AgNbO ₃的铁电性，并且提高了高达494 kV cm ^-1的介电击穿强度，而纯AgNbO ₃陶瓷则为178 kV cm ^-1。这些结果不仅揭示了La修饰的AgNbO ₃的高潜力 用于储能应用的陶瓷，也为开发新型无铅储能电介质材料开辟了可行的领域工程方法。