Synergistic Enhancement of Energy Storage Performance in NaNbO₃‐Based Lead‐Free Relaxor Ferroelectrics via Weakly Coupled Relaxation Behavior

Abstract

Advancements in pulsed electronic power systems depend significantly on high‐performance dielectric energy storage ceramics. Lead‐free NaNbO3‐based energy‐storage ceramics are important materials for next‐generation pulsed power capacitors owing to their large polarization and bandgaps. However, the high energy loss caused by the antiferroelectric‐ferroelectric phase transition leads to low recoverable energy storage density and efficiency, which hinders its practical application. Herein, a weakly coupled relaxor ferroelectric is designed via chemical modification, which realises a high recoverable density of 12.7 J cm−3 and a decent η of 85.7%. Compositionally induced domain‐size refinement effectively delays low‐field polarization saturation and elevates η. Experimental characterization and theoretical‐model analysis confirm that the superior comprehensive energy‐storage performance is attributed to the component‐driven formation of polar nano‐micro‐regions with weak interactions, which suppresses the polarization hysteresis and improves the polarization difference. This study demonstrates that component‐driven construction of weakly coupled relaxor ferroelectric materials is an effective strategy for achieving ultrahigh energy‐storage characteristics.