Engineering Ordered‐Disordered Domains for High‐Performance Energy Storage in BCZT‐Based Relaxor Ferroelectrics

Abstract Dielectric capacitors have attracted considerable interest for energy storage applications owing to their ultra‐fast charge–discharge capabilities. However, the concurrent realization of high recoverable energy storage density ( W rec ) and energy efficiency ( η ) remains a persistent challenge. In this study, NaNbO 3 (NN) is introduced into the 0.85Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 –0.15Bi(Zn 2/3 Ta 1/3 )O 3 (BCZT–0.15BZT) lattice, resulting in the emergence of a unique structural feature identified as ordered–disordered domains ( O – DO – Ds ). Detailed analysis reveals that the ordered domains exhibit ferroelectric hysteresis behavior, consistent with previous reports, while the disordered domains play a critical role in enhancing both breakdown strength and energy storage efficiency. These improvements are primarily attributed to energy dissipation mechanisms and the stabilization of a triple‐phase coexistence. Additionally, the formation of defect dipoles and the presence of weakly coupled orthorhombic–tetragonal–cubic ( O–T–C ) asymmetric phases contribute synergistically to achieving high polarization and low hysteresis. Consequently, the optimized composition, (1‐ x )BCZT–0.15BZT– x NN with x = 0.15 exhibits an exceptionally high W rec of 9.12 J cm −3 and an η of 95.3%. These findings offer a promising and innovative strategy for the design of next‐generation high‐performance energy storage capacitors.