Engineering <i>Ordered‐Disordered Domains</i> for High‐Performance Energy Storage in BCZT‐Based Relaxor Ferroelectrics

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, NaNbO₃ (NN) is introduced into the 0.85Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃-0.15Bi(Zn_2/3Ta_1/3)O₃ (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-xNN 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.