Simulation-Guided Engineering of Hierarchical Domain Structures for High-Efficiency MLCCs

The miniaturization of modern electronic systems demands multilayer ceramic capacitors (MLCCs) capable of delivering high energy density without compromising efficiency or reliability. Herein, guided by phase-field simulations, this work establishes a rational design protocol that demonstrates the superiority of paraelectric modulation in maintaining robust polarization. We implement this strategy within a 0.88 Ba0.8Sr0.2TiO3-0.12Bi(Li0.5Ta0.5)O3 system via precise atomic-scale regulation. Multiscale characterization uncovers a critical structural duality: while high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) confirms the breakdown of global domains into polar nanoregions (PNRs), which are essential for minimizing hysteresis; piezoelectric force microscopy (PFM) and phase-field simulations reveal the preservation of medium-to-long-range ferroelectric correlations. This hierarchical architecture effectively reconciles high polarization with low energy loss. Consequently, the fabricated MLCCs achieve a high recoverable energy density of 10.17 J/cm3 and an exceptional efficiency of 98.3%. Furthermore, the devices exhibit robust operational stability under 691 kV/cm. This work provides a comprehensive pathway for advancing dielectric energy storage technology from theoretical prediction to reliable device fabrication.