Morphology, structure, and defect design of BaTiO3-based ceramics for optimizing energy storage performance

Ba 0.85- x (Bi 0.58 Na 0.42 ) x Ca 0.15 Ti 0.85 Zr 0.15 O 3 (BCTZ- x BN) was employed as the research focus to modulate grain size, lattice distortion, and defect concentration by adjusting the BN content, thereby regulating energy storage performance. The influence mechanisms of grain size, lattice distortion, and defect concentration on energy storage performance were investigated through experimental and numerical calculations. Experimental characterization (XRD diffraction, high-resolution transmission electron microscopy, and impedance testing) and theoretical analysis (V-F model, macroscopic and phenomenological models, and Landau Devonshire theory) revealed that the polar nanoregions (PNRs) induced by lattice distortion and charge defects improved energy storage efficiency. Finite element simulation and impedance analysis indicate that fine grain size and fewer charge defects contribute to improved breakdown strength. As a result, the W rec and η of the modified samples were significantly improved by 6 and 1.7 times, respectively. This work provides insights into the design of high-performance ceramic capacitors and establishes a theoretical framework for understanding the energy storage mechanism.