Enhancing the Energy‐Storage Density and Breakdown Strength in PbZrO ₃ /Pb _0.9 La _0.1 Zr _0.52 Ti _0.48 O ₃ ‐Derived Antiferroelectric/Relaxor‐Ferroelectric Multilayers

Multilayer thin-film dielectric capacitors with high energy-storage performance and fast charge/discharge speed have significantly affected the development of miniaturized pulsed-power devices. Here, the interfacial strain in epitaxial multilayers of antiferroelectric PbZrO3 and relaxor-ferroelectric Pb0.9La0.1Zr0.52Ti0.48O3 is shown to significantly enhance the maximum polarization of the multilayer thin-film capacitors, beyond that of the composing individual layers. Insights obtained from atomically resolved energy-dispersive X-ray spectroscopy and high-resolution X-ray diffraction analysis of the interface and domain structure are used to develop phenomenological models that explain the observed trends in breakdown strength and energy-storage density as a function of multilayer period number. The underlying mechanism is the mechanical coupling between the layers that depends on the individual layer thicknesses. These factors result in a strongly enhanced recoverable energy-storage density (increased by a factor of 4 to ≈128.4 J cm−3) with high efficiency (≈81.2%). Moreover, the multilayer films show almost fatigue-free energy-storage performance after 1010 switching cycles, even at elevated temperatures up to 220 °C, demonstrating their robustness. The outstanding properties show the great potential of epitaxial multilayers for energy-storage applications, due to the well-defined separate layers and coupling of properties across the interfaces, not present in ceramic composites.