Enhancing the Energy-Storage Density and Breakdown Strength in PbZrO₃/Pb_0.9La_0.1Zr_0.52Ti_0.48O₃-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 Pb_0.9La_0.1Zr_0.52Ti_0.48O₃ 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.