Strain and temperature engineering of energy storage performance in ferroelectric/paraelectric superlattices

This study investigates the effects of biaxial strain and temperature on polarization domains and energy storage properties of lead titanate/strontium titanate superlattices through phase-field simulations. The superlattice exhibits periodic polarization vortices with alternating symmetries, whose distribution is strain-dependent: compressive strain enlarges vortex regions, while tensile strain suppresses them, favoring uniform alignment. These domain reconfigurations govern hysteresis, with compressive strain yielding single-loop and tensile strain producing double-loop polarization–electric field responses. Energy storage performance exhibits strong strain dependence, under tensile strain achieving optimal discharge energy density of 74.03 J/cm³ and efficiency of 99.74%, a 25% enhancement over compressive conditions. Thermal analysis confirms stable energy storage up to 500°C, highlighting operational robustness. By correlating mechanical-thermal stimuli with domain evolution, this work establishes strain engineering as an effective strategy for designing ferroelectric superlattices with on-demand energy storage capabilities, advancing the development of adaptive dielectric capacitors.