Advancing Energy-Storage Performance in Freestanding Ferroelectric Thin Films: Insights from Phase-Field Simulations

Advances in flexible electronics are driving the development of ferroelectric thin-film capacitors toward flexibility and high energy storage performance. In the present work, the synergistic combination of mechanical bending and defect dipole engineering is demonstrated to significantly enhance the energy storage performance of freestanding ferroelectric thin films, achieved through the generation of a narrower and right-shifted polarization-electric field hysteresis loop. The recoverable energy storage density of freestanding PbZr_0.52Ti_0.48O₃ thin films increases from 99.7 J cm⁻³ in the strain (defect) -free state to 349.6 J cm⁻³, marking a significant increase of 251%. The collective impact of the flexoelectric field, bending tensile strain, and defect dipoles contributes to this enhancement. The demonstrated synergistic optimization strategy has potential applicability to flexible ferroelectric thin film systems. Moreover, the energy storage properties of flexible ferroelectric thin films can be further fine-tuned by adjusting bending angles and defect dipole concentrations, offering a versatile platform for control and performance optimization.