Work

Giant recoverable energy storage density for lead-free SrTiO 3 -based dielectric films coated by the amorphous Al 2 O 3 insulating layers

Year: 2025

Type: article

Abstract: SrTiO3 paraelectric materials, characterized by their linear polarization behavior, low polarization loss, and lead-free composition, are promising candidates for environmentally friendly energy storage dielectrics. However, their energy storage capabilities are limited by low breakdown field strength and polarization intensity. This work proposes a design strategy involving an insulator-paraelectric heterojunction multilayers by incorporating the amorphous Al2O3 (AO) insulating layers into SrTi0.99Mn0.01O3 (STM) thin films. By adjusting the number and spatial placement of the Al2O3 insulating layers, the effect mechanisms of Al2O3 layers on the microstructure and energy storage performance of STM films have been revealed. The results demonstrate that the AO/STM/AO top-bottom configuration exploits the synergistic effects of electrode interface barriers and the built-in electric field (Ein) within the heterojunction to create a full-path charge transport barrier. This arrangement significantly enhances breakdown strength and reduces conduction losses. The optimized composite film exhibits a breakdown field strength of 6467 kV/cm and a giant recoverable energy storage density of 73.33 J/cm3, with an energy storage efficiency of 80.17%, outperforming existing SrTiO3-based energy storage materials. Furthermore, the composite film demonstrates excellent stability across a wide temperature range (20-250 °C), a broad frequency band (0.2-10 kHz), and high-frequency switch cycles (107 cycles).

Source: Journal of Advanced Ceramics

DOI: 10.26599/jac.2025.9221175