Enhanced high-temperature energy storage in polyetherimide dielectric films via coating PZT/SiO2 heterostructural barrier layers

Conventional polymer film capacitors suffer from significant performance degradation at high temperatures due to increased conductivity loss. This study aims to enhance the high-temperature energy storage performance of polyetherimide (PEI) films by constructing a PZT/SiO 2 heterojunction composite dielectric structure. PEI films were prepared by solution casting and then modified by magnetron sputtering to deposit PZT and SiO 2 layers. At 150 °C, the composite films exhibited a high breakdown strength of 636.7 MV/m, a discharged energy density of 4.28 J/cm 3 , and a charge–discharge efficiency exceeding 90%. The PZT/SiO 2 heterojunction effectively inhibited charge injection, reducing leakage current and improving cyclic stability with minimal degradation after 50000 charge–discharge cycles. This scalable method offers a promising approach for developing high-performance polymer-based energy storage materials suitable for high-temperature applications.