Heterostructure is highly effective to improve the energy storage properties of the thin films for one phase provides large polarization and the other phase maintains high electrical breakdown strength. In this paper, the two-layered and the sandwich-structured BFO/STO thin films were prepared by a sol–gel method, respectively. The influence of BFO layer positions on the electrical properties was investigated. The results show that compared with the two-layered film, the breakdown strength of the sandwiched film is increased by 29.2% to 2.431 MV/cm, the energy storage density is significantly improved. The recoverable energy storage density is 29.5 J/cm³ with an efficiency of 54.8%. Its dielectric properties at 10 kHz are: the dielectric constant is 111, the dielectric loss is 0.036 and the capacitance-temperature variation from room temperature to 145 °C is lower than 15%. It indicates that the sandwich structure is superior to the two-layered film since the former shows more interface which is beneficial to inhibit electronic tree growth.

异质结构对于提高薄膜的能量存储性能非常有效，因为一相提供大极化，而另一相保持高电击穿强度。在本文中，两层和三明治结构的 BFO/STO 薄膜分别通过溶胶-凝胶法制备。研究了 BFO 层位置对电性能的影响。结果表明，与两层薄膜相比，夹层薄膜的击穿强度提高了29.2%，达到2.431 MV/cm，储能密度显着提高。可恢复储能密度为29.5 J/cm ³效率为 54.8%。其在 10 kHz 的介电性能为：介电常数为 111，介电损耗为 0.036，从室温到 145 °C 的电容-温度变化低于 15%。这表明夹心结构优于两层薄膜，因为前者显示出更多的界面，有利于抑制电子树的生长。