薄膜电容器是现代电力装置与电子设备的核心电子元件, 受限于薄膜介质材料的介电常数偏低, 当前薄膜电容器难以获得高储能密度(指有效储能密度, 即可释放电能密度), 从而导致薄膜电容器体积偏大, 应用成本过高。将具有高击穿场强的聚合物与高介电常数的纳米陶瓷颗粒复合, 制备聚合物/陶瓷复合电介质, 是实现薄膜电容器高储能密度的有效策略。对于单层结构的0-3型聚合物/陶瓷复合电介质, 其介电常数与击穿场强难以同时获得有效提升, 限制了储能密度的进一步提高。为了解决此矛盾, 研究者们叠加组合高介电常数的复合膜与高击穿场强的复合膜, 制备了2-2型多层复合电介质, 能够协同调控极化强度与击穿场强来获取高储能密度。研究表明, 调控多层复合电介质的介观结构与微观结构, 可以实现优化电场分布、协同调控介电常数与击穿场强等目标。本文综述了近年来包括陶瓷/聚合物和全有机聚合物在内的多层聚合物基复合电介质的研究进展，重点阐述了多层结构调控策略对储能性能的提升作用，总结了聚合物基多层复合电介质的储能性能增强机制, 并讨论了当前多层复合电介质面临的挑战和发展方向。

Film capacitors are the core electronic components of modern power devices and electronic equipment. However, due to the low dielectric constant, it is difficult to obtain high energy storage density (effective energy storage density or discharged energy density) for present film capacitors, leading to a large device size and high application cost. To improve the energy storage density of film capacitors, a nanocomposite approach is an effective strategy via combining high dielectric constant of the ceramic nanoparticles with high breakdown strength of the polymer matrix. Nevertheless, for single-layer structure of 0-3 polymer/ceramic composites, the dielectric constant and breakdown strength are difficult to be effectively enhanced at the same time, which limits the further improvement of energy storage density. To solve this contradiction, researchers have combined the composite film with high dielectric constant and high breakdown strength in a superposition to prepare 2-2 type multilayer composite dielectrics, which can achieve synergistic regulation of polarization strength and breakdown strength to obtain high energy storage density. The optimization of electric field distribution and the synergistic regulation of dielectric constant and breakdown strength can be achieved through mesoscopic and microstructural modulation of multilayer composite dielectrics. In this paper, the research progress of multilayer polymer-based composite dielectrics including ceramic/polymer multilayer structure and all-organic polymer multilayer structure in recent years is reviewed. Effect of multi-layer structure control strategy on the improvement of energy storage performance is emphasized. Moreover, enhancement mechanism of energy storage performance of polymer-based multilayer structure composite dielectric is summarized. Finally, challenges and development directions of multilayer composite dielectrics are discussed.