Over the past decades, energy densities have always been considered as the key factors for realizing compact and highly efficient dielectric polymer capacitors. However, high-energy-density polymer dielectrics are limited by insurmountable drawbacks of high energy loss and low charge-discharge efficiency, which are far behind the industrial requirement for application under high temperature/voltage working conditions. Herein, a versatile method to suppress the energy loss of polymer dielectrics is presented, whereby two-dimensional montmorillonite nanosheets are interposed at the interfaces of a sandwich-structured barium titanate/polyamideimide film. The anisotropic electrical conductivity of the nanosheets provides paths to relationally regulate the charges transport along the in-plane direction while suppressing the through-plane conduction. As a result, nearly 50% of the energy loss can be eliminated with an applied electric field of 400 MV m⁻¹ at 150 °C, thus leading to a ~100% enhancement of energy density (3.6 J cm⁻¹), accompanied with a high charge-discharge efficiency of 70%, which outperforms all commercial high-temperature polymers. This work uncovers an effective and scalable pathway to enable high-density dielectric energy storage applicable to a wide range of polymer dielectrics at harsh operating conditions while promoting mechanism understanding of interfaces for interfacial engineering of high-performance dielectrics.

在过去的几十年中，能量密度一直被认为是实现紧凑高效的介电聚合物电容器的关键因素。然而，高能量密度的聚合物电介质受到高能量损失和低充放电效率的不可克服的缺点的限制，这远远不能满足在高温/高压工作条件下应用的工业要求。在此，提出了抑制聚合物电介质的能量损失的通用方法，由此将二维蒙脱土纳米片插入在夹心结构的钛酸钡/聚酰胺酰亚胺膜的界面处。纳米片的各向异性电导率提供了路径，以相关地调节沿着平面内方向的电荷传输，同时抑制了贯穿平面的传导。在150°C时为^-1，因此导致能量密度（3.6 J cm ^-1）增大约100％，并伴随着70％的高充放电效率，这优于所有商用高温聚合物。这项工作揭示了一种有效且可扩展的途径，可以在苛刻的工作条件下实现适用于各种聚合物电介质的高密度电介质能量存储，同时促进对高性能电介质界面工程接口的机理的理解。