Meng Xiang-Shuo, Zhou Yujiu, Li Jianfeng, Ye Hu, Chen Fujia, Zhao Yuetao, Pan Qifeng, Xu Jianhua
Ocean College, Jiangsu University of Science and Technology, Zhenjiang 212100, China.
Department of Film Capacitors, China Zhenhua (Group) Xinyun Electronic Components and Development Company Limited, Guiyang 550018, China.
Polymers (Basel). 2023 Mar 5;15(5):1305. doi: 10.3390/polym15051305.
Plastic film capacitors are widely used in pulse and energy storage applications because of their high breakdown strength, high power density, long lifetime, and excellent self-healing properties. Nowadays, the energy storage density of commercial biaxially oriented polypropylene (BOPP) is limited by its low dielectric constant (~2.2). Poly(vinylidene fluoride) (PVDF) exhibits a relatively high dielectric constant and breakdown strength, making it a candidate material for electrostatic capacitors. However, PVDF presents significant losses, generating a lot of waste heat. In this paper, under the guidance of the leakage mechanism, a high-insulation polytetrafluoroethylene (PTFE) coating is sprayed on the surface of a PVDF film. The potential barrier at the electrode-dielectric interface is raised by simply spraying PTFE and reducing the leakage current, and then the energy storage density is increased. After introducing the PTFE insulation coating, the high-field leakage current in the PVDF film shows an order of magnitude reduction. Moreover, the composite film presents a 30.8% improvement in breakdown strength, and a 70% enhancement in energy storage density is simultaneously achieved. The all-organic structure design provides a new idea for the application of PVDF in electrostatic capacitors.
塑料薄膜电容器因其高击穿强度、高功率密度、长寿命和优异的自愈性能而广泛应用于脉冲和能量存储应用中。如今，商业双轴取向聚丙烯（BOPP）的储能密度受到其低介电常数（约2.2）的限制。聚偏二氟乙烯（PVDF）具有相对较高的介电常数和击穿强度，使其成为静电电容器的候选材料。然而，PVDF存在显著的损耗，会产生大量废热。在本文中，在泄漏机制的指导下，在PVDF薄膜表面喷涂了高绝缘聚四氟乙烯（PTFE）涂层。通过简单地喷涂PTFE并降低泄漏电流，提高了电极 - 电介质界面处的势垒，进而提高了储能密度。引入PTFE绝缘涂层后，PVDF薄膜中的高场泄漏电流降低了一个数量级。此外，复合薄膜的击穿强度提高了30.8%，同时储能密度提高了70%。全有机结构设计为PVDF在静电电容器中的应用提供了新思路。
