Meng Guodong, She Junyi, Wang Changling, Wang Wenke, Pan Cheng, Cheng Yonghong
State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an, China.
School of Electrical Engineering, Wuhan University, Wuhan, China.
Front Chem. 2022 Jul 4;10:910305. doi: 10.3389/fchem.2022.910305. eCollection 2022.
Energy storage film is one of the most important energy storage materials, while the performance of commercial energy storage films currently cannot meet the growing industrial requirements. Hence, this work presents a h-BN/PVDF/h-BN sandwich composite structure film prepared by laminating a large area of ultrathin hexagonal boron nitride (h-BN) and polyvinylidene fluoride (PVDF), the existence of which was confirmed by using an optical microscope and elemental composition analysis based on scanning electron microscopy and X-ray diffraction. This film has an ultrahigh dielectric strength of 464.7 kV/mm and a discharged energy density of up to 19.256 J/cm, which is much larger than the commercial energy storage film biaxially oriented polypropylene (BOPP) (<2.5 J/cm). Although the thickness of the h-BN film is only 70 nm compared with that of PVDF (about 12 m), the dielectric strength of the sandwich-structured film presents a great increase. It is because of the excellent insulation performance of the h-BN film that helps to resist the electron injection and migration under high electric field, and then suppress the formation and growth of the breakdown path, leading to an improvement of the charge-discharge efficiency.
储能薄膜是最重要的储能材料之一，然而目前商业储能薄膜的性能无法满足不断增长的工业需求。因此，这项工作展示了一种通过层压大面积超薄六方氮化硼（h-BN）和聚偏氟乙烯（PVDF）制备的h-BN/PVDF/h-BN三明治复合结构薄膜，通过光学显微镜以及基于扫描电子显微镜和X射线衍射的元素组成分析证实了其存在。该薄膜具有464.7 kV/mm的超高介电强度和高达19.256 J/cm的放电能量密度，这比商业储能薄膜双向拉伸聚丙烯（BOPP）（<2.5 J/cm）大得多。尽管与PVDF（约12 µm）相比，h-BN薄膜的厚度仅为70 nm，但三明治结构薄膜的介电强度有了很大提高。这是因为h-BN薄膜具有优异的绝缘性能，有助于抵抗高电场下的电子注入和迁移，进而抑制击穿路径的形成和生长，从而提高了充放电效率。
