Improving breakdown strength and energy storage efficiency of poly(vinylidene fluoride-co-chlorotrifluoroethylene) and polyurea blend films by double layer structure design

• Published in: Polymer testing 2020-01, Vol.81, p.106261, Article 106261
• Main Authors: Zhou, Yujiu, Liu, Qingxia, Chen, Fujia, Zhao, Yuetao, Xu, Jianhua, Yang, Wenyao, He, Xin, Mao, Xiling, Yang, Yajie
• Format: Article
• Language: English
• Subjects: Double layer composite structure; Energy storage efficiency; Polyurea
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/j.polymertesting.2019.106261

All-organic composites are widely used in energy storage application due to the high breakdown strength performance, but the improvement of energy storage was limited by the relatively low dielectric constant. Therefore, to satisfy the high demands of dielectric materials, energy storage properties of polymer composites should be further enhanced. In this article, poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-CTFE)) and polyurea (PUA), which are known as high dielectric ferroelectric material and linearly high energy storage efficiency material respectively, are composited through double layer (DL) casting method for the first time. The properties of DL structured composite film is contrasted with solution blending structure especially in energy storage efficiency, and the results demonstrate that DL structure design can make great use of advantages of two materials and also can avoid the influence of phase separation between P(VDF-CTFE) and PUA efficiently. Moreover, high breakdown strength (6180 kV/cm) and high energy storage efficiency (77%) of DL composites can be realized simultaneously by incorporating PUA as an insulating layer, and the mechanism is discussed in detail. This work provides an effective route to improve the energy storage properties of polymer dielectric materials and shows great application potential. [Display omitted] •A PUA and P(VDF-CTFE) double layer (DL) composite structure is designed for the first time.•The DL structure can make a good use of all the advantages of PUA and P(VDF-CTFE).•The DL structure can avoid the phase separation effectively.•The breakdown strength of DL structure are improved obviously.•A high energy storage efficiency (77%) of DL structure can be realized simultaneously.