Well-balanced high permittivity and low dielectric loss obtained in PVDF/graphite/BN ternary composites by depressing interfacial leakage conduction

• Published in: Microelectronic engineering 2020-07, Vol.231, p.111404, Article 111404
• Main Authors: Deng, Qihuang, Li, Xiaoxiao, Li, Qin, Xia, Xiaofeng, He, Cheng’en, Feng, Yefeng, Peng, Cheng
• Format: Article
• Language: English
• Subjects: Boron nitride; Ceramics; Composite; Composite materials; Conductivity; Dielectric loss; Dielectric properties; Dielectrics; Electrical properties; Electrical resistivity; Energy storage; Fillers; Fluoropolymers; Graphite; Leakage; Loss; Permittivity; Polymer matrix composites; Polymers
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2020.111404

High permittivity can be easily obtained in the polymer/inorganic conductive ceramic composites for energy storage. However, in these composites, the elevated high conductivity and dielectric loss are accompanied with high permittivity. To balance the requirements of high permittivity and low loss, in this work, we employed physical blending and solution casting to fabricate the ternary polymer/graphite/boron nitride composite films with the improved comprehensive electrical properties. The inexpensive graphite was used as the conductive filler for elevating the dielectric response based on an interface polarization. Hexagonal boron nitride (BN) was utilized as the insulating nanofiller for reducing the leakage conduction. The semi-crystalline fluoropolymer was adopted as the matrix. Compared with the binary polymer/graphite composites, their ternary counterparts were measured to have a reduced conductivity and dielectric loss along with a favourable high permittivity. The best ternary composite filled with 5.0 wt% BN and 1.5 wt% graphite had a permittivity of ~64, loss of ~0.097 and conductivity of ~5.7 × 10−7 S m−1 at 100 Hz. This work may provide a rational approach for preparing high-performance composite dielectrics through an excellent synergy of conductive and insulating fillers. [Display omitted] •Novel ternary composite dielectrics with high overall electric traits were fabricated.•Excellent synergy between graphite and BN fillers was realized.•Leakage-conduction depressing mechanism was well clarified.