Enhanced breakdown strength and energy density of PVDF composites by introducing boron nitride nanosheets
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Boron nitride nanosheets (BN NSs) with about 2 nm thickness and 200–400 nm lateral sizes were prepared by ultrasonically exfoliating bulk boron nitride (BN) powders in deionized water (DI). BN NSs/polyvinylidene fluoride (PVDF) composites were fabricated by a solution casting method. The enhanced breakdown strength and energy density of the composites were obtained at a low BN NSs weight fraction. The maximum breakdown strength and discharged energy density of 8 wt% BN NSs/PVDF composites reached to 486 kV/mm and 7.25 J/cm3, respectively, which led to 54 and 99% increase compared with pure PVDF (306 kV/mm, 3.63 J/cm3). Meanwhile, the loss tangent of BN NSs/PVDF composites was lower than pure PVDF. The enhanced dielectric properties could be attributed to BN NSs with high insulation and wide band gap. In addition, two-dimensional (2D) BN NSs fillers tended to be perpendicular to the applied electric field and effectively acted as insulating barriers to improve the breakdown strength and energy density.
This work was supported by National Natural Science Foundation of China (CN) (Grant No. 51372014).
- 15.J.E. Padilha, R.B. Pontes, A. Fazzio, J. Phys.: Condens. Matter 4, 075301 (2012)Google Scholar