Improved thermal conductivity and breakdown strength of PVDF‐based composites by improving the dispersion of BN

In order to adapt to the development of electronic devices, it is necessary to improve the thermal conductivity and breakdown strength of composites. Boron nitride (BN) is an ideal candidate material with high breakdown strength and thermal conductivity. Therefore, the introduction of BN nanosheets into the polyvinylidene fluoride (PVDF) matrix can improve the thermal conductivity and breakdown strength of the composites at the same time. However, BN nanosheets can easily agglomerate in the matrix, which limits the improvement of the properties of the composites. To overcome this difficulty, appropriate water-bath heating was used to improve the fluidity of PVDF. Therefore, the dispersion of the filler is improved. When the volume fraction of BN nanosheets is 3% and the preparation temperature is 45°C, the energy storage density of the composites reached 18.5 J/cm3 at 540 kV/mm. At this point, the thermal conductivity was 0.49 W/(m⋅K), 3.5 times that of the pure PVDF film.