Enhanced dielectric properties through using mixed fillers consisting of nano-barium titanate/nickel hydroxide for polyvinylidene fluoride based composites

The dispersion of nano-barium titanate(NBT) in polyvinylidene fluoride(PVDF) is one of the key issues in dielectric composites. Various NBT surface modification strategies which suffer from complex process and small-scale production have been reported. Herein, in-situ synthesized three-dimensional Ni(OH)2 is introduced to improve NBT dispersion in PVDF. During hydrothermal reaction, NBT aggregates are dispersed on the petals of in-situ grown Ni(OH)2 crystals as small aggregates. The three-dimensional structure of Ni(OH)2 can act as physical barrier to prohibit secondary agglomeration in PVDF to allow rather uniform NBT dispersion. Meanwhile, these hydroxyl groups on Ni(OH)2 ensures good interaction between filler and PVDF, and trigger β crystals. Comparing with NBT/PVDF containing the same amount of filler(2.5 wt%), the breakdown strength and maximum energy density containing mixed filler increases 14% and 70%, reach 282.6 KV/mm and 6.13 J cm−3, respectively. This study provides a new approach to uniformly disperse nanofillers in polymer for enhanced dielectric properties.