Improvement of dielectric performance and interfacial polarization of polyvinylidene fluoride composites with CaCu₃Ti₄O₁₂@Ni hybrid nanofibers

In this paper, CaCu₃Ti₄O₁₂ (CCTO) and Ni-deposited CCTO (CCTO@Ni) hybrid nanofibers were fabricated using electrospinning and electroless plating method, respectively, and then corresponding CCTO/PVDF and CCTO@Ni/PVDF nanocomposites were also prepared. The influences of the diameter, morphology and loading content of CCTO and CCTO@Ni on the dielectric properties of the composites were studied systematically. The results showed that the CCTO nanofibers with a 400 nm diameter displayed a perfect crystallization and smooth surface and possessed polycrystalline structure consisting of many particles in line. Additionally, Ni nanoparticles with a 50 nm diameter were deposited uniformly on the surface of CCTO under a plating time of 5 min to form CCTO@Ni hybrid nanofibers. Moreover, CCTO (400 nm) and CCTO@Ni-5 min nanofibers all exhibited the optimal enhancing effect on the dielectric property of PVDF materials. Remarkably, the dielectric permittivity of CCTO@Ni/PVDF composite with 20 vol% loading was 89.3 at 10 Hz, which was 10.51 times higher than that of pure PVDF (8.5), and even 3.71 times higher than that of CCTO/PVDF (24.1). Simultaneously, it exhibited relatively low dielectric loss (0.60) and low conductivity (2.91 × 10⁻¹⁰ S/cm). The enhanced dielectric performance ought to be attributed to strengthened interfacial polarizations of CCTO@Ni/PVDF composites, which was proved by the analysis of the electric modulus formalism. This approach provides an interesting alternative to fabricate high performance dielectric nanocomposites for practical applications in the electronic industry.