One-dimensional (1D) materials as fillers introduced into polymer matrixes have shown great potential in achieving high energy storage capacity because of their large dipole moments. In this article, 1D lead-free 0.5(Ba0.7Ca0.3)TiO3-0.5Ba(Zr0.2Ti0.8)O3 nanofibers (BCZT NFs) were prepared via electrospinning, and their formation mechanism was systematically studied. Polypropylene acyl tetraethylene pentamine (PATP) grafted into the surface of BCZT NFs was embedded in the polymer matrixes, which effectively improved the distribution and compatibility of the fillers via chemical bonding and confined the movement of the charge carriers in the interface filler-matrix. The energy density at a relatively low electric field 380 MV m-1 was increased to 8.23 J cm-3 by small loading of fillers, far more than that of biaxially oriented polypropylene (BOPP) (≈ 1.2 J cm-3 at 640 MV m-1). Moreover, the nanocomposite loaded with 2.1 vol % BCZT@PATP NFs exhibits a superior discharge speed of ≈0.189 μs, which indicates the potential application in practice. The finite element simulation of electric potential and electric current density distribution revealed that the PATP grafted into the BCZT NFs surface could significantly improve the dielectric performances. This work could provide a new design strategy for high-performance dielectric polymer nanocomposite capacitors.
Keywords: capacitors; dielectric properties; energy density; lead-free; nanocomposites.