High energy density nanocomposites based on surface-modified BaTiO(3) and a ferroelectric polymer.

TLDR: Comparisons with model calculations indicate the important roles of nanoparticle percolation and porosity of the nanocomposites on the dielectric properties, and the calculated maximum energy densities indicate maximal extractable energy for two different particle volume fractions.

Abstract: The dielectric permittivity and electric breakdown strength of nanocomposites comprising poly(vinylidene fluoride-co-hexafluoro propylene) and phosphonic acid surface-modified BaTiO3 nanoparticles have been investigated as a function of the volume fraction of nanoparticles. The mode of binding of pentafluorobenzylphosphonic acid on the BaTiO3 particles was investigated using infrared and 31P solid-state nuclear magnetic resonance spectroscopy, and the phosphonic acid was found to form well ordered, tightly bound monolayers. The effective permittivity of nanocomposites with low volume fractions (<50%) was in good agreement with standard theoretical models, with a maximum relative permittivity of 35. However, for nanoparticle volume fractions of greater than 50%, the effective permittivity was observed to decrease with increasing nanoparticle volume fraction, and this was correlated with an increase in porosity of the spin-coated nanocomposite films. The dielectric breakdown strength was also found to decre...