Epoxy-based/BaTiO3 nanodielectrics: Relaxation dynamics, charge transport and energy storage

Epoxy/BaTiO3 nanocomposites developed at low nanofiller concentrations with their dielectric relaxations, charge transport dynamics and capacitive energy storage were investigated via dielectric spectroscopy and dc charge-discharge experiments. Two relaxation processes were observed, namely the alpha- and beta-relaxations, attributed to the dynamic T-g process and local motions, respectively. Another process located at low frequencies and high temperatures was identified as interfacial polarization. The charge transport properties were examined via the ac conductivity and impedance formalisms, indicating a beneficial effect with the increase of the nanofiller content. The dc conductivity was calculated from the ac spectra and exhibited Arrhenius temperature dependence. The theoretical energy density was found to increase up to 3.5 times comparing to the neat epoxy resin, highlighting the reinforcing dielectric/capacitive effect of the BaTiO3 nanoparticles on the epoxy resin. Comparisons between the theoretical energy densities and experimentally determined values were also discussed in detail.

Automated summary

The dielectric relaxations, charge transport dynamics, and capacitive energy storage of epoxy/BaTiO3 nanocomposites developed at low nanofiller concentrations were investigated. Two relaxation processes, alpha- and beta-relaxations, were observed, attributed to different mechanisms. The increase in nanofiller content was found to have a beneficial effect on charge transport properties.