Silicon/epoxy nanocomposites for capacitors as the energy storage element

Silicon/epoxy nanocomposites were synthesized in order to investigate potential improvement of electrical energy storage capability and mechanical properties of epoxy resin on addition of Si nanospheres. Nanospheres with mean diameter 130 nm were homogenized within epoxy monomers at 5 and 10 wt.%. The dielectric behavior of the resulting nanocomposites was investigated using broadband dielectric spectroscopy from 10^-2 to 10⁶ Hz at room temperature. The dielectric constant, ε´_r, of the composite with 10 wt.% Si loading is ~ 5.1 at 10^-2 Hz, a 25% increase compared with the value for neat epoxy, whereas tan ô remains low (<; 0.035). On the other hand, a 17% increase of storage modulus was shown in the composite with 5 wt.% Si loading, compared with that of neat epoxy, and T_g of the polymer matrix was slightly elevated with Si incorporation. The increases in both permittivity and storage modulus suggest that Si/epoxy nanocomposites are suitable for multifunctional application; e.g. as structural capacitors.