Synthesis and characterization of epoxy-aluminum nanocomposites for energy storage applications

In this paper, electrical properties of nanocomposites made of epoxy resin filled with oxide coated aluminum particles are investigated. Nanocomposite samples were prepared and experiments were performed to measure the dielectric properties including breakdown strength with respect to different filler concentrations. Material characteristics were analyzed using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD) and Thermogravimetric (TGA) techniques. Maximum electric energy density in the epoxy nanocomposite dielectric material was evaluated for different filler concentrations and compared with that of pure epoxy. Both large permittivity and high breakdown strength are required for large electric energy storage. The addition of nanoparticles enhanced the permittivity and resulted in potential gain in electric energy density even if there is slight reduction in breakdown strength. Experimental results show that permittivity increased by factor 7 and electric energy density enhanced by factor 4 as that of pure epoxy at a relatively low filler concentration of 18 wt%. Theoretical modeling of the nanocomposite was done and influence of filler loading on the permittivity, breakdown strength and electric energy density of the nanocomposites were evaluated. From the results, it is seen that theoretical model approximates the experimental values at low filler concentrations.