Improved energy storage density of composite films based on poly(arylene ether nitrile) and sulfonated poly(arylene ether nitrile) functionalized graphene

Sandwich-like structured sulfonated polyarylene ether nitrile (SPEN) /graphene oxide (GO) hybrid was prepared to improve the energy density of polyarylene ether nitrile (PEN). Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) illustrate that SPEN were successfully coated on the graphene oxide through chemical bond linkage. The surface of SPEN functionalized graphene oxide not only prevent the reunion of initial GO but also improve the compatibility between PEN and SPEN@GO. The dielectric properties of SPEN@GO/PEN and GO/PEN composites films were tested from 0.04 kHz to 200 kHz. Compared to GO/PEN composites films, the SPEN@GO/PEN composites films exhibit higher dielectric strength while synchronously possess lower dielectric loss element. The dielectric constant of SPEN@GO/PEN films was 23 (at 1 kHz) with the content of SPEN@GO researched 15 wt%. The electrical breakdown strength (Eb) was 190 kV/mm, which was much higher than that of GO/PEN films. Furthermore, the energy density was calculated as 3.1 J/cm(3), which was three times more than that of pure PEN. This category of SPEN@GO/PEN composite films with low dielectric loss has a great potential application at flexible film capacitors.