Ordered multiphase polymer nanocomposites for high-performance solid-state supercapacitors

Multilayered ordered nanostructures were fabricated by assembling in-situ grown polyaniline nanowire arrays with graphene oxide nanosheets. As-fabricated nanostructure was subsequently impregnated with the (H₃PO₄-Nafion)/polyvinyl alcohol solution to create a multiphase composite, which was used as a solid-state supercapacitor where graphene oxide/polyaniline nanowires served as electrode and (H₃PO₄-Nafion)/polyvinyl alcohol served as solid electrolyte. The ordered polyaniline (PANI) nanostructures facilitated the charge transfer and resulted in the specific capacitance of 83 F/g even if the discharge current was 5 A/g. The efficient charge transportation and electrode-electrolyte interaction resulted in small equivalent series resistance as low as 5.83 Ω, and thus outstanding electrochemical performance. The charge transfer resistance was much smaller than other commonly used solid-state electrolyte and almost negligible. As a result only 7% capacitance loss was found when the frequency increased from 100 to 1000 Hz. The energy density was as high as 26.5 Wh/kg while the power density was ∼3600 W/kg. The energy storage performance was also very stable since 82% specific capacitance was maintained after 1000 cycles.