Highly porous and electrically conductive three-dimensional CNT/graphene hybrid carbon nanostructure (3D CNS) was manufactured and its electrochemical performance was further enhanced by coating of polydopamine (PDA). Because PDA can provide an additional graphitic structure, a nitrogen-doping effect, and a hydrophilic effect with unshrinkable structure, the PDA-coated 3D CNS can have superior specific capacitance and energy density. In this work, the PDA-coated 3D CNS was used as structural supercapacitor electrodes by coating on the surface of carbon fiber plain-woven fabrics. As a mechanically robust electrolyte, aramid nanofibers (ANF) were uniformly dispersed into epoxy resin, and the ANF-reinforced epoxy was mixed with ionic liquid (LiTFSI/BMIM-TFSI). Therefore, the severe degradation of epoxy resin by introducing liquid electrolyte, can be successfully minimized by using highly stiff ANFs. Finally, we fabricated bi-functional carbon fiber composites can be successfully presented having structural load-bearing and energy storable characteristics.