Structural energy storage system using electrospun carbon nanofibers with carbon nanotubes

In the present study, carbon nanofibers containing multi-walled carbon nanotubes (MWCNTs) were fabricated and employed as electrodes for structural supercapacitors. Carbon nanofibers were utilized as the electrode material in structural supercapacitors to increase the specific surface area. Electrospun polyacrylonitrile (PAN) nanofibers underwent conversion to carbon nanofibers through stabilization and carbonization processes aided by thermal treatment. The specific surface area of the electrospun carbon nanofiber electrodes was further increased approximately 118 times (1946.9 m(2)/g) using an activation process in comparison with that of non-activated carbon nanofibers (16.43 m(2)/g). Multifunctional supercapacitors were fabricated by employing electrospun carbon nanofibers and a vacuum resin infusion technique. The specific capacitance of activated carbon nanofibers (ACNF) and ACNF-MWCNT exhibited significant improvement (14.87 and 48.25 mF/cm(2), respectively) compared to non-activated carbon nanofibers (CNF-MWCNT: 1.71 mF/cm(2)). This improvement was attributed to the reduction in equivalent series resistance and the increase of the surface area of the nanofiber electrodes. Additionally, the carbon nanofiber electrodes contributed to an increased interlaminar fracture toughness of structural supercapacitors, acting akin to "Velcro" between fabric interfaces. This work serves as a "proof of concept" for a straightforward and efficient method to manufacture electrodes for structural supercapacitors based on the electrospinning technique.Highlights Fabrication of carbon nanofibers containing MWCNTs using electrospinning. The carbon nanofiber as an electrode for structural supercapacitors. Simple and effective method. Dramatically improving specific capacitance of the supercapacitors.