Binder-free Ruthenium Oxide/MXene/Carbon Nanofiber Ternary Composite Electrode for Supercapacitors

Carbon nanofiber-based electrodes are generally embedded with either metal oxides or two-dimensional materials to enhance their specific capacitance and rate performance. For the first time in this study, a flexible carbon nanofiber electrode consisting of metal oxide (RuO₂) and two-dimensional MXene was prepared to realize the synergetic effect on the electrochemical performance. This ternary composite electrode was prepared by electrospinning RuO_2, and MXene dispersed polyacrylonitrile precursor solution, followed by thermal treatment. The distribution of RuO₂ nanoparticles and delaminated MXene sheets within a carbon nanofiber matrix was examined using X-ray diffraction (XRD) and transmission electron microscopy (TEM), while morphological analysis was carried out using scanning electron microscopy (SEM). The electrode with pseudocapacitive RuO₂ and layered MXene facilitated charge storage by faradic reactions and intercalation of electrolyte ions. Electrochemical studies demonstrated that the prepared ternary composite electrodes exhibit a specific capacitance of 322 F g⁻¹ with a capacitance retention of 90% after 2500 cycles at 1 A g⁻¹. Additionally, the ternary composite showed an excellent rate capability with a minimal drop in capacitance when the current density was varied from 2 A g⁻¹ to 10 A g⁻¹.