Development of carbon nanofiber based hybrid electrodes and supercapacitors applications

Energy storage is of vital importance to increase the use of sustainable energy sources, balance energy demand and support transformation in the energy sector. Supercapacitors, also known as electrochemical capacitors, which store energy through Faradaic or non-Faradaic processes, have gained popularity recently as they complement or even replace traditional energy storage systems in a variety of applications. The performance of supercapacitors can be significantly increased by developing new nanoparticle-containing hybrid electrodes that use both energy storage processes simultaneously. Within the scope of this thesis, different hybrid carbon nanofiber (CNF) electrode materials were synthesized for supercapacitors. These materials were characterized by using XRD, Raman, XPS, SEM, EDX, TEM and BET techniques. The electrochemical performances of symmetric supercapacitor cells constructed from heteroatom-doped CNF-based hybrid electrodes containing ZrO2, La2O2S, Nb2O5, Eu2O3 and Gd2O3 nanoparticles were examined. As a result, the optimized CNF/ZrO2, CNF/La2O2S, CNF/Nb2O5, CNF/Eu2O3 and CNF/Gd2O3 hybrid electrode materials provided high specific capacitance (Csp), high specific energy and high cycle life. In particular, the CNF/Nb2O5-1 electrode material provided a high specific capacitance (200 F/g) and high specific energy (10 Wh/kg at a specific power of 300 W/kg) in the 0-1.2 V potential range. It retained 90% of its capacitance even after 10000 cycles. According to these results, these hybrid electrode materials exhibited a high potential for use in supercapacitors for energy storage applications.