A Flexible Asymmetric Supercapacitor with High-Performance and Long-Lifetime: Fabrication of Nanoworm-Like-Structured Electrodes Based on Polypyrrole-Thiosemicarbazone Complex.

A thiosemicarbazone-based iron(III) complex is prepared and used in the preparation of a supercapacitor electrode material. This electrode is produced by a solvothermal reaction of polypyrrole and the complex on carbon felt. The characterization of the complex and material is carried out using UV-vis, elemental analysis, FT-IR, XRD, BET, and TGA methods, and the surface morphology is examined using SEM technique. Because the interaction of electrode and electrolyte is of great importance in energy storage systems, as the surface area and pore volume increase, electrode ions at the electrode/electrolyte interface leak to the inner surfaces and interact with the larger surface area, which increases the charge storage performance. The electrode material, nano-worm structure, reached the highest specific capacitance value of 764.6 F g^-1 at 5 mV s^-1. Compared to the capacitance value of polypyrrole in its pure form, it is observed to exhibit an 187.2% increase. The highest specific capacitance value of the asymmetric supercapacitor (ASC) formed with a graphite electrode is 318.1 F g^-1 at the current density of 1 Ag^-1. Moreover, ASC reached a wide working potential of 1.8 V in an aqueous electrolyte and exhibited ultra-long cycle life (112%), maintaining its stability after 10 000 cycles.