Synthesis, characterizations and supercapacitor applications of some thiophene and thienothiophene derivatives

The aim of this doctoral thesis is to design, synthesize, and investigate the potential use of new organic molecules containing thiophenothiophene, thiophene-triazine, thiophene-quinoxaline, and thiophene-pyrrole derivatives as electrode materials in supercapacitors. In addition to experimental studies, computational studies have been conducted to shed light on the electronic properties of the synthesized molecules. Changes in the electronic properties of the materials have been examined by altering the substituents in the molecules. The characterization of the synthesized molecules has been carried out using various analytical techniques, including NMR, FTIR, and UV-VIS. Furthermore, the electrochemical performance of these materials has been evaluated as electrode materials for supercapacitors. The hybrid material based on thiophenothiophene and single-walled carbon nanotubes, TT-HB-SWCNT, has been used as a flexible and binder-free high-performance asymmetric supercapacitor. Additionally, thiophene-based triazine (DTTz), quinoxaline (DTQx), and pyrrole-pentatriene (DTPhPy) molecules have been utilized to produce high-capacitance composite electrode materials as additives on pencil lead/polyaniline. Comprehensive electrochemical evaluations, including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy, have been conducted to measure supercapacitor performance metrics such as capacity, energy density, and cycle stability. The results have shown significant improvements in charge storage capacity and lifespan, highlighting the potential of these heterocyclic derivatives for hybrid electrodes in next-generation supercapacitors. This study represents an important step towards diversifying the existing material toolkit for high-performance energy storage applications.