3,4-Ethylenedioxythiophene-quinoxaline based polymer electrode for symmetric supercapacitors on rigid and flexible platforms

The increasing demand for lightweight, flexible, and reliable energy storage devices drives the exploration of advanced electrode materials for supercapacitors. Conjugated donor-acceptor polymers are promising candidates because of their tunable electronic structures, redox activity, and mechanical durability. In this work, rigid and flexible symmetric supercapacitor devices were fabricated using electrochemically deposited films of a donor-acceptor polymer composed of 3,4-ethylenedioxythiophene (EDOT) and 1,2,3,4-tetrahydrophenazine (a quinoxaline derivative). The “EDOT-quinoxaline-EDOT” motif was deliberately chosen to couple the high conductivity of EDOT with the strong electron-accepting character of quinoxaline, thereby enhancing both charge storage capability and long-term stability on rigid and flexible platforms. The rigid (ITO-coated glass) and flexible (ITO-coated PET) polymer electrodes exhibited maximum areal capacitances of 5.3 and 4.5 mF/cm 2 , respectively. Moreover, notable power densities (746 μW/cm 2 for the rigid and 426 μW/cm 2 for the flexible electrode) were obtained from both of the electrodes. Then, the symmetric supercapacitor devices were constructed using both rigid and flexible substrates to investigate the influence of substrate flexibility on electrochemical performance. The rigid device demonstrated excellent cycling stability, retaining 98.3 % of its capacitance over 7000 cycles. Meanwhile, the flexible device preserved its electrochemical behavior under repeated bending, even at a 90°-bent state. The results highlight the potential of EDOT-quinoxaline-EDOT-based electrodes for integration into both rigid and flexible supercapacitor platforms, particularly for applications in wearable and portable energy storage systems. • Capacitive behavior of EDOT-Quinoxaline based donor-acceptor polymer. • Rigid and flexible supercapacitor devices were fabricated. • The flexible device maintained its electrochemical activity in different bent states. • The rigid device showed remarkable cycling stability. • The proposed polymer suits both rigid and flexible energy storage applications.