A novel high-capacity retention supercapacitor based on donor-acceptor-donor conjugated polymers

Homopolymer and copolymer prepared from E2-NBT, containing 3,4-ethylenedioxythiophene as donor and nonylbithiazole as acceptor units, were used for the supercapacitor application. Homopolymer, PE2-NBT and copolymer with E (coPE2-NBT/E) were electropolymerized on ITO. Redox and capacitive behaviors of PE2-NBT and (coPE2-NBT/E) were performed by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charging-discharging. Furthermore, these polymer coatings were modified by the Au nanoparticles to obtain PE2-NBT/Au and coPE2-NBT/E/Au and their conductivity and stability were enhanced. coPE2-NBT/E/Au showed a specific capacitance of 4.9 mF cm⁻² at a current density of 0.02 mA cm⁻², has a satisfactory area-specific capacitance among Donor-Acceptor-Donor type conjugated polymer films. Upon evaluating the capacity retention performance of the coPE2-NBT/E/Au supercapacitor device, it demonstrated stability for up to 10,000 cycles, with a retention value of 77 %. The combination of three supercapacitor devices can power a 2.0 V, 0.04 W red LED light for 15 s. This study demonstrates that PE2-NBT is a promising candidate for Donor-Acceptor-Donor structured polymers in smart micro-supercapacitor device applications.