Regulating monomer assembly to enhance PEDOT capacitance performance via different oxidants

The development of poly(3,4-ethylenedioxythiophene) (PEDOT) with high specific capacitance is the key to pursuing high-performance supercapacitors, and the electrochemical properties of PEDOT are closely related to the oxidation degree and conjugated chain length of its molecular chain. In this work, the influences of various oxidants (FeCl3, Fe(Tos)3 and MoCl5) on the molecular chain structure and capacitive properties of PEDOT via vapor phase polymerization were systematically investigated. Fe(Tos)3 can significantly improve the degree of oxidation and the length of the conjugated chain of PEDOT compared to FeCl3 and MoCl5, enhancing the conductivity and providing more active sites for Faraday reaction. Therefore, the PEDOT/P(Fe(Tos)3) electrode displays a considerable conductivity of 73 S cm-1, high areal capacitance (419 mF cm-2) and excellent electrochemical stability under the different bent state. Moreover, the conjugated structure strengthens the interaction between PEDOT chains, achieving good cycle stability. Therefore, Fe(Tos)3 is an ideal oxidant for obtaining high-performance PEDOT electrode materials.