Poly(bis‐ EDOT ‐benzothiadiazole): a p/n dopable conducting polymer for type III electrochemical supercapacitors

Donor–acceptor conducting polymers are well suited for organic storage systems because of their ambipolar character making them organic materials capable of acting as both anode and cathode. For this application, balanced p‐ and n‐doping charges are required for stability upon cycling, and the potential difference between positive and negative charges determines the cell voltage in a full‐cell configuration. In a symmetric version, the same polymer serves as anode and cathode, and the system is categorized as a type III supercapacitor. We propose to use a donor–acceptor monomer structure composed of two electron donor EDOT units coupled at both sides of an electron acceptor benzothiadiazole unit. Two films of polymer were deposited onto platinum collectors by electropolymerization, and the system was tested as a type III supercapacitor in acetonitrile + 1 mol L −1 Et 4 NPF 6 . The all‐organic storage system obtained showed a cell voltage of 2.5 V, a specific charge delivered of 40 C g −1 at 2 A g −1 , an energy density of 9.5 Wh kg −1 at 2 A g −1 , a power density of 31.25 kW kg −1 at 50 A g −1 and a high stability with 80% charge retention after 200 cycles at 2 A g −1 .