Synthesis of poly(N-alkyl-3,4-dihydrothieno[3,4-b][1,4]oxazine) derivatives and investigation of their supercapacitive performances for charge storage applications

Herein, pseudocapacitive performances of novel poly(4-methyl-3,4-dihydro-2H-thieno[3,4-b][1,4]oxazine) and poly(4-ethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]oxazine) have been investigated for supercapacitor applications as electrode materials. Initially, N-alkyl-dihydro-1,4-oxazine ring fused thiophene monomers were synthesized for the first time. These monomers were polymerized electrochemically on a stainless steel electrode and well characterized. Stainless steel electrodes coated with these polymers have been used as an anode material against poly(ethylenedioxythiophene) (pEDOT) coated cathode in an asymmetric pseudocapacitor cell and as both anode and cathode material in a symmetric pseudocapacitor cell. Capacitive behaviors of n/p type pseudocapacitors have been tested by cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS) techniques. Specific capacitance (Cspec) values of the pseudocapacitor cells, observed with electrochemical performance tests, are in the range of 285.6 F g−1 and 325.1 F g−1. Additionally, specific energy (SE) values for the symmetric and asymmetric pseudocapacitor cells have been calculated in the range of 64.26–86.74 Wh kg−1 from electrochemical tests data.