Role of Phenylenediamine Isomers on Polyaniline Copolymers in Advancing Supercapacitor Electrode Materials: Exploring Electrochemical Performance

This study investigates the copolymerization of the phenylenediamine (PDA) compound with different isomeric structures (ortho/oPDA, meta/mPDA, and para/pPDA). The aim is to eliminate the disadvantages of polyaniline (PANI), such as its low cycle number, and to improve its electrochemical properties. Furthermore, the study investigates the impact of various isomeric structures of PDA on the synthesized copolymer in terms of its physical, chemical, morphological, and electrochemical properties. The outcomes show the surface morphologies of the copolymers obtained from the copolymerization of PDAs with PANI [P(ANI-PDA) isomers] exhibit distinct differences observed through SEM scans. The impedance analysis revealed decreased resistance and increased electrochemical properties in the designs when utilizing PANI copolymerized with oPDA P(ANI-co-oPDA) as an electrode. P(ANI-co-oPDA) designs yielded a significant specific capacitance (Cs) of 541.7 F/g and notable energy and power density values of 7.5 Wh/kg and 23.9 kW/kg, respectively. Furthermore, defect structures of PANI and P(ANI-PDA isomers) copolymers were analyzed using EPR, revealing notable alterations in the g-factor values and peak intensities of the materials due to the incorporation of PDA with varying isomeric structures. Results demonstrate that utilizing PDA with various isomers in synthesis of materials can improve the electrochemical properties and cyclic stability of PANIs in energy storage systems.