Exploration of acid-doped polyureas with redox-active aniline oligomers for supercapacitor applications

• Novel redox-active polyurea DPTA and DPTAni systems are fabricated. • ACTA and ACTAni displays excellent electrochemical properties. • DPTA and DPTAni in the 3E SC systems delivers C sp of 269.3 and 232.01 F/g, respectively. • For 2E SSC system the DPTA and DPTAni exhibits C sp of 130 and 160 F/g, respectively. In the rapidly growing modern era, the advancement of electrochemical energy storage (EES) materials for electronic devices is a key challenge. Herein, we report the synthesis of novel redox-active polyureas (PUrs) bearing carbonyl functional group and repeated redox segments starting from the redox-active amine-capped trianiline (ACTA) and amine-capped tetraaniline (ACTAni). These materials are doped with 2 M HCl and designated as DPTA and DPTAni. The material properties and surface analysis are thoroughly analyzed by fourier transform infrared (FT-IR) spectroscopy, UV–Vis absorption spectroscopy, field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) techniques. In a three-electrode (3E) system, DPTA achieves a high specific capacitance ( C sp ) of 260.9F/g, outperforming DPTAni of 239F/g, as determined by galvanostatic charge–discharge (GCD) measurements. However, long-term cycling stability exhibits the capacitance retention for DPTA and DPTAni was about 59.12 % and 46.38 %, respectively, for 2000 cycles and with a significant decrement of C sp for 5000 cycles owing to an increase in the solution resistance, as confirmed by Electrochemical impedance spectroscopy (EIS). This study highlights the potential of carbonyl-functionalized PUrs as promising candidates for next-generation pseudo-capacitive materials, with further optimizations for enhancing cycling stability.