High-performance supercapacitors enabled by N/S dual-doped porous carbon and DMO-regulated electrolyte

The demand for high-performance supercapacitors exceeds the capabilities of pristine carbon materials and traditional electrolytes. To address this gap, we prepared a petal-like multicyclic polycondensate precursor (PCDP) using Knoevenagel reaction and amine/aldehyde condensation between 3-aminorhodanine and p-phthalaldehyde. The subsequent activation of PCDP by KOH and carbonization at various temperatures (600–900 °C) were employed to produce N/S-dual doped porous carbon (N/S-DDPCs) for use as electrode materials. For N/S-DDPC8 carbonized at 800 °C, the specific surface area measured as the highest at 2047 m2 g−1 with a significant number of interconnected micro/mesoporous structures and higher N and S contents of 3.57 % and 2.31 %, respectively. Furthermore, Zn(CF3SO3)2 aqueous electrolyte was developed using dimethyl oxalate (DMO) to regulate and improve the electrochemical performance of the N/S-DDPCs while also providing better stability. In comparison to the conventional Zn(CF3SO3)2 electrolyte, the utilization of N/S-DDPC8 in DMO-regulated Zn(CF3SO3)2 electrolyte resulted in a noteworthy enhancement in energy density and power density, soaring to 36.4 Wh kg−1 from 11.7 Wh kg−1 and to 642 W kg−1 from 250 W kg−1 at a current density of 0.5 A g−1, respectively. It is particularly noteworthy that N/S-DDPC8-DMO-D can maintain 100 % specific capacitance even after 10,000 cycles, demonstrating its high-level electrochemical consistency. In brief, the porous N/S-DDPCs and DMO-regulated electrolyte created in this study serve as a valuable guide for boosting the electrochemical performance of supercapacitors.