High-performance Supercapacitors Enabled by N/S Dual-doped Porous Carbon and DMO-regulated Electrolyte

Abstract The pristine carbon materials and traditional electrolytes can not fully meet the increasing practical demand for the high-performance of supercapacitors. Herein, a petal-like multicyclic polycondensate precursor (PCDP) was first prepared by Knoevenagel reaction and amine/aldehyde condensation between 3-aminorhodanine and p-phthalaldehyde. The subsequent activation of PCDP by KOH and final carbonization at different temperatures (600–900 ℃) was performed to get N/S-dual doped porous carbon (N/S-DDPCs) as electrode materials. For N/S-DDPC8 carbonized at 800 ℃, the highest specific surface area was measured as 2047 m2 g− 1, with a large number of interconnected microporous and mesoporous structures and the higher N and S contents of 3.57% and 2.31%, respectively. In addition, Zn(CF3SO3)2 aqueous electrolyte regulated by dimethyl oxalate (DMO) was fabricated in order to further enhance and stabilize the electrochemical performance for N/S-DDPCs. In contrast to the traditional Zn(CF3SO3)2 electrolyte, the energy density and power density of N/S-DDPC8 in DMO-regulated Zn(CF3SO3)2 electrolyte was significantly increased 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. Most excitedly, N/S-DDPC8-DMO-D can maintain 100% specific capacitance even after 10000 cycles, showing the superhigh electrochemical stability. In brief, N/S-dual doped porous N/S-DDPCs and DMO-regulated electrolyte prepared in this study provides a useful reference for the synergistically enhancing the electrochemical performance for the supercapacitors.