Facile preparation of N,S-doped hierarchical porous carbons based on 3-aminophenol-3-mercaptophenol co-resins for supercapacitor applications

Abstract

Hierarchical porosity and heteroatom-doping have been proved to be desirable for carbon electrode materials in advanced supercapacitors. In this study, dual N,S-doped hierarchical carbon materials were facilely prepared via a simple carbonization of the potassium salts of 3-aminophenol-3-mercaptophenol co-resin. The morphology, structure and surface properties of the carbon materials were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption, X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDS). It is proposed that the fast nucleophilic addition between the phenols and formaldehyde produces nano-sized gel particles, followed by carbonization into carbon particles, finally packing to the mesopores. The in situ activation of potassium ions creates abundant ultra-microporosity. Due to the synergistic effects of the tailored porosity and N,S,O-doping, the prepared carbons show a high specific capacitance (252 F g⁻¹ for NSHPC-700), good capacitance retention (63.3% for NSHPC-900) in the range of 0.2–20 A g⁻¹ and very low relaxation time constant of 0.16 s in a KOH electrolyte.