Dopamine derived nanoarchitectonics nitrogen and sulfur dual doped hollow carbon spheres with interconnected micro-mesopores for supercapacitor application

Abstract

Nitrogen and sulfur dual-doped hollow carbon spheres were synthesized using dopamine as carbon precursor and L-cysteine as catalyst. The resulting hollow carbon spheres exhibited a uniform diameter of approximately 80 nm and featured a well-developed interconnected micro-/mesoporous structure. The synergistic effect of nitrogen and sulfur co-doping contributed to their superior electrochemical performance. The materials achieved a high specific capacitance of 320 F g⁻¹ at a current density of 0.5 A g⁻¹ in a three-electrode configuration with 6 M KOH as the electrolyte. Furthermore, in a symmetric all-solid-state supercapacitor, they demonstrated a competitive specific capacitance of 256 F g⁻¹ at 1 A g⁻¹, along with a good rate capability, retaining 79% of the capacitance as the current density increased twentyfold. In addition, the carbon spheres exhibited a favorable energy density of 9.8 Wh kg⁻¹ at a power density of 100 W kg⁻¹, highlighting their potential for high-performance energy storage applications.