Carbon Thin Film Wrapped around a Three-Dimensional Nitrogen-Doped Carbon Scaffold for Superior-Performance Supercapacitors

A carbon thin film/carbon foam core/ sheath structure was synthesized by chemical vapor deposition (CVD) on carbonized melamine foam. It has a specific capacitance of 310 Fg @ 1 at a current density of 1 Ag @ 1 and shows outstanding electrochemical performance in both aqueous and water-in-salt electrolytes. Electrochemical analysis by cyclic voltammetry and galvanostatic charge/discharge testing re-vealed a large capacitive contribution up to more than 90% of its total capacitance. The core/sheath structure has advantages in ion transport and a high degree of utilization of the electrode surface, and the synthetic process provides a way to coat carbon thin film on any substrate by nickel-catalyzed CVD.