Ternary atomized Hollow carbon spheres for high-performance symmetric supercapacitors

Hollow carbon spheres are among the most promising materials for supercapacitor electrodes. Here, N, S, and F-doped hollow carbon spheres have been synthesized, and their electric double layer supercapacitor (EDLC) performances have been investigated in a KOH electrolyte. It is found that the device with electrodes having N, S, and F ternary atom-doped material delivers superior performance and rate capability compared to N-doped and N, S co-doped materials. The ternary atom-doped device delivered a specific energy of 11.15 Wh kg^-1 at a power density of 208 W kg^-1. The EDL symmetric capacitor delivered 6.83 Wh kg^-1 even at a higher specific power of 10 kW kg^-1 (5 A g^-1). The EDL symmetric capacitor exhibited excellent capacitance retention of 89% and a coulombic efficiency of 100% after 22,000 cycles at 1 A g^-1. Thus, the ternary atom-doped material emerges as a better candidate for versatile and high-performance devices in a wide range of high-energy, high-power applications.