Synthesis\nof N‑Doped Hollow-Structured Mesoporous Carbon Nanospheres\nfor High-Performance Supercapacitors

Abstract

We have demonstrated\na facile and controllable synthesis of monodispersed N-doped hollow\nmesoporous carbon nanospheres (N-HMCSs) and yolk–shell hollow\nmesoporous carbon nanospheres (N-YSHMCSs) by a modified “silica-assisted”\nroute. The synthesis process can be carried out by using resorcinol-formaldehyde\nresin as a carbon precursor, melamine as a nitrogen source, hexadecyl\ntrimethylammonium chloride as a template, and silicate oligomers as\nstructure-supporter. The morphological (i.e., particle size, shell\nthickness, cavity size, and core diameter) and textural features of\nthe carbon nanospheres are easily controlled by varying the amount\nof ammonium. The resultant carbon nanospheres possess high surface\nareas (up to 2464 m² g^–1), large pore\nvolumes (up to 2.36 cm³ g^–1), and uniform\nmesopore size (∼2.4 nm for N-HMCSs, ∼ 4.5 nm for N-YSHMCSs).\nThrough combining the hollow mesoporous structure, high porosity,\nlarge surface area, and N heteroatomic functionality, the as-synthesized\nN-doped hollow-structured carbon nanospheres manifest excellent supercapacitor\nperformance with high capacitance (up to 240 F/g), favorable capacitance\nretention (97.0% capacitive retention after 5000 cycles), and high\nenergy density (up to 11.1 Wh kg^–1).