Tunable N-doped hollow carbon spheres induced by an ionic liquid for energy storage applications

Herein, feasible ionic liquid co-assembly with a silica precursor and carbon precursor was employed to prepare N-doped mesoporous carbon materials with tunable structures. The utilization of an ionic liquid realizes the co-assembly process of silica and resin to form spherical hollow structures under a suitable ethanol/water volume ratio and leads to nitrogen doping for the prepared N-doped hollow carbon spheres (N-HCSs) in situ. The ethanol/water volume ratio strongly affects the morphologies of the N-HCSs, in which an appropriate volume ratio is crucial for the effective formation of a regular spherical morphology. The addition of the silica precursor is key to the formation and enrichment of mesopores, and thus it is helpful to improve the charge transport. N-HCSs with regular spherical morphology, large hollow structure, and rich mesoporous structure show better performance. As a supercapacitor electrode material, the N-HCSs achieve a high capacity and present high cycling stability, suggesting potential for energy storage applications.