Tuning Confined Nanospace for Preparation of N‐doped Hollow Carbon Spheres for High Performance Supercapacitors

The structural parameters and surface functionalities of hollow carbon spheres are critical for their electrochemical performance. Herein, preparation of N-doped-hollow carbon spheres (N-HCS) with tunable structural parameters and surface properties is reported by using a confined pyrolysis strategy. Polystyrene/polyaniline (PSPAN) was pyrolyzed in a silica shell, which provided a confined nanospace. PSPAN functioned as both the core and a source of carbon and nitrogen. The surface properties and structural parameters of the obtained N-HCS could be optimized by regulating the pore size of the silica shell. The silica shell coating also prevented agglomeration of the N-HCS, leading to a regular and well-distributed spherical morphology. The N-HCS synthesized in relatively porous conditions had thinner shell, larger mesopore size, higher surface area, and higher nitrogen content and showed excellent electrochemical performance as a supercapacitor with a specific capacitance of 436.5 F g-1 at 0.5 A g-1 .