A Simple and Green Preparation Method of Nitrogen‐Doped Carbon Nanocages for Supercapacitor Application

Abstract The exploration of porous carbon materials with excellent electrochemical capacity is urgently needed for the development of the next generation of energy storage devices. Cage‐like carbon nanomaterials have been extensively studied for their excellent capacitive properties, but the current preparation methods for carbon nanocages are generally costly. A simple and green preparation method for nitrogen‐doped carbon nanocages is proposed in this study. In the synthesis process, the growth of the carbon nanocages is realized by using potassium chloride as a hard template, which can be removed by washing with hot water, avoiding the use of corrosive reagents and realizing the reuse of the template by recrystallization. The carbon materials exhibit unique nanocage morphology with macropores, which can provide fast ion diffusion pathways. Meanwhile, nitrogen doping enhances electrolyte ion interactions with carbon surfaces, leading to improved capacitances and rate capabilities. By the synthetical effect of the above characteristics, the specific capacitance reaches 251 F g⁻¹ at 0.1 A g⁻¹ and 201 F g⁻¹ at 10 A g⁻¹. This work introduces a new method for preparing high‐performance carbon electrode materials.