Boron-Induced Nitrogen Fixation in 3D Carbon Materials for Supercapacitors
2020
Sun, Peng | Huang, Jian | Xu, Feng | Xu, Jijian | Lin, Tianquan | Zhao, Wei | Dong, Wujie | Huang, Fuqiang
Nitrogen-rich carbon materials attract great attention because of their admirable performance in energy storage and electrocatalysis. However, their conductivity and nitrogen content are somehow contradictory because good conductivity requires high-temperature heat treatment, which decomposes most of the nitrogen species. Herein, we propose a facile method to solve this problem by introducing boron (B) to fix the nitrogen in a three-dimensional (3D) carbon material even at 1000 °C. Besides, this N-rich carbon material has a high content of pyrrolic nitrogen due to the selective stabilization of B, which is favorable in electrochemical reactions. Density functional theory (DFT) investigation demonstrates that B reduces the energy level of neighboring N species (especially pyrrolic nitrogen) in the graphene layer, making it difficult to escape. Thus, this carbon material simultaneously, achieves high conductivity (30 S cm–¹) and nitrogen content (7.80 atom %), thus showing an outstanding capacitance of 412 F g–¹ and excellent rate capability.
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