Edge-nitrogen synergize with micropores to realize fast and durable potassium storage for carbon anode

• Published in: Carbon (New York) 2023-09, Vol.213, p.118291, Article 118291
• Main Authors: Yuan, Fei, Wang, Jian, Ma, Qian, Sun, Huilan, Li, Zhaojin, Zhang, Di, Wang, Qiujun, Wu, Yusheng, Li, Wen, Wang, Bo
• Format: Article
• Language: English
• Subjects: Carbon anode; Edge-N doping; Micropores; Potassium ion battery
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2023.118291

Edge-N (pyridinic/pyrrolic-N) functionalized carbon is a promising anode for potassium-ion batteries, while micropores have been proven to be effective in increasing capacity and cyclability. However, the obtained carbon materials usually exhibit a low N-doping level and edge-N species based on the conventional pyrolysis method, and the exploration of the synergistic effect of edge-N doping and micropores on the potassium-storage performance is still lacking. Herein, a novel strategy is proposed to prepare edge-N doped carbon (ENC-850) by directly pyrolyzing supermolecule precursors self-assembled by terephthalic acid (BDC) and melamine (MA). Because the s-triazine structure in MA is more stable than BDC, which can easily ensure a higher N-doping content in carbon, and the decomposition of s-triazine structure is accompanied by the release of NCNH2 gas, which enables most doped N-atoms to be of edge-N configurations, favoring the adsorption storage of K-ions. Besides, the released small molecules can create numerous micropores, not only providing active sites, but accommodating volume fluctuation. Therefore, the optimized ENC-850 with the most suitable edge-N content of 60.6% (7.73 at% of total 11.71 at% N-doping) and micropores delivers a high capacity (280 mAh g−1 at 0.5 A g−1) and superior cycling stability (over 2000 cycles). A novel strategy is proposed to prepare edge-N doped carbon (ENC-850) by directly pyrolyzing supermolecule precursors self-assembled by terephthalic acid (BDC) and melamine (MA), and thus the resulting product delivers an excellent cycling stability. [Display omitted] •A supermolecule precursors self-assembly strategy was proposed based on terephthalic acid (BDC) and melamine (MA).•The unique merits of s-triazine structure enables a higher N-doping content and edge-N species.•The obtained sample delivered an excellent capacity and cycling stability of over 2000 cycles.