富缺陷N/O共掺杂多孔碳框架材料作为高性能钾、钠离子电池负极材料

Defect-rich N/O-co-doped porous carbon frameworks as anodes for superior potassium and sodium-ion batteries

  • 摘要: 炭材料因其高导电性、高化学稳定性和有效缓解体积变化的能力成为钠、钾离子电池最富前景的负极材料。本文报道了一种由N/O共掺杂的介孔碳纳米片组成的富缺陷N/O共掺杂多孔碳框架材料 (简称DRPCF). 其中DRPCF-2/1-700拥有最高的比表面积、孔体积和最高的N/O含量的活性缺陷位点。结果DRPCF-2/1-700 展现出超高的赝电容行为主导的钠、钾离子存储行为。作为钠、钾离子电池的负极材料,DRPCF-2/1-700均展现出高倍率和长循环性能,在1 A g−1电流密度下分别900和1200圈后质量比容量仍保持在328.2和321.5 mAh g−1,以上性能优于大部分已报道的碳基负极材料。非原位拉曼光谱分析结果进一步证实了钾、钠离子从电化学活性缺陷位点的填充和脱除是赋予DRPCF-2/1-700高容量、超高倍率和超长循环性能的机理。

     

    Abstract: Carbon with high electrical conductivity, chemical stability, and capability to alleviate massive volume expansion are the most promising anode materials for sodium and potassium ion batteries. Herein, we develop a defect-rich porous carbon framework (denoted as DRPCF) built with N/O-co-doped mesoporous nanosheets. The as-prepared DRPCF-2/1-700 demonstrates the largest specific surface area with the enormous pore volume and has the highest N/O heteroatom contained active defect sites. Consequently, DRPCF-2/1-700 exhibits superior pseudocapacitive behavior dominated sodium and potassium ion storage performance. As anode materials for sodium and potassium ion batteries, they exhibit high rate and long-term cyclic performance with a mass-specific capacity of 328.2 and 321.5 mAh g−1 at a current density of 1 A g−1 over 900 and 1200 cycles, which outperform most reported carbonaceous materials. The ex-situ Raman spectroscopy results further confirm that the filling and removing of K+ and Na+ from the site of the electrochemically active defect should be responsible for the high capacity, superior rate, and cyclic performance of DRPCF-2/1-700.

     

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