The zeolitic imidazolate framework 67 (ZIF67) derivative is a potential active material of supercapacitors (SC), owing to high specific surface area and porosity and possible formation of cobalt compounds. A novel ZIF67 derivative is synthesized using a one-step solution process with cobalt precursor 2-methylimidazole (2-Melm) and ammonia fluoride in our previous work. Due to its facile synthesis and excellent electrocapacitive behavior, it is crucial to understand the competition between ammonia fluoride and 2-Melm on forming derivatives with cobalt ions and to create more efficient ZIF67 derivatives for charge storage. In this work, several ZIF67 derivatives are designed using a one-step solution process with 2-Melm and ammonia fluoride incorporated in different sequences. The reaction durations for a single ligand and two ligands are controlled. The largest capacity of 176.33 mAh/g corresponding to the specific capacitance of 1057.99 F/g is achieved for the ZIF67 derivative electrode prepared by reacting ammonia fluoride and a cobalt precursor for 0.5 h and then incorporating 2-Melm for another 23.5 h of reaction (NM0.5). This derivative composed of highly conductive CoF₂, NiF₂, Co(OH)F, and Ni(OH)F presents high specific surface area and porosity. The relevant SC presents a maximum energy density of 19.5 Wh/kg at 430 W/kg, a capacity retention of 92%, and Coulombic efficiency of 96% in 10000 cycles.

中文翻译：

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将序列依赖性 ZIF67 衍生物作为超级电容器活性材料的配体：氟化氨与 2-甲基咪唑的竞争

沸石咪唑骨架 67 (ZIF67) 衍生物是超级电容器 (SC) 的潜在活性材料，因为它具有高比表面积和孔隙率以及可能形成钴化合物。在我们之前的工作中，使用钴前体 2-甲基咪唑 (2-Melm) 和氟化氨的一步溶液法合成了一种新型 ZIF67 衍生物。由于其易于合成和优异的电容行为，了解氟化氨和 2-Melm 在与钴离子形成衍生物方面的竞争以及创造更有效的用于电荷存储的 ZIF67 衍生物至关重要。在这项工作中，使用一步溶液工艺设计了几种 ZIF67 衍生物，其中 2-Melm 和氟化氨以不同的顺序结合。控制单个配体和两个配体的反应持续时间。氟化氨与钴前驱体反应 0.5 小时，然后加入 2-Melm 再反应 23.5 小时制备的 ZIF67 衍生电极实现了 176.33 mAh/g 的最大容量，对应的比电容为 1057.99 F/g（ NM0.5)。这种由高导电性 CoF 组成的衍生物_如图2所示，NiF ₂、Co(OH)F和Ni(OH)F具有高比表面积和孔隙率。相关 SC 在 430 W/kg 时的最大能量密度为 19.5 Wh/kg，容量保持率为 92%，10000 次循环的库仑效率为 96%。