School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459, Singapore.
Angew Chem Int Ed Engl. 2016 May 10;55(20):5990-3. doi: 10.1002/anie.201600133. Epub 2016 Apr 5.
Hierarchical tubular structures composed of Co3 O4 hollow nanoparticles and carbon nanotubes (CNTs) have been synthesized by an efficient multi-step route. Starting from polymer-cobalt acetate (Co(Ac)2 ) composite nanofibers, uniform polymer-Co(Ac)2 @zeolitic imidazolate framework-67 (ZIF-67) core-shell nanofibers are first synthesized via partial phase transformation with 2-methylimidazole in ethanol. After the selective dissolution of polymer-Co(Ac)2 cores, the resulting ZIF-67 tubular structures can be converted into hierarchical CNTs/Co-carbon hybrids by annealing in Ar/H2 atmosphere. Finally, the hierarchical CNT/Co3 O4 microtubes are obtained by a subsequent thermal treatment in air. Impressively, the as-prepared nanocomposite delivers a high reversible capacity of 1281 mAh g(-1) at 0.1 A g(-1) with exceptional rate capability and long cycle life over 200 cycles as an anode material for lithium-ion batteries.
通过一种高效的多步路线，合成了由 Co3 O4 中空纳米粒子和碳纳米管（CNTs）组成的分级管状结构。从聚合物-醋酸钴（Co(Ac)2 ）复合纳米纤维开始，首先通过在乙醇中与 2-甲基咪唑进行部分相转化，合成了均匀的聚合物-Co(Ac)2 @沸石咪唑酯骨架-67（ZIF-67）核壳纳米纤维。在选择性溶解聚合物-Co(Ac)2 核后，通过在 Ar/H2 气氛中退火，得到的 ZIF-67 管状结构可以转化为分级 CNT/Co-碳杂化物。最后，通过在空气中进行后续热处理，得到了分级 CNT/Co3 O4 微管。令人印象深刻的是，作为锂离子电池的阳极材料，所制备的纳米复合材料在 0.1 A g-1 时具有高达 1281 mAh g-1 的高可逆容量，具有出色的倍率性能和超过 200 次循环的长循环寿命。
