Liu Hua, Song Weiguo, Xing Aihua
National Institute of Clean-and-Low-Carbon Energy Beijing 102211 P. R. China
Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190 P. R. China.
RSC Adv. 2019 Oct 18;9(57):33539-33548. doi: 10.1039/c9ra06847c. eCollection 2019 Oct 15.
Porous electrospun carbon nanofibers (CNFs) can be produced by a more advantageous ' activation' method by electrospinning polyacrylonitrile (PAN) with an activation agent. However, most activated electrospinning processes yield porous CNFs with rather limited surface area and less porosity due to the inappropriately selected activation agents. Here we found KS could perfectly meet both compatibility and reactivity requirements of PAN electrospinning to generate hierarchical meso/micropores inside electrospun CNFs. During the whole fabrication process, KS experiences a phase evolution loop and the hierarchical pore structures are formed by the reaction between KS oxidative derivatives and the as-formed carbon during heat treatment. The hierarchical meso/microporous CNFs not only showed a large surface area (835.0 m g) but also exhibited a high PAN carbonization yield (84.0 wt%) due to improved cyclization of PAN's nitrile group during the pre-oxidation stage. As an electrode material for supercapacitors, the corresponding electrodes have a capacitance of 210.7 F g at the current density of 0.2 A g with excellent cycling durability. The hierarchically porous CNFs produced activation by KS combine the advantages of interconnected meso/micropores and are a promising candidate for electrochemical energy conversion and storage devices.
通过将聚丙烯腈（PAN）与活化剂进行静电纺丝，可以采用一种更具优势的“活化”方法来制备多孔静电纺丝碳纳米纤维（CNF）。然而，由于活化剂选择不当，大多数活化静电纺丝工艺所产生的多孔CNF表面积相当有限且孔隙率较低。在此，我们发现KS能够完美满足PAN静电纺丝的相容性和反应性要求，从而在静电纺丝的CNF内部生成分级介孔/微孔。在整个制备过程中，KS经历一个相演变循环，分级孔结构是由KS氧化衍生物与热处理过程中形成的碳之间的反应形成的。这种分级介孔/微孔CNF不仅具有较大的表面积（835.0 m²/g），而且由于在预氧化阶段PAN腈基的环化得到改善，其PAN碳化产率也很高（84.0 wt%）。作为超级电容器的电极材料，相应电极在0.2 A/g的电流密度下电容为210.7 F/g，具有出色的循环耐久性。通过KS活化制备的分级多孔CNF兼具相互连通的介孔/微孔的优点，是电化学能量转换和存储器件的有前途的候选材料。
