KS activated electrospun carbon nanofibers with hierarchical meso/microporous structures for supercapacitors.

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.