Activated carbon with micrometer-scale channels prepared from luffa sponge fibers and their application for supercapacitors

In this paper, we report the preparation of macrochanneled activated carbon (MCAC) with a novel structure combining micropores, mesopores, and macrochannels and its electrochemical properties for supercapacitor applications. The MCAC was prepared by carbonizing luffa sponge fibers and subsequent activation with KOH. The MCAC has densely packed and parallel channels of 4-10 mu m in diameter and 0.3-1 mu m in wall thickness, which are inherited from the natural structure of the luffa sponge fibers. Micro- and mesopores were produced on the inner surface of the channel walls, forming a hierarchically porous structure. The MCAC exhibits excellent electrochemical performance for application as electrode materials of supercapacitors in appropriate electrolytes. The specific capacitances of the MCAC at 1 A g(-1) are 167, 196, and 249 F g(-1) in Na2SO4, KOH, and H2SO4 solutions, respectively. The MCAC materials reported here may have broad applications such as for supercapacitors, catalysis, and templates for supporting various functional materials.