Hollow-tubular porous carbon derived from cotton with high productivity for enhanced performance supercapacitor

Hollow-tubular porous carbon is synthesized from NaH2PO4 layer coating natural biomass cotton fiber through a facile carbonization and KOH–KNO3 activation process. It shows that the obtained porous carbon keeps the initial fiber structure of hollow-tubular, resulting in a high surface area of 1508 m2 g−1 and obvious mesoporous structure (9.18 nm). With coating of NaH2PO4 layer, high productivity (27.3%) of the obtained carbon can be achieved which is two times higher than the untreated cotton. The obtained porous carbon exhibits high specific capacitance (278 F g−1 at 1 A g−1) and excellent rate capability (208 F g−1 at 100 A g−1), showing the much higher rate performance than that of other biomass-derived carbon materials. Moreover, the carbon also displays a superior-short charge-discharge time (1.89 s at 100 A g−1) and super long cycle life (94.3% retention over 10 × 104 cycles at 100 A g−1). This excellent electrochemical performance mainly belongs to its special hollow-tubular morphology and activated porous structure. Hence, this method is a new strategy for the porous carbon production as high-power supercapacitor material with larger product yield and special structures which are inherited from natural biomass.