Porous N-doped carbon microfibres derived from cattail as high-performance electrodes for supercapacitors

Abstract

Nitrogen-doped carbon microfibres were produced by carbonisation of cattail seeds and subsequent KOH activation. The KOH activation process produces a large surface area of 2,486 m2 g−1. The carbon derived from cattail contains N heteroatom with a content of 1.6%. Benefiting from the large surface area and unique microstructure of the nitrogen-doped carbon microfibres material, these materials demonstrate superior capacitive properties with a large capacitance of 214 F g−1 at the current density of 1 A g−1 and excellent cycle stability. When current densities is increased to 10 and 90 folds from 1 A g−1, capacitance retention is about 87 and 52%, implying excellent rate performance and high power densities. Based on the nitrogen-doped carbon microfibres, a symmetrical and aqueous supercapacitor device was also assembled, which show a considerable capacitance of 105 F g−1 at the current density of 1 A g−1 and perfect long ability. Such excellent performance is at least comparable to the best reports in the literature for two-electrode configuration under aqueous system. The facile method and excellent capacitive properties of nitrogen doped carbon fibres suggest promising applications as advanced supercapacitors.