Dilute NiO/carbon nanofiber composites derived from metal organic framework fibers as electrode materials for supercapacitors

摘要

A new type of carbon nanofiber (CNF) dominated electrode materials decorated with dilute NiO particles (NiO/CNF) has been in situ fabricated by direct pyrolysis of Ni, Zn-containing metal organic framework fibers, which are skillfully constructed by assembling different proportional NiCl2.6H(2)O and Zn (Ac)(2).2H(2)O with trimesic acid in the presence of N,N-dimethylformamide. With elegant combination of advantages of CNF and evenly dispersed NiO particles, as well as successful modulation of conductivity and,porosity of final composites, our NiO/CNF composites display well-defined capacitive features. A high capacitance of 14,926 F g(-1) was obtained in 6 M KOH electrolyte when the contribution from 0.43 wt% NiO was considered alone, contributing to over 35% of the total capacitance (234 F g(-1)). This significantly exceeds its theoretical specific capacitance of 2584 F g(-1). It has been established from the Ragone plot that a largest energy density of 33.4 Wh kg(-1) was obtained at the current density of 0.25 A g(-1). Furthermore, such composite electrode materials show good rate capability and outstanding cycling stability up to 5000 times (only 10% loss). The present study provides a brand-new approach to design a high capacitance and stable supercapacitor electrode and the concept is extendable to other composite materials. (C) 2016 Elsevier B.V. All rights reserved.