Construction of reduced graphene oxide nanofibers and cobalt sulfide nanocomposite for pseudocapacitors with enhanced performance

Construction of metal oxide/sulfide and carbon-based material nanocomposites is an effective strategy to obtain high-performance electrode materials for supercapacitors. In the present work, graphene oxide nanofibers (GONFs) are selected as the support materials, and the nanocomposite of reduced graphene oxide nanofiber and cobalt sulfide (rGONF/CoS2) is synthesized via a simple and facile method. As an electrode material for pseudocapacitors, the rGONF/CoS2 nanocomposite exhibits a high specific capacitance of 635.8 F g(-1) at a current density of 1 A g(-1) measured in 6 M KOH electrolyte, which is much higher than that of bare cobalt sulfide. Furthermore, the rGONF/CoS2 nanocomposite has also shown excellent cycling performance with 95.4% capacitance retention over 2000 cycles. In addition, the assembled asymmetric supercapacitor (ASC) device using rGONF/CoS2 nanocomposite as cathode material and activated carbon (AC) as anode material can work at a high operating voltage of 1.65 V and show a maximum energy density of 13.8 W h kg (1) at a power density of 824.6 W kg (1). (C) 2017 Elsevier B.V. All rights reserved.