Metal organic frameworks derived cobalt sulfide/reduced graphene oxide composites with fast reaction kinetic and excellent structural stability for sodium storage

We report a metal-organic framework-derived Co9S8 nanofiakes on reduced graphene oxide sheet composites as an advanced sodium-ion battery anode. Using a galvanostatic intermittent titration technique, we reveal that the sodium diffusion coefficient of the composite is higher than that of its counterpart. Ex situ scanning electron microscopy images suggest the excellent mechanical stability of Co9S8 nanofiakes on the reduced graphene oxide sheet electrode during cycling, thereby facilitating cyclic stability. The partial surface-induced capacitive effect also contributes to electrochemical performance. With the reduced graphene oxide, the Co9S8 nanofiakes on the reduced graphene oxide sheet electrode deliver a high discharge capacity of 551 mA h g(-1) at 0.1 A g(-1), a good rate capability at 10 A g(-1), and an excellent cyclic stability up to 500 cycles. rGO/Co9S8 shows potential for practical applications in Na3V2(PO4)(3)parallel to rGO/Co9S8 full cells. (C) 2018 Elsevier Inc. All rights reserved.