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

Graphical abstract We first report a Co 9 S 8 nanoflakes on reduced graphene oxide sheets (rGO/Co 9 S 8) composites derived from metal-organic frameworks (MOFs) with enhanced the sodium diffusion coefficient, excellent mechanical stability and partial surface-induced capacitive effect. The rGO/Co 9 S 8 electrode delivered a high discharge capacity of at 0.1 A g−1, good rate capability at 10 A g−1 and excellent cyclic stability up to 500 cycles. It also shows a good potential as an anode in Na 3 V 2 (PO 4) 3 ‖rGO/Co 9 S 8 full cell application. Abstract We report a metal-organic framework-derived Co 9 S 8 nanoflakes 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 Co 9 S 8 nanoflakes 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 Co 9 S 8 nanoflakes 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/Co 9 S 8 shows potential for practical applications in Na 3 V 2 (PO 4) 3 ‖rGO/Co 9 S 8 full cells. [ABSTRACT FROM AUTHOR]