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

• Published in: Journal of colloid and interface science 2018-12, Vol.532, p.407-415
• Main Authors: Huang, Jing, Tang, Xuekun, Li, Zishun, Liu, Kun
• Format: Article
• Language: English
• Subjects: Ion diffusion coefficients; Long-term stability; Metal organic frameworks; Sodium ion battery; Transition metal sulfides
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2018.08.002

We first report a Co9S8 nanoflakes on reduced graphene oxide sheets (rGO/Co9S8) composites derived from metal-organic frameworks (MOFs) with enhanced the sodium diffusion coefficient, excellent mechanical stability and partial surface-induced capacitive effect. The rGO/Co9S8 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 Na3V2(PO4)3‖rGO/Co9S8 full cell application. [Display omitted] We report a metal-organic framework-derived Co9S8 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 Co9S8 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 Co9S8 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/Co9S8 shows potential for practical applications in Na3V2(PO4)3‖rGO/Co9S8 full cells.