Hierarchical nickel cobalt sulfide nanosheet on MOF-derived carbon nanowall arrays with remarkable supercapacitive performance. (June 2019) - Wang, Ying
Abstract: Nickel cobalt sulfide (CoNi2 S4 )-based materials have attracted extensive attention as electrodes which arise from their high theoretical capacitance, but their wide application is limited by relatively low electrical conductivity and electrochemical stability. Herein, the metal-organic framework (MOF) derived carbon nanowall arrays (CNWAs) are successfully fabricated on carbon cloth (CC) as secondary substrate, which provides more sites for electrodeposition of CoNi2 S4 . Furthermore, the integration of Ni layer to bridge CoNi2 S4 and CNWAs, which is favorable for fast charge transfer, as well as improved conductivity. Thus, the CC/CNWAs@Ni@CoNi2 S4 electrode exhibits a remarkable specific capacitance (3163 F g −1 /2825 F g −1 at 1 A g −1 /5 mV s −1 ) and rate capability (1503 F g −1 /1500 F g −1 at 40 A g −1 /50 mV s −1 ), outperforming others CoNi2 S4 -based electrodes reported previously. The as-prepared CC/CNWAs@Ni@CoNi2 S4 //commercial activated carbon asymmetric supercapacitor demonstrates superior electrochemical performance with maximum energy density of 53.8 W h kg −1 at a power density of 801 W kg −1 and long-term cycling stability with 90.1% retention after 10 000 cycles. These remarkable supercapacitive performances are attributed to the rationally hierarchical architecture, high utilization ratio of active materials and aligned ion diffusion channels of the CC/CNWAs@Ni@CoNi2 S4 electrode. Graphical abstract: Image 1 Highlights: Carbon nanowall arrays (CNWAs) was derived from metal-organic framework as porous scaffold to provide more active-sites. The hierarchical CoNi2 S4 nanosheets@CNWAs modified with Ni layer on carbon cloth was fabricated. CC/CNWAs@Ni@CoNi2 S4 electrode exhibited remarkable specific capacitance, rate capability and long-term cycling.