Thiol-functionalized conductive Co-MOF and its derivatives S-doped Co(OH)2 nanoflowers for high-performance supercapacitors

The low conductivity of many traditional metal–organic-framework (MOF)-based electrode limits their developments in the field of electrochemical energy storage and still of great challenge. The controllable preparation of various kinds of nanomaterials using thiol-functionalized MOF shows great prospects. In this work, a thiol-functionalized metal–organic framework sheet structure ( Co-MOF/NF ) on nickel foam was successfully prepared by in situ interfacial growth synthesis, which was transformed into its derivatives S-doped β-Co(OH) 2 nanoflowers Co-x/NF ( x  = 1, 2 and 6) in different concentrations of KOH solutions through ion etching/exchange reaction. The pristine thiol-functionalized Co-MOF/NF and its derivatives Co-x/NF ( x  = 1, 2 and 6) nanoflower-like arrays could be used as positive electrode materials for effective supercapacitors. Among them, the transformation of the nanoflower-like Co-1/NF electrode exhibits excellent electrochemical properties with high areal capacitance (1925 ± 23 mF/cm 2 at 1 mA/cm 2 ), good rate performance, excellent conductivity and decent cycling stability. The Co-1//AC ASC device provides a high energy density of 0.176 mWh/cm 2 (92.6 Wh/kg) at a power density of 0.745 mW/cm 2 (392.1 W/kg). And this Co-1//AC ASC device exhibits a good cycling stability and practical application in energy storage field. This study provides a new strategy for the pristine thiol-functionalized MOF and its conversion nanostructures for energy storage applications.