High-performance asymmetric supercapacitor based on Co–Mo–S/ Co–Mo-LDH nanosheets grown on Co-MOF square tetrahedral structure

Herein, two component ultrathin nanosheets containing Mo–Co–S and Co–Mo–OH coated on the ZIF-67-derived cobalt MOF (named Mo–Co–S/Co-MOF and Mo–Co–OH/Co-MOF) are obtained via solvothermal process combined hydrothermal method. Based on the characterization analysis, the Co-MOF metal organic framework presents a square tetrahedron and the Mo–Co–S/Co-MOF hybrids consisted of the tetragonal nuclear structure morphology with many ultrathin flowers like nanosheets arrays on the shell. The ultrathin Co–Mo–OH nanosheets stacked on the Co-MOF tetragonal surface presenting nanocage structure. When used as the electrodes in three electrode system, the Mo–Co–OH/Co-MOF and Mo–Co–S/Co-MOF exhibit high specific capacitance of 1927.44 ​F ​g-1 and 690.54 ​F ​g-1 at 1 ​A ​g-1, respectively. In addition, they are assembled into an asymmetric supercapacitor, which has a higher specific capacitance of 199.82 ​F ​g-1 under 1 ​A ​g-1. At the same time, this device not only has a high capacitance retention rate of 96.59% after 5000 cycles, but also has a high energy density of 51.60 ​Wh kg-1 when the power density is up to 8000 ​W ​kg-1.