A facile synthesis of flower-like NiCo-LDH for high specific capacitance pseudosupercapacitor positive materials

The original MOFs exhibit poor electrochemical performance when used as electrode materials for supercapacitors. To improve their conductivity and stability, in situ growth of high specific capacitance and conductivity layered double hydroxide (LDH) on the MOFs surface is an ideal approach. In this study, we employed the MOF as a template and employed a secondary hydrothermal synthesis method to enable in situ growth of NiCo-LDH on the surface of the MOF. The utilization of the MOF template enhances the stability of NiCo-LDH, while the flower-like structure of LDH exposes more active sites. By optimizing the Ni:Co molar ratio to 1:2 and the urea:NH 4 F molar ratio to 2:1, the resulting material exhibits higher specific capacitance and improved cycle stability. Specifically, at a current density of 1 A g −1 , the specific capacitance reaches 1674 F g −1 . At a current density of 5 A g −1 , the capacity retention rate after 2000 cycles is 80%. When NiCo-LDH/HKUST-1 is assembled with activated carbon as a supercapacitor, it exhibits a significant energy density of 33.96 Wh kg −1 and a power density of 745.4 W kg −1 . This work provides a novel approach for utilizing MOF-based composite materials as positive electrode materials for supercapacitors. Graphical Abstract