Three-Dimensional Porous Flower-like NiCo-MOF@Ni-LDH Composite Electrode for High-Performance Supercapacitors

Abstract

Metal–organic frameworks (MOFs) are renowned for their high porosity and meticulously structured pores. Nonetheless, intrinsic shortcomings, namely, low electrical conductivity and inadequate stability, impede their broad application as electrode materials. Herein, the bimetallic nickel–cobalt MOF (NiCo-MOF) was prepared using layered double hydroxides (LDH) as precursors by a reverse design strategy, and then the flower-like NiCo-MOF@Ni-LDH was synthesized by hydrothermal recombination of NiCo-MOF with nickel layer double hydroxide (Ni-LDH). The NiCo-MOF@Ni-LDH demonstrates an exceptional specific capacitance of 1880 F g–1 at 1 A g–1, coupled with an outstanding rate performance, maintaining 81.49% of its capacitance at a higher current density of 10 A g–1. The excellent electrochemical characteristics can be ascribed to the unique porous structure, which significantly enhances the specific surface area and augments the availability of active sites, while the presence of open pore channels on the surface facilitates ion diffusion. Moreover, at a power density of 799.9 W kg–1, an asymmetric supercapacitor (ASC) employing a NiCo-MOF@Ni-LDH//activated carbon configuration exhibits a remarkable energy density of 69.9 Wh kg–1, concurrently preserving 75.6% capacity retention following 5000 charging and discharging cycles. These exceptional electrochemical properties highlight the promising potential of the NiCo-MOF@Ni-LDH nanocomposite as an electrode material for supercapacitors.