Facile preparation of Ni@C/hierarchically porous carbon nanocomposites with excellent electrochemical performance from Ni-MOF/porous polymers

High performance supercapacitors are significant for the practical application of the novel renewable energies. Comparisons suggest that hybrid supercapacitor (HSC) is a fairly promising type for application since it combines high power density and high energy density. In this study, hierarchically porous carbons (HPCs) supported Ni@C nanoparticles (Ni@C/HPCs) were obtained by pyrolyzing the precursors of Ni-based MOF/porous polymers (NiMOF/polyHIPEs) which were prepared by high internal phase emulsion (HIPE) polymerization followed with solvothermal Ni-MOF growing. The composition and morphology of the Ni@C/HPCs can be controlled by changing the growth time of Ni-MOF. The optimized sample Ni@C/HPC-15 demonstrates a high specific capacity of 215.0 C g-1 at 1 A g-1 and a high rate performance of 82.3% when the current density increases from 1 A g-1 to 10 A g-1. Furthermore, Ni@C/HPC//HPC HSC was assembled and achieved an energy density of 40.9 Wh kg-1 at a power density of 747.2 W kg-1. In particular, the assembled HSC exhibited a remarkable initial capacitance retention of 86.3% after 5000 cycles at 6 A g-1. The reported convenient method may provide inspiration in the preparation and optimization of HPC-based electrode materials with satisfactory performances for energy storage.