Synthesis and electrochemical capacitive properties of nitrogen-doped porous carbon micropolyhedra by direct carbonization of zeolitic imidazolate framework-11

• Nitrogen-doped porous carbon micropolyhedra (N-PCMPs) were prepared from ZIF-11.
• The activated N-PCMPs with fused KOH (N-PCMPs-A) have high specific surface area.
• N-PCMPs-A exhibits high specific capacitance.
• N-PCMPs-A reveals good cycling performance even at a high current density.

Nitrogen-doped porous carbon micropolyhedra (N-PCMPs) were successfully prepared by direct carbonization of ZIF-11 polyhedra and further activated with fused KOH to obtain N-PCMPs-A. The morphology and microstructure of samples were examined by scanning electron microscopy, X-ray diffraction, and micropore and chemisorption analyzer. Electrochemical properties were characterized by cyclic voltammetry and galvanostatic charge/discharge method in 1.0 M H2SO4 aqueous solution on a standard three-electrode system. Results show that, compared with N-PCMPs, N-PCMPs-A has higher specific surface area (2188 m2 g−1) and exhibits improved electrochemical capacitive properties (307 F g−1 at 1.0 A g−1). The mass specific capacitance of N-PCMPs-A is also higher than that of most MOF-derived carbons, some carbide-derived carbons and carbon aerogel-derived carbons. In addition, the capacitance of the N-PCMPs-A retains 90% after 4000 cycles even at a high current density of 10 A g−1. These imply that N-PCMPs-A is the promising materials for the construction of a high-performance supercapacitor.

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