Broccoli-like porous carbon nitride from ZIF-8 and melamine for high performance supercapacitors

Broccoli-like porous carbon nitride is synthesized by simple one-step carbonization of a composite comprising a Zn-based zeolitic imidazolate framework (ZIF-8) and melamine. The introduction of melamine into the ZIF-8 framework not only increases the N content of the composite and the surface area of the carbonization product, but also induces the formation of a flower-like structure. The carbon obtained from the ZIF-8/melamine composite by the proposed carbonization process at a temperature of 800 degrees C (ZM-C-800) is found to have a unique three-dimensional broccoli-like shape, a nanoscale size, and an extremely high doping N content (28.3 at.%). These properties substantially improve the electrochemical performance of ZM-C-800, as represented by a high specific capacitance of 359.1 F g(-1) at a current density of 1 A g(-1) , much higher than that of ZIF-8. Furthermore, a symmetric supercapacitor fabricated with two ZM-C-800 electrodes exhibits a power density of 498.5 W kg(-1) for an energy density of 11.4 Wh kg(-1) . This indicates the strong potential of ZM-C-800 for use in the fabrication of energy storage devices. (C) 2017 Elsevier B.V. All rights reserved.