Synthesis of Mesoporous ZIF-8 Nanoribbons and their Conversion into Carbon Nanoribbons for High-Performance Supercapacitors.

ZIF-8 nanoribbons, with tunable morphology and pore structure, were synthesized by using the tri-block co-polymer Pluronic F127 as a soft template. The as-synthesized ZIF-8 nanoribbons were converted into carbon nanoribbons by thermal transformation with largely preserved morphology and porosity. The resulting carbon nanoribbons feature both micro- and meso-pores with high surface areas of over 1000 m2  g-1 . In addition, nitrogen-doping in the carbon nanoribbons was achieved, as confirmed by XPS and EELS measurements. The hybrid carbon nanoribbons provide pseudo-capacitance that promotes electrochemical performance, rendering a high specific capacitance of up to 297 F g-1 at a current density of 0.5 A g-1 in a three-electrode system. A long cycle life was also demonstrated by recording a 90.26 % preservation of capacitance after 10 000 cycles of charge-discharge at a current density of 4.0 A g-1 . Furthermore, a symmetrical supercapacitor is fabricated by employing the carbon nanoribbons, which shows good electrochemical performance with respect to energy, power and cycle life.