Formation of CoS2/N, S-codoped porous carbon nanotube composites based on bimetallic zeolitic imidazolate organic frameworks for supercapacitors

Metal-organic frameworks featuring controllable morphologies and tunable compositions and pore structures are widely used as precursors for supercapacitors electrode materials. A zinc/cobalt-based zeolitic imidazolate framework was utilized as a precursor to synthesize N, S-codoped porous carbon supported CoS2 nanocomposites, using a two-step (carbonization and sulfurization) procedure. The as-prepared materials maintained the rhombic dodecahedral structure of the precursors, and carbon nanotubes were rooted onto the nanocomposite surface. The N, S-codoped porous carbon supported CoS2 nanocomposite hybrid electrode exhibited excellent electrochemical performance: high specific capacitance (635.8 F/g at 1 A/g), good rate capability (544.2 F/g at 10 A/g), and long-term cycling stability (88.0% retained after 2000 cycles). Moreover, the energy density of the N, S-codoped porous carbon-supported CoS2 nanocomposites//activated carbon asymmetric supercapacitor reached 14.1 Wh/kg at the power density of 0.71 kW/kg, and its capacitance remained 92.2% after 2000 cycles in the 0–1.4 V potential range.