Designing metal-organic frameworks@nickel sulfide to obtain long cycle life asymmetric supercapacitors

In this work, Ni(OH)2 was used as a sacrificial template and the rigid ligand 1,4,5,8-naphtalenetetracarboxylic acid (NTC) was introduced to synthesize metal-organic framework Ni-NTC. The obtained Ni-NTC was partially vulcanized to produce the heterostructure Ni-NTC@NiS. The presence of NiS nanosheets can increase the conductivity and specific surface area of heterostructures, therefore, the electrochemical performance of Ni-NTC@NiS improved with respect to Ni-NTC. At a current density of 1 A g−1, the specific capacitance of Ni-NTC@NiS could reach 1996.8 F g−1 and has a rate performance of 80% at 10 A g−1. The hybrid supercapacitor composed of Ni-NTC@NiS and activated carbon could also reach a specific capacitance of 489.9 F g−1 at a current density of 4 A g−1, and at 10 A g−1, the retention rate could be up to 119.1% after 20000 cycles. The herein-synthesized Ni-NTC@NiS has wide application prospects in the field of energy storage.