Metal–Organic Framework-Derived CoS1.097/Ni9S8 Heterostructure for Hybrid Supercapacitors

Metal–organic frameworks (MOFs) are regarded as materials with the most potential for supercapacitors due to their unique porous structure, high surface area, and active sites. Here, we rationally designed and fabricated a nickel–cobalt sulfide heterostructure on a carbon cloth (CoS1.097/Ni9S8/CC). The CoS1.097/Ni9S8 heterostructure electrode material was formed using MOFs as templates or precursors, and the electrode provided a capacitance of 596.4 C g–1, which is more than that of CoS1.097/CC of 92.6 C g–1, at 2 A g–1. The high electrochemical behavior can be ascribed to the high hydrophilicity, abundant active sites, and good electrical conductivity of the interlinked structure of CoS1.097/Ni9S8 nanosheets. The asymmetric supercapacitor with positive and negative electrodes of CoS1.097/Ni9S8/CC and activated carbon, respectively, delivered a high energy/power density of 37.2 W h kg–1/375.9 W kg–1, presenting 99.3% retention after 10,000 cycles. Therefore, designing an easy-to-operate and reasonable method to increase the conductivity of MOFs is of great significance for their application in supercapacitors.