Preparation of high-performance asymmetric supercapacitors based on NiCo2S4 nanospheres and CuO-MOF nanosheets on carbon fibers

Highly efficient and low-cost supercapacitors (SCs) with excellent energy storing capacity are highly demanded to fabricate modern portable and wearable electronic devices. Herein, NiCo2S4 nanospheres and CuO-MOF nanosheets were fabricated on flexible carbon fibers (CF) by one-step hydrothermal solvent method, employed as two effective electrode materials. Accordingly, the cathode (CuO-MOF@CF) and anode (NiCo2S4@CF) plays a prominent role in energy storage properties due to large specific surface areas, by providing comparative capacities of 953 F/g and 1571 F/g, respectively. Remarkably, benefited from the synergistic effect, the designed asymmetric supercapacitor (SC) CuO-MOF@CF//NiCo2S4@CF exhibits a voltage window of ∼3.0 V, which demonstrates an impressive specific capacitance of 2426.6 F/g at a current density of 700 mA/g, the maximum energy density (ED) of 164.85 Wh/kg, as well as an excellent power density (PD) of 3780 W/kg. Even after 10,000 cycles of charge and discharge, the specific capacitance retention rate still reaches 96.43 %. This study offers a cost-effective and simple strategy for rational design of energy storage configurations for favorable electrochemical performances, emphasizing great potentials in next-generation supercapacitors application.