High Surface Area NiCo2O4@Ni-MOF Core-Shell Nanoarrays Are Grown on Nickel Foam As High-Performance and Stably Asymmetric Supercapacitors

Among the electrode materials for supercapacitors (SCs), metal-organic framework (MOFs) is attracting huge research interest as a new type of energy storage electrode materia. However, due to their poor conductivity and stability, the practical application of original MOFs in the field of energy storage has been greatly hindered. Here, we demonstrate a special core-shell structure, which the synergistic action of NiCo2O4 and Ni-MOF forms a tight conductive network that speeds up electron transport and larger specific surface area, more active sites were obtained and mechanical stability that indicates its outstanding long life. The test results show that it has a high specific capacity of 4.23 F cm–2 at 5 mA cm–2, and the capacity retention rate is maintained at 97.5% after 8000 cycles. In addition, an asymmetric supercapacitor device, using NiCo2O4@Ni-MOF and activated carbon (AC) as anode and cathode, has a high specific capacity of 3.21 F cm–2 at 5 mA cm–2 and excellent cycling performance (83.8% retention over 8000 cycles at 10 mA cm–2). Our work demonstrates the possibility of using novel structured Ni-MOF-based hybrid arrays as electrodes for SCs with enhanced electrochemical performance compared to Ni-MOF and NiCo2O4, providing a reliable prospect for flexible energy storage devices.