One-step synthesis of NiCo-MOF@LDH hybrid nanosheets for high-performance supercapacitor

Metal-organic frameworks (MOFs) have garnered significant attention as supercapacitor electrode materials on account of their large specific surface area, regulatable structure and composition. However, the serious aggregation and low active sites result in the low specific capacitance and impede their application for high-performance supercapacitor. Herein, two-dimensional NiCo-MOF@LDH hybrid nanosheets were synthesized by a one-step solvothermal process utilizing 1, 4-terephthalic acid and urea. The hydrolysis of urea releases OH− that not only serves as the deprotonation of terephthalic acid but also react with Ni and Co ions to produce NiCo-LDH nanosheets. The produced NiCo-MOF@LDH-2 nanosheets displays high specific capacitance of 1873.9 F g−1 at 0.5 A g−1 as well as excellent rate performance. Furthermore, the constructed asymmetric supercapacitor device has a high energy density of 49.8 Wh kg−1 when the power density is 422.4 W kg−1. Meanwhile, the capacitance retention can maintain 83 % after 10,000 cycles even at a current density of 5 A g−1. The excellent electrochemical properties of NiCo-MOF@LDH are assigned to the high specific surface area and abundant active sites generated by the cross-linked nanosheet structure.