Fabrication of S, N and O conjugated coordination Ni-MOFs with high electrochemical performance for self-regenerative asymmetric supercapacitor

Metal-organic frameworks (MOFs) exhibit promising prospects as supercapacitor electrode materials due to the high specific surface area, adjustable pore structure and flexible structural design, but suffer from low conductivity, unstable structure and easy collapse. In this work, by selecting nickel (Ⅱ) nitrate hexahydrate and 2-amino-5-mercapto-1,3,4-thiadiazole (EAMTD, containing various functional groups), a series of Ni-MOFs-EAMTD samples were fabricated in a mixed solvent system of N, N-dimethylformamide and ethylene glycol. EAMTD and mixed solvents provided a coordination environment rich in S, N and O heteroatoms for Ni ions, enhancing the delocalization of charge throughout the framework. The synergistic electronic interaction improved electrical conductivity and electrochemical performance of the Ni-MOFs-EAMTD, which demonstrated a high specific capacitance of 1608.0 F·g -1 at 1 A·g -1 . And assembled into an asymmetric supercapacitor (ASC) with activated carbon, it exhibited high energy density (39.2 Wh·kg -1 ) and power density (850.0 W·kg -1 ). More significantly, the ASC exhibits self-regenerative property. After 10000 cycles, the specific capacitance of ASC dropped to 45%, then recovered to 65%, which was attributed to the decomposition of Ni-MOFs-EAMTD into smaller nanoparticles and the release of active sites to compensate for the capacitance. This work provides a feasible strategy to develop MOFs-based electrode materials, paving the way for secondary resource utilization and extended industrial chain development.