Construction of MOF-Based Electrodes via Hydrogen-Bonding Enhancement

As a highly potential energy storage material, two-dimensional metal–organic frameworks (2D MOFs) are developing slowly due to the underutilization of active sites and poor structural stability. In this work, aminopyridines were utilized to introduce defects into MOFs due to their monocoordination with metal ions; their −NH 2 groups were utilized to graft UPy-NCO groups to further introduce multiple hydrogen bonds (H-bonds) into MOF frameworks. The self-healing property of H-bonds was utilized to improve MOF structural stability, resulting in novel hydrogen-bonded MOF-based electrodes. The defects caused by the monocoordination of pyridines enhanced ion transport, while the introduction of multiple hydrogen bonds inhibited the stacking of MOF layers and promoted their delamination and cross-linking. Thus, the surface capacitive behavior of MOFs was strengthened, thereby improving the electrochemical performance. Specifically, H–Ni/Co-TCPP-DAP exhibits a three-dimensional network structure, achieving a specific capacitance of 370 F g –1 (0.5 A g –1 ), which is 2.2 times higher than that of Ni/Co-TCPP (164.7 F g –1 ). With the current density increased to 5 A g –1, it presents an 86% capacity retention, surpassing that of Ni/Co-TCPP (70%). After 5000 cycles, the capacity retention is 88%, exceeding that of Ni/Co-TCPP (69%). This proves that the cross-linked networks of multiple hydrogen bonds are beneficial for enhancing the structural stability of MOF frameworks, which also provides new insights for designing novel porous framework materials.