A mixed-ligand approach to a cobalt-based electroactive framework for superior supercapacitor performance

Abstract

The development of supramolecular frameworks with tailored structural features remains challenging. Here, we report a novel cobalt-based functionalized layered framework (Co-FLF) synthesized via a mixed-ligand strategy using azopyridine (AzPY) and 2,3,5,6-tetrafluoro-1,4-benzenedicarboxylic acid (TF). The framework possesses unique structural advantages, including stable hydrogen bonding, π–π stacking, and a fluorinated functionalized network. Co-FLF features a Co(O₄N₂) coordination environment with two coordinated water molecules, contributing to an extended hydrogen-bonding network. Its electrochemical performance as an electrode material for supercapacitors was evaluated. Electrochemical analysis reveals that Co-FLF exhibits a significantly higher specific capacitance of 956 F g⁻¹ at 1 A g⁻¹, along with an excellent cycling stability. Real-time device performance further confirms its enhanced energy density. These results highlight the potential of integrating electroactive building blocks with functionalized frameworks into real-world applications to achieve superior electrochemical properties. By precisely controlling ligand size, functional groups, and solvent-mediated synthesis, this strategy paves the way for the design of next-generation electrode materials for high-performance supercapacitors.