A Facile Grinding Method for the Synthesis of 3D Ag Metal-Organic Frameworks (MOFs) Containing Ag₆ Mo₇ O₂₄ for High-Performance Supercapacitors

Successful synthesis of three kinds of dynamically stable compounds by a simple grinding method is reported, giving Ag₆ Mo₇ O₂₄ , Ag-BTC (Ag-MOF, BTC=benzene-1,3,5-tricarboxylic acid), and {Ag₆ Mo₇ O₂₄ }@Ag-MOF metal-organic frameworks (MOFs). According to the electrochemical dynamic analysis, these materials have pseudocapacitor behavior and high capacitance. The unique nanorod structure of {Ag₆ Mo₇ O₂₄ }@Ag-MOF provides more active sites, faster ion/electron transfer, and electrolyte diffusion pathways, resulting in excellent specific capacitance (971 F g^-1 ) higher than the other compounds. {Ag₆ Mo₇ O₂₄ }@Ag-MOF (glassy carbon electrode) also has an excellent rate ability (60.1 %) and long cycle stability (98 % retention after 5000 cycles). In addition, the fully symmetrical button battery (with nickel foam as the current collector) fabricated with {Ag₆ Mo₇ O₂₄ }@Ag-MOF delivers an energy density of 11.1 Wh kg^-1 at 600.1 Wh kg^-1 coupled with excellent cycling stability (86.4 %) at 1.2 V. These results demonstrate a new simple grinding method to prepare polyoxometalate-based metal-organic frameworks (POMOFs) for high-performance materials.