A Facile Grinding Method for the Synthesis of 3D Ag Metal–Organic Frameworks (MOFs) Containing Ag₆Mo₇O₂₄ for High‐Performance Supercapacitors

Abstract

Successful synthesis of three kinds of dynamically stable compounds by a simple grinding method is reported, giving Ag6Mo7O24, Ag‐BTC (Ag‐MOF, BTC=benzene‐1,3,5‐tricarboxylic acid), and {Ag6Mo7O24}@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 {Ag6Mo7O24}@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. {Ag6Mo7O24}@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 {Ag6Mo7O24}@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.

Synthesis of FeNiCo Ternary Hydroxides through Green Grinding Method with Metal‐Organic Frameworks as Precursors for Oxygen Evolution Reaction

“…Mechanochemical synthesis, a prospective solid‐phase synthesis method, is stimulated and sustained through a mechanical force, involving ball milling or grinding to obtain multi‐functional materials [16,17] . This synthesis method exhibits numerous advantages including simple operation, short synthesis period, and flexible scalability, among others [18,19] . Meanwhile, mechanochemical synthesis is also identified as a green synthesis method, which can avoid bulk solvents and reduce environmental pollution, promising for large‐scale production [20,21] .…”

A new route to polyoxometalates via mechanochemistry

“…[28][29][30][31][32][33][34] Although POMs are used in mechanochemical synthesis, e.g. to exchange the cation 35,36 or to encapsulate the POM inside of a metal-organic framework (MOF) [37][38][39][40] , there is, to the best of our knowledge, no description of a direct mechanochemical synthesis. Such an alternative route could make the use of strong acids obsolete as well as decrease reaction times and the energy consumption.…”

A hybrid borotungstate-coated metal–organic framework with supercapacitance, photocatalytic dye degradation and H2O2 sensing properties

“…Moreover, Pang et al 40 synthesized POM-wrapped core–shell ZIF-67@POM heterojunctions on ZIF-67 via a solution method, with the material showing good supercapacitance properties due to the synergistic effect of POM and ZIF-67. Recently, our group prepared {Ag 6 Mo 7 O 24 }@Ag-MOF 41 and Zn-BTC@Ag 5 [BW 12 O 40 ] 42 via a mechanical grinding method with specific capacitance values of 161.7 F g −1 and 55.4 F g −1 , respectively, and excellent cycling stability (retention rates of 92.8% and 98%, respectively, after 5000 cycles), indicating that the POMOFs obtained via a grinding method have good stability. The above findings can prove that the synthesized POMOF materials fully combine the advantages of POMs and MOFs to form supercapacitors with high-speed electron transfer capabilities.…”

“…Additional coordination configurations between metal ions, organic ligands, and POMs were found using a simple grinding method. 47–50 Therefore, on the basis of previous studies, 41,42 {Ag 5 BW 12 O 40 }@[Ag 3 (μ-Hbtc)(μ-H 2 btc)] n hybrids with a core–shell structure were synthesized via a grinding method. The supercapacitance properties, H 2 O 2 sensing properties, and photocatalytic dye-degradation properties of these synthetic hybrids were studied in detail, laying the foundation for further POMOF applications.…”