A Metal–Organic Framework of Organic Vertices and Polyoxometalate Linkers as a Solid-State Electrolyte

Abstract

A new three-dimensional metal−organic framework (MOF) was synthesized by linking ditopic a m i n o f u n c t i o n a l i z e d p o l y o x o m e t a l a t e [ N -(C 4 H 9 ) 4 ] 3 [MnMo 6 O 18 {(OCH 2 ) 3 CNH 2 } 2 ] with 4-connected tetrahedral tetrakis(4-formylphenyl)methane building units through imine condensation. The structure of this MOF, termed MOF-688, was solved by single crystal X-ray diffraction and found to be triply interpenetrated diamond-based dia topology. Tetrabutylammonium cations fill the pores and balance the charge of the anionic framework. They can be exchanged with lithium ions to give high ionic conductivity (3.4 × 10 −4 S cm −1 at 20 °C), a high lithium ion transference number (t Li+ = 0.87), and low interfacial resistance (353 Ω) against metallic lithiumproperties that make it ideally suited as a solid-state electrolyte. Indeed, a prototype lithium metal battery constructed using MOF-688 as the solid electrolyte can be cycled at room temperature with a practical current density of ∼0.2 C.

Recent advances in process engineering and upcoming applications of metal–organic frameworks

“…Overcoming the issue of lithium dendrite formation within solid-state MOF electrolytes is a considerable challenge. Yaghi and coworkers developed a new Li-exchanged Anderson-type polyoxometalate (POM)-based MOF network (MOF-688) [338] . The prepared MOF had a highly porous structure and exhibited high Li-ion conduction for application as the solid-state electrolyte in LIBs ( Fig.…”

“…(c) Ionic conductivity as a function of temperature from −40 to 60 °C. Reprinted with permission from [338] . Copyright 2019 American Chemical Society.…”

Pore Chemistry of Metal–Organic Frameworks

“…[28] Coulombic interactions can be established between charged framework backbone and counterions residing in the pore. [29] The presence of hydrogen bond donors or acceptors in MOF backbone can recognize the matching partners with relatively high affinity. [30]…”

Ligand engineering to achieve enhanced ratiometric oxygen sensing in a silver cluster-based metal-organic framework

“…Metal-organic frameworks (MOFs) feature flexible secondarybuilding units (SBUs) and infinite tunable organic linkers, as well as abundant and distinctive pores or channels, and hence have shown great potential for separation and sensing [8][9][10][11][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] . Traditionally, dual emission in MOFs is mostly achieved with lanthanide ion or luminescent linker on a host MOF framework as one emissive center and a post-introduced luminescent species including lanthanide ion, dye or carbon dot as another emissive center, which make it difficult to realize ultrasensitive and ratiometric detection towards oxygen gas 11 .…”

“…Silver-chalcogenolate-cluster-based metal-organic frameworks (SCC-MOFs) [33][34][35][36][37][38] , in which each SBU consists of tens of silver and chalcogen atoms, have become a new member of the MOF family. SCC-MOFs combine the advantages of silver clusters [39][40][41][42][43] and MOFs [8][9][10][11][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] ; SCC-MOFs have shown remarkably improved luminescent properties relative to discrete silver clusters and unique excellent luminescent responses for sensing gases and volatile organic compounds (VOCs) [33][34][35][36][37] . We previously reported a SCC-MOF, that is, Ag 12 bpy 33 , ([Ag 12 (S t Bu) 8 (CF 3 COO) 4 (bpy) 4 ] n , bpy = 4,4′-bipyridine), whose single green Ph is sensitive to oxygen (Fig.…”