Two Carboxyl-Decorated Anionic Metal–Organic Frameworks as Solid-State Electrolytes Exhibiting High Li⁺ and Zn²⁺ Conductivity

Abstract

A highly electronegative carboxyl-decorated anionic metal−organic framework (MOF), (Me 2 NH 2 ) 2 [In 2 (THBA) 2 ]-(CH 3 CN) 9 (H 2 O) 21 (InOF; H 4 THBA = [1,1′:4′,1″-terphenyl]-2′,3,3″,5,5′,5″-hexacarboxylic acid), with high-density electronegative functional sites was designed and constructed. One unit cell of InOF possesses 12 negative sites that originate from the negatively charged secondary building unit [In(COO) 4 ] − and exposed carboxyl groups on the ligand. The abundant electronegative sites can facilitate the hopping of ions in channels and thus result in highly efficient ion conductivities for various metal ions. Our results show that Li + -loaded materials have a remarkably high ion conductivity of 1.49 × 10 −3 S/cm, an ion transference number of 0.78, and a relatively low activation energy of 0.19 eV. The Na + , K + , and Zn 2+ ion conductivities of InOF are 7.97 × 10 −4 , 7.69 × 10 −4 , and 1.22 × 10 −3 S/cm at 25 °C, respectively.

Rapid adsorption and selective capture of methylene blue by anionic In‐based MOF with carboxyl‐decorated pore surface

“…InOF was synthesized at 85 °C under the solvothermal reaction of [1,1′:4′,1′′‐terphenyl]‐2′,3,3′′,5,5′,5′′‐hexacarboxylic acid (H 4 THBA) and In(NO 3 ) 3 ⋅4H 2 O in DMF/CH 3 CN/HNO 3 mixture. The thermal stability and bulk purity of InOF were verified by TG analysis and PXRD (Figure S1), respectively [37] . The framework of InOF was constituted by [In(COO) 4 ] secondary building units with both −COOH decorated linkers to form a 3D PtS‐type porous structure [37] .…”

“…In addition, modifying functional groups on organic linker can also add the charge of framework material and further enhance interaction with dye molecules. In the previous work, we designed and synthesized a carboxyl‐decorated anionic MOF, InOF, which exhibited a remarkably high ion conductivity of 1.49×10 −3 S/cm and 1.22×10 −3 S/cm for Li + and Zn 2+ [37] . Because of the anionic skeleton with suitable pore size and high‐density electronegative sites, the material might also have remarkable rapid capture and separation of dyes.…”

Enhancing Capacity and Stability of Anionic MOFs as Electrode Material by Cation Exchange

“…Notwithstanding this fact, anionic frameworks are clearly an interesting subclass of MOFs, particularly in that they offer the advantage of tuning their pore sizes via post-synthetic cation exchange (Yang et al, 2008;Procopio et al, 2010;Akintola et al, 2017a;Liu et al, 2017). A further positive consequence of the negatively charged nature of the framework is the abundance of electronegative sites that enable ion mobility within the channels (Duan et al, 2021), which has been exploited in proton conductivity applications (Liu et al, 2016) and could play a role in making them more amenable for the use as electrodes in a similar way. Furthermore, prealkalation of the MOF with the target inorganic cations via cation exchange could provide a path to improving their performance by preparing the materials for insertion.…”

A Ratio Fluorescence Thermometer Based on Carbon Dots & Lanthanide Functionalized Metal‐Organic Frameworks

“…Thanks to the flexible tunability of MOFs, there are various strategies to introduce luminescence centers, and post-synthetic modification (PSM) is regarded as a simple way to overcome the limits of harsh conditions via direct synthesis, which is essential for fabricating MOFs thermometry based on lanthanide fluorescence. [22][23][24] On the other hand, several kinds of fluorescence thermometers such as organic dyes are usually based on temperature-dependent fluorescence intensity mechanism, which are heavily influenced by probe concentration, optoelectronic drifts of the excitation source and detectors and other subtle changes, resulting in a loss of the detection accuracy. In contrast, the dual-emitting measurements can avoid the above shortcomings by making use of the intensity ratio of two independent emissions as the ratiometric parameter, guaranteeing the accurate temperature detection.…”

“…Although Ln‐MOFs as fluorescent thermometry exhibit various advantages, however, the synthesis of Ln‐MOFs are usually under tough conditions and suffered from unsatisfactory water stabilities. Thanks to the flexible tunability of MOFs, there are various strategies to introduce luminescence centers, and post‐synthetic modification (PSM) is regarded as a simple way to overcome the limits of harsh conditions via direct synthesis, which is essential for fabricating MOFs thermometry based on lanthanide fluorescence [22–24] . On the other hand, several kinds of fluorescence thermometers such as organic dyes are usually based on temperature‐dependent fluorescence intensity mechanism, which are heavily influenced by probe concentration, optoelectronic drifts of the excitation source and detectors and other subtle changes, resulting in a loss of the detection accuracy.…”