Ion transport and conduction in metal–organic framework glasses

Abstract

Metal-organic frameworks (MOFs) are a group of highly tunable porous materials composed of metal nodes and organic linkers. Although MOF research has predominantly focused on crystalline frameworks, amorphous MOFs with...

Insight into the Isoreticularity of Li-MOFs for the Design of Low-Density Solid and Quasi-Solid Electrolytes

“…However, in our case, as evidenced from the XPS and XRD analysis, none of the isoreticular Li-MOFs has solvent molecules coordinated to the tetrahedron Li-ion metal centers, where unsaturated OMSs can readily generate by removing the coordinated solvent molecules via inert thermal activation processes. Thus, our thesis hypothesis for the Li + conduction may follow a pore filling mechanism of lithium salts via occupying mobile Li-ions in accessible pores of the framework. , Successive pore filling of lithium salts (LEC) into the framework’s cavities may allow us to verify and establish the Li + conduction in isoreticular Li-MOFs. The differences in ionic conductivities could reveal the subtle effect of their isoreticular framework expansion, thereby varying the pore filling capacity and binding with the framework for the mobile Li-ions.…”

“…To date, the solid electrolytes such as inorganic and polymer electrolytes exhibit Li + ion hopping mechanisms, which either follow hopping from one coordination site to the vacant nearest site in inorganic solid electrolytes , or follow the segmental motion of the polymer chains, inducing the ligand exchange of Li + and Li + hopping in polymer electrolytes . In MOF-based SSEs, prior research has shown that Li + transport in the framework channels involves complex interactions between cations, anions, and framework segments . For example, a free motion of Li + conduction mechanism involving cationic and anionic interactions has been revealed in MOFs by creating anionic channels via post modifications of OMCs of the MOF framework with anions like ClO 4 – , BF 4 – , NO 3 – , Cl – , and Br – .…”

“…For example, a free motion of Li + conduction mechanism involving cationic and anionic interactions has been revealed in MOFs by creating anionic channels via post modifications of OMCs of the MOF framework with anions like ClO 4 – , BF 4 – , NO 3 – , Cl – , and Br – . Additionally, in a recent study, adapting an open-pore conformation concept, free and bound states of Li + conduction mechanism for the transfer of Li + through nanochannels of metallacarborane (CoD – ) ions incorporated into the MOF framework by post synthetic modification were demonstrated . Augmenting a similar approach of free and bound states of Li + conduction through porous channels, which are preside by the isoreticular framework expansion of Li-MOFs, our findings strongly suggest that reticularly tailored pore channels and the framework functional sites cooperatively participate in a pore-filling-driven Li + conduction mechanism.…”

“…The Li-BPDC structures, optimized by introducing Li + , ClO 4 − , and EC (Figure 13a Based on the binding interactions deduced from the experimental and simulated absorption spectral traces of LEC@Li-MOFs, we can now associate our results to postulate the Li + ion conduction mechanism for LEC@Li-MOF electrolytes and validate the mechanisms by elucidating the Li + conduction pathway using the computation methods. To date, the solid electrolytes such as inorganic and polymer electrolytes exhibit Li + ion hopping mechanisms, which either follow hopping from one coordination site to the vacant nearest site in inorganic solid electrolytes 11,56 or follow the segmental motion of the polymer chains, inducing the ligand exchange of Li + and Li + hopping in polymer electrolytes. 11 In MOF-based SSEs, prior research has shown that Li + transport in the framework channels involves complex interactions between cations, anions, and framework segments.…”

“…14 Additionally, in a recent study, adapting an open-pore conformation concept, free and bound states of Li + conduction mechanism for the transfer of Li + through nanochannels of metallacarborane (CoD − ) ions incorporated into the MOF framework by post synthetic modification were demonstrated. 56 Augmenting a similar approach of free and bound states of Li + conduction through porous channels, which are preside by the isoreticular framework expansion of Li-MOFs, our findings strongly suggest that reticularly tailored pore channels and the framework functional sites cooperatively participate in a porefilling-driven Li + conduction mechanism. The coordination sites of the metal oxide nodes and metal-carboxylate segments in the framework edges and the plasticizer (EC) occupied in the pores enable Li + ions to move through the porous channels.…”