Designable Guest‐Molecule Encapsulation in Metal–Organic Frameworks for Proton Conductivity

Abstract

Metal-organic frameworks (MOFs), as a porous frame material, exhibit considerable electrical conductivity. In recent decades, research on the proton conductivity of MOFs has made gratifying progress. In this review, the designable guest molecules encapsulated into MOFs are summarized and generalized into four types in terms of promoting proton conductive performance, and then recent progress in the promotion of proton conductivity by MOFs encapsulating guest molecules is discussed. The existing challenges and prospects for the development of this strategy for promoting MOFs' proton conductivity are also listed.

New group IIIA metal phosphate–oxalates containing dimethylammonium cations with proton conductivity

“…42,50 In addition, the hydrogen bonding network in the structure also contributes to the transfer of protons. 51,52 Three current compounds all contain a large number of phosphate groups, protonated dimethylamine cations and an extensive hydrogen bonding network. These distinctive structural features prompt us to investigate their proton conduction by alternating current impedance spectroscopy.…”

Imparting Stable and Ultrahigh Proton Conductivity to a Layered Rare Earth Hydroxide via Ion Exchange

“…In contrast to amorphous polymers, highly crystalline coordination polymers (CPs), metal–organic frameworks (MOFs), and other crystalline compounds have emerged as promising candidates for proton conductors due to their numerous advantages. − First, these crystalline materials offer a rich variety of geometries, large surface areas, and excellent electrochemical properties. − Second, their well-organized structural frameworks allow for the precise incorporation of various functional groups and the efficient construction and design of proton transport channels. − This enables the controlled realization of desired proton-conduction behavior, ultimately aiding in the establishment of a controllable proton conductivity. − Moreover, the inherent high crystallinity of these compounds plays a crucial role in visualizing proton transport pathways, providing a powerful platform for understanding proton transport mechanisms at the molecular and even atomic levels. Therefore, crystalline compounds hold the potential for making new breakthroughs in the field of proton-conducting materials.…”

Syntheses and High Proton Conductivities of Two 3D Zr(IV)/Hf(IV)-MOFs from Furandicarboxylic Acid

“…As pointed out by Kitagawa and Lim, the papers about such kinds of MOFs have radically increased from a few/per year in 2006 to 140/per year in 2020 . According to the latest results of our search from the Web of Science, the number of related papers is close to 300/year in 2021 and 2022, indicating that the investigation on these MOFs is gaining more and more attention and becoming a new highlight in the field of energy as well as electrochemistry. − Up to now, several reviews have summarized and outlined the preparation strategies of proton-conducting MOFs, proton-conducting enhancement strategies, − post-modification strategies, proton-conducting MOFs based on different organic ligands (e.g., phosphonic acid, sulfonic acids, − carboxylic acids, aza-carboxylic acids, etc. ), and proton-conducting MOFs based on different metal nodes in a more comprehensive and in-depth manner. , …”