Proton Conduction of an Acid-Resistant Open-Framework Chalcogenidometalate Hybrid in Anhydrous versus Humid Environments

Abstract

Solid proton conductors are broadly applicable to various electrochemical devices; therefore, it is highly desirable to develop robust materials with high proton conductivity under both anhydrous and humid environments within a wide temperature range. In this work, we investigated the proton conducting properties of a 3D open-framework chalcogenidometalate hybrid, [CH3NH3]2­[H3O]­Ag5Sn4Se12·C2H5OH (1), which exhibited both anhydrous and water-assisted proton conduction. Importantly, the excellent thermal and chemical stabilities of hybrid 1 are superior to many MOF-based proton conducting materials. This present study proved to be a considerable advance based on open-framework chalcogenidometalates in the design of robust solid proton conducting materials that are capable of operating under humid and anhydrous environments in a wide temperature range.

Microwave-Assisted Rapid Synthesis of Nanoscale MOF-303 for Hydrogel Composites with Superior Proton Conduction at Ambient-Humidity Conditions

“…Interestingly, the MeSA@MOF-303-PVA hydrogels show high proton conductivity at subzero temperatures, i.e., 1.05 × 10 –3 and 1.26 × 10 –3 S cm –1 at 268 K for MeSA@MOF-303-PVA-40 and MeSA@MOF-303-PVA-50 , respectively. The proton conductions of the MeSA@MOF-303-PVA hydrogels at subzero temperature are superior to those of many reported porous proton conductors. ,− More importantly, the MeSA@MOF-303-PVA hydrogels show high proton conductivities of over 10 –3 S cm –1 in the whole temperature range of 268–353 K at ambient-humidity conditions. In particular, for MeSA@MOF-303-PVA-50 , the room-temperature proton conductivity reaches 2.8 × 10 –3 S cm –1 and the maximum proton conductivity of 9.88 × 10 –3 S cm –1 is attained at 353 K, which are ∼4 orders of magnitude higher than those of the MeSA@MOF-303 nanocrystals at the same conditions (Figure S15).…”

SCSC Transformation and Post-Synthesis Modification of MOFs with Proton Conduction and Ratiometric Fluorescence-Sensing Properties

“…16 MOF conductors have attracted much attention as solid electrolytes. 17 The high conductivity of MOF is due to the strong hydrogenbonding network in MOF that enables efficient proton transfer. 18 The current strategies to improve proton conductivity are as follows: using acid organic ligands with high proton carrier; 19 grafting acidic and hydrophilic functional groups onto the primitive framework; 20 and introducing guest species into the cavity to build more hydrogen bonds.…”

“…Designing and synthesizing functional materials with desired properties is the ultimate goal of chemical researchers . MOF conductors have attracted much attention as solid electrolytes . The high conductivity of MOF is due to the strong hydrogen-bonding network in MOF that enables efficient proton transfer .…”

Recent Progress of Crystalline Porous Frameworks for Intermediate-Temperature Proton Conduction

“…In the meantime, the frameworks can confine proton carriers inside the channels and prevent proton carriers leaking during operation, thus improving long-term stability. − (2) It is more feasible to study proton conduction mechanisms based on MOFs or COFs, due to the highly ordered crystalline structure. − However, MOFs and COFs generally lack intrinsic proton conductivity. Efforts have been made toward improving the proton conductivity of MOFs and COF by decorating functional groups onto the frameworks and loading guest components into cavities. − Progress has been achieved on MOF/COF proton conductors with water molecules as proton carriers under moderate temperatures (<80 °C) and high humidity. − However, when the operating temperature rises above 100 °C, the proton conductivity dramatically decreases due to the loss of water. − To achieve ideal proton conductivity, nonvolatile acids were applied as proton carriers to build a proton transport pathway through MOFs and COFs under intermediate-temperature and anhydrous conditions. − …”