An open-framework manganese(ii) phosphite and its composite membranes with polyvinylidene fluoride exhibiting intrinsic water-assisted proton conductance

Abstract

Proton conducting materials have important technological applications as key components in electrochemical devices, including fuel cells, electrochemical sensors, electrochemical reactors and electrochromic displays. And the exploration of novel proton conducting materials is significant for the development of efficient electrochemical devices. In this study, we have investigated the proton conductance of an open-framework manganese(ii) phosphite, (NH)(HO)Mn(HPO) (1). The open-framework manganese(ii) phosphate shows superior water-stability and excellent thermal stability. There was intrinsic water-assisted proton conductivity with σ = 3.94 × 10 S cm at 328 K and 98% RH. Furthermore, composite membranes have further been fabricated using polyvinylidene fluoride (PVDF) and 1, labeled as 1@PVDF-X, where the symbol X represents the mass percentage of 1 (as X%) in the composite membrane and X = 10-55%. The composite membranes display good mechanical performance and durability for practical applications, and the proton conductivity of 1@PVDF-55 reaches 3.32 × 10 S cm in deionized water at 336 K.

Anisotropic Proton Conductivity Arising from Hydrogen-Bond Patterns in Anhydrous Organic Single Crystals, Imidazolium Carboxylates

“…The probes were separately attached to the two opposite sides by using silver paste and gold wires (15 μm diameter). (Note: This combination (silver paste and gold wires) is one of the typical ones to make the electrical contact for measuring the ac conductivity of solid materials, including proton conductors. , ) The complex impedance of the samples was measured from 1 Hz to 1 MHz in the temperature range of 59–94 °C for Im-Glu and 103–116 °C for Im-Suc, where the temperature was controlled by using a home-built high-temperature cryostat. The upper limit temperature of each compound (94 °C for Im-Glu and 116 °C for Im-Suc) was set to the temperature at which the endothermic reaction (or melting) started to appear in the DSC curve (see Figure S1).…”

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

“…It should be mentioned that the H 3 O + ions and the lattice ethanol molecules are disordered even if the temperature is down to 100 K, meaning that these proton carriers are mobile under the perturbation of thermal activation or electrical field. Extensive studies on proton conducting materials based on MOFs and open-framework phosphates revealed that the protonated counterions embedded in the channels, including CH 3 NH 3 + and H 3 O + , are good proton carriers. − ,− Therefore, proton conduction in these materials can be achieved either via proton transfer within the hydrogen-bonding network in the framework (Grotthuss mechanism) or via the proton diffusion through the proton carrier species in the channels of the framework (Vehicle mechanism) …”

“…A variety of porous materials, including chalcogenidometalate hybrids, , open-framework transition metal phosphates, − MOFs, − COFs, − etc. have been extensively researched for their proton conduction properties over the past decade.…”

A Polyoxometalate-Based Inorganic Porous Material with both Proton and Electron Conductivity by Light Actuation: Photocatalysis for Baeyer–Villiger Oxidation and Cr(VI) Reduction

“…Conductive porous crystalline metal–organic frameworks (MOFs) are an emerging class of multidimensional frameworks with high designability and tunability in structure and properties . Especially the high crystallinity and void space of MOFs are beneficial for understanding the conducting path and incorporation of conducting media. , For example, in 2017, Chen’s group reported a structurally flexible and chemically stable MOF, BUT-8­(Cr)­A, with high proton conductivity in a wide RH range of up to 1.27 × 10 –1 S cm –1 at 80 °C and 100% RH, which possesses hydrophilic pores functionalized by large numbers of −SO 3 H sites and a water-content-dependent structural transformation . In 2018, Das’ group proposed a simple yet powerful template-assisted strategy for synthesizing the proton-conducting coordination polymers Co-tri, and the proton conduction value reaches 1.49 × 10 –1 S cm –1 under 98% relative humidity and 80 °C .…”