Proton Conductivity Of Membranes Research Articles

Proton transfer efficiency enhanced over wide relative humidity: Etidronic acid-modified polyphosphazenes cross-linked polybenzimidazoles membranes

To enhance the proton conductivity and oxidative stability of the proton exchange membrane, an effective strategy to construct robust high-temperature PEMs (HT-PEMs) is proposed. The polyoxy(etidronic acid)phazenes cross-linked m-polybenzimidazole membranes (POHP-mPBI) are prepared by solution casting, thermal-crosslinking and acidification. Polyoxy(etidronic acid sodium)phazenes (Na–POHP) is cross-linkable proton conductors by partially phosphonic acid functionalized polyphosphazenes, which ensures proton transport while retaining the cross-linked groups. After covalent cross-linking between Na–POHP and mPBI, the cross-linked macromolecular structure stably locks the proton conductor in the polymer matrix, which ensures the construction of the proton transfer pathway at wide relative humidity (RH). The molecular dynamics simulation was conducted to verify the hydrogen bonds network with the POHP-mPBI membrane. The POHP-mPBI cross-linked membranes exhibit good oxidative stability, mechanical strength, proton conductivity and low fuel transmembrane permeability. At 180 °C and different RH (100% RH, 50% RH, 30% RH and 0 RH), the proton conductivity of POHP(50)-mPBI membrane is 0.150, 0.076, 0.055 and 0.048 S cm−1, respectively. After the water washing for 96 h, the durability of proton conductivity and weight loss shows a rare decline. The incorporation of proton conductors (POHP) into the PBI matrix by cross-linking is a perspective method to enhance the comprehensive performance of HT-PEM.

Performance evaluation of polymer electrolyte membranes based on hydrogen sulfite ionic liquid for application in direct methanol fuel cell (DMFC)

Series of proton conductive membranes were prepared by mixing different weight ratio of 3-hexyl-1-methylimidazolium hydrogensulfite ([C6C1Imi][HSO3]), and N-hexyl-pyridinium hydrogensulfite ([C6Py][HSO3]) ionic liquids with poly vinyl alcohol (PVA) polymer. To characterize the PVA-ILs membranes, different methods have been used such as X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and scanning electron microscope (SEM). Moreover, the water uptakes, ion exchange capacity, methanol permeability, and proton conductivity of prepared PVA membranes doped with different weight ratio of ILs have been investigated to find the optimum formulation to use as electrolytes membranes for direct methanol fuel cell. The proton conductivity and the ion exchange capacity were improved as the ILs content increased. At 25 °C, The PVA-60 wt.% of [C6C1Imi][HSO3] membrane had a maximum proton conductivity of 17,47 mS.cm−1, and a methanol permeability of 8.17 10−7 cm2.s − 1. Mechanical and thermal data confirmed that addition of ILs improve the membrane flexibility and thermal stability up to 200 °C.

Proton-conductive aromatic membranes reinforced with poly(vinylidene fluoride) nanofibers for high-performance durable fuel cells.

Durability and ion conductivity are counteracting properties of proton-conductive membranes that are challenging to achieve simultaneously and determine the lifetime and performance of proton exchange membrane fuel cells. Here, we developed aromatic ionomers reinforced with nonwoven poly(vinylidene fluoride) (PVDF) nanofibers. Because of the right combination of an isotropic nonwoven PVDF with high porosity (78%) and partially fluorinated aromatic ionomers (SPP-TFP-4.0), the resulting composite membrane (SPP-TFP-4.0-PVDF) outperformed state-of-the-art chemically stabilized and physically reinforced perfluorinated Nafion XL membrane, in terms of fuel cell operation and in situ chemical stability at a high temperature (120°C) and low relative humidity (30%). The SPP-TFP-4.0-PVDF membrane exhibited excellent chemical stability and stable rupture energy at high and low RH levels, allowing it to be an alternative proton-conductive membrane to meet the U.S. Department of Energy target to be used in automobile fuel cells in 2025.

Phosphonate poly(vinylbenzyl chloride)-Modified Sulfonated poly(aryl ether nitrile) for Blend Proton Exchange Membranes: Enhanced Mechanical and Electrochemical Properties.

Blend proton exchange membranes (BPEMs) were prepared by blending sulfonated poly(aryl ether nitrile) (SPAEN) with phosphorylated poly(vinylbenzyl chloride) (PPVBC) and named as SPM-x%, where x refers to the proportion of PPVBC to the weight of SPAEN. The chemical complexation interaction between the phosphoric acid and sulfonic acid groups in the PPVBC-SPAEN system resulted in BPEMs with reduced water uptake and enhanced mechanical properties compared to SPAEN proton exchange membranes. Furthermore, the flame retardancy of the PPVBC improved the thermal stability of the BPEMs. Despite a decrease in ion exchange capacity, the proton conductivity of the BPEMs in the through-plane direction was significantly enhanced due to the introduction of phosphoric acid groups, especially in low relative humidity (RH) environments. The measured proton conductivity of SPM-8% was 147, 98, and 28 mS cm-1 under 95%, 70%, and 50% RH, respectively, which is higher than that of the unmodified SPAEN membrane and other SPM-x% membranes. Additionally, the morphology and anisotropy of the membrane proton conductivities were analyzed and discussed. Overall, the results indicated that PPVBC doping can effectively enhance the mechanical and electrochemical properties of SPAEN membranes.

Enhancing proton conduction of high temperature proton exchange membranes based on carbon dots doped polyvinyl chloride nanofibers

Carbon dots (CDs) as the easy-to-get and cheap carbon nanomaterials exhibited the great potential in various high-performance electrolytes. In this research, we constructed high temperature proton exchange membranes with multilayered microstructures through a couple of polyvinyl chloride (PVC) nanofibers layers wrapping a thin CDs layer. In the prepared (PVC/CDs/PVC)es membrane, the CDs provided a mount of sites to anchor phosphoric acid (PA) molecules with the formation of the (PVC/CDs/PVC)es/PA membrane. The proton conduction was accelerated by the continuous proton conduction channels consisting of the CDs layer and PA molecular chains. Notably, the proton conduction behavior was guided by the PVC nanofibers in the (PVC/CDs/PVC)es/PA membrane. Furthermore, a large number of hydrophilic oxygenated functional groups surrounding CDs facilitated the proton conduction process owing to the reduced proton conduction resistance in the hydrophilic membrane. For the PVC/ImCDs/PA membrane, the imidazolium groups could enhance proton conductivity. From our perspective, the imidazolium groups grafted CDs (ImCDs) participated into the proton conduction process through providing imidazolium groups for ameliorating proton conduction network. The enhanced proton conduction was achieved through constructing multilayered structure. Specifically, the (PVC/CDs/PVC)es/PA membrane exhibited the proton conductivity of 5.61 × 10-3 S/cm at 150 °C, which was higher than 7.73 × 10-4 S/cm of the PVC/CDs/PA membrane. Notably, the PA doped membrane could retain the mechanical strength without microstructure expansion.

Porous lanthanum titanium oxide nanostructure composite membrane to enhance the power output and chemical durability of low-humidifying polymer electrolyte fuel cells: impact of additive morphology

Tuning the morphologies for improving the properties of the additive materials receives immense attention during the fabrication of proton-exchange membranes for fuel cells. This study reports the synthesis of lanthanum titanium oxide (LTO) nanostructures with different morphologies (cube, spherical, and tubular) via the pyrolysis of nanofibers containing metal precursors. A mixed matrix membrane is fabricated by incorporating LTO cubes (LTO-C), LTO spheres (LTO-S), or LTO tubes (LTO-T) into a Nafion matrix, with improved physicochemical, thermomechanical, and electrochemical properties compared to those of the unmodified Nafion and Nafion-212 membranes. We investigate the effect of LTO morphology on the performance of the Nafion membranes in low-humidity polymer electrolyte fuel cells (LH-PEFCs). The water retention and diffusion behavior of LTO-T nanostructures improve the proton conductivity and LH-PEFC performance of the Nafion composite membranes. The coexistence of La3+ and Ti4+ affords efficient radical scavenging during long-term LH-PEFC operation, which realizes higher durability for the composite membranes compared to Nafion. Accordingly, this study proposes a novel strategy to resolve the major challenges associated with the operation of LH-PEFCs with Nafion membranes: dehumidification and oxidative degradation.

Effect of Lu-Doping on Electrical Properties of Strontium Zirconate.

SrZrO3-based perovskites are promising proton-conducting membranes for use in fuel and electrolysis cells, sensors, hydrogen separators, etc., because they combine good proton conductivity with excellent chemical stability. In the present research, the effect of Lu-doping on microstructure, phase composition, and electrical conductivity of SrZr1-xLuxO3-δ (x = 0-0.10) was investigated via X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and impedance spectroscopy. Dense ceramic samples were obtained by the solution combustion synthesis and possessed an orthorhombic perovskite-type structure. The solubility limit of Lu was revealed to lie between x = 0.03 and 0.05. The conductivity of SrZr1-xLuxO3-δ increases strongly with the addition of Lu at x < 0.05 and just slightly changes at x > 0.05. The rise of the water vapor partial pressure results in an increase in the conductivity of SrZr1-xLuxO3-δ ceramics, which confirms their hydration ability and significant contribution of protonic defects to the charge transfer. The highest conductivity was achieved at x = 0.10 (10 mS cm-1 at 700 °C, wet air, pH2O = 0.61 kPa). The conductivity behavior was discussed in terms of the defect formation model, taking into account the improvement in ceramic sintering at high lutetium concentrations.

A comparative study on sPEEK‐based composite membranes with various inorganic fillers using different preparation routes for DMFCs

AbstractIn this study, proton‐conducting sulfonated polyether ether ketone (sPEEK) membranes including tungstic acid, organically modified montmorillonite, and silicon dioxide were prepared using solution casting method for direct methanol fuel cells. All obtained composite membranes had adequate thermal stability for fuel cells, and their surfaces became more hydrophilic due to the incorporation of additives. The ion exchange capacities of the composite membranes were found to be very close to the sPEEK membrane. While the proton conductivity of the sPEEK membrane was 8.6 mS cm−1, the addition of additives led to an enhancement in the proton conductivity values. Among the prepared composite membranes, sPEEK‐H2WO4‐5 had the highest proton conductivity (36.5 mS cm−1) which was comparable to Nafion117 in water at room temperature. On the other hand, the methanol permeabilities of the composite membranes were in the same order compared to sPEEK but showed minor changes depending on the added materials and their compositions. Among the membranes obtained by solution casting, sPEEK‐H2WO4‐5 was found to be the best composite membrane due to its high proton conductivity and acceptable methanol permeability. Layer‐by‐layer modified sPEEK membranes were also obtained in the study for comparison and it was found that sPEEK‐PAH/H2WO4‐2 displayed the best selectivity value.

Novel proton-conducting materials based on a polyethylene terephthalate track-etched membrane modified with an N, P-containing ionic liquid

The development of novel membrane materials for hydrogen fuel cells, a promising environmentally friendly technology, represents a relevant research task. In this work, we propose an approach to creating proton-conducting membranes from an industrial polyethylene terephthalate (PET) dielectric track-etched film. An N, P-containing ionic liquid was used as a modifying agent, whose polymerization was carried out directly in the PET membrane pores. The ionic liquid was obtained using a novel approach to the directed synthesis of organophosphorus compounds from elemental phosphorus via the Trofimov-Gusarova reaction developed at the A.E. Favorsky Institute of Chemistry of the Siberian Branch of the Russian Academy of Sciences. The ionic liquid properties were characterized by NMR and IR spectroscopy. The application of the obtained N, P-containing ionic liquid onto a PET membrane was shown to yield a material exhibiting the required mechanical parameters for operation as proton-conducting membranes. The novel proton-conducting materials demonstrate a high proton conductivity of 77.76 mS·cm-1 at 353 K. The obtained proton-conducting membranes seem promising for application in hydrogen fuel cells, thus contributing to the development of effective alternative energy sources.

Facile synthesis of a mixed matrix membrane based on PTA@MOF-199 nanoparticles with proton conductivity

Firstly, H3[P(W3O10)4]@MOF-199 nanoparticles (PTA@MOF-199) of uniform morphology, about 80-125 nm, were successfully synthesized by a simple one-step reaction under solvothermal conditions and then these as-prepared nanoparticles were incorporated into polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) with solution-cast technique to fabricate a series of proton-conducting mixed matrix membranes with different mass percentage of PTA@MOF-199. These membranes were characterized by XRD and FT-IR. Afterwards, the influence of the mass percentage of PTA@MOF-199 and temperature on the proton-conducting properties were evaluated. Our work confirmed that the polyoxometalate (POM) functionalized MOFs had great application potential as proton conductive materials and provided a basis for further studies on other POM@MOFs based proton-conducting membranes fabrication.

Studies on Polybenzimidazole and Methanesulfonate Protic-Ionic-Liquids-Based Composite Polymer Electrolyte Membranes.

In the present work, different methanesulfonate-based protic ionic liquids (PILs) were synthesized and their structural characterization was performed using FTIR, 1H, and 13C NMR spectroscopy. Their thermal behavior and stability were studied using DSC and TGA, respectively, and EIS was used to study the ionic conductivity of these PILs. The PIL, which was diethanolammonium-methanesulfonate-based due to its compatibility with polybenzimidazole (PBI) to form composite membranes, was used to prepare proton-conducting polymer electrolyte membranes (PEMs) for prospective high-temperature fuel cell application. The prepared PEMs were further characterized using FTIR, DSC, TGA, SEM, and EIS. The FTIR results indicated good interaction among the PEM components and the DSC results suggested good miscibility and a plasticizing effect of the incorporated PIL in the PBI polymer matrix. All the PEMs showed good thermal stability and good proton conductivity for prospective high-temperature fuel cell application.

Development and hydrogen permeation of freeze-cast ceramic membrane

BaCe0.65Zr0.20Y0.15O3-δ - Gd0.2Ce0.8O2-δ (BCZY-GDC) is currently one of the most investigated composites as ceramic membranes for H2 separation and membrane reactors. In this context, we will present for the first time the possibility to exploit the ice-templating method coupled with screen printing to obtain hierarchically-structured proton-conducting ceramic membranes. All the processing steps to obtain a defect free dense/porous structure were considered and analysed. In particular, the formulation of screen printing ink was optimized in terms of nature/amount of deflocculant and type of starting BCZY powder. An innovative membrane constituted by a 50 %-porous support with well-organized and aligned porosity and a 13 ± 3 μm thick dense layer on the top, was produced. The compressive strength (20.6 ± 5.6 MPa), were considered acceptable for practical applications. Promising H2 fluxes of 0.36 and 0.42 mL min-1 cm−2 at 750 °C, using a feed stream with 50 and 80% H2 in He (H2 %vol.) respectively, were obtained.

High-Conductive CsH2PO4 Membranes with PVDF-Based Polymers Additives.

The study is devoted to one of the important problems of hydrogen energy-the comparative analysis and creation of novel highly conductive and durable medium-temperature proton membranes based on cesium dihydrogen phosphate and fluoropolymers. The proton conductivity, structural characteristics and mechanical properties of (1 - x)CsH2PO4-x fluoropolymer electrolytes (x-mass fraction, x = 0-0.3) have been investigated and analyzed. UPTFE and PVDF-based polymers (F2M, F42, and SKF26) with high thermal stability and mechanical properties have been chosen as polymer additives. The used fluoropolymers are shown to be chemical inert matrices for CsH2PO4. According to the XRD data, a monoclinic CsH2PO4 (P21/m) phase was retained in all of the polymer electrolytes studied. Highly conductive and mechanically strong composite membranes with thicknesses of ~50-100 μm were obtained for the soluble fluoropolymers (F2M, F42, and SKF26). The size and shape of CsH2PO4 particles and their distribution have been shown to significantly affect proton conductivity and the mechanical properties of the membranes. The thin-film polymer systems with uniform distributions of salt particles (up to ~300 nm) were produced via the use of different methods. The best results were achieved via the pretreatment of the suspension in a bead mill. The ability of the membranes to resist plastic deformation increases with the growth of the polymer content in comparison with the pure CsH2PO4, and the values of the mechanical strength characteristics are comparable to the best low-temperature polymer membranes. The proton-conducting membranes (1 - x)CsH2PO4-x fluoropolymer with the optimal combination of the conductivity and mechanical and hydrophobic properties are promising for use in solid acid fuel cells and other medium-temperature electrochemical devices.

Nanoarchitectonics of fibrous clays as fillers of improved proton-conducting membranes for fuel-cell applications

This work reports on the development of various nanostructured materials based on the assembly of SiO2, TiO2 and ZnO nanoparticles to sepiolite fibers (Sep) and their incorporation as a filler of Nafion to improve their performance as proton exchange membrane for fuel cells applications. Various nanoarchitectures, SiO2-Sep, TiO2-SiO2-Sep and ZnO@SiO2-Sep, were prepared following a colloidal route based on the controlled hydrolysis of alkoxide precursos (tetramethoxysilane and titanium tetraisopropoxide) in the presence of hexadecyltrimethylammonium-sepiolite. The SiO2 and TiO2 nanoparticles were consolidated after a thermal treatment that also removes the surfactant and assures their assembly to the clay. In the case of the ZnO@SiO2-Sep nanostructured material, previously formed ZnO nanoparticles were assembled to the intermediated produced after the hydrolysis-polycondensation of tetramethoxysilane on the organoclay, followed by a thermal treatment that consolidates the nanoarchitecture. The resulting nanoarchitectures were characterized by XRD, FTIR, SEM, TEM and N2 adsorption-desorption isotherms, confirming the formation of the nanoparticles and their assembly through silanol groups at the external surface of the clay. Nafion-based composite membranes were prepared using as nanofiller the produced SiO2-Sep, TiO2-SiO2-Sep and ZnO@SiO2-Sep nanoarchitectures. Thermal properties, water uptake and proton conductivity of the resulting composite membranes were evaluated in comparison to those of a neat Nafion membrane to ascertain their potential usefulness for applications in PEMFC.

PEM Electrochemical Hydrogen Compression with Sputtered Pt Catalysts.

This work presents research on thin magnetron-sputtered platinum (Pt) films deposited over commercial gas diffusion electrodes and applied to convert and pressurize hydrogen in an electrochemical hydrogen pump. The electrodes were integrated into a membrane electrode assembly with a proton conductive membrane. Their electrocatalytic efficiency toward hydrogen oxidation and hydrogen evolution reactions was studied in a self-made laboratory test cell by means of steady-state polarization curves and cell voltage measurements (U/j and U/pdiff characteristics). The achieved current density at a cell voltage of 0.5 V, the atmospheric pressure of the input hydrogen, and a temperature of 60 °C was more than 1.3 A cm-2. The registered increase in the cell voltage with the increasing pressure was only 0.05 mV bar-1. Comparative data with commercial E-TEK electrodes reveal the superior catalyst performance and essential cost reduction of the electrochemical hydrogen conversion on the sputtered Pt films.

Recent Advanced Synthesis Strategies for the Nanomaterial-Modified Proton Exchange Membrane in Fuel Cells.

Hydrogen energy is converted to electricity through fuel cells, aided by nanostructured materials. Fuel cell technology is a promising method for utilizing energy sources, ensuring sustainability, and protecting the environment. However, it still faces drawbacks such as high cost, operability, and durability issues. Nanomaterials can address these drawbacks by enhancing catalysts, electrodes, and fuel cell membranes, which play a crucial role in separating hydrogen into protons and electrons. Proton exchange membrane fuel cells (PEMFCs) have gained significant attention in scientific research. The primary objectives are to reduce greenhouse gas emissions, particularly in the automotive industry, and develop cost-effective methods and materials to enhance PEMFC efficiency. We provide a typical yet inclusive review of various types of proton-conducting membranes. In this review article, special focus is given to the distinctive nature of nanomaterial-filled proton-conducting membranes and their essential characteristics, including their structural, dielectric, proton transport, and thermal properties. We provide an overview of the various reported nanomaterials, such as metal oxide, carbon, and polymeric nanomaterials. Additionally, the synthesis methods in situ polymerization, solution casting, electrospinning, and layer-by-layer assembly for proton-conducting membrane preparation were analyzed. In conclusion, the way to implement the desired energy conversion application, such as a fuel cell, using a nanostructured proton-conducting membrane has been demonstrated.

Effect of zinc oxide on the mechanical, thermal and physiochemical properties of chitosan-based hybrid membrane for DMFC application

This work uses zinc oxide (ZnO) as a filler to prepare a chitosan-based hybrid membrane. The mechanical, thermal and physiochemical properties of the membranes were studied using different experimental techniques. The water uptake capacity and swelling degree of the composite membranes were increased whereas ion exchange capacity (IEC) decreases with the increase of ZnO content. The ZnO filler reduces the crystalline phase of the hybrid membranes. The hybrid membrane's proton conductivity was measured by EIS experiment and fitted into a comparable circuit model. The ZnO filler improves the membrane's proton conductivity, and the proton transport is controlled by the Grotthus mechanism.

A high-efficiency electrochemical proton-conducting membrane reactor for ammonia production at intermediate temperatures

•Efficient electrochemical nitrogen reduction is successfully achieved at 350°C •The NH3 production and H2 purification processes are coupled in one reactor •The in situ supplied protons greatly accelerate the NH3 production rate Ammonia is a ubiquitous chemical raw material and hydrogen carrier with a wide range of industrial applications, which is mainly derived from the energy-intensive Haber-Bosch process. Herein, a high-efficiency ammonia synthesis technology through an excellent CO2-tolerant La5.5WO11.25 − δ (LWO) membrane reactor has been developed to improve electrocatalytic nitrogen reduction reaction performance by coupling with hydrogen purification at intermediate temperatures. From molecular hydrogen, the produced protons can be supplied in situ for ammonia synthesis by nitrogen hydrogenation. As a result, the superior ammonia synthesis performance with the highest Faradaic efficiency (FE) of 43.8% and corresponding ammonia rate of 231.1 μg h−1 cm−2 is achieved at 2,500 μA cm−2 at 350°C. This promising electrochemical membrane reactor for ammonia production at intermediate temperatures provides a feasible direction to promote the development of the ammonia synthesis industry. Ammonia is a ubiquitous chemical raw material and hydrogen carrier with a wide range of industrial applications, which is mainly derived from the energy-intensive Haber-Bosch process. Herein, a high-efficiency ammonia synthesis technology through an excellent CO2-tolerant La5.5WO11.25 − δ (LWO) membrane reactor has been developed to improve electrocatalytic nitrogen reduction reaction performance by coupling with hydrogen purification at intermediate temperatures. From molecular hydrogen, the produced protons can be supplied in situ for ammonia synthesis by nitrogen hydrogenation. As a result, the superior ammonia synthesis performance with the highest Faradaic efficiency (FE) of 43.8% and corresponding ammonia rate of 231.1 μg h−1 cm−2 is achieved at 2,500 μA cm−2 at 350°C. This promising electrochemical membrane reactor for ammonia production at intermediate temperatures provides a feasible direction to promote the development of the ammonia synthesis industry.

Self-Phosphorylated Polybenzimidazole: An Environmentally Friendly and Economical Approach for Hydrogen/Air High-Temperature Polymer-Electrolyte Membrane Fuel Cells.

The development of phosphorylated polybenzimidazoles (PBI) for high-temperature polymer-electrolyte membrane (HT-PEM) fuel cells is a challenge and can lead to a significant increase in the efficiency and long-term operability of fuel cells of this type. In this work, high molecular weight film-forming pre-polymers based on N1,N5-bis(3-methoxyphenyl)-1,2,4,5-benzenetetramine and [1,1'-biphenyl]-4,4'-dicarbonyl dichloride were obtained by polyamidation at room temperature for the first time. During thermal cyclization at 330-370 °C, such polyamides form N-methoxyphenyl substituted polybenzimidazoles for use as a proton-conducting membrane after doping by phosphoric acid for H2/air HT-PEM fuel cells. During operation in a membrane electrode assembly at 160-180 °C, PBI self-phosphorylation occurs due to the substitution of methoxy-groups. As a result, proton conductivity increases sharply, reaching 100 mS/cm. At the same time, the current-voltage characteristics of the fuel cell significantly exceed the power indicators of the commercial BASF Celtec® P1000 MEA. The achieved peak power is 680 mW/cm2 at 180 °C. The developed approach to the creation of effective self-phosphorylating PBI membranes can significantly reduce their cost and ensure the environmental friendliness of their production.

Copolymer of VDF/TFE as a Promising Polymer Additive for CsH2PO4-Based Composite Electrolytes.

The composite polymer electrolytes (1-x)CsH2PO4-xF-2M (x = 0-0.3) have been first synthesized and their electrotransport, structural, and mechanical properties were investigated in detail by impedance, FTIR spectroscopy, electron microscopy, and X-ray diffraction methods. The structure of CsH2PO4 (P21/m) with salt dispersion is retained in the polymer electrolytes. The FTIR and PXRD data are consistent, showing no chemical interaction between the components in the polymer systems, but the salt dispersion is due to a weak interface interaction. The close to uniform distribution of the particles and their agglomerates is observed. The obtained polymer composites are suitable for making thin highly conductive films (60-100 μm) with high mechanical strength. The proton conductivity of the polymer membranes up to x = 0.05-0.1 is close to the pure salt. The further polymers addition up to x = 0.25 results in a significant decrease in the superproton conductivity due to the percolation effect. Despite a decrease, the conductivity values at 180-250 °C remain high enough to enable the use of (1-x)CsH2PO4-xF-2M as a proton membrane in the intermediate temperature range.