High-temperature proton exchange membrane systems (HT-PEM) based on polybenzimidazole (PBI) membranes are a promising technology offering significant advantages over their low-temperature counterparts. A key challenge limiting its long-term durability is the leaching of phosphoric acid (PA) from the membrane during operation. This work introduces, for the first time, the strategy of modifying polybenzimidazole (PBI) membranes with amino-functionalized porous aromatic frameworks (PAF-20-NH2) to fundamentally enhance their PA retention and operational stability, a critical challenge for high-temperature PEM technologies. We propose that the synergistic combination of the framework’s nanoscale porosity and the specific interaction of its amino groups create an unprecedented network for acid immobilization via reinforced hydrogen bonding. A comprehensive study of the membranes’ physicochemical and structural properties reveals that PAF-20-NH2 modification results in a significant and quantitatively demonstrated improvement in acid retention capacity, directly translating into a notable increase in proton conductivity compared to both pristine PBI and membranes modified with the non-functionalized PAF-20. These findings establish a new, highly effective pathway for the rational design of next-generation high-performance PBI-based membranes.

The performance of proton-exchange membrane fuel cells (PEMFCs) is constrained by coupled transport and reaction processes within the catalyst layer (CL). In this study, oxygen mass transfer in reconstructed porous CL structures was analyzed using the lattice Boltzmann method (LBM) and the quartet structure generation set (QSGS). A three-dimensional microstructure was reconstructed by prescribing phase fractions and growth probabilities. Pt agglomeration, carbon-support corrosion, and ionomer degradation were represented to analyze morphological evolution and its influence on transport. The results reveal that integrated degradation triggers a complex, non-monotonic evolution of mass transfer resistance (Rcl). In the early stages, the thinning of the ionomer film and initial structural reconfiguration shorten the gas diffusion pathways, leading to a transient reduction in Rcl. However, as degradation intensifies, the massive loss of electrochemical active surface area (ECSA), the structural collapse of the carbon skeleton, and the diminished proton conductivity of the ionomer phase collectively lead to a non-linear spike in Rcl. The resulting structure-transport mapping provides a pore-scale basis for durability-oriented catalyst layer design.

Integrity of Nafion membranes in freeze-thaw cycles is an important factor which should be considered when developing proton exchange membrane fuel cells (PEMFC) for the wide range of operating temperatures. Freezing of the Nafion membrane swollen in water leads to desorption of free water/ice on the membrane surface, which causes delamination of catalyst layer, and changes in membrane microstructure. To increase Nafion stability, in situ sol-gel modification with silica nanoparticles was carried out. Morphological changes of pristine and modified membranes during freeze-thaw cycles were investigated by small angle X-ray scattering (SAXS), in addition water uptake and proton conductivity were determined. Stabilization of the structure of ionic domains due to the introduction of silica nanoparticles into the membrane was shown. The observed changes can be attributed to a decrease in the intensity of water sorption-desorption processes and stabilization of ionic domains by modifier nanoparticles. The MEAs fabricated using modified membranes demonstrated enhanced stability during freeze-thaw cycling.

This paper presents a comprehensive review of the transition to zero-emission hydrogen-based automotive transport, evaluating its alignment with modern carbon-free policy objectives. The analysis demonstrates that current decarbonization pathways for vehicles - including internal combustion engines (ICEs), battery electric vehicles (BEVs), and their hybrid derivatives - are insufficient to achieve true zero emissions by 2050. Proton exchange membrane fuel cell (PEMFC) systems present a highly efficient and eco-friendly alternative, but their commercialization is impeded by critical challenges. This review examines the principal obstacles to PEMFC adoption in the automotive industry, including the lack of hydrogen infrastructure, reliance on unsustainable hydrogen production methods, challenges with onboard hydrogen storage, high costs and persistent technical limitations. As these barriers cannot be rapidly overcome, this work concludes that a gradual transition via PEMFC/Li-ion battery hybrid vehicles represents the most viable strategy for the complete decarbonization of the automotive sector in the foreseeable future.

The activities of Pt electrocatalysts modified with a prepared silica powder (with SiO2 contents of 3 and 7 wt%) in the oxygen reduction reaction in the temperature range from 0 °C to 50 °C were investigated by the rotating disk electrode technique to evaluate their efficiency in the process of the cold start of a proton-exchange membrane fuel cell (PEMFC). An increase in the mass activity of the Pt-SiO2/C electrocatalyst in comparison with Pt/C was observed, which can be attributed to a more dispersed distribution of platinum particles on the support surface and a decrease in their size. The activity values of the silica-modified electrocatalysts in the oxygen reduction reaction were approximately two-fold higher at 1 °C and four-fold higher at elevated temperatures of up to 50 °C in comparison with Pt/C, which makes their application in PEMFCs at low temperatures, including in the process of cold start, a promising avenue for further investigation.

Proton exchange membrane (PEM) is a key component of PEM fuel cells, where the membrane plays a decisive role in determining system efficiency and overall performance. The modification of PEMs with hydrophilic dopants represents a promising strategy for extending the operational range of these devices, particularly in low-humidity and high-temperature regimes. In this study, Nafion membranes were modified with silica nanoparticles via the sol-gel method; samples with 1, 3, 5, and 10 wt.% of SiO2 were obtained. Evaluation of key parameters demonstrated improvement of water uptake and proton conductivity for modified membranes with silica content up to 5 wt.%, while no significant changes in thermal stability (30-700 °C) were observed. The structural changes in the composite membranes were investigated using the small-angle X-ray scattering (SAXS) technique. SAXS data were analyzed using a model-dependent approach: the spherical ionic domain model was modified to account for the scattering contribution from silica nanoparticles. The results obtained demonstrated a reduction in the size of unmodified ionic domains, indicating reorganization of the composite membrane's microstructure.

The global issue for proton exchange membrane fuel cell market development is a reduction in the device cost through an increase in efficiency of the oxygen reduction reaction occurring at the cathode and an extension of the service life of the electrochemical device. Losses in the fuel cell performance are due to various degradation mechanisms in the catalytic layers taking place under conditions of high electric potential, temperature, and humidity. This review is devoted to recent advances in the field of increasing the efficiency and durability of electrocatalysts and other electrode materials by introducing structured carbon components into their composition. The main synthesis methods, physicochemical and electrochemical properties of materials, and performance of devices on their basis are presented. The main correlations between the composition and properties of structured carbon electrode materials, which can provide successful solutions to the highlighted issues, are revealed.

Increasing the service life of electrochemical devices is an important task, the solution of which will ensure their competitiveness and commercial attractiveness. One of the methods of protecting device elements from corrosion is the application of coatings of various compositions. Various methods are used, both chemical and physical. Recently, plasma methods, especially magnetron sputtering, have attracted increasing attention. Control of the plasma parameters allows the deposition of crystalline and amorphous coatings and films of different thicknesses (even very thin ones) having the required composition, structure, stoichiometry, density, and porosity. A detailed description and analysis of nanometer coatings and island films of noble metals (Pt, Au, Ir, Pd), which are traditionally used for protective coatings, is presented. We also describe promising nanostructured coatings from carbides and nitrides of transition metals of Groups IV–VI (Ti, Zr, V, Nb, Ta, Mo, W) and carbon-based nanostructured films (amorphous carbon, diamond-like, graphite). They are synthesized under various modes and conditions of magnetron sputtering using plasma- and heat-treatment methods. Tests under conditions close to real ones show their high efficiency in extending the service life of devices. The magnetron-sputtering method is a promising technology with a wide range of applications for coating electrochemical devices, which is confirmed by the references. The optimization of application modes and conditions will make it possible to achieve the greater efficiency and stability of nanostructured coatings.

Magnetron sputtering is a well-known method of obtaining various coatings and surface modifications, but nowadays it is successfully used for the synthesis of electrocatalysts. One of the main advantages of the method is the possibility to vary the parameters during the process, such as the mode (direct current sputtering, pulsed medium-frequency sputtering, high radio frequency sputtering), potential supply to the sputtered substrate or catalyst carrier, pressure in the vacuum chamber, atmosphere composition, which allows to change the composition and structure of the obtained coatings and catalysts very widely. Changing the modes of sputtering makes it possible to create both dense (porous) protective/catalytic coatings and coatings with a very developed surface, i.e. for obtaining electrode materials

Abstract The paper report on the cold start of fuel cell with proton exchange membrane (PEMFC) at – 40 °C using a catalytic heating unit integrated directly into the PEMFC bipolar plates. This technical solution increases the heat transfer efficiency up to 60% due to direct contact of the membrane-electrode assembly with the heating unit, and ensure a successful cold start of the fuel cell from – 40 °C to an operating temperature of 35 °C within 6 minutes at air flow rate of 150 mL/min. The hydrogen flow rate is 45 cm3/s, which corresponds to a hydrogen concentration in the air flow of ca. 1.8 vol.%, which is below the autoignition point and ensures the safety of the proposed method. Uniform distribution of heat over the bipolar plates surface prevents dehydration and thermal degradation of the membrane electrode assembly components and improve the PEMFC performance after cold start.

The global issue for proton exchange membrane fuel cell market development is a reduction in the device cost through an increase in efficiency of the oxygen reduction reaction occurring at the cathode and an extension of the service life of the electrochemical device. Losses in the fuel cell performance are due to various degradation mechanisms in the catalytic layers taking place under conditions of high electric potential, temperature, and humidity. This review is devoted to recent advances in the field of increasing the efficiency and durability of electrocatalysts and other electrode materials by introducing structured carbon components into their composition. The main synthesis methods, physicochemical and electrochemical properties of materials, and performance of devices on their basis are presented. The main correlations between the composition and properties of structured carbon electrode materials, which can provide successful solutions to the highlighted issues, are revealed.

Platinum electrocatalysts on graphene-like supports have recently attracted research interest as components of electrochemical devices based on hydrogen oxidation reactions in acid media due to their improved electrochemical properties, high stability, and conductivity. Within the current work, hydrogen adsorption and the recombination effects of a proton and hydroxonium on a graphene-based electrocatalyst were investigated using density functional theory. The interaction between ions and the platinum surface was simulated for various configurations, including different initial ion distances and angles relative to the surface of the graphene sheet as well as different adsorptions on various Pt atoms (vertices or faces for Pt13 and Pt14 nanoclusters). Then, the geometry optimization was performed. Changes in the density of states during the reactions were studied to analyze the occurrences and alterations of the interactions. A comparative analysis of the obtained adsorption energies of H+ and H3O+ with experimental data was conducted. The energy was calculated to be less in absolute value, and intermediates were more stable in adsorption models with the H–Pt–Gr angle of 90° than in models with the angle of 180°. Strong chemical bonding for models with H–Pt distances less than 2 Å was observed from the DOS.

For successful operation of a fuel cell, its lifetime should be at least 40,000 h. Durability tests are usually limited by certain/standard conditions. On the other hand, operation of a proton exchange membrane fuel cell (PEMFC) under real, nonstandard conditions may lead to an irreversible reduction in the device efficiency and/or degradation of its components. This review deals with the PEMFC performance under a variety of nonstandard conditions, including low and high humidity, and low and high temperatures. Mechanisms of influence of operating conditions on the device performance are identified and analyzed. It is shown that operation of a PEMFC with standard components under nonstandard operating conditions leads to irreversible consequences and reduces the expected lifetime of the device.

One of the most important problems in the development of proton exchange membrane fuel cells remains the selection of an efficient electrocatalyst support capable of providing a low loading of active metal with minimal changes in the electrochemical surface, electronic conductivity, and activity. In this work, carbon nanotube arrays (CNTAs) grown directly on commercial gas diffusion layers (GDLs) are used to form electrodes of a new type. The CNTAs are used in the electrode as a microporous layer. The catalytic layer is formed in the microporous layer by a method that does not destroy the carbon support structure and consists of the controlled impregnation of CNTAs with the Pt-precursor with subsequent reduction in platinum particles in the surface volume of the layer. The resulting electrode was studied by scanning/transmission electron microscopy and Raman spectroscopy. This electrode provides increased electrical conductivity of the layer and can also improve stability and longer service life due to the enhanced adhesion of carbon materials to the GDL.

An electrochemical hydrogen pump (EHP) with a proton exchange membrane (PEM) used as part of fusion cycle systems successfully combines the processes of hydrogen extraction, purification and compression in a single device. This work comprises a novel study of the effect of ionizing radiation on the properties of the PEM as part of the EHP. Radiation exposure leads to nonspecific degradation of membranes, changes in their structure, and destruction of side and matrix chains. The findings from this work reveal that the replacement of sulfate groups in the membrane structure with carboxyl and hydrophilic groups leads to a decrease in conductivity from 0.115 to 0.103 S cm−1, which is reflected in halving the device performance at a temperature of 30 °C. The shift of the ionomer peak of small-angle X-ray scattering curves from 3.1 to 4.4 nm and the absence of changes in the water uptake suggested structural changes in the PEM after the irradiation. Increasing the EHP operating temperature minimized the effect of membrane irradiation on the pump performance, but enhanced membrane drying at low pressure and 50 °C, which caused a current density drop from 0.52 to 0.32 A·cm−2 at 0.5 V.

An electrochemical hydrogen pump (EHP) is a promising technology for hydrogen purification and compression, for instance, it can be used in the fusion devises in systems with low and high pressure. This study aims to determine the possibility of using EHP in systems with wide pressure range (reduced pressure in particular). Experiments were carried out on the «Sivka» installation that allows you to set the hydrogen pressure (from 0.01 to 0.3 MPa) in the anode space, perform electrochemical measurements, control the temperature of the electrochemical (EC) cell (from 20 to 90°C). The dependence of the current-voltage curve (IV curve) on the pressure in the anode space and on the temperature of the EC cell was obtained in the work. At room temperature no pressure dependence on the IV curve was found, which indicates the kinetic-limiting regime. As the temperature rises, the IV curve – pressure dependence is observed which indicates the transition of the EC cell to the diffusion-limited (or mixed diffusion/kinetic) mode of operation.

The present research deals with the adaptation of hydrogen-air fuel cells with proton exchange membrane (PEMFC) to autonomous periodic operation at subzero ambient temperatures. The main goal of the research is to limit the influence of subzero temperatures on component integrity and electrochemical performance stability of PEMFC in the cause of the freeze-thaw (F/T) cycling test. The MEAs stability in cycling from subzero (−35 °C) to operating temperature (+35 °C) was ensured without any specific preparatory operations modeling the PEMFC stop and “cold start” procedure. This is provided through the use of hydrogen-methanol compositions (no more than 4 vol % of methanol vapor) as fuel and a composite anode. Advanced membrane-electrode assembly (MEA) based on the composite anode layer (Pt40/C + Pt20/10 wt%–SnO2/C) for efficient and stable subzero operation during F/T cycling. High stability of electrochemical performance of the MEA with the composite anode at subzero ambient temperatures is shown. Advantages of use a two-component fuel PEMFC for autonomous periodic operation at subzero ambient temperatures are highlighted.

An important stage in the development of platinum electrocatalysts on carbon support is the analysis of their basic parameters. Cyclic voltammetry is an effective tool for analyzing the structural and electrochemical properties of such electrocatalysts. Using Frumkin adsorption isotherms, the contribution of the platinum surface to the hydrogen adsorption region was well described by three peaks corresponding to different crystal structures. The screening was carried out for platinum black and platinum electrocatalysts supported by carbon black, reduced graphene oxide (RGO), carbon nanotubes (CNTs), and nanofibers (CNFs). For most samples, the peak contribution to the electrochemical surface area (ESA) and corresponding hydrogen adsorption energies had close values, but the parameters deviated for Pt black and RGO-based samples was observed. The dependence of the calculated peak parameters on the number of accelerated stress test cycles was used to evaluate the effect of the type of carbon support on the stability of the electrocatalyst and the structure of platinum nanoparticles. The experimental results indicate a high degree of stability and differences in the degradation mechanisms of electrocatalysts based on nanostructured carbon compared to carbon black, which are explained by differences in the metal-support interaction and corrosion resistance of nanostructured carbon supports.

An electrochemical hydrogen pump (EHP) can be used in the fuel cycle of fusion devices for purifying (separating) and compressing fuel (a mixture of hydrogen isotopes). One of the distinguishing features of the fuel cycle of fusion devices is a relatively narrow range of operating pressures of the fuel mixture from high vacuum (similar to 1-10 Pa) to several atmospheres (2-310(5) Pa), and in most of the fuel cycle systems, especially in transmission systems (like gas lines), the pressure shall not exceed atmospheric. In this study, the possibility of using EHP with a proton exchange membrane (PEM) in the fuel cycle of fusion devices in the pressure range of 0.01 - 0.30 MPa and temperatures of 20 - 70 degrees C was considered, and i-V curves were obtained. A regression analysis of the i-V curves was carried out. The temperature dependence of limiting current and resistance of EHP cell was obtained as follows: ln(i(lim)) = -(1140 +/- 1001)1/T + (3.0 +/- 0.3) and ln(p) = (1780 +/- 2801)1/T + (6.5 +/- 1.1). It is shown that there is no dependence of these parameters on pressure. The EHP cell productive capacity was determined in the studied ranges of pressure and temperature as follows: lni/2F = -0.0119 x T -4.2 x E-cell/0.05 + E-cell + 20.4. The results obtained allow one to predict the performance of the EHP device under conditions of subatmospheric hydrogen pressure at the anode and to select the most effective operating parameters of the EHP.

During the operation of electrochemical devices with a proton exchange membrane, the electrode is gradually destroyed and degrades at the anode side under the influence of oxygen. Performance and service life of electrodes in electrochemical devices can be increased by applying Ti-based protective coatings to the surface of current collectors. Nanostructured coatings of Ti, TiO _x , TiN _y , TiO _x N _y compositions were obtained by magnetron sputtering using a titanium target under various conditions. The structure and composition of the samples were studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray phase analysis. The influence of various modes and conditions of magnetron sputtering on the composition and structure of titanium coatings has been established. The service life of the TiN _y coated electrode in the electrolyzer mode is two times higher than that of the uncoated anode under similar conditions with comparable performance.