Exchange Membrane Technology Research Articles

Hydrogen Terminal Braunschweig – a Research Demonstration Facility Along the Hydrogen Value Chain

Two of the greatest challenges in the energy transition are still the transportation and storage of renewable energy. For a green hydrogen economy, electrochemistry will play a major role. This project will show a comprehensive integration of various hydrogen technologies to an integrated physical network at megawatt scale. Our demonstration facility, namely Hydrogen Terminal Braunschweig, is located in Lower Saxony, Germany and was established in Summer 2024 [1].In the Hydrogen Terminal Braunschweig, the green hydrogen (H2) is generated by the world's first commercially available 1 MW electrolyzer prototype of anion exchange membrane (AEM) technology [2]. The produced H2 from the renewable energy will be stored and used for a heavy-duty truck refilling station (350 bar) as well as transported to internal and external fuel cell test benches via pipelines. In addition to the H2 supply, one of the external consumption points is also fed with electrolysis “waste” heat. The waste heat from the 1 MW electrolyzer is collected, processed in a high-temperature heat pump and supplied via a local heating network. Moreover, the technical interplay and conjunction between electrolyzers and fuel cells with a large battery storage system (1.1 MWh storage capacity) and photovoltaic systems to stabilize the electrical grid will be investigated in detail. Here, a medium-voltage switchgear enables off-grid island operation as well as partial load and full load scenarios of all connected electrical components via switch positions. Last but not least, we will develop an education and training program for various target groups in the field of hydrogen technologies and energy transition in the near future.

Recent advances in anion exchange membrane technology for water electrolysis: a review of progress and challenges

AbstractClean energy and environmental pollution are two key concerns of modern society and are pivotal necessities for the economic, social, and sustainable development of the world. Today around 80% of energy is generated using nonrenewable resources and fossil fuels (oil, gas, coal) which ultimately results in hazardous global emissions. As a clean substitute for fossil fuels, hydrogen has emerged as a promising and renewable energy resource. Utilization of this energy resource requires the development of active, stable, low‐cost environmentally friendly techniques. Water splitting electrolysis is a method for producing clean and efficient hydrogen using an environmentally benign technique that is currently at its most mature stage. Electrolysis is attracting ever‐increasing attention, as it is a promising electrochemical device for hydrogen production from water due to the high conversion efficiency and relatively low energy input required when compared to thermochemical and photocatalytic methods. This paper will outline the need, performance, and insight of anion exchange membrane (AEM) electrolyzer. Recent developments in the design and preparation of AEM. New strategies for activity, stability, and efficiency improvement of AEM. Membrane types, and factors affecting AEM performance in an electrolyzer. This review also discusses the effects, operating characteristics, and energy consumption of electrocatalysts in the AEM electrolyzer. Hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) pathways and mechanisms in acidic and alkaline media. This study seeks to provide a detailed overview of recent accomplishments in the field of the hydrogen economy, particularly electrolysis, to inspire further research and development to address the technology's obstacles.

Impact of functionalized titanium oxide on anion exchange membranes derived from chemically modified PET bottles

The accessibility of newly affordable materials has drawn significant attention to the anion exchange membrane (AEM) technology. However, developing a high-performance AEM with excellent hydroxide conductivity and long-term durability is still challenging. The present work aims to improve the overall properties of AEMs synthesized by chemical modification of Polyethylene terephthalate (PET) bottles as the starting material. The modified PET structure was confirmed using IR, NMR, and HPLC-ESIMS analyses. AEMs were developed by incorporating quaternary ammonium (QA) functional groups into the modified PET structure, necessary for transporting anionic species (OH−). In addition, TiO2 nanoparticles grafted with silane coupling agents containing amine functional groups were synthesized via the sol-gel method and embedded in the polymer matrix. Then, the prepared nanocomposite membranes were thoroughly characterized, and the results displayed an overall improvement in the membrane's physicochemical properties. The composite membrane with 3wt% content of nanoparticle (NC3 %/M-PETm) showed remarkable conductivity, reaching 126 mS/cm at 80 °C, doubling the value of pristine membranes (64 mS/cm) while also displaying alkaline stability, retaining up to 92.2 % of conductivity after 20 days in harsh 2 M KOH at 80 °C. These results proved the suitability of these membranes for electrochemical energy applications. This innovative approach offers potential cost savings in preparing the new membranes while aligning with sustainable and circular economy principles.

Enriching wind power utility through offshore wind-hydrogen-chemicals nexus: Feasible routes and their economic performance

The offshore wind-hydrogen strategy is crucial for achieving carbon neutrality, yet faces challenges like wind power variability, surplus hydrogen, and elevated costs. Recently, linking offshore wind, hydrogen, and chemicals is proposed to address these challenges. However, there is a lack of a comprehensive techno-economic analysis of this nexus. This study, as one of the first attempts, performs the techno-economic analysis of 8 feasible offshore wind-hydrogen-chemical nexus routes, in which factors of technology, economics, and financial policy are considered. The research indicates that Route 7, which incorporates offshore wind power utilizing proton exchange membrane technology for hydrogen production and blends it with natural gas on offshore platforms, demonstrates the most cost-effective outcome. The key factors influencing the cost reduction of these routes encompass the green hydrogen price, capital costs, internal rate of return, electricity price, value-added tax rate, and loan ratio. Among these, the green hydrogen price is the primary determinant influencing the cost of green products. If the price of green hydrogen decreases to 2.19 USD/kg, green synthetic ammonia can meet the current standard of 605.47 USD/t. Finally, the results can provide important reference to support stakeholders for seeking cost-effective routes of offshore wind-hydrogen-chemical nexus in China and other regions.

Sustainable hydrogen production by integrating solar PV electrolyser and solar evacuated tube collector with hybrid nanoparticles enhanced PCM

The investigation is motivated to analyze the influence of Phase change material (PCM), nano PCMs, and hybrid Nano PCM in sustainable hydrogen production systems. An emerging and highly effective method for hydrogen production involves the use of proton exchange membrane (PEM) technology, which separates water into its constituent parts through electrolysis. Its susceptibility to performance deterioration over time, however, demandsroutine maintenance and component replacement, which negatively impacts operational effectiveness and cost-effectiveness. In this study, the PEM system for electricity and water heating was integrated with the evacuated tube collector and photovoltaic panel to produce hydrogen. Additionally, hybrid Al2O3 and SiO2 nanoparticles with a combined concentration of 0.1 % in equal shares improved the thermal characteristics of PCM in heat exchangers. The research result shows that the heat exchanger of the ETSC circuit with the hybrid nanoparticles enhanced PCM demonstrated improved thermal performance as well as increased hydrogen production. With hybrid nanoparticles enhanced PCM in the heat exchanger, the maximum energy and electrical energy were observed as246.5 kWh and 44.7 kWh, respectively. The ETSC efficiency, electrical efficiency, and PEM electrolyser efficiency reached their highest points at 93.1 %, 15.5 %, and 39.2 %, respectively. Furthermore, hybrid nanoparticle-enhanced PCM produces an average of 25.9 g of hydrogen.

(Digital Presentation) Integrated Membrane Electrode Assembly in Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cells (PEMFCs), an electrical device with high energy conversion efficiency and zero-carbon emission, has attracted more attention. The membrane electrode assembly (MEA) is the core component of PEMFCs, mainly including proton exchange membrane (PEM), catalyst layer (CL), microporous layer (MPL) and carbon fiber gas diffusion layer (GDL), which has different structures and significantly affects its power density and durability [1].Generally, MEA is fabricated by catalyst coated electrodes (CCE) and catalyst coated membrane (CCM) methods, which often results in a huge interface resistance between electrode and membrane, the weak adhesion and poor proton and electron transfer, limiting the electrochemical surface area (ECSA) and the power density of PEMFCs [2].To solve this problem, many approaches have been adopted, such as improving sintering temperature for MEA, incorporating a guided cracked layer between cathode and membrane, double-layered catalyst and direct deposition method. Zhao et al prepared an integrated membrane electrode assembly structure to reduce the contact resistance between proton exchange membrane and catalyst layer, which significantly improves the efficiency and stability of water electrolysis [4]. At the same time, Klingele and Breitwieser developed a direct deposition of proton exchange membrane technology to improve high performance and long-term stability of PEMFCs. However, these methods are complex and almost impossible to industrialize [5].In this study, integrated membrane electrode assembly (I-MEA) was prepared by combining casting and doctor blade method techniques. The results show that the casting method is more suitable for fabricating I-MEALT in low-temperature proton exchange membrane fuel cells. The power density of the I-MEALT cell is increased by 18% compared with that of the conventional MEALT (Fig. 1). The doctor blade method is more suitable for preparing I-MEAHT in high-temperature proton exchange membrane fuel cells. The maximum power density of I-MEAHT is increased by about 57% compared with that of the conventional MEAHT. The electrochemical impedance shows that this is mainly attributed to the reduced interface resistance between the electrode and the membrane, which facilitates the proton transfer.

Water transport across the membrane of a direct toluene electro-hydrogenation electrolyzer: Experiments and modelling

Toluene/methylcyclohexane is a promising liquid organic hydride for hydrogen storage and transport under ambient conditions. Direct toluene electro-hydrogenation electrolyzers, utilizing proton exchange membrane technology, offer benefits in reducing the reversible decomposition voltage and eliminating theoretical heat losses associated with conventional hydrogenation methods. Nevertheless, water transport across the membrane can inhibit the supply of toluene to reaction sites at the cathode. This study investigates water transport across the Nafion™ 117 membrane of an in-house electrolyzer cell, employing sulfuric acid and toluene solutions as the anode and cathode reactant, respectively, and operating at current densities from 0.1 to 0.8 A/cm2. The experiments show that the cathode toluene concentration has a negligible effect on drag water, while water flux increases with electric current and decreases with higher anode sulfuric acid concentrations. The modelling approach assumes electro-osmosis and diffusion mechanisms govern water transport. Simulations predict a linear decrease in the electro-osmotic drag coefficient from 2.3 to 1.6 as the sulfuric acid concentration rises from 0.1 to 1.5 mol/L, while the back diffusion flux increases linearly up to 2 mg/(min·cm2). These findings closely align with experimental data and previous literature, despite the high complexity of water transport in polymer electrolyte membranes.

Porous Ruthenium-Tungsten-Zinc Nanocages for Efficient Electrocatalytic Hydrogen Oxidation Reaction in Alkali.

With the rapid development of anion exchange membrane technology and the availability of high-performance non-noble metal cathode catalysts in alkaline media, the commercialization of anion exchange membrane fuel cells has become feasible. Currently, anode materials for alkaline anion-exchange membrane fuel cells still rely on platinum-based catalysts, posing a challenge to the development of efficient low-Pt or Pt-free catalysts. Low-cost ruthenium-based anodes are being considered as alternatives to platinum. However, they still suffer from stability issues and strong oxophilicity. Here, we employ a metal-organic framework compound as a template to construct three-dimensional porous ruthenium-tungsten-zinc nanocages via solvothermal and high-temperature pyrolysis methods. The experimental results demonstrate that this porous ruthenium-tungsten-zinc nanocage with an electrochemical surface area of 116 m2 g-1 exhibits excellent catalytic activity for hydrogen oxidation reaction in alkali, with a kinetic density 1.82 times and a mass activity 8.18 times higher than that of commercial Pt/C, and a good catalytic stability, showing no obvious degradation of the current density after continuous operation for 10,000 s. These findings suggest that the developed catalyst holds promise for use in alkaline anion-exchange membrane fuel cells.

Optimal scheduling and real-time control of a microgrid with an electrolyzer and a fuel cell systems using a reference governor approach

This paper proposes a novel approach for the optimal scheduling and control of a microgrid with an electrolyzer and fuel cell systems, both of proton exchange membrane (PEM) technology. It is based on a hierarchical procedure constituted of two levels of optimization: a higher level based on an economic optimization for the optimal scheduling of different components of the microgrid, and a lower level for the real-time control of the hydrogen systems: PEM electrolyzer (PEMEZ) and PEM fuel cell (PEMFC). The flexible operation imposed by the higher level leads to a violation of the limits designed by the manufacturer of the hydrogen components, specifically when switching from one power level to another. The current proportional-integral (PI) controllers integrated into those systems cannot handle this issue, which provokes a premature aging phenomenon of the materials and leads to poor performance of the systems. In the present paper, at the lower level, a reference governor (RG) real-time control approach has been added on top of the PI controller to ensure the respect of the operating limits and guarantee better performances. The focus has been given to the stack's temperature in both the electrolyzer and fuel cell systems as the control objective because of its direct influence on the material's durability and, by extension, on the efficiency. The bi-level optimization and control architecture has been applied and validated through simulations using data from a real-world case study, specifically the Savona Campus Smart Polygeneration Microgrid in Italy. The results showed a significant reduction in the overshoots of the stack's temperature compared to the PI controller.

Hydrogen production by water electrolysis technologies: A review

Hydrogen as an energy source has been identified as an optimal pathway for mitigating climate change by combining renewable electricity with water electrolysis systems. Proton exchange membrane (PEM) technology has received a substantial amount of attention because of its ability to efficiently produce high-purity hydrogen while minimising challenges associated with handling and maintenance. Another hydrogen generation technology, alkaline water electrolysis (AWE), has been widely used in commercial hydrogen production applications. Anion exchange membrane (AEM) technology can produce hydrogen at relatively low costs because the noble metal catalysts used in PEM and AWE systems are replaced with conventional low-cost electrocatalysts. Solid oxide electrolyzer cell (SOEC) technology is another electrolysis technology for producing hydrogen at relatively high conversion efficiencies, low cost, and with low associated emissions. However, the operating temperatures of SOECs are high which necessitates long startup times. This review addresses the current state of technologies capable of using impure water in water electrolysis systems. Commercially available water electrolysis systems were extensively discussed and compared. The technical barriers of hydrogen production by PEM and AEM were also investigated. Furthermore, commercial PEM stack electrolyzer performance was evaluated using artificial river water (soft water). An integrated system approach was recommended for meeting the power and pure water demands using reversible seawater by combining renewable electricity, water electrolysis, and fuel cells. AEM performance was considered to be low, requiring further developments to enhance the membrane's lifetime.

Solid Oxide Fuel Cells for Aviation

Airbus has revealed ZEROe, three concepts for the world’s first zero-emission commercial aircraft which could be brought to market by 2035. The ZEROe concept aircrafts, which support Airbus’ commitment to lead the decarbonisation of the aviation industry, all rely on hydrogen as a primary power source, which would be deployed via a hybrid-hydrogen configuration featuring modified gas-turbine engines complemented by fuel cells for electrical power. Although the Proton Exchange Membrane (PEM) technology is one of the most matured fuel cell types, Airbus Central Research and Technology (CRT) is also investigating novel SOFC concepts for potential hybrid-hydrogen configurations.The Solid Oxide Fuel Cell (SOFC) offers major benefits, namely electrical efficiency and fuel versatility, for hybrid-electric aircraft propulsion. Although the SOFC’s area specific power density has drastically increased within the last decade, more needs to be done to make the technology accessible for aviation applications. The combined development of novel SOFC concepts and corresponding manufacturing processes are regarded as key objectives for the SOFC activities at Airbus Central Research and Technology. Airbus is designing, manufacturing and testing SOFC concepts with the aim to achieve highest gravimetric power densities.Novel manufacturing technologies for metallic and ceramic materials have the potential to enable lighter functional layers for SOFCs with increased intrinsic mechanical stability and surface area. Different cell concepts with an optimized current collection are currently under development at Airbus. The micro-tubular and monolithic SOFC are seen as the most promising concepts, whereas around 2 kW/kg on a cell level has recently been achieved in a performance test at Airbus.

Development of High Durable Pore-Filling Anion Exchange Membranes for Water Electrolysis Application

Water electrolyzer is a device that converts renewable electrical energy into environmentally friendly chemical energy, hydrogen. Water electrolysis is mainly categorized into proton exchange membrane water electrolysis (PEMWE) and anion exchange membrane water electrolysis (AEMWE). Non-precious electrocatalysts and hydrocarbon-based polymeric membranes are used for two different systems. It is advantageous for AEMWE in terms of cost. However, low current density and chemical stability for current anion exchange membrane technology (AEM) restricts early market penetration. Thus, thedevelopment of low resistance and high durable AEMs is of importance. In this study, superior ion conductivity and high durable pore-filling AEMs were developed for AEMWE. Pore-filling AMEs with different contents of crosslinking monomers were prepared by the monomers using chemically stable anion exchangeable functional groups in a porous polyethylene(PE) substrate. Properties of the AEMs were characterized through areal resistance, ionic conductivity, ion exchange capacity, water uptake, swelling ratio, mechanical strength and hydrogen crossover. In addition, AEMWE performance and durability tests were also conducted. Acknowledgments This research was supported in part by Cooperative Research Program for Agriculture Science and Technology Development (Project No. PJ016253), Rural Development Administration, Republic of Korea and by 2021 Green Convergence Professional Manpower Training Program of the Korea Environmental Industry and Technology Institute funded by the Ministry of Environment.

Ecological Hydrogen Production and Water Sterilization: An Innovative Approach to the Trigeneration of Renewable Energy Sources for Water Desalination: A Review

In this study, hydrogen production by solar thermal energy has been studied in terms of economics, technology and hydrogen sources. Methane was captured and subjected to solar photovoltaic steam, solar methane cracking, high-temperature water electrolysis and thermochemical cycles. The price of hydrogen production was calculated compared to other methods, and means of using and exploiting hydrogen as an energy carrier were examined in addition to verifying the industrial need for hydrogen, especially in the presence of high solar energy, which improves hydrogen production. The study was carried out in order to generate hydrogen using a solar electrolyzer based on polymeric exchange membrane technology. The study was carried out using two methods. The first was involved the direct connection of the photovoltaic system to the hydrogen analyzer, and the second was a system for a solar electrolysis hydrogen analyzer consisting of a PV array and a maximum power tracker MPPT meant to operate the system at the maximum power of the photovoltaic system at all times uses a DC converter to supply the analyzer. With the necessary current and hydrogen tank, the results showed that the first method was less effective compared to the second method due to the instability of the intensity of solar radiation during the day, and the results show that adding potassium hydroxide, for example, enhances ionization and improves hydrogen supply.

Integration of ion exchange resins and membrane technology for purification of boron from seawater desalination brines

Integration of ion exchange resins and membrane technology for purification of boron from seawater desalination brines

Experimental Study on the Catalyst-Coated Membrane of a Proton Exchange Membrane Electrolyzer

Proton exchange membrane (PEM) technology may regulate the electrical grid connected to intermittent power sources. The growing pace of R&D in alternative components is widening manufacturing methods and testing procedures across the literature. This turns the comparison between performances into a more laborious task, especially for those starting research in this area, increasing the importance of testing components accessible to all. In this study, an electrochemical characterization is performed on a commercial single-cell PEM water electrolyzer with commercial catalyst-coated membranes (CCMs) and one prepared in-house. Two membrane thicknesses and the effect of different catalysts are assessed. The thicker membrane, Nafion 117, operates with 5% greater ohmic overvoltage than the thinner Nafion 115, resulting in up to 1.5% higher voltage for the former membrane. Equivalent Ir black CCMs provided by different suppliers and one prepared in-house perform similarly. Regarding the influence of the anode catalyst, Ir black, IrRuOx and IrRuOx/Pt have similar performance, whereas IrOx has worse performance. Compared with Ir black, the mix of IrRuOx/Pt operated with 1.5% lower voltage at 2.6 A cm−2, whereas IrRuOx performed with 2% lower voltage at 0.3 A cm−2. A temporary increase in performance is observed when the anode is purged with hydrogen gas.

Power quality improvement for 20 MW PEM water electrolysis system

Hydrogen is an important alternative as a clean fuel for industry and power-to-gas energy storage. The water electrolysis process is a promising technology in green hydrogen production where proton exchange membrane (PEM) technology has been keenly interested. Industrial large-scale PEM electrolyzers need a high current power supply. When connected to an alternating current (AC) source, high current power rectifiers are used to convert AC to DC. Currently, the most commonly used topology in large-scale PEM electrolysis systems is the thyristor-based topology due to its technology maturity and low cost. However, this topology presents several drawbacks in terms of power quality and consequently leads to higher stack-specific energy consumption (SEC) and additional losses. In the present research, we demonstrate the potential power quality improvement for a 20 MW PEM water electrolysis system by rectifier topology upgrade. Rather than traditional thyristor-based topology, a 3-phase interleaved buck rectifier topology is proposed. The new topology presents advantages on both AC and DC sides via a validated simulation model, which is built using MATLAB/Simulink and then validated with experimental data from an industrial 20 MW PEM water electrolyzer at Air Liquide's Bécancour plant. Results show a great improvement in terms of power factor, Total Harmonic Distortion (THD), and DC-current ripple reducing the total losses and the SEC of the PEM stack, especially under partial load. Towards a higher power efficiency, the proposed rectifier topology may be considered in the construction of future large-scale PEM systems.

Recent Advances in Anion Exchange Membrane Technology for Water Electrolysis: A Review of Progress and Challenges

Recent Advances in Anion Exchange Membrane Technology for Water Electrolysis: A Review of Progress and Challenges

(Invited) Advancements in Alkaline Water Electrolysis: The Future of Clean Hydrogen Production

Hydrogen is a leading clean energy among the global initiatives to combat climate change. Currently, the primary source of hydrogen is produced from steam methane reforming (SMR), will produced 5.5 tons of carbon dioxide for every ton of hydrogen. Elimination of carbon dioxide in hydrogen production can be accomplished via water electrolysis.One commercially available water electrolysis system currently relies on proton exchange membrane (PEM) technology. Such electrolyzers require the use of expensive platinum group metal (PGM) catalysts and perfluorinated membranes. With respect to the PGM catalysts, iridium is used for the oxygen evolution reaction (OER) and only 7-8 tons of Ir is produced globally per year. Iridium’s scarcity and increased demand from PEM water electrolyzer (PEMWE) has led to its cost rising to > $6,400 per ounce. The reliance on PGM catalysts alone will significantly hinder the green hydrogen future. The solution to eliminating or dramatically reducing the need for PGM materials is alkaline exchange membrane water electrolysis.Alkaline exchange membrane electrolysis (AEMWE) is a burgeoning technology that combines a solid-state electrolyte (alkaline exchange membrane) with the ability to use PGM-free earth abundant catalyst materials. Currently AEMWE is in its adolescence. Many advancements have been made in membrane technology producing materials which are more chemically stable and operationally robust. Such advances have enabled demonstration of AEMWE without the use of supporting electrolyte thus further decreasing the technology’s cost witthout requiring corrosion resistant materials. Furthermore, advances in PGM-free catalysts, mainly NiFeM OER materials, have demonstrated comparable to improved performance with respect to iridium oxide. Therefore, the previous decade of research has indeed breathed increased interest and research effort into AEMWE.Here in, we report high performance and durability demonstrations of state of the art AEMWE technology. In this work, it is shown that the AEMWE with novel alkaline exchange membranes can operate for hundreds of hours on pure water only at 1000 mA/cm2. Such achievement is however not only limited to novel membrane development, but also due to membrane electrode assembly (MEA) design. The MEA fabrication is a critical step in determining performance and durability owing to the severely limited processing options in current alkaline exchange membrane technology. Furthermore, it is also demonstrated that in collaboration with the State University of New York Buffalo and University of Delaware, that NiFeM OER catalysts are indeed capable of replacing iridium oxide, achieving a similar potential of 1.8 V at 1000 mA/cm2.

Evaluation of Speek |Chitosan As a Proton Exchange Membrane in Electrochemical Hydrogen Pumping

In recent years, climate change has become more evident, requiring the use of renewable energy sources. In this context, energy conversion advanced technologies demand greater attention of the scientific and industrial community for the transition to the so-called "Global Hydrogen Economy" based on the hypothesis that hydrogen can play a role as an energy carrier [1] due its high energy content per unit weight.Proton Exchange Membrane Technology (PEM-Technology) responds to different industrial issues through different systems such as PEM-Electrolyser to produce hydrogen [2] or Electrochemical Hydrogen Pumping / Compression (EHP / EHC) to purify or compress hydrogen to finally distribute it [3–5].In our previously reported works, we prepared SPEEK-Chitosan blends, and we demonstrate with physicochemical characterization (SEM-EDS, TGA-DSC, Water Uptake, Proton Conductivity, etc.). This time we evaluated the best membrane blend S-CS 10%(SPEEK with a 80% of sulfonation degree and 10% of chitosan) in chronopotentiometry at different current density. The S-CS 10% membrane was compared with pristine SPEEK and Nafion115. Our membrane blend exhibited low cell voltage at high current density.In the Figure 1, results obtained via chronopotentiometry are shown for three different membranes for a continuous operating time of t = 1 h at T = 37.5 ° C and 100% RH. From this graph, the Nafion 115 membrane, when demanding a current density of j=1 A cm-2 loses stability and is not able to cover the demanded current; however, it shows some stability when the current demand decreases (j= 0.8 A cm-2). On the other hand, SPEEK and SQ 10% synthesized membranes present a better stability with demanding currents up to j=1 A cm-2 and j=1.3 A cm-2, respectively. The better performance of S-CS 10% is probably due to as there are sulfonic groups interacting with the protonated amine group, a Zwitterion effect is created, causing the water molecules to remain strongly trapped in the membrane by an electrostatic effect, preventing the membrane from dehydrating when working at higher current densities and therefore it consumes less energy [6]. Figure 1

(Invited) Hydrogen Generation and Compression

Compression of hydrogen has the same importance then producing the same, since hydrogen applications require hydrogen on elevated pressure levels, however, those levels are quite divers. As hydrogen generation, also compression is possible on various ways. Next to mechanical compression, also electrochemical hydrogen compression, in the generation unit itself (direct co-compression) or in additional unit (electrochemical hydrogen compressor (EHC)), is seen as a promising alternative in the context of power-to-gas plants.This contribution summarizes the different options and lists the pro and cons of the different techniques, whereas the focus is on the electrochemical systems. It shows that the decision also depends on the application. Herein, the specific energy demand for hydrogen generation and compression is used as measure.The study analyses hydrogen generation and compression pathways using water electrolysis and hydrogen compression pathways, based on proton exchange membrane (PEM) technology, for pressures up to 1000 bar. Energy demands are systematically investigated as a function of design parameters such as pressure, current density, temperature and membrane thickness. The analysis looks deeper into the underlying reasons and intrinsic difference of one or the other pathway, considering aspects on overpotential and gas-crossover.The study shows that the water splitting process itself causes large energetic disadvantages. Also, using EHC enables design parameters to be optimized separately regarding hydrogen generation and compression, giving an important degree of freedom for system design.