Exchange Membrane Fuel Cell Applications Research Articles

MoS2 nanosheet assisted poly vinyl alcohol cross-linked with carboxylated acryl-amido-2-methyl-1-propanesulfonic acid in medium temperature proton exchange membrane fuel cell application

ABSTRACT Initially, the carboxylated-acryl amido propane sulfonic acid (C-AMPSA) was synthesized through the thiol-ene reaction using 2-acrylamido-2-methylpropane sulfonic acid and 3-mercapto propane sulfonic acid monomers. The C-AMPSA was cross-linked with polyvinyl alcohol to create a non-perfluorinated membranes were of these acid group-containing monomers. Using a cross-linking technique, a poly vinyl alcohol cross-linked C-AMPSA (PVA-C-AMPSA) polymer was prepared. Following that, the MoS2 nanosheets (NSs) were synthesized through the one-pot hydrothermal method, and their phase purity, functionality, and morphology were evaluated by p-XRD, FT-IR, and FE-SEM analyses. These nanosheets were then incorporated into PVA-C-AMPSA polymer nanocomposite membranes at various concentrations (0%, 1%, 2%, 3%, and 5% by weight). In addition, the physicochemical properties of bare and MoS2 nanosheets incorporated PVA-C-AMPSA polymer nanocomposite membranes were assessed, including water uptake, swelling ratio, and ion-exchange capacity. Remarkably, the membrane with 5% of MoS2 NSs in PVA-C-AMPSA displayed an ion-exchange capacity of 1.13 mmol g−1 and a proton conduction of 1.8 × 10−3 S cm−1 at 110°C. The Arrhenius plot indicated that the proton transport was involved in both Grotthuss and vehicular mechanisms. In the fuel cell testing, the PVA-C-AMPSA polymer nanocomposite membrane containing MoS2 NSs demonstrated superior performance, achieving a peak power density (PD) exceeding 0.7 W cm−2 and an open-circuit voltage (OCV) surpassing 0.93 V at 110°C. In contrast, the pure PVA-C-AMPSA membrane exhibited a peak PD of over 0.4 W cm−2 and an OCV of around 0.6 V at the same temperature. Additionally, the 5% of MoS2 NSs incorporated PVA-C-AMPSA polymer nanocomposite membrane exhibited outstanding oxidative stability with 87.7% of degradation when exhibited to a Fenton reagent at 80°C for 8 h.

A Review on Most Recent Development of Electrode Structures for Proton Exchange Membrane Fuel Cell Application with Upcoming Prospects

A Review on Most Recent Development of Electrode Structures for Proton Exchange Membrane Fuel Cell Application with Upcoming Prospects

High proton conduction in zirconium silicate/lignin/ionic liquids based- membranes for high temperature PEM fuel cells

In this work, novel Nafion-free membranes composed of zirconium silicate, lignin, and ionic liquids supported on polytetrafluoroethylene have been synthesized for high-temperature applications. Incorporating lignin into zirconium silicate at room temperature has significantly increased the zirconium silicate’s proton conductivity by two orders of magnitude, from 10−4 to 10−2 S/cm. Furthermore, the addition of ionic liquids caused more enhancement in proton conductivity. Two ionic liquids were studied in this work, 1-Ethyl-3-methylimidazolium bis (trifluoromethyl sulfonyl) imide and 1-Hexyl-3-methylimidazolium tricyanomethanide). The incorporation of 1-Hexyl-3-methylimidazolium tricyanomethanide demonstrated the highest proton conduction at room temperature, reaching 0.106 S/cm with an ion exchange capacity of 1.67 meq/g. This most conductive membrane has also demonstrated a slight decrease in proton conductivity (10−3 S/cm) at 150°C showing a high anhydrous conductivity. The membranes’ conductivity was shown to be stable over time as well. The water uptake and swelling ratio results showed improved water retention and dimensional stability. Additional characterization techniques demonstrated positive effect of lignin and ionic liquids inclusion into zirconium silicate on morphology and mechanical properties. Overall, the reported membranes appear to be suitable for high-temperature proton exchange membrane fuel cell applications.

Manufacturing protocol and post processing of ultra-thin gas diffusion layer using advanced scanning techniques

The typical commercial size of a Gas Diffusion Layer (GDL) for Proton Exchange Membrane Fuel Cell (PEMFC) application is around 180 μm up to 290 μm. GDL facilitates the diffusion of reactants to the catalyst layers and liquid removal from the membrane to the flow field. In this regard, GDL should be a porous region with conductive materials as thin as possible to reduce the size and the costs. Lowering the thickness of the GDL also results in better performance of the stack since it increases the speed of reactants to reach the catalysts. However, the main obstacle is the formation of ultra-thin porous GDL, which can be also named as standalone microporous layer (MPL). The novelty of this study is the manufacturing process and production of ultra-thin porous GDL with carbon and Polytetrafluoroethylene (PTFE) as the main materials. The produced GDL has the thickness of 28.9 μm, which has been measured using microscope imaging. This novel GDL can be used as the conductive diffusive region inside the PEM fuel cells, Alkaline fuel cells, and the cathode of PEM and Alkaline electrolyzers. Additionally, the novel invention can be considered as a 2D membrane for carbon capture purposes after being functionalized.

Unveiling zirconium phytate-heteropolyacids-ionic liquids membranes for PEM fuel cells applications up to 150 °C

In the context of escalating energy demands and the pressing issues of climate change, fuel cells emerge as a pivotal, economically feasible, and environmentally sound renewable energy alternative. This study highlights the importance of fuel cells, specifically focusing on high-temperature and Nafion-free membranes. Membranes composed of zirconium phytate, silicotungstic acid, polyethylene glycol, and ionic liquids employing porous polytetrafluoroethylene polymer for support are reported. Investigating varying ratios of silicotungstic acid, polyethylene glycol, and ionic liquids, electrochemical spectroscopy revealed heightened proton conductivity upon ionic liquids integration. Initially, the unmodified zirconium phytate membrane demonstrated a conductivity of 6.65 × 10−4 S/cm, escalating tenfold (2.23 × 10−3 S/cm) with silicotungstic acid addition. Further enhancements, such as incorporating polyethylene glycol, led to an increase in the conductivity to 3.81 × 10−2 S/cm. The maximum conductivity value obtained in this work (0.1 S/cm), comparable to Nafion, was achieved with 5.86 wt% of the 1-Hexyl-3-methylimidazolium tricyanomethanide. Testing at elevated temperatures up to 150 °C revealed a drop in conductivity by two orders of magnitude (10−3 S/cm), highlighting their remarkable conductive properties. Additionally, water uptake analysis demonstrated the membranes' ability to retain more than 60 wt% water molecules within their matrix. Furthermore, thermogravimetric analysis revealed the thermal stability of membranes at high temperatures up to 600 °C. These findings strongly indicate that these synthesized membranes possess considerable potential for high temperature proton exchange membrane fuel cell applications.

A high step‐up DC/DC converter with capacitor‐clamped double‐switch structure for proton exchange membrane fuel cell application

A high step‐up DC/DC converter with capacitor‐clamped double‐switch structure for proton exchange membrane fuel cell application

Ionic Liquid Modification of High-Pt-Loading Pt/C Electrocatalysts for Proton Exchange Membrane Fuel Cell Application

Ionic Liquid Modification of High-Pt-Loading Pt/C Electrocatalysts for Proton Exchange Membrane Fuel Cell Application

Poly(benzimidazole)s containing trifluoromethyl substituents and aryl ether linkages for high-temperature proton exchange membrane fuel cell applications

Poly(benzimidazole)s containing trifluoromethyl substituents and aryl ether linkages for high-temperature proton exchange membrane fuel cell applications

Enhanced Mass Activity and Durability of Bimetallic Pt-Pd Nanoparticles on Sulfated-Zirconia-Doped Graphene Nanoplates for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cell Applications.

Developing highly active and durable Pt-based electrocatalysts is crucial for polymer electrolyte membrane fuel cells. This study focuses on the performance of oxygen reduction reaction (ORR) electrocatalysts composed of Pt-Pd alloy nanoparticles on graphene nanoplates (GNPs) anchored with sulfated zirconia nanoparticles. The results of field emission scanning electron microscopy and transmission electron microscopy showed that Pt-Pd and S-ZrO2 are well dispersed on the surface of the GNPs. X-ray diffraction revealed that the S-ZrO2 and Pt-Pd alloy coexist in the Pt-Pd/S-ZrO2-GNP nanocomposites without affecting the crystalline lattice of Pt and the graphitic structure of the GNPs. To evaluate the electrochemical activity and reaction kinetics for ORR, we performed cyclic voltammetry, rotating disc electrode, and EIS experiments in acidic solutions at room temperature. The findings showed that Pt-Pd/S-ZrO2-GNPs exhibited a better ORR performance than the Pt-Pd catalyst on the unsulfated ZrO2-GNP support and with Pt on S-ZrO2-GNPs and commercial Pt/C.

Synthesis of poly N-aryl piperidinium membrane and ionomer for anion exchange membrane fuel cell applications

Ether free backbones have recently attracted widespread attention in anion exchange membrane fuel cells (AEMFCs). Here we report the synthesis of two poly N-aryl piperidinium (PNAP) membranes from their monomers by the polycondensation method using trifluoromethanesulfonic acid as a catalyst. Density functional theory identifies the chemical reaction, and the radial distribution function represents the interactions between a water molecule and a functional group of PNAP membranes. The performance of the anion exchange membrane can be enhanced by varying the monomer ratios of PNAP. An optimized PNAP-2 membrane exhibits a hydroxide conductivity of 183 mS cm−1 at 90 °C and PNAP-2 ionomers with Pt/C catalysts display a greater half-wave potential (E1/2) of 0.81 V and a lower Tafel value of 65 mV dec−1. In fuel cell tests, a PNAP-2 ionomer alongside a 60% platinum-on-carbon (Pt/C) membrane electrode assembly achieved a peak power density of 2.07 W cm−2. The PNAP-2 remained stable for more than 230 h at a constant current density of 0.3 A cm−2. PNAP-2 also displays exceptional resistance to alkaline conditions, lasting for more than 1000 h in both 1 M and 5 M NaOH solutions at 60 °C.

High-temperature inorganic anion exchange membranes based on layered double hydroxides for anion exchange membrane fuel cell applications

Anion-exchange membrane fuel cells (AEMFCs) have garnered substantial attention over the past two decades due to their numerous advantages, positioning them as promising alternatives to proton exchange membrane fuel cells (PEMFCs). However, their rapid development faces notable challenges, including the limited high-temperature and alkaline stability of anion-exchange membranes due to the incorporation of cationic functional groups, as well as intricate preparation processes. In this study, we propose a high-temperature inorganic anion exchange membrane based on layered double hydroxide doped with K2CO3 prepared by a simple process. This innovative approach optimizes the ionic transport pathway within the LDHs inorganic membrane and enhances water retention performance at elevated temperatures. The maximum cross-plane ionic conductivity of the membrane can reach up to 10−2 S cm−1. Remarkably, the peak power density attains an impressive level of 215.2 mW cm−2 at 110 °C and 200 kPa during the fuel cell testing.

Advances of high-performance and stable finely-ordered patterned membrane for proton exchange membrane fuel cell applications

Large-area ultra-thin patterned membrane with finely ordered micropillars is fabricated with structured poly (dimethyl siloxane) mold as template. The performance and stability are evaluated for fuel cell automotive application. It shows 38 mVs higher performance than its flat counterpart (0.66 V versus 0.622 V at 2000 mA cm−2) in a 25 cm2 MEA with 0.15 mgPt cm−2 cathode loading, 100 % humidified air. Five pieces of 11-μm-thickness patterned membrane are further applied in a 300 cm2 stack. With 0.15 mgPt cm−2 cathode loading, the stack exhibits a high performance of 0.634 V at 2000 mA cm−2 under real fuel cell vehicle operation conditions. To our best knowledge, it is not only the first time the patterned membrane is utilized in a full-size stack for fuel cell vehicles, but also the highest performance of patterned membrane ever reported at such low Pt loading. The reasons for the exceptional performance of the patterned membrane could be due to the direct proton transport path formed by the pillars, resulting in a more effectively utilized catalyst layer. After humidity and voltage cycling, the membrane's three-dimensional structure shows excellent stability, neither micropillars collapsing nor performance decaying observed, demonstrating a great potential for industrial applications.

Starch-chitosan-ionic liquids-based composite membranes for high temperature PEM fuel cells applications

This work reports the fabrication of a starch-chitosan-based membrane for proton exchange membrane fuel cell applications at high temperatures, up to 145 °C. The membranes were fabricated by the solution casting method. Ionic liquids (ILs) were incorporated into the fabricated membranes to examine how they impact the proton conductivity. All the modified membranes generally demonstrated very good proton conductivity values in the range of 10−3 S/cm at room temperature. A noticeable increase in the proton conductivity was observed as the temperature was increased for the IL-based membranes. The IL-based membranes gave very high proton conductivities at 145 °C with a percentage increase of 209 % and 900 % compared to the reference membrane that contains starch and chitosan without any additives. The study reported structural interactions, particularly with the hydrophilic groups like the hydroxyl group, as revealed by FTIR analysis. These findings were supported by EIS measurements. The SEM images showed morphological alterations, and the XRD characterization indicated a shift toward an amorphous structure, implying more water retention in the polymer matrix, which explains the improved proton conductivity. The proton conductivity results as well as relevant water uptake properties reported in this work, appear to be promising for fuel cells operating above the boiling point of water.

Synthesis and characterization of ionic liquid incorporated quaternized poly(2,6-dimethyl-1,4-phenylene oxide) and NiO/IrO2 electrocatalyst for anion exchange membrane fuel cell applications

Incorporating an ionic liquid into QPPO enhances ionic conductivity and single cell performance. Additionally, a homemade NIF ORR electrocatalyst was utilized in the cathode chamber of the fuel cell system to develop low-cost MEA for AEMFCs.

Palladium phosphoselenide (PdPSe) – Reduced graphene oxide composite: A tri-functional electrocatalyst and a cathode catalyst for alkaline fuel cells

Developing a new and efficient electrocatalyst is highly desirable for fundamental electrochemical energy applications such as fuel cells. In this work, we have introduced palladium phosphoselenide (PdPSe), a layer-type ternary material, as a tri-functional electrocatalyst in the three most fundamental electrochemical reactions, such as oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), and oxygen evolution reaction (OER). To enhance the electrocatalytic activity and stability of the electrode material, reduced graphene oxide (rGO) is incorporated into the system by making a composite (rGO-PdPSe), which effectively reduces the overpotentials and increases the current densities for HER and OER. Moreover, in ORR, it turns into a four-electron pathway with comparable kinetics. Further, the composite material is applied in anion exchange membrane fuel cell application as a cathode catalyst. This composite's facile kinetics and robust performance suggests that ternary phosphoselenides based trifunctional electrocatalysts would be a promising material for large-scale application of clean energy conversion devices.

High-Entropy Alloys as Oxygen Reduction Reaction Electrocatalysts for Proton Exchange Membrane Fuel Cells Application

High entropy alloys (HEA) are complex multi-element materials. Owing to their multi-elemental nature, they can finetune surface adsorption energy and active sites which make them appealing to various catalytic reactions. HEI is a subclass of HEA that consist of an ordered alloy structure rather than a random alloy structure. The order-ness may induce more stable structures and uniform active sites, which in turn enhance the durability and activity under catalytic conditions. Here, we have synthesized a HEI(Pt40Ni20Co20Mn10Ir10) supported on porous carbon via a seed-mediated impregnation method. The intermetallic characteristics with periodic trends can be seen in the HAADF-STEM image (Fig. 1a). Based on the atomic arrangement, the HEI resembled a L12 structure. The corresponding EDX mapping the catalyst also showed the presence of all alloying species in the nanoparticles. The catalyst performance of the catalysts was evaluated in a 3-electrode liquid cell set-up with catalyst coated glassy carbon rotating disk electrode, Ag/AgCl and Pt mesh as working, reference and counter electrode, respectively. The catalyst’s mass activity (MA) was calculated based on the result obtained from ORR polarization test conducted under O2 saturated 0.1M HClO4. The initial mass activities for PtCo and HEA in ORR were 0.81 and 1.23 A mg-1 Pt, respectively (Fig. 1b), while that of Pt/C was only 0.26 A mg-1 Pt. A subsequent accelerated degradation test (ADT) was conducted under Ar-saturated 0.1M HClO4 with 0.6-1.0 V vs RHE square-wave cycling (3s hold at each potential) for 30k cycles. MA was measured after 10k and 30k cycles. HEA retained a MA of 0.48 A mg-1 Pt after the ADT, above the DOE target (0.44 A mg-1 Pt). We also compared our HEI samples synthesized with different annealing temperatures and duration (Fig. 1c), and it showed that 800◦C with 20 mins temperature hold showed the highest MA and electrochemical surface area (ECSA).Extended X-ray absorption spectroscopy (EXAFS) for the catalyst has also been conducted to further elucidate the structural-performance relationship of HEI (Fig.1d). From Pt L3 edge EXAFS fitting, the fitted R space showed that the Pt-Pt bond length was around 2.704 ± 0.004 Å, which was same as that of the PtCo (Fig. 1e). Therefore, it is believed that both HEI and PtCo has the same strain effect but HEI possessed stronger ligand effect than PtCo due to its unique Pt-M coordination, hence resulting in superior ORR performance over PtCo and Pt. Figure 1

Pressure and Impedance Based in Situ Diagnostic Methods for Water Management in Proton Exchange Membrane Fuel Cells Applications

Recent advancements in proton exchange membrane fuel cells (PEMFCs) have led to significant developments in low-carbon transport technology, enabling the generation of clean, efficient electricity with minimal noise and toxic emissions for heavy-duty applications. However, effective water management remains a critical challenge in PEMFCs due to the intricate phase changes and liquid-gas transport processes within key components, which significantly impact cell performance and longevity in industrial applications. Given the rapid dynamics of water activities and material responses within cells, in situ diagnostic techniques for water management in PEMFCs are essential for optimizing cell performance and extending the lifespan of fuel cell stack and system.Water, electrochemically produced on the cathode side, can cause potential flooding in key components including the catalyst layer (CL) and gas diffusion layers (GDLs), impeding air/oxygen supply to the cathode side. To characterize the performance loss induced by water flooding, Electrochemical Impedance Spectroscopy (EIS) is commonly employed as a fuel cell diagnostic tool. EIS records the contributions of different polarization processes to the global impedance with individual time constants during operation. However, the interpretation of complex EIS spectra can be very challenging, as polarization processes may overlap in frequency and be difficult to identify. To address this issue, Distribution of Relaxation Times (DRT) analysis is implemented as a powerful tool that allows for a clear separation and quantification of the polarization processes showing as peaks in a frequency domain [1]. Thus, we utilize EIS-based DRT analysis as an in-situ diagnostic tool to detect cathode flooding during cell operation. To validate this approach, we have conducted tests on a 300 cm2 low temperature PEMFC, varying one operation parameter at a time and evaluating its effects on cathode flooding by studying the frequency and height evolution of DRT peaks.Nevertheless, water flooding is not confined to the cathode side, as water can also permeate through the proton exchange membrane (PEM) and reach the anode side, resulting in potential fuel starvation on the cathode's counterpart and subsequent degradation of carbon-based materials. To address the sensitivity limitation of the EIS-based DRT method in detecting anode flooding, we employ an in-house developed pressure drop indicator (PDI) tool, as a non-invasive and real-time approach for diagnosing water flooding in the anode. The PDI tool assesses the pressure drop across anode channels, which is a function of the liquid water contents in bipolar plates considering the pressure reduction mainly caused by the frictional drag [2]. The effectiveness of the PDI tool is validated through cell testing at different water flooding levels by varying relative humidity and pressure conditions. This technique offers timely and sensitive detection of anode water flooding in PEMFCs, which is crucial for alarming irreversible material degradation in the electrode and facilitating appropriate follow-up actions.To conclude, we have developed and employed in situ PDI and EIS-based DRT methods within our water management framework for diagnosing water flooding in both the anode and cathode of PEMFCs in industrial applications. The combination of these techniques offers real-time and accurate assessments on water management conditions, which is crucial for optimizing overall performance and longevity of PEMFC stacks and systems.[1] Heinzmann, M., Weber, A., Ivers-Tiffée, E. (2018). Advanced impedance study of polymer electrolyte membrane single cells by means of distribution of relaxation times. Journal of Power Sources, 402, 24-33.[2] Barbir, F., Gorgun, H., & Wang, X. (2005). Relationship between pressure drop and cell resistance as a diagnostic tool for PEM fuel cells. Journal of Power Sources, 141(1), 96-101. Figure 1

New Advances in Graded PEMFC Catalyst Layers

Ohmic and mass transport overpotentials remain investigation and optimization areas for Proton Exchange Membrane Fuel Cell (PEMFC) applications. One potential optimization approach involves the preferential distribution of the chemical substituents spatially in the catalyst layer. This would ultimately result in graded catalyst layers (GCLs). The spatial grading directions can thereby be in the in plane and/or through plane direction(s). Chemical constituents often graded in both directions include the binder and the catalyst[1, 2]. The ionomer, an essential constituent for PEMFC applications has also been a key focus area for many research institutes and groups. Novel optimization approaches include finding new ionomers with low equivalent weights (EWs).Typically, in a PEMFC, the highest proton conduction rate is at the membrane interface and decreases towards the GDL[3, 4]. Hence, previous studies with gradients containing high ionomer contents close to the membrane and lower ones at the GDL interface resulted in improved performances. The higher ionomer content at the membrane interface resulted in better protonic conductions, and the bigger void spaces in the GDL interface resulted in improved mass transport properties[1, 5]. Though precise electrochemical analysis is lacking, it is commonly agreed that the graded layers have lower mass transport and ohmic resistances. However, the studies encountered in the literature are almost exclusively based on high EW ionomers, such as Nafion. In contrast, low EW ionomers, which have higher protonic conductivity and water uptake capabilities have not yet been a focus of researchers. Additionally, the few reports encountered in the literature focus solely on GCLs while often disregarding other contributing effects to the overall cell voltage such as the equivalent weight.Low EW ionomers offer a wider operation range for PEMFCs in terms of relative humidities. By combining the low EW ionomers with graded catalyst layers, the operation range becomes even more flexible, and the limits are further stretched. In this study, we push the operating range limits of low EW graded catalyst layers and compare them to non-graded ones. We investigate different manufacturing techniques and use suitable scalable coating methods for the manufacturing of the electrodes. Afterwards, suitable in situ and ex situ analysis techniques are used in detail to trace down the improvements for the gradients. Among the key findings, we notice that potential improvements for low EW ionomer graded catalyst layers become apparent at considerable low relative humidities. The improvements are visible in the kinetic, ohmic, and mass transport regions.

Electrospun High Performance Polymer Reinforced Membranes for Exceptional Durability Fuel Cell Membrane Electrode Assemblies

Adequate material selection is one of the most important aspects in component design. Therefore, high-performance polymers have garnered significant interest for Proton Exchange Membrane Fuel Cell (PEMFC) and Water Electrolysis (WE) applications due to their exceptional mechanical, thermal, and chemical properties. This 'beginning by design' strategy requires a deep knowledge of environmental stressors and degradation mechanisms and focuses on proposing next-generation advanced materials able to withstand defined stress conditions for lightweight and heavy-duty transport applications. This presentation presents recent advances and challenges encountered in the preparation of high-performance polymer-reinforced membranes and highlights their specific properties resulting in exceptional durability of nearly 120,000 cycles when tested under combined Open Circuit Voltage (OCV) with Relative Humidity (RH) cycling.This work was supported by the Fuel Cells and Hydrogen 2 Joint Undertaking under grant agreement No 101006641 IMMORTAL. This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme, Hydrogen Europe and Hydrogen Europe Research.

Guanidinium/Hydroxyl-Functionalized Polybenzimidazole for High-Temperature Proton Exchange Membrane Fuel Cell Applications

Guanidinium/Hydroxyl-Functionalized Polybenzimidazole for High-Temperature Proton Exchange Membrane Fuel Cell Applications