bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suppression of Chemical Degradation By Gas Barrier Polymer Electrolyte Membranes
Authors: Nishihara Masamichi , Gautama Zulfi , I Yang , Hutapea Yasir , Sasaki Kazunari 
Published: February 2024

[Introduction]
Polymer electrolyte fuel cell (PEFC) is one of the promising technologies for decarbonization. Especially, PEFC is suitable to power heavy-duty vehicles (HDV) because of its high efficiency and high fuel capacity. However, there are some serious technical challenges for PEFC application for HDV such as the durability. When we focus on the chemical degradation of polymer electrolyte membranes (PEMs), it happens due to attack by radical species. One of the radical formation mechanisms is the reaction at the anode side by the penetrated oxygen from cathode. Therefore, a promising mitigation strategy against chemical degradation is the suppression of oxygen permeability through the PEM.
To verify this concept, we developed high gas barrier PEM. As a model gas barrier PEM, we made a sandwich type PEM with high oxygen barrier property. The sandwich PEM was prepared by depositing a thin interlayer consisting blended poly(vinyl alcohol) (PVA) as a gas barrier material and poly(vinyl sulfonic acid) (PVS) as a proton conductor in between two layers of Nafion 211 membranes. We evaluate chemical durability using the sandwich gas barrier PEM and discuss about the mechanism.
[Experimental]
To fabricate thin sandwich PEMs (15-20 µm), ethanol diluted Nafion dispersion solution (20 mg/ml) and PVA/PVS solution (10 mg/ml) were sprayed on a polytetrafluoroethylene (PTFE) sheet by a spray gun (Tamiya HG wide airbrush). The thickness of each layer was controlled by controlling the deposited weight. Then, membrane characterization procedures such as surface roughness, proton conductivity, and dimensional stability were performed. To evaluate fuel cell performance, the PEMs were mounted to a JARI cell with 1 cm2 active area. Chemically accelerated stress test was performed by open circuit voltage (OCV) holding test following NEDO protocol.
[Results and Discussion]
Several areal densities of PVA/PVS interlayer were successfully incorporated into Nafion membrane to make sandwich PEM. The sandwich PEM shows considerable fuel cell performance, and thin sandwich PEMs show higher performance than the 50 µm sandwich PEM, although it is lower than the thin sprayed Nafion. For example, the peak power density of 15 µm sandwich PEM was 0.44 W cm-2 compared to 0.30 W cm-2 and 0.50 W cm-2 for 50 µm sandwich PEM and 15 µm Nafion, respectively. Furthermore, the incorporation of interlayer to thin PEM can suppress the hydrogen crossover current density from 7.8 mA cm-2 to 5.5 mA cm-2 indicating superior gas barrier property. From the higher gas barrier property, it is predicted thin sandwich PEMs will have higher chemical durability than Nafion with similar thickness.
Improving the Durability and Performance of Anion Exchange Membranes for Water Electrolyzers
Authors: Ceron Maira Raquel , Clemens Auston L. , Yassa Magi Mettry , Karnes John Joseph , Oakdale James Spencer 
Published: February 2024

The two major drawbacks of most renewable sources are intermittency and availability. Renewables will naturally need to be efficiently integrated with electrochemical methodologies for storage (batteries), conversion (fuel cells) and application (electrolysis, CO2 reduction reactions). Alkaline anion exchange membranes (AAEM) have attracted considerable interest to navigate some of the economic hurdles native to polymer electrolyte membrane-based technologies. Despite many advances over the past decade, AAEM long-term stability towards hydroxide mediated degradation remains a significant challenge. Here we integrate anion exchange membrane synthesis, accelerated stress testing and characterization (structural, chemical, electrochemical) to understand and mitigate the effect of degradation of AAEM under electrochemical conditions on the performance of these materials.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Funding was provided by Lawrence Livermore National Laboratory Directed Research and Development (LDRD) Grant 21-ERD-013. IM # LLNL-ABS-846373
(Invited) Strategies to Improve the Stability of Fe/N/C Catalysts in PEM Fuel Cells
Authors: Zhang Gaixia , Yang Xiaohua , Dodelet Jean-Pol , Sun Shuhui 
Published: February 2024

Proton-exchange membrane (PEM) fuel cells hold promising applications in transportation and stationary, however, their widespread commercialization is greatly hindered by the high cost. Platinum (Pt) represents one of the largest cost components of a fuel cell, therefore, my research interests have been focusing on strategies that will increase the activity and utilization of platinum group metal (PGM) catalysts, and improve the performance and stability, as well as prolong the lifetime of the PGM-free catalysts. In this talk, I will first briefly present our work on developing low-PGM catalysts (various unique nanostructured Pt nanowires, nanotubes, and single atoms) to significantly increase the activity and stability of the Pt-based catalysts for ORR in fuel cells. Then, I will mainly focus on our work on PGM-free catalysts. Based on the major breakthroughs on Fe/N/C catalyst achieved by the Dodelet team at INRS (with the MEA activity and performance approaching that of Pt catalyst) [1,2], in collaboration with Ballard Power Systems and Toyota, we have made important progress on improving the stability of PGM-free catalyst [3-17]. Specifically in the following aspects: (i) identifying the active sites, (ii) understanding the fuel cell degradation mechanisms experimentally and theoretically, (iii) developing approaches to improving the stability of the Fe/N/C catalyst, such as pore size control, and fluorination, and (iv) catalyst layer and electrode optimization, such as catalyst hydrophobicity adjustment, Fe/N/C and ultra-low loading Pt/C hybrid catalyst.
References:

M. Lefèvre, E. Proietti, F. Jaouen, J.P. Dodelet, Science, 324, 71 (2009).

E. Proietti, F. Jaouen, J.P. Dodelet, et al, Nature Communications, 2, 416 (2011)

G. Zhang, S. Sun, J.P. Dodelet, et al, Nano Energy, 29, 111,125 (2016).

R. Chenitz, G. Zhang, J.P. Dodelet, et. al, Energy Environmental Science, 11, 365 (2018).

G. Zhang, S. Sun, J.P. Dodelet, et. al, Energy Environmental Science, 12, 3015 (2019).

J.P. Dodelet, G. Zhang, S. Sun et. al, Energy Environmental Science, 14, 1034 (2021).

V.P. Glibin, Cherif M, Vidal F, et al. J. of The Electrochemical Society. 166, F3277 (2019).

V.P. Glibin, G. Zhang, J.P. Dodelet. J. of The Electrochemical Society. 168, 094502 (2021).

V.P. Glibin, G. Zhang, J.P. Dodelet. SusMat. 2, 731 (2022).

X. Yang, G. Zhang, S. Sun, et al, ACS Applied Materials & Interfaces., 12, 13739 (2020).

X. Yang, G. Zhang, S. Sun, et al, Applied Catalysis B: Environmental., 264, 118523 (2020).

Q. Wei, G. Zhang, S. Sun, et. al, Applied Catalysis B: Environmental., 237, 85 (2018).

Q. Wei, G. Zhang, S. Sun, et. al, Nano Energy, 62, 700 (2019).

G. Zhang, S. Sun, Nature Sustainability, 2023, accepted.

X. Tong, G. Zhang, S. Sun, et al, ACS Applied Materials & Interfaces, 13, 30512 (2021).

N. Komba, G. Zhang, S. Sun, et. al, Applied Catalysis B: Environmental. 243, 373 (2019).

G. Zhang, S. Sun, et al, Advanced Energy Materials, 10, 2000075 (2020).
Fe-N-C Oxygen Reduction Catalysts Via Chemical Vapor Deposition in Fluidized Bed Reactor
Authors: Primbs Mathias , Hornberger Elisabeth , Schroeer Pierre , Selve Sören , Strasser Peter 
Published: February 2024

Metal nitrogen carbon catalysts (MNC) are an attractive substitute for platinum-based catalysts in the oxygen reduction reaction (ORR) in PEM fuel cells. However, state-of-the-art MNC catalysts still suffer from low activity and instability. Li et al. [1] demonstrated the use of zinc imidazolate frameworks (ZIF-8) in chemical vapor deposition (CVD) to form active sites without unwanted particle formation or additional treatment steps. In this method, gaseous iron chloride exchanges the zinc in the precatalyst to form active sites.
In this work, we introduce a vertical fluidized bed reactor (FBR) for high-scale synthesis of FeNC via CVD, allowing for uniform dispersion of the precatalyst and better zinc-iron exchange. Furthermore, we investigated the influence of differently sized ZIF-8 on the CVD and the formation of the FeNC catalyst.
The final catalysts were characterized for their electrochemical activity in a rotating ring disc setup, their site density via CO-chemisorption, and their respective turnover frequency. The physicochemical characterization includes the analysis of surface area and pore structure via nitrogen physisorption, SEM, and TEM, as well as surface structure and compositional analysis via elemental analysis, ICP-OES, and XPS.
The exchange of Zn was in the range of 90%, resulting in an iron content of 3.8 wt% with only the formation of desired Fe-Nx active sites. STEM-EDX imaging shows an even distribution of iron and nitrogen in the catalyst, with mean particle sizes of 110 nm. In rotating disc electrode experiments with 0.5 M sulfuric acid, mass activities of 0.23 A/g at 0.9 V vs RHE were achieved.
Commercially nano-scaled ZIF-8 with mean particle sizes of 500 nm, synthesized particles with mean sizes of 110 nm were tested, compared to the commercial ZIF-8 Basolite Z1200 with mean particle sizes of 4.9 µm. We could show improved activity in RRDE of the nano-scaled ZIF-8 materials compared to the macro-scaled Basolite.
Applying this highly scalable synthesis method for MNC catalysts could be a viable way to achieve high-performance catalysts for ORR.
[1] Li Jiao, Jingkun Li, Lynne Larochelle Richard, Qiang Sun, Thomas Stracensky, et al.. Chemical vapour deposition of Fe–N–C oxygen reduction catalysts with full utilization of dense Fe–N4 sites. Nature Materials, 2021, 20, pp.1385-1391.
Relationship between Electrode’s Composition, Porosities and Performance on Mesoporous Pt/C Catalysts
Authors: Blanchard Rémi , El harrati Wissam , Manikandan Maidhily , Halim El Mahdi , Durst Julien 
Published: February 2024

The FCEVs have earned more attention in the past years, with the urge of finding green alternatives for fuel cells. Very convincing small series vehicles (such as the new Mirai) are spearheads for PEMFC technologies and shows how complex both the system and the MEAs have to be designed. More specifically, in the case of the MEA, the importance of mesoporous carbons as carbon support [1], enabling lower Pt poisoning, but also lower O2 resistance in the catalytic layer [2] has been clearly emphasized. In addition, the porosity distribution of the material was concluded to be both favourable to O2 transport, but also to ionomer film continuity onto the carbon support [2]. However, recent literature also indicated with DFT technologies that the solvent system used (hence the ink formulation) could have a major impact on the performance [3], with possible ionomer penetration in the pore, making sluggish performance with an important bottleneck to oxygen transport.
In this study, we aim at demonstrating how solvents modify the interaction between the ionomer and the mesoporous carbon, with a systematic performance screening in PEMFC configuration (25 cm²), while changing ink formulation or parameters, linking the change of the pore distribution of the coated electrode (N2 adsorption), with the performances.
[1] T. Yoshizumi, H. Kubo, M. Okumura, and T. Motor, SAE inernational, 1–6 (2021).
[2] N. Ramaswamy, W. Gu, J. M. Ziegelbauer, and S. Kumaraguru, J. Electrochem. Soc., 167, 064515 (2020).
[3] N. Kikkawa and R. Jinnouchi, J. Phys. Chem. C, 126, 11518–11528 (2022).
(Invited) Structure-Reactivity Relationship for Pt-Rare Earth Electrocatalysts for Oxygen Reduction Reaction
Authors: Cavaliere Sara , Campos-Roldán Carlos Augusto , Blanchard Pierre-Yves , Chattot Raphael , Rozière Jacques , Jones Deborah J. 
Published: February 2024

Alloys of Pt with rare-earth metals (REM) have been demonstrated as one of the most promising candidates with high activity towards oxygen reduction reaction and durability with respect to pure Pt and Pt-alloys with late transition metals1,2. However, due to very low reduction potentials and high oxygen affinity of such elements, the synthesis of Pt-REM nanoalloys by conventional chemical methods is not trivial.
Our group prepared and characterized a series of carbon supported Pt-REM nanocatalysts using a solid-state route3. A systematic investigation of the influence of the type of rare earth metal (Y, Gd, Nd), of the Pt:REM ratio4, and of the post-synthesis treatment5, on the structural, morphological and electrochemical properties of the prepared electrocatalysts was performed. Operando techniques were used to investigate the evolution of the nanoalloys during the electrochemical experiments, providing evidence for the structural transitions and strain dynamics that govern the electrocatalytic activity towards the ORR. For instance, the evolution of the structural, morphological and compositional properties of Pt-Nd nanoalloys occurring during electrochemical activation was studied by online ICP-MS6.
In this presentation an overview of the results obtained on these carbon-supported Pt-REM nanostructured electrocatalysts will be given and the challenges for their application at the PEMFC cathode presented.

J. Greeley et al., Nat. Chem., 1, 552–6 (2009).

C. A. Campos-Roldán, D. J. Jones, J. Rozière, and S. Cavaliere, ChemCatChem, 14 (2022)

Y. Hu, J. O. Jensen, L. N. Cleemann, B. A. Brandes, and Q. Li, J. Am.
Chem. Soc., 142, 953–961 (2020)

C. A. Campos-Roldán et al., ACS Catal., 11, 13519–13529 (2021).

C. A. Campos-Roldán et al., Nanoscale Adv., 4, 26–29 (2022)

C. A. Campos-Roldán et al., sumbitted.

The research leading to these results has received funding from the IMMORTAL project, which receives funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under Grant Agreement No. 101006641. This Joint Undertaking receives support from the European Union's Horizon 2020 research and innovation programme, Hydrogen Europe and Hydrogen Europe Research.
Covalent Crosslinking of High-Density Polyethylene Trimethylammonium-Based Radiation-Grafted Anion Exchange Membranes for Reduced Water Uptakes and Swelling
Authors: Periasamy Arun Prakash , Bance-Souahli Rachida , Whelligan Daniel K , Varcoe John R 
Published: February 2024

Anion exchange membranes (AEMs) are polymer membranes of varying thickness (10 - 50 µm) with covalently bound quaternary ammonium cations, which have been evaluated in fuel cells (AEMFCs) and green hydrogen electrolysis.1,2 Radiation-grafted AEMs made from high-density polyethylene (RG-HDPE) with ca. 30 microns hydrated thickness exhibit high hydroxide conductivities, promising mechanical stabilities, and high AEMFC performances.1,3 The enhanced water transport properties is hypothesized to be from nano and microscale level structural and morphological changes.3 Our best performing ultrathin RG-HDPE films exhibited excellent conductivity and AEMFC performance retention over the 400 h.3 However, the water uptake of RG-HDPE film is ca. 150%, hence, it is important to add a controlled amount of crosslinking.4-7

In previous studies of radiation-grafted membranes for use in reverse electrodialysis, crosslinking + amination was achieved by using a heated amination fabrication step involving a mixture of liquid, high boiling point mono-amines (such as N-methylpiperidine) and a crosslinking diamine (such as N,N,N',N'-tetramethyl-1,6-hexane diamine - TMHDA).8 However, a thermal method is not viable or safe when using the commonly supplied aqueous solutions of dissolved trimethylamine (TMA) gas. This presentation will discuss a variety of approaches, to target controlled TMHDA-crosslinking of TMA-based RG-AEMs, targeting reduced water uptakes and swelling with retention of ion conductivity (Figure 1). The most promising approach involved two steps with the initial amination of the poly(VBC)-grafted HDPE intermediate membranes using a sub-stoichiometric amount of TMHDA. Square wave voltammetry analysis of the solution recovered from amination step 1 confirmed complete reaction of the added TMHDA. In the second step, the membranes were then quickly [important] reacted with aqueous TMA to complete the amination process. TMA can displace TMHDA-based head-groups after long step 2 amination times, hence, we emphasize the use of short TMA amination times in the second step.

References

[1] Wang, Lianqin, et al., J. Mater. Chem. A, 6, 15404 (2018).
[2] Ferriday, T. B., and Peter H. Middleton, Int. J Hydrogen Energy, 46, 18489 (2021).
[3] Wang, Lianqin, et al., Energy Environ. Sci.,
12, 1575 (2019).
[4] T Willson, Terry R., et al., Sustain. Energy Fuels, 3, 1682 (2019).
[5] Iravaninia, Mona, et al., Int. J hydrogen energy 42, 17229 (2017).
[6] Hossain, Md Masem, et al., J Power Sources,
390, 234 (2018).
[7] Xu, Shuai, et al., Mater. Chem., 22, 13295 (2012).
[8] Bance-Soualhi, Rachida, et al., J. Mater. Chem. A,
9, 22025 (2021).

Figure 1
(2022-2023 ECS Toyota Young Investigator Fellowship)
Enhanced Water Electrolysis Using Layered Coaxial Nanowire Electrodes
Authors: Arman Tanvir Alam , Yilmaz Abdurrahman , O. Godoy Andres , Liyanage Wipula Priya Rasika , Routkevitch Dmitri , Komini Babu Siddharth , Jankovic Jasna , Pasaogullari Ugur , Spendelow Jacob S. 
Published: February 2024

Novel electrocatalytic approaches are urgently needed to increase the energy efficiency and decrease the cost of hydrogen production by PEM water electrolyzers. Recently, we developed a novel catalytic platform, the layered coaxial nanowire electrode (LCANE), which enables PEM water electrolyzers with higher energy efficiency and reduced usage of precious metal catalysts. Electrolyzers based on the LCANE approach use a thin film of IrO2-decorated Pt that is intimately interfaced with an ionomer membrane in the form of vertically-aligned coaxial nanowires. Each nanowire consists of a Pt shell encapsulating an ionomer core, with the Pt shell further decorated by IrO2 clusters. The top region of each nanowire bends to form a layer of in-plane aligned Pt/IrO2 nanowires, providing excellent in-plane electronic conductivity. This unique catalyst/electrode geometry offers several key advantages. By localizing ionomer within the nanowire core, the exterior surface of the catalyst remains free from ionomer, eliminating thin-film transport barriers and preventing catalyst poisoning by ionomer adsorption. The vertically aligned sections of the nanowires provide non-tortuous transport of reactants and products, with abundant pore space for facile access of water and removal of oxygen. Close integration of catalyst and ionomer provides improved proton access and eliminates stranding of catalyst. By incorporating catalyst in the form of a thin film and replacing some of the Ir with Pt, lower Ir loading (as low as 0.1 mg/cm2) is achieved without sacrificing surface area or performance.
Acknowledgment
This work was supported by the ECS-Toyota Young Investigator Fellowship and by the Laboratory Directed Research and Development program at Los Alamos National Laboratory.
Visualization of Oxygen Bubbles on a Flat Ionomer-Coated Platinum Electrode
Authors: Suwa Hideki , Kanemoto Ryo , Toyama Kohei , Kishi Sota , Araki Takuto 
Published: February 2024

To improve the performance of polymer electrode membrane electrolyzers, it is necessary to grasp oxygen transport from the reaction site. This paper presents a visualization study which examines the effect of ionomers on the behavior of oxygen bubbles generated from the catalyst covered with ionomers. For the sake of visualization, a flat electrode was fabricated on a glass plate as shown Fig.1 (a). The reaction area was plated with platinum and covered entirely with ionomer using a spin coater.
As shown Fig.1 (b), oxygen bubbles generated on ionomer surface were successfully captured with a high-speed camera. As shown Fig.1 (c), (d) the post visualization by electron microscopy with EDX showed that there were no significant cracks and damages on the ionomers. In other words, oxygen bubbles are generated on the ionomer surface without an apparent three-phase boundary (i.e., catalyst-ionomer-water). This suggests oxygen generated on the Pt surface was transported through the ionomer layer. The three-phase boundary may not be mandatory for the catalyst layer. The results presented in this research can provide better understanding of oxygen transport properties inside catalyst layer, thereby contributing to the future optimization of the structural design of catalyst layers.

Acknowledgement

This study was based on results obtained from the Development of Fundamental Technology for Advancement of Water Electrolysis Hydrogen Production in Advancement of Hydrogen Technologies and Utilization Project (P14021) commissioned by the New Energy and Industrial Technology Development Organization (NEDO).
Fig.1 (a) Flat electrode on a glass plate, (b) Figure of the oxygen bubbles when electrolyzing, Element mapping of (c) Platinum and (d) Fluorine

Figure 1
Manufacturing Challenges, Opportunities, and Successes for PEM Electrolysis at Scale
Authors: Capuano Christopher B. , Ayers Katherine E. , Fortiner Serafina , Ouimet Ryan 
Published: February 2024

Hydrogen generation via electrolysis has gained much attention internationally as not only a sustainable source of fuel for the transportation, but as a carrier of energy to capture stranded renewable energy due to the carbon-free chemical cycle and response characteristics of the technology. The barrier to entry preventing this technology from being widely adopted is the overall cost associated with both the upfront capital expense as well as the operating cost incurred over the product life. The majority of this cost is driven by 1) low electrical efficiencies due to the high ohmic resistance of thicker membranes required by electrolysis systems to electrochemically compress generated hydrogen for storage and the overpotential associated with the water splitting oxygen evolution reaction (OER) catalysts typically used, 2) high cost of system and cell stack materials, which need to be durable for up to 100,000hrs at potentials approaching 2V in both reducing and oxidizing environments, and 3) the lack of a robust supply chain for high volume manufacturing to further drive down cost through economies of scale.
With 95% of hydrogen currently being produced through the reformation of cheap natural gas, significant cost reductions are necessary for electrolysis to become a viable alternative to the incumbent. Commercial proton exchange membrane (PEM)-based electrolysis has reached scales of several hundred kg/day, providing a relevant pathway for industrial scale hydrogen generation with tremendous opportunity for continuing cost reduction by leveraging system and manufacturing scaling laws and advancements in PEM fuel cell materials, manufacturing, and analysis tools. Order of magnitude improvements in some of the highest cost elements are easily achievable and with more research funding being directed towards hydrogen production, the realization of these reductions is occurring at a faster rate. While many improvements in stack design and materials of construction have been identified and implemented, there are still numerous opportunities to explore that would move electrolysis towards a viable, cost-effective alternative to natural gas reformation. This talk will describe some of the areas of success, where research is still needed, and ultimately how each of these improvements translate into cost and the path to reformation parity.