bluuebunny/crossref_metadata_2025_split huggingface dataset:
How Electrochemical Impedance Spectroscopy Helps Drive Innovation in Fully Hydrocarbon, Reinforced Polymer Electrolyte Membranes
Authors: Adamski Mike , Lee Hsu-Feng , Britton Benjamin 
Published: July 2022

The realm of hydrocarbon-based polymer electrolyte membranes (PEMs) has undergone substantial changes over the past decade. A new era has emerged, based upon strong, fundamental R&D emphasizing both improved performance across a wider range of operating conditions, and greater combined chemical-mechanical stability, when integrated into a state-of-the-art fuel cell. The groundwork has been laid for commercialization of highly promising, fluorine-free technologies which simultaneously outperform previous generation materials, and address weaknesses historically attributed to all hydrocarbon-based membranes. Hydrocarbons address critical issues with perfluorinated sulfonic acid (PFSA) materials. Reduced gas crossover allows longer component lifetimes, operational window for system pressures, and reduced hydrogen venting. Higher temperature tolerances allow system operation or excursions to ≥ 100 °C, which affords a myriad of potential benefits such as reduction in heat exchanger volume, improved system water management, and increased catalyst activity due to mitigated activation losses. Furthermore, higher operating temperatures go hand-in-hand with greater pollution tolerance, and hence reduced hydrogen purity requirements.
The award-winning hydrocarbon-based PEM, Pemion®, produced by Ionomr Innovations, is nested at the center of these exciting developments. Mechanically reinforced composite membranes are produced at scale utilizing advanced roll-to-roll manufacturing techniques, affording a hydrocarbon-based PEM that, for the first time, exhibits performance parallel to or greater than incumbent perfluorinated sulfonic acid (PFSA)-based PEMs. These developments, however, would not be possible without powerful characterization methods such as electrochemical impedance spectroscopy (EIS). Assessments of a membrane’s in-plane and through-plane proton conductivity are used to derive valuable insight to its constituents, the ion-conducting ionomer and chemically-inert mechanical reinforcement, as well as their interrelation. The anisotropic nature of the composite membranes is probed via comparison of in-plane and through-plane conductivity. The sensitivity of through-plane conductivity measurements to experimental parameters such as cell pressure are probed, and a new cell design is realized to reduce measurement error. These data help identify favorable and unfavorable material processing and manufacturing techniques, and their implications to in-situ fuel cell performance. The net consequence of these findings is establishing EIS as a core component of an iterative material design and production process for output of consistent, high-performance PEMs.
Understanding the Effect of Blending Ethanol with Formic Acid on Pd Activity Towards Acidic Oxidation of Concentrated Formic Acid
Authors: Al Najjar Taher , Ahmed Nashaat , El Sawy Ehab 
Published: July 2022

Direct liquid fuel cells are among the most promising energy conversion devices for sustainable energy applications, especially as portable energy sources. The two most effective fuels are methanol and formic acid (FA), and even though methanol has higher energy content, it is toxic, non-renewable, and has high fuel crossover. However, FA can be produced easily from biomass and it is non-toxic and has a higher open circuit potential among other factors1. Usually, FA can be oxidized through two pathways, a direct pathway that is most desirable and directly produces CO2
2. While the indirect pathway produces CO as an intermedia that can adsorb to the catalyst surface deactivating it (poisoning effect)3. Palladium is known to be the most active catalyst for FA oxidation in acidic media4 but it is also easily poisoned by CO accumulation on its surface. The increase in FA concentration to get higher energy density would make the indirect oxidation pathway more favorable lowering the efficiency of the fuel cell. To overcome this problem low molecular weight organic additives were suggested to be used in combination with FA to suppress this poisoning effect by competing with CO molecules for the adsorption sites on the catalyst surface.
In this work, the effect of using ethanol and FA blend fuels on the behavior of Pd/C towards FA oxidation was investigated. The preliminary cyclic voltammetry study showed promising results about ethanol's ability to inhabit the indirect FA oxidation pathway. However, the results obtained by the chronopotentiometry and by studying the first derivatives of the cyclic voltammetry data give more insightful results on the effect of ethanol in the fuel blend. It was found that ethanol will inhabit the indirect oxidation of FA up to specific concentration but it will also affect the direct oxidation after a giving time and that the applied potential will have an effect on the adsorption orientation of Ethanol molecules on the catalyst surface.

References

1) Sun, J.; Luo, X.; Cai, W.; Li, J.; Liu, Z.; Xiong, J.; Yang, Z. Ionic-Exchange Immobilization of Ultra-Low Loading Palladium on a RGO Electro-Catalyst for High Activity Formic Acid Oxidation. RSC Adv. 2018, 8 (33), 18619–18625.
2) Jiang, K.; Zhang, H.-X.; Zou, S.; Cai, W.-B. Electrocatalysis of Formic Acid on Palladium and Platinum Surfaces: From Fundamental Mechanisms to Fuel Cell Applications. Phys Chem Chem Phys 2014, 16 (38), 20360–20376.
3) Gunji, T.; Matsumoto, F. Electrocatalytic Activities towards the Electrochemical Oxidation of Formic Acid and Oxygen Reduction Reactions over Bimetallic, Trimetallic and Core–Shell-Structured Pd-Based Materials. Inorganics 2019, 7 (3), 36.
4) Gharib, A.; Arab, A. Improved Formic Acid Oxidation Using Electrodeposited Pd–Cd Electrocatalysts in Sulfuric Acid Solution. Int. J. Hydrog. Energy 2021, 46 (5), 3865–3875.
How to Impede Hydrogen Evolution on Carbon Based Materials?
Authors: Oates Rose Patricia , Murawski James , Hor Carys , Shen Xuyang , Weber Daniel J , Oezaslan Mehtap , Shaffer Milo S P , Stephens Ifan Erfyl Lester 
Published: July 2022

Hydrogen is a highly attractive zero-emission energy sector. However, in many electrochemical systems, such as carbon dioxide reduction, batteries and supercapacitors hydrogen evolution reaction (HER) is an undesired competing reaction. It is therefore important to tailor these electrochemical systems in order to minimise hydrogen production. Carbon black materials are often added to the catalyst layers as they are low cost, abundant, inert, and have a high conductivity and surface area. This work has investigated HER activities for seven different commercial carbon materials to identify the required structural properties of carbon for minimizing the hydrogen evolution reaction.
Rotating disk electrode, X-ray diffraction, and nitrogen adsorption/ desorption were used to determine the electrochemical and physical characteristics of the carbon materials. An on-chip electrochemical mass spectrometer was used to further probe the gaseous products being produced at the electrode insitu; we established that the exact onset of the HER at -0.4 V vs RHE, as shown in Figure 1. Furthermore, we have correlated our electrochemical experiments to earlier characterization data on the same carbon materials, including: X-ray photoelectron spectroscopy, elemental analysis (e.g. Fe, H, S, C) using neutron activation analysis.1 Our results indicate that the most graphitic carbons with low amount of metal impurities are the best for inhibiting H2 evolution.

V Čolić, S. Yang, Z Révay, I E L Stephens & I Chorkendorff, Electrochim
Acta, 2018,
272, 192–202.

Figure 1
Toward a Fundamental Understanding of Strain Generation and Strain Tuning for the Fuel Cell Applications
Authors: Zeng Zhenhua , Liu Guangdong , Shih Arthur J , Deng Huiqiu , Steinbach Andrew , Koper Marc T. M. , Greeley Jeffrey 
Published: July 2022

The development of industrial electrocatalysts with excellent performance in fuel cells strongly relies on the fundamental understanding of governing principles of catalysis from fundamental research on well-defined model systems. One particularly successful strategy has been to tune surface strain and thereby modulate the surface electronic structure and energetics of reaction intermediates, leading to a fundamental understanding and identification of catalysts with improved activity. For the well-known example of the oxygen reduction reaction (ORR) on platinum in fuel cells, previous studies indicated that a 1% compressive strain could improve the activity by more than 300%.
While the concept of tailoring the reactivity of metal catalysts through surface strain has been discussed over two decades, fundamental challenges remain regarding both strain generation and strain tuning. In the present contribution, We will share our recent progress on these topics, including [1] tunable intrinsic strain in two-dimensional transition metal electrocatalysts, [2] tunable intrinsic strain in stepped transition metal electrocatalysts, and [3] strain tuning of supported transition metal overlayers. We will demonstrate [1] how these fundamental understanding can be used to understand terrace-width dependent ORR activity of stepped Pt surfaces that have puzzled the community over a decade; and [2] how they pave the way toward developing both model electrocatalysts and industrial electrocatalysts with significantly improved performance toward the oxygen reduction reaction.
References

Wang, Z. Zeng*†, W. Gao, T. Maxson, D. Raciti, M. Giroux, X. Pan, C. Wang, J. Greeley,. Science 2019, 363, 870-874.

Wang, W. Gao, Z. Liu, Z. Zeng, Y. Liu, M. Giroux, M. Chi, G. Wang, J. Greeley, X. Pan, C. Wang, ACS Catal. 2018, 8, 35-42.

J. Steinbach, C. Duru, A. T. Haug, A. E. Hester, M. Kuznia, K. A. Lewinski, S. M. Luopa, J. T. Petrin, G. M. Thoma, A. J. Kropf, D. J. Myers, D. Yang, D. A. Cullen, J. Greeley, Z. Zeng, ECS Transactions 2017, 80, 659-676.

Zeng, J. Greeley, Nano Energy 2016, 29, 369.
Synthesis and Characterization of Efficient Nitrogen-Doped Carbon Materials for Supercapacitors Application
Authors: Norkus Eugenijus , Jablonskiene Jolita , Urbanas Davyd , Jasulaitiene Vitalija , Niaura Gediminas , Drabavicius Audrius , Plavniece Ance , Volperts Aleksandrs , Dobele Galina , Zhurinsh Aivars , Tamasauskaite-Tamasiunaite Loreta 
Published: July 2022

N-doped carbons are widely used in the energy storage and conversion field because of their excellent electrical conductivity, high specific surface area, and superb electrochemical stability. Herein, high-efficiency carbon material has been derived using the kraft pulping residues – black liquor as the carbon source. The carbon material was prepared from black liquor through a two-step process, including chemical activation with NaOH at high temperature and doping with nitrogen using dicyandiamide (DCDA). The synthesized catalyst's morphology, structure, and composition were characterized using TEM, XPS, Raman Spectroscopy, and ICP-OES. The electrochemical performance has been evaluated using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques.
The synthesized nitrogen-doped carbon material had a high specific surface area of 2481 m2 g−1. Moreover, this catalyst had a high nitrogen content of 4.33 at%. Most of the nitrogen was in the pyridinic-N (66.58 at%) and graphitic-N forms (33.42 at%). It was found that the specific capacitance of catalysts depends on the catalyst loading. The specific capacitance of ca. 50 F g-1 was achieved in the 1 M Na2SO4 aqueous solution at the scan rate of 5 mV s-1. Besides, the specific capacitance retention was 99% after 100 cycles indicating good electrochemical stability. Our present results demonstrated that kraft pulping residue, such as black liquor, can be employed as a promising carbon precursor to synthesize low-cost and efficient catalysts for supercapacitors.
Acknowledgment
This project has received funding under the Baltic Research Programme project “Sustainably produced nanomaterials for energy applications (SuNaMa)” (No. S-BMT-21-12, LT08-2-LMT-K-01-055).
Characterisation of Novel Nitrogen Doped Reduced Graphene Oxide
Authors: Nerut Jaak , Teppor Patrick , Palm Rasmus , Jäger Rutha , Thomberg Thomas , Tuul Kenneth , Koppel Miriam , Aruväli Jaan , Kikas Arvo , Mondal Jay , Iakimov Valentino , Lust Enn 
Published: July 2022

The utilisation of fuel cells in everyday life is of critical importance for the introduction of clean energy and departure from carbon-based economy. The oxygen reduction reaction (ORR) rate on the cathode is the key factor for effective polymer electrolyte membrane fuel cells. Therefore, novel cathode catalysts have to be designed to reduce the ORR over voltage. One of the most efficient ways to increase the ORR rate is to use nitrogen doping of carbon materials.1 Such materials are also promising for applications in supercapacitors and other energy storage devices.2

In this work, experimental results based on a nitrogen-doped reduced graphene oxide are presented. The nitrogen-doped reduced graphene oxide has been produced by Sea Further SARL using a biological micro-organisms and non-toxic chemicals.3

The material has been characterised by several physical methods: particle size distribution analysis, X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, gas adsorption method, and electrical conductivity measurements. X-ray diffraction data reveal the presence of peaks characteristic to reduced graphene oxide. The specific surface area of the bulk material is around 2.4 m2 g−
1 based on the nitrogen adsorption method. The bulk sample, in powder form, exhibited considerable specific conductance under pressure.
Additionally, electrochemical measurements have been conducted in 0.1 M HClO₄ and 0.1 M KOH solutions. The electrochemical stability, capacitive behaviour, and ORR activity of nitrogen-doped reduced graphene oxide have been determined using cyclic voltammetry, rotating disc electrode and electrochemical impedance spectroscopy methods. The material under discussion has a good electrochemical stability within the investigated potential region in both media. The measurement data show that the ORR kinetics in alkaline media is much faster than in acidic media. Surprisingly, this material has a high gravimetric capacitance. Therefore, nitrogen-doped reduced graphene oxide has high potential for energy storage devices and is promising co-catalyst material in fuel cell.

Acknowledgements

This work was supported by the EU through the European Regional Development Fund under project TK 141 “Advanced materials and high-technology devices for energy recuperation systems” (grant number 2014 2020.4.01.15 0011); and by the Estonian Research Council (grant number PUT PRG 676).

References

N. Daems, X. Sheng, I.F.J. Vankelecom, and P.P. Pescarmona, J. Mater. Chem. A, 2, 4085 (2014).

N.A. Elessawy, J.E. Nady, W. Wazeer, and A.B. Kashyout, Sci. Rep., 9, 1129 (2019).

V. Iakimov, International Patent Application No. WO2021/059152, WIPO, April 1st 2021.
Metal Fluoride Particles to Enhance Durability of Composite Membranes at MT-PEM Fuel Cell Operating Temperatures
Authors: Kutter Maximilian , Hilgert Annika , Hagemeier Wiebke , Rosin Andreas , Gerdes Thorsten , Roth Christina 
Published: July 2022

Fuel cells, as a local, emission-free and versatile system, promise to overcome our dependence on fossil fuels.[1] Polymer electrolyte membrane fuel cells (PEMFCs) are considered one of the most promising technologies among the various kinds of existing fuel cells and offer an attractive alternative for automotive and stationary energy applications. Especially PEMFCs operating at an increased temperature range (MT-PEM) offer an enhanced performance. Operating temperatures between 100 – 130 °C lead to better reaction kinetics, higher tolerance to fuel impurities and to an improved heat, water and power management of the system.[2] However, some issues regarding durability and performance, such as low proton conductivity of PFSA-based membranes, higher membrane degradation and lower long-term stability at increased temperatures, are still unsolved.[3]

In previous works we have shown that various metal fluorides implemented into perfluorosulfonic acid (PFSA)-membranes have a positive impact on performance and mechanical stability at operating temperatures above 100 °C.[4] In this work, we describe the modification of lithium fluoride nanoparticles, their influence on membrane durability in single cell tests at enhanced PEMFC operating temperatures and the morphology of the composite membranes, at different temperatures and degree of hydration, by in-situ small-angle X-ray scattering (SAXS). The lithium fluoride modified membrane showed increased cell performance under both standard and harsher cell conditions as well as in various long-term stability tests, such as accelerated OCV tests, load cycles and on-off cycles.One explanation for the performance boost, in addition to the increased mechanical stability of the membrane, would be an increased water uptake and storage capability, especially at low humidity levels during cell operation. We assume that the nanoparticles adsorb water molecules by hydrogen bond formation, which leads to an enhanced proton conductivity even at high temperatures. To confirm this assumption, we applied in-situ SAXS to analyze the water uptake of the modified membranes at various relative humidity and temperatures to understand the structural changes. In addition, we hope to connect different nanoparticle shapes to their influence on water uptake and retention.
[1] I. Staffell, D. Scamman, A. Velazquez Abad, P. Balcombe, P. E. Dodds, P. Ekins, N. Shah, K. R. Ward, Energy Environ. Sci.
2019, 12, 463–491.
[2] R. E. Rosli, A. B. Sulong, W. R. W. Daud, M. A. Zulkifley, T. Husaini, M. I. Rosli, E. H. Majlan, M. A. Haque, Int. J. Hydrogen Energy
2017, 42, 9293–9314.
[3] L. Mazzapioda, S. Panero, M. A. Navarra, Polymers
2019, 11, 914.
[4] A. Moszczynska, H. Wolf, M. A. Willert-Porada, Patent WO/2009/014930, 2009.
Anode Defects’ Propagation to the Electrolyte and Catalyst Layers in Polymer Electrolyte Membrane Fuel Cells
Authors: Salah Touhami , Crouillere Marie , Mainka Julia , Dillet Jérôme , Nayoze-Coynel Christine , Bas Corine , Dubau Laetitia , El Kaddouri Assma , Dubelley Florence , Micoud Fabrice , Chatenet Marian , Bultel Yann , Lottin Olivier 
Published: July 2022

Defects known to shorten the lifetime of polymer electrolyte membrane fuel cells (PEMFC) can appear on different membrane electrode assembly (MEA) components and under different forms due to manufacturing processes or operational aging of the fuel cell [1, 2]. Defects-propagation in polymer electrolyte membrane fuel cells membrane electrode assemblies (MEA) is investigated via Accelerated Stress Tests (AST) combining load (hence potential) cycling, load-driven humidity cycling, and open-circuit voltage. Customized MEA with lack of anode catalyst layer at two different locations -near the hydrogen inlet or outlet- are fabricated and subjected to the AST. Periodical electrochemical characterizations are performed using a segmented and instrumented cell, enabling to track the cell performance and anode/cathode electrochemical surface area (ECSA) over the test period with a spatial resolution along the gas channels. These observations are completed by post mortem analyses of the MEA.
The MEA accelerated degradation is obvious, with multiple impacts on the cell performance and materials. More specifically, the results brought first evidence of defects propagation in terms of membrane thinning and anode ECSA loss: significant membrane thinning is observed for the defective segments, while anode ECSA loss is measured downstream in the direction of the hydrogen flow. The cathode degradation is poorly affected by the presence of the anode defects. In addition, membrane degradation also appears to propagate downstream the channels when the AST is prolonged for a long period of time. Anode and cathode local potential monitoring during the AST reveals the absence of cathode high-potential excursion, in both the segments with/without initial defects. However, oxygen crossover -toward the hydrogen compartment- is probably detected through slight variations in the anode local potential: this lead to the conclusion that the membrane and anode accelerated degradations are seemingly governed by chemical mechanisms like gas crossover rather than electrochemical mechanisms induced by high-potential excursions.

Guilminot, E. et al. Membrane and Active Layer Degradation upon PEMFC Steady-State Operation. J. Electrochem. Soc. 154, B1106 (2007).

Dubau, L. et al. A review of PEM fuel cell durability: Materials degradation, local heterogeneities of aging and possible mitigation strategies. Wiley Interdiscip. Rev. Energy Environ. 3, 540–560 (2014).

Figure 1
(Energy Technology Division Supramaniam Srinivasan Young Investigator Award) Materials and Capability Development in Photo- and Electro-chemical Electrons-to-Molecules (E2M) Device Research
Authors: Young James L. 
Published: July 2022

In this talk, I will first give an overview of some recent work in photoelectrochemical (PEC) materials and device development as part of the HydroGEN Consortium. Within this consortium, I serve as the NREL lead and a capability expert for the PEC water splitting technology. Our group supports several, university-led seedling projects in developing various PEC materials and plays the central role in a national laboratory collaboration focused on improving PEC device durability. I will highlight the development and demonstration of our flagship capability for PEC device benchmarking and on-sun testing.
In the second part of this talk, I will present some efforts in low-temperature electrolysis (LTE) research as part of the H2NEW Consortium and a Technology Commercialization Fund project. My work focuses on ex-situ characterization of membrane electrode assembly (MEA) performance and development of porous transport layer (PTL) materials and surface modifications. The ex-situ characterization approaches are used in concert with in-situ testing to understand and improve LTE materials and interface properties.
Finally, I will give an overview of NREL’s recent E2M electrochemical device testbed development for CO2 and N2 reduction research. This includes powerful, inline product analysis systems and custom hardware to study electrocatalyst integration, evaluate cell architectures, and conduct spatial and combinatorial studies.