bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gaseous Nitric Oxide As Probe Molecule for Fe-N-C ORR Electrocatalysts
Authors: Wang Xiaoping , Ferrandon Magali S. , Kowalski Peter , Park Jaehyung , Kropf A. Jeremy , Zhang Hanguang , Zelenay Piotr , Zeng Yachao , Wu Gang , Myers Deborah J. 
Published: August 2024

Iron nitrogen carbon (Fe-N-C) electrocatalysts remain the most promising platinum group metal-free (PGM-free) catalysts for the oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs). Although significant progress has been made in recent years in improving both the ORR activity and stability of the Fe-N-C catalysts, further enhancement in the catalyst durability while maintaining the activity is imperative for the practical applications. One of the major factors that hinders the further enhancement of the catalysts is the lack of clear understanding of the nature of the active sites and density of the active sites in the Fe-N-C catalysts due to the complexity of the Fe-N-C catalysts’ composition and structure. Gaseous nitric oxide was proven to be a suitable probe molecule that can bond to Fe and impede the ORR of the Fe-N-C catalysts. In recent years, we have studied the effects of gas-phase adsorption and desorption of nitric oxide on the redox features and ORR activity on Fe-N-C catalysts synthesized by different methods. We have used various characterization tools to quantify the amount of nitric oxide adsorbed and to identify the adsorption sites and geometry, including electrochemical stripping, temperature programmed desorption, and in situ X-ray techniques. The corresponding results obtained will be summarized in this talk. The implication of these results on the nature of the ORR active sites of the Fe-N-C catalysts will be discussed.
Acknowledgements
This work was supported by the U.S. Department of Energy (DOE), Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (HFTO) under the auspices of the Electrocatalysis Consortium (ElectroCat 2.0). This work utilized the resources of the Advanced Photon Source, a U.S. DOE Office of Science user facility operated by Argonne National Laboratory for DOE Office. This work was partially authored by Argonne, a U.S. Department of Energy (DOE) Office of Science laboratory operated for DOE by UChicago Argonne, LLC under contract no. DE-AC02-06CH11357.
(Invited) Next Generation Designer Carbon Supports for Durable Polymer Electrolyte Fuel Cell Cathode Catalysts
Authors: Atanassov Plamen , Wang Hanson , Ferro Giovanni , Chen Celine H. , Roiron Camille , Zenyuk Iryna 
Published: August 2024

The implementation of polymer electrolyte membrane fuel cells (PEMFC) in medium- and heavy-duty vehicles is a promising strategy to eliminate greenhouse gas emissions as the only byproduct is water. However, the durability of PEMFC catalysts, especially for the kinetically sluggish oxygen reduction reaction (ORR) that occurs at the cathode, remains a significant obstacle. Current state-of-the-art electrocatalysts are comprised of platinum-based nanoparticles anchored on high surface area carbon black supports (Pt/C). While these catalysts meet the U.S. Department of Energy’s near-term activity benchmarks [2], they suffer heavily from degradation mechanisms that can lead to catastrophic failure of PEMFCs. Hence, carbon support materials that promote durability are crucial to further development of ORR catalysts. Here, we report on the physical and electrochemical characterization of next-generation commercial FCX carbon supports that aim to mitigate these degradation mechanisms.
We synthesized Pt/C electrocatalysts by decorating FCX carbons with spherical Pt nanoparticles approximately 2-3 nanometers in diameter. The surface and pore structure of the supports were extensively probed to determine their effects on anchoring of Pt nanoparticles and ultimately catalytic activity. After physical and electrochemical characterization of the catalysts, structure-to-property relationships were established, leading to a schematic for an “ideal” Pt/C electrocatalyst as shown in Figure 1. The hierarchical pore structure is crucial for mass transport, and Pt nanoparticles are housed on the edges of stable graphitic carbon domains. Lastly, a promising alternative to the traditional Pt/C synthesis pathway is shown. As degradation is more pronounced on the catalyst’s exterior surfaces, this novel electrocatalyst contains Pt nanoparticles inside the support’s mesopores to mitigate the loss of electrochemically active surface area [3]. The insights gained from this work can be applied to optimizing carbon support morphology and chemistry for durable and highly active ORR electrocatalysts.
[1] M. Rezaei Talarposhti, T. Asset, S. T. Garcia, Y. Chen, S. Herrera, S. Dai, E. J. Peterson, K. Artyushkova, I. Zenyuk, P. Atanassov, ChemPhysChem, 21 (2020) 1331-1339.
[2] D.A. Cullen, K.C. Neyerlin, R.K. Ahluwalia, R. Mukundan, K.L. More, R.L Borup, A.Z. Weber, D.J. Myers, A. Kusoglu, Nature Energy, 6 (2021) 462–474.
[3] G.S. Harzer, A. Orfanidi, H. El-Sayed, P. Madkikar, H.A. Gasteiger, J. Electrochem. Soc. 165 (2018) F770-F779.

Figure 1
Unsuspected Organometallic Fibers Used As Potential Separators for Supercapacitors Device
Authors: Maaliki Carine , Flamme Benjamin , Ah-Lung Guillaume , Nnandi Shyamapada , Mouchaham Georges , Thibonnet Jérôme , Montigny Bénédicte 
Published: August 2024

Since the last decade, the interest of organic frameworks for electrochemical application the been more studied.1 In general, very few works have been found in the literature. We can mainly mention the use of these derivatives in the presence of inorganic materials both to form solid electrolytes or to protect electrodes. For example, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (H4DOTA) has been used to functionalize PVA to coat the surface of the negative electrode in order to suppress its degradation.2 This resulted in the improvement of the electrochemical properties of the LMNO/graphite cell. Recently, Kim et al. reported the addition of 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane to a carbonate-based electrolyte intended to stabilize the Li metal-electrolyte interface by improving the solid electrolyte interphase.3 More recently, Liu et al. reported a novel carbonyl network polymer NP4 used as a cathode material for organic lithium batteries.4 Very few examples of fully organic frameworks used as separators have been reported.
Therefore, our investigation to develop new supramolecular metal-based objects via a self-assembly process of molecular bricks will be presented. The work on cyclen derivatives allows to obtain metal complexes very stable able to pack in a well oriented dimension. Cyclen derivatives, in the presence of metal salts such as copper or zinc chlorides and polar solvents such as aliphatic alcohols, have a strong affinity for metals and spontaneously assemble in some conditions.5

In terms of applications, these self-assembled "organometallic" fibers represent an original and relatively easy to access substrate for fabricating 1D organic objects. Moreover, taking advantage of the properties and potentialities of these materials, we format an adequate shape to handle it as a potential separator for application in Energy Storage Systems (ESS).
After a presentation of their synthesis and their formatting as potential separators for supercapacitors, preliminary electrochemical studies will be discussed.

1. J. Mater.Chem. A
2016,
4, 16812; ACS Energy let.,
2022,
7, 885.
2. ACS Appl. Energy Mater.,
2021, 4, 128.
3. ACS Appl. Matter. Interface,
2022, 14, 35645.
4. J. Electoanalytical. Chem.
2023, 117251.
5. Chem. Commun.
2010, 46, 1464.

Figure 1
In-situ X-ray Fluorescence Analysis of In-plane Cerium-ion Distribution Under Humidity Gradients in Proton Exchange Membrane
Authors: Morita Kaoruko , Takezawa Aika , Kitano Naoki , Kuwaki Akira , Kato Akihiko , Yamaguchi Satoshi , Shinozaki Kazuma , Orikasa Yuki 
Published: August 2024

For the wide application of polymer electrolyte fuel cells, durability of more than 50,000 hours is necessary. Chemical degradation of the perfluorosulfonic acid (PFSA) membrane electrolyte is one of the degradation factors. Hydrogen peroxide generated from crossover gas reacts with impurities, and the resulting radicals break the chemical bonds in the electrolyte membrane. To quench the radicals, cerium ions are added to the membrane electrode assembly (MEA) as a radical quencher. However, cerium ions are known to move in the in-plane direction due to the humidity gradient during fuel cell operation. In areas where cerium ions are depleted, the chemical bonds of the PFSA are attacked by radicals. Therefore, it is necessary to understand the in-plane transport phenomena of cerium ions under fuel cell operating conditionsand incorporate into the development of MEAs. In this study, we developed an operando measurement cell that can track the change of cerium ion distribution over time by X-ray fluorescence spectroscopy (XRF) using high energy X-rays under fuel cell operation while controlling the in-plane humidity gradient. The in-plane transport of cerium ions, driven by the humidity and concentration gradients, was analyzed.
Two gas inlets were connected to an end plate with an X-ray transmission window to control two humidity environments on the left and right sides with in-plane direction of MEA. For MEA, Pt/C catalyst layer was coated on PFSA membranes in which a part of sulfonic acids were exchanged with cerium ions. GDL without cerium was used. Operando XRF measurements were performed at beamline BL37XU on SPring-8. The incident energy was 60 keV X-rays, and Ce-Kα fluorescence X-rays were counted. The beam size was 0.5×0.5 mm2. The cell temperature was 60°C, the different relative humidity (RH) in the in-plane direction was set to 90% and 50% using N2 gas, then the RH of the whole MEA was set to 95% to measure the relaxation behavior of cerium.
Fig. 1 shows the Ce intensity variation at the vertical center of the MEA under the condition of humidity difference with in-plane direction. The x-axis corresponds to the horizontal position of the MEA, with RH 90% on the left side and RH 50% on the right side. The y-axis corresponds to the time under the humidity gradient. The darker blue indicates weaker intensity of the Ce-Kα fluorescence X-ray and the white indicates stronger Ce intensity. This suggests that cerium ions move from the high humidity side to the low humidity side with the humidity gradient as the driving force. The time scale for this movement of a few millimeters was shown to be about tens of minutes.

Acknowledgments

The authors would like to thank M. Toida (Toyota Motor Corporation) for providing samples and for in-depth discussions.

Figure 1
Introducing Platinum Cryoaerogel As a Low Loading Cathode Catalyst in PEM Water Electrolysis
Authors: Stein Lukas , Moß Christopher , Ismael Mohammed , Trinke Patrick , Bensmann Boris , Hanke-Rauschenbach Richard , Borg Hadir , Zhao Zhijun , Dorfs Dirk , Bigall Nadja 
Published: August 2024

An important cost factor for polymer electrolyte membrane water electrolysers is precious metals as the catalyst layers. Therefore, reducing of the platinum loading on the cathode side and the iridium on the anode is essential to reduce the overall costs of hydrogen production. Cryoaerogels from noble metal nanoparticles are a suitable, yet unexplored material for use as a catalyst in water electrolysis. They combine high porosity and surface area with an excellent catalytic activity at low loadings of noble metal.[1] Recently, we have succeeded in producing a carbon-based gas diffusion electrode (GDE) coated with platinum cryoaerogel as the catalyst. The mechanical connection to the carbon underneath as well as maintaining a high protonic conductivity in contact to the Nafion membrane allowed the application to the water electrolysis cell. The manufacturing includes an oven treatment, whose temperature is particularly decisive for the structure of the cryoaerogel. Figure 1 left shows the polarization curves of the samples pyrolyzed at 300°C, 350°C and 500°C compared to a commercial GDE (platinum loading of 0.5 mg/cm²). All measurements are repeated three times and showed good reproducibility, as indicated by the error bars on the graph. Among the different temperatures, 300°C is the optimum for the pyrolysis process as it showed the lowest voltages. The catalytic performance of the different samples can be correlated to the micro-structure of the cryoaerogel layer represented by the SEM images and the electronic-structure of the platinum as shown by X-ray photoelectron spectroscopy (XPS). Although in figure 1 the performance of the cryoaerogel catalyst layers is not better than the commercial GDE, however, the platinum loading is significantly reduced by 70% (0.15 mg/cm2). Moreover, the reproducibility of the measurements proofs the possibility of using cryoaerogels in the full water electrolysis cell.
[1] Müller, D., Zámbó, D., Dorfs, D., Bigall, N. C., Cryoaerogels and Cryohydrogels as Efficient Electrocatalysts. Small 2021, 17, 2007908. https://doi.org/10.1002/smll.202007908

Figure 1
Regulated Interfacial Proton and Water Activity Enhances Mn2+/MnO2 Platform Voltage and Energy Efficiency
Authors: Xue Xinzhe , Liu Zhen , Eisenberg Sam , Ren Qiu , Lin Dun , Coester Emma , Zhang Heng , Zhang Jin , Wang Xiao , Li Yat 
Published: August 2024

Aqueous zinc battery (AZB) is one of the most promising energy storage systems for large-scale applications due to its high safety, low cost, and environmental friendliness. To match the high capacity of zinc metal (~820 mAh g-1), various cathode materials, such as oxides, open structure analogues, chalcogens, and halogens, have been explored for AZBs. Among them, manganese dioxide (MnO2) has been considered to be one of the most attractive candidates due to its high capacity (~308 mAh g-1 for one-electron transfer) and adequate redox potential (~0.70 V vs. SHE). Recently, the MnO2 dissolution/deposition charge storage mechanism has been demonstrated to further increase the voltage and capacity of Mn-based AZBs. The dissolution/deposition (Mn2+/MnO2) is a two-electron transfer process, which doubles the theoretical capacity of MnO2 cathode to ~616 mAh g-1 and considerably increases the redox potential (~1.229 V vs. SHE). The charge storage via the dissolution/deposition mechanism pushes the aqueous-based energy density even higher, to over 1000 Wh kg-1.
However, this charge storage mechanism involves liquid-solid transition, as well as the thermodynamics and kinetics of this reaction are highly dependent on the acidity and interfacial environment. Yet, the opposite effect of interfacial H+ on the dissolution/deposition processes and the role of interfacial H2O are rarely discussed. Here we introduce tetrafluoroborate anion (BF4
-) into the sulfate-based electrolyte to regulate the interfacial H+ and H2O activity. First, BF4
- hydrolysis increases the electrolyte’s acidity, promoting MnO2 dissolution. Second, BF4
- forms an H-bond network with interfacial H2O that assists H+ diffusion while retaining sufficient H2O supply to facilitate MnO2 deposition. As a result, the cathode-free Zn//MnO2 electrolytic cell achieves a high plateau of ~1.92 V and energy efficiency of ~84.23 % in the BF4
- containing electrolyte. Significantly, the cell delivers 1000 cycles at 1 C with ~100 % Coulombic efficiency and a high energy efficiency retention of 93.65 %. Our findings disclose a new strategy to promote Mn2+/MnO2 platform voltage and energy efficiency for future large-scale energy storage systems.
Thermal Modeling of Li-Ion Cylindrical Cells at Scale
Authors: Sare Hadarou , Dong Dongmei 
Published: August 2024

The electric vehicle industry has created a demand for batteries with higher power densities. The current design choice for low-weight lithium-ion battery packs for electric vehicles is to create stacks arranged in parallel or series configurations to match the power demands. The individual cells are separated and placed in a cooling duct to pull heat away from the longitudinal surface convective. The amount of cooling is dependent on the internal temperature of batteries core. The current design of the cylindrical cell is to roll the cathode, anode, and separators into a jelly roll together and attach a tab to the cathode and anode at opposite corners of the sheet. The tabs connect to the positive and negative terminals of the cell to draw current away from the cell. The tabs may act as an agent for drawing heat away from the center of the battery. Currently, commonly used cylindrical cells have a form factor of 18650, 21700, or 26650. The thermal, geometrical, and electrical properties of 18650 and 21700 cylindrical cells are studied and it is found that the 21700 cells showed additional degradation and stronger heating. Recently, companies like Tesla have produced cylindrical cells with a 4680-form factor, which is a decent way to increase the ratio of active material vs. inactive material in a cylindrical cell. However, large diameter thick cylindrical cells suffer from thermal issues. Even large format pouch cells suffer through heat trapped within the stack.
Since the thermal conductivity of the anode and cathode electrodes is often near 1 W/m-K, it becomes difficult for the heat to be extracted from the center of a large-diameter cylindrical cell without forming a considerable thermal gradient. PyBaMM, an open-source mathematical modeling software written in Python programming language, has the capability to simulate different electrochemical models such as the Doyle-Fuller-Newman (DFN), Single particle model (SPM), and SPMe, and varying chemistry. The software provides easy access to the cell parameters modification and graphical user interface capabilities. The PyBaMM framework also allows to simulation lumped, isothermal, and base thermal models which are electrochemically coupled. PyBaMM uses CasADi (computer algebra systems algorithmic differentiation). The thermal gradient and heat dynamics within a porous electrode are modeled using PoreSpy and openpnm, two open-source Python libraries used to design porous networks and model physical equations such as governing heat flow, concentration gradient, and movement of water/oil through porous shale media.
We have explored and combined heat dynamic models for Li-Ion cylindrical cells at both cell and electrode levels with reduced-order Doyle-Fuller-Newman electro-chemical model frameworks implemented in the PyBaMM python library. Radial temperature gradient at cell and electrode levels were both generated from simulations with a distributed parameter model as a function of electrolyte and separator thickness and thermodynamic properties.

Figure 1
Exploring the Role of Redox-Shuttle Mediators in Lithium-Sulfur Batteries
Authors: Vailaya Ganesh , Holc Conrad , Townsend William , Kibler Alexander , Newton Graham , Walsh Darren , Johnson Lee 
Published: August 2024

The lithium-ion battery (LIB) is widely acknowledged as the state-of-the-art battery technology today and is used in consumer electronics, stationary storage, and electrified transportation1,2. However, there is a drive towards developing technologies with higher energy densities. The lithium-sulfur battery is one of the most promising next-generation batteries for high-energy applications, due to its high theoretical gravimetric energy density of 2567 W h kg-1, low raw material costs, and reduced environmental impact3. Despite these potential advantages, lithium-sulfur batteries are still beset with difficulties, one of the most significant is the so-called “polysulfide shuttle effect.” Operation of the battery involves the conversion of sulfur to polysulfide species, which dissolve into the electrolyte and diffuse to the lithium metal electrode, leading to loss of active material. This results in poor cycle life, rapid capacity fading and low coulombic efficiencies4.
The use of dissolved, electrochemically active redox mediators could mitigate these effects by catalysing sulfur redox reactions during cell cycling. While it is generally agreed that the redox potential of the mediators is a key factor in their operation, no report to date has conclusively demonstrated how mediators of varying potentials can target specific sulfur redox reactions. Herein, we report a study of the mediators 9-fluorenone (9-FO), duroquinone (DQ), 2,6-di-tert-butyl-1,4-benzoquinone (TBBQ) and 1,5-bis(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)anthra-9,10-quinone (AQT) to understand their interactions with sulfur, lithium polysulfides, lithium sulfide and lithium metal5. We use liquid-chromatography mass spectrometry (LC-MS) to isolate various polysulfide chain lengths after reaction with mediators. It is observed that high potential redox mediators, such as TBBQ, are better able to drive Li2S oxidation to higher polysulfide chain lengths, and low potential redox mediators such as 9-FO push sulfur towards lower chain polysulfides. This offers a novel and effective approach to screening suitable redox-active molecules. Galvanostatic cycling is employed to relate these chemical interactions to enhanced cell performance. Developing a fundamental understanding of how redox mediators operate in a cell will aid in the molecular design of novel redox-active compounds.
[1] J. Vetter, P. et al: Ageing mechanisms in lithium-ion batteries, J. Power Sources, 2005, 147, 269–281.
[2] D. Castelvecchi: Electric cars: the battery challenge, Nature, 2021, 596, 336–339.
[3] P. G. Bruce et al: Li-O2 and Li-S batteries with high energy storage, Nat. Mater., 2012, 11, 19–29.
[4] S. Zhang et al: Recent advances in electrolytes for lithium-sulfur batteries, Adv. Energy Mater., 2015, 5, 1–28.
[5] Y. Tsao et al: Designing a quinone-based redox mediator to facilitate Li2S oxidation in Li-S batteries, Joule, 2019, 3, 872–884.
Lithium Superoxide in Li-O2 Batteries: Performance and Mechanisms
Authors: Park Moon Gyu , Wang Hau , Amine Rachid , Assary Rajeev S , Amine Khalil , Curtiss Larry A. 
Published: August 2024

Lithium superoxide (LiO2) is generally regarded as an intermediate formed during the Li-O2 battery discharge and transformed into lithium peroxide (Li2O2). Indeed, its chemical/electrochemical stability is low, making it recognized as a temporary discharge product in Li-O2 battery chemistry. However, in 2016, utilizing an iridium (Ir)-based electrocatalyst, Curtiss and Amine et al. found that LiO2 can be epitaxially grown on the surface of Ir catalyst and can be stable under cycling conditions.1 In the study, a templating mechanism was suggested, where a good lattice matching of LiIr3 surfaces (formed on the Ir catalyst) with that of LiO2 facilitates LiO2 formation as a singular discharge product. Following studies showed some superior electrochemical properties of LiO2 in comparison to Li2O2, including lower charge overpotentials. Meanwhile, some other transition metal compounds have recently exhibited LiO2 formation, where the formation mechanism suggested may not be a templating method. In this case, there could be strong adsorption of LiO2 in specific structures, resulting in suppressed Li2O2 generation. Herein, we will present experimental and computational results on some new catalysts for LiO2 formation and discuss possible underlying mechanisms.
Acnowledgement
This work was primarily supported by the US Department of Energy under contract DE-AC02-06CH11357 from the Vehicle Technologies Office, Department of Energy, Office of Energy Efficiency and Renewable Energy.
Reference
1 Curtiss. L. and Amine. K. et al. A lithium–oxygen battery based on lithium superoxide. Nature 2016, 529, 377-382