bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cation-Modified Anionic Redox Mechanism for High-Performance Layered Oxide As Sodium-Ion Batteries Cathode Material
Authors: Kang Jin-Wei , Chen Han-Yi 
Published: July 2022

Sodium-ion batteries (NIBs) have been selected as a promising candidate for large-scale energy storage systems due to their abundance. Among several NIB cathode materials, P2-type transition metal layered oxides (NaxTMO2, TM = Ti, V, Cr, Mn, Fe, Co, Ni) featuring high theoretical capacity and better rate performance have attracted much attention. However, the practical applications have to endure the low energy density of NIB cathode materials compared to lithium-ion batteries. In tradition, the capacity is constrained by transition metal ions and is closed to their limits. Hence,in order to obtain extraordinarily high capacity in cathode materials, both anionic and cationic redox chemistry are utilized. Nevertheless, their performance is impeded by irreversible structure evolution and lattice oxygen emission. Therefore, it is highly urgent to develop stable anionic redox chemistry for high energy density and long-cycle-life layered oxide cathode materials.
In this study, cation-doped NaxMgyCuzMn(1−y−z)O2 cathode material featuring synergistic effects of cationic and anionic redox was reported. By cations doping, the inhibited structure evolution and lattice oxygen stabilization were achieved. Moreover, the effects of cation-doped NaxMgyCuzMn(1−y−z)O2 were also studied by electrochemical measurements. Also, the mechanism of cation-doped NaxMgyCuzMn(1−y−z)O2 was confirmed by operando synchrotron X-ray absorption spectrum, operando X-ray diffraction, and density functional theory computations. Cation-doped NaxMgyCuzMn(1−y−z)O2 was synthesized through a facile sol-gel method followed by heat treatment. The cation-doped NaxMgyCuzMn(1−y−z)O2 showed high specific capacity (203 mAh g−
1 cycled at 0.1C) as well as better cycling stability, providing sodium layered oxides a new developing stage toward high-performance cathode materials in NIBs for large scale energy storage systems.

Keywords: Na-ion batteries, layered oxides, anionic redox, cathode
In Situ Stress Generation during Oxygen Evolution and Reduction Reactions on Au Positive Electrode in Li-O2 Batteries
Authors: Dykes Hannah , Ozdogru Bertan , Capraz Omer Ozgur Özgür 
Published: July 2022

Li-O2 batteries have received enormous interest from the scientific community due to its extremely high theoretical specific energy density, which is originated from the oxygen reduction reactions during discharge at the surface of the cathode electrode. Unfortunately, the commercial implementation of this technology is hindered by the poor cycling performance, mostly due to the sluggish oxygen evolution/reduction kinetics and the nature of the discharge reaction product. The lithium peroxide (Li2O2) is the discharge reaction product and its insulating nature limits to harvest the theoretical capacity of the Li-O2 batteries practically. The impact of the salt and solvent species on the formation mechanisms of the discharge product has been reported widely. However, underlying mechanisms dictating the reaction pathway is still under debate.
In this study, we employed in situ stress measurement to investigate the impact of the electrolyte salt on nanoscale dynamic changes on the surface of the thin Au film cathode (1-D) during charge / discharge of Li-O2 batteries. Stress measurements have been applied to various electrochemical and electrocatalytic application areas in order to probe the dynamic changes on the surface of the materials. The electrolyte was prepared by mixing 1 M LiTFSI or LiNO3 salts in DMSO or Diglyme solvents. Electrolytes were saturated either with oxygen or argon prior to performing electrochemical measurements. In situ stress measurements were conducted using a multiple beam optical sensor (MOS). A custom cell was designed to monitor the physical response of the cathode during cycling while enabling optical access to the back of the substrate for stress measurements1. In situ curvature evolution on Au thin film cathode was monitored during discharge and charge via galvanostatic cycling and cycling voltammetry.
In this talk, we will present the impact of the electrolyte salt on the potential-dependent surface stress generation during the formation and oxidation of electrochemical redox reaction products at nanoscale on the Au thin film cathode. Shortly, in situ stress measurements pointed out the contribution of charge-induced stress, electrostriction stress, and intrinsic stress associated with the formation of discharge reaction products. Revealing the mechanical response of the discharge products on cathode electrode will shed light into the formation mechanisms of these products, which is crucial to design new electrolyte and cathodes for Li-O2 batteries.
Acknowledgement:
This work was supported by the Binational Science Foundation (#2018327), and we are thankful to both Dr. Malachi Noked and Rosy for fruitful discussions.
References:

Dykes, H., . R., Sharon, D., Noked, M. & Capraz, O. O. In Situ Stress Measurements on Thin Film Au Positive Electrode during the First Discharge of Li-O2 Batteries. J. Electrochem. Soc. (2021). doi:10.1149/1945-7111/AC3937
(Digital Presentation) Higher Surface Area Lithium Anode for Mediated Lithium-Sulfur Flow Batteries
Authors: Meyerson Melissa L , Small Leo J. 
Published: July 2022

There is a need for safe, reliable, high capacity storage for long duration energy storage. The low cost and high capacity of sulfur make Li-S batteries ideal for this purpose. However, sulfur has poor electrical conductivity and Li-S batteries are prone to polysulfide shuttling that decreases the battery life. Additionally, lithium metal cannot be cycled at high rates or dendritic growth is produced. We have previously addressed the issues with the S by combining aspects of a static Li-S battery with aspects of a redox targeting system and flow battery. With this system we demonstrated that fundamental Li-S chemistry and novel SEI engineering strategies can be adapted to the hybrid redox flow battery architecture, obviating the need for ion-selective membranes or flowing carbon additives, and offering a potential pathway for inexpensive, scalable, safe MWh scale Li-S energy storage.
However, with a planar Li anode the current density was limited to 0.5 mA cm-2, severely limiting the flow battery power output. In this study we present recent progress developing higher surface area anodes to enhance the rate performance of Li metal anodes in flow batteries. The high effective surface area of these structures decreases the local current density while maintaining a high device-level current and thus charge rate. The low local current density and seeded nucleation points on the scaffold promote uniform Li deposition during charging. Candidate electrode materials are evaluated in a mediated Li-S flow battery and cycling rate and capacity retention are compared against a traditional planar Li anode.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
OH- Conductivity and Water Uptake of Anion Exchange Thin Films Under Humidity Control
Authors: Nagao Yuki , Wang Fangfang , Wang Dongjin 
Published: July 2022

Anion exchange membrane fuel cells (AEMFCs) have attracted widespread attention because of the lower cost of using non-precious metal catalysts and high oxygen reduction reaction (ORR) kinetics in alkaline conditions.[1] The previous research focused on the water uptake and OH- conduction properties of anion exchange membranes (AEMs) as thick forms.[2–5] The fuel cell reaction occurs at the triple-phase interface where the junction of ion-conductive ionomer, catalyst, and fuel/oxidant. The ionomer plays an important role to deliver OH- ion between the thick membrane andto electrochemical catalysts in fuel cells. However, the investigation of OH- ion conduction and hydration properties of thin ionomers is important but not sufficient.
This work demonstrated the relations between OH- conductivity and water uptake of anion exchange thin films for the first time.[6] The reported poly[(9,9-bis(6′-(N,N,N-trimethylammonium)-hexyl)-9H-fluorene)-alt-(1,4-benzene)] (PFB+)[6] was synthesized as a model ionomer. We established in situ methods for measuring OH- conductivity and water uptake of anion exchange thin films[7] because OH- ion easily exchanges for carbon dioxide in the air. The OH- conductivity of 273 nm-thick PFB+ thin film form at 25 °C under 95 % relative humidity (RH) is comparable to the reported OH- conductivity value of PFB+ bulk membrane. Reduced OH- conductivity and water uptake were observed in 30 nm-thick PFB+ film compared to thicker 273 nm-thick PFB+ film. This reduced OH- conductivity was caused by the decreased number of water molecules contained in thinner PFB+ films. Under the same number of water molecules contained, similar OH- conductivity results can be obtained for both 273 and 30 nm-thick films as shown in Figure. Results show a different trend compared to the case of the proton conductive thin films.[8]

References

[1] G. Merle, M. Wessling, K. Nijmeijer, J. Memb. Sci.
2011, 377, 1–35.
[2] J. Y. Jeon, S. Park, J. Han, S. Maurya, A. D. Mohanty, D. Tian, N. Saikia, M. A. Hickner, C. Y. Ryu, M. E. Tuckerman, S. J. Paddison, Y. S. Kim, C. Bae, Macromolecules
2019, 52, 2139–2147.
[3] J. Chen, M. Guan, K. Li, S. Tang, ACS Appl. Mater. Interfaces
2020, 12, 15138–15144.
[4] U. Salma, Y. Nagao, Polym. Degrad. Stab.
2020, 179, 109299.
[5] C. G. Arges, L. Zhang, ACS Appl. Energy Mater.
2018, 1, 2991–3012.
[6] W. H. Lee, A. D. Mohanty, C. Bae, ACS Macro Lett.
2015, 4, 453–457.
[7] F. Wang, D. Wang, Y. Nagao, ChemSusChem
2021, 14, 2694–2697.
[8] Y. Nagao, Sci. Tech. Adv. Mater. 2020, 21, 79–91.

Figure 1
Novel Anion-Exchange Blend Membranes Comprised of a Commercially Available & Water-Soluble Ionomer for All-Vanadium Redox Flow Batteries
Authors: Stonawski Julian , Thiele Simon , Kerres Jochen Alfred 
Published: July 2022

The All-Vanadium Redox Flow Battery is a promising technology for solving the problem of cost-efficient and safe large-scale storage of renewable energies [1]. One key component of the batteries, which alters the performance and long-term stability of those systems, is the membrane. For this purpose, Nafion based membranes are often used. However, these membranes are high in cost and show a significant capacity fading and reduction of coulombic efficiency mainly due to crossover of vanadium species [2]. One way around this is to use commercially available, low-cost materials with positively charged ammonium groups, which can effectively repel positively charged vanadium species due to the Donnan exclusion effect [3, 4].
In this work we present novel anion-exchange blend membranes comprised of a commercially available and water-soluble ionomer and a PBI blend matrix, which can be used in All-Vanadium Redox Flow batteries. For this approach the water-soluble ionomer was modified to achieve solubility in organic solvents and miscibility with the matrix polymer. The resulting membranes show good mechanical properties even at high IECs and can be modified in a wide range of properties by adjusting the amounts of ionomer and matrix polymer and/or by the addition of crosslinking agents.
The above-mentioned membranes were characterised ex-situ by using EIS, NMR spectroscopy, IR spectroscopy, DMA, TGA, tensile tests and permeability tests. In addition, first promising in-situ characterisations were performed in a VRFB single-cell test station.
Literature
[1] Fan, X; Liu, B; Liu, J; Ding, J; Han, X; Deng, Y; Lv, X; Xie, Y; Chen, B; Hu, W; Zhong, C.: Battery Technologies for Grid-Level Large-Scale Electrical Energy Storage. Trans. Tianjin Univ.
2020, 92 – 103.
[2] Düerkop, D; Widdecke, H; Schilde, C; Kunz, U; Schmiemann, A.: Polymer Membranes for All-Vanadium Redox Flow Batteries: A Review. Membranes
2021.
[3] Xi, J; Wu, Z; Teng, X; Zhao, Y; Chen, L; Qiu, X.: Self-assembled polyelectrolyte multilayer modified Nafion membrane with suppressed vanadium ion crossover for vanadium redox flow batteries. J. Mater. Chem.
2008, 1232.
[4] Mohammadi, T; Kazacos, M.: Modification of anion-exchange membranes for vanadium redox flow battery applications. Journal of Power Sources
1996, 179 – 186.
Novel Sulfonated and Phosphonated Ionomers and Ionomer (blend) Membranes for Electrochemical Applications
Authors: Martschin Philipp , Thiele Simon , Kerres Jochen Alfred 
Published: July 2022

The heart of a HT-PEM fuel cell is represented by the proton conductive membrane. Nowadays PFSA-based materials e.g. Nafion are state of the art in large scale energy applications. However, the PFSAs are relatively expensive, and give rise to concerns regarding toxic intermediates in the production process, and the questionability of their recyclability. This leads to a strong need for development of cost effective alternatives. Such alternatives have to exihibit customized properties, like reduced gas crossover, high ionic conductivity, mechanical strength, thermal stability and durability.
In this work, we present novel cation-exchange ionomers, which are suitable as proton exchange membranes in electrochemical applications such as fuel cells, electrolysers, and redox-flow batteries. For our approach we developed novel fully and partially aromatic polymers with customized mechanical behavior, using two different synthetic pathways, the first being modification of the aromatic building blocks to more flexible ones and/or introduction of flexible side chains into the monomers or polymers.
With these two approaches it was possible to synthesize ionomer materials which are less brittle than our earlier developed sulfonated[1] or phosphonated[2] poly(pentafluorostyrene) ionomers. Our development lead to ionomers which are suitable in pure form or as blend in proton exchange membranes with promising proton conductivity, mechanical and thermal stability.
The novel ionomers and ionomer membranes were characterized in terms of ex-situ characterization including impedance spectroscopy, IR spectroscopy, NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. Moreover, preliminary in-situ tests of the ionomer membranes in low and high-temperature fuel cells have been performed, yielding promising results. Furthermore the synthesized membranes were characterized in-situ in redox-flow batteries, yielding promising results.

[1] Highly phosphonated polypentafluorostyrene. V. Atanasov, J. Kerres, Macromolecules 2011, 44, 6416–6423; DOI: 10.1021/ma2011574

[2] Sulfonated poly(pentafluorostyrene): synthesis & characterization. V. Atanasov, M. Bürger, S. Lyonnard, G. Gebel, J. Kerres, Solid State Ionics, 2013, 252, 75-83; DOI: 10.1016/j.ssi.2013.06.010
Tuning Electrode-Membrane Interface for Highly Efficient Polymer Electrolyte Membrane Fuel Cells
Authors: Yang Gaoqiang , Lee ChungHyuk , Komini Babu Siddharth , Martinez Ulises , Wang Xiaojing , Spendelow Jacob S. 
Published: July 2022

Polymer electrolyte membrane fuel cells (PEMFCs) are typically comprised of porous electrodes with randomly distributed mixtures of Pt/C catalyst and ionomer formed during the ink deposition process. The randomness of catalyst particles, ionomer films, and voids, create a non-ideal disordered electrode structure with high tortuosity. These intrinsic characteristics of conventional electrodes create significant challenges during PEMFC operation. These challenges include: 1) low catalyst utilization; 2) high O2 transport resistance to catalyst through the ionomer and pores of carbon support; and 3) limited electronic/protonic conductivities. To improve the performance of the PEMFC electrode, we have previously shown that structured electrodes based on a patterned membrane surface can increase the interfacial area between the electrode and the membrane, enhancing mass transport at high current densities, and augmenting its ionic conductivity.[1][2] In this work, we will present further optimization of these type of structured electrodes using free-standing architectures, reduced ionomer content, and new catalyst deposition processes. More importantly, these newly tuned electrode structures can improve the performance of PEMFCs by maximizing three-phase boundaries and optimizing the electron, proton, gas, and water transport paths.

Acknowledgement:

We gratefully acknowledge support from the Laboratory Directed Research & Development Program at Los Alamos National Laboratory.

Reference:

[1] S. K. Babu, R. Mukundan, D. A. Cullen, and J. S. Spendelow, “Co-Axial Nafion Nanowire Electrode.” ECS, Oct. 15, 2019.
[2] S. K. Babu, J. S. Spendelow, and R. L. Borup, “Meso-Structured Array Electrode for Polymer Electrolyte Fuel Cells.” ECS, Oct. 03, 2017.
Fabrication and Scale-up of Highly Durable Heavy Duty Fuel Cell MEAs
Authors: Macauley Natalia , Zhong Sichen , Zeng Yachao , Zhang Bingzhang , Wu Gang , Xu Hui 
Published: July 2022

Medium and heavy-duty PEM fuel cells operate under much harsher conditions than light duty fuel cells and are expected to last 25,000 hours in the field. These systems must therefore operate successfully in the presence of impurities, starting and stopping, freezing and thawing, humidity and load cycling. Therefore, materials, components, and interfaces used in such systems need to be highly resistant to severe mechanical and chemical stress.
Novel, highly active stable Pt and ordered PtCo intermetallic nanoparticles with well-controlled particle size and composition have been synthesized on a highly efficient PGM-free single metal active site rich carbon, to maximize their synergistic effects for enhanced performance and durability. These catalysts were integrated with a variety of ionomers (Aquivion, Nafion, HOPI and high O2 permeability ionomer (HOPI)) to further improve fuel cell performance and to achieve >600 mA/mgPt at 0.9 VIR-free with a mass activity loss less than 30% after 150k square wave accelerated durability cycles; and > 600 mA/cm2 (~65% efficiency) at 0.8 V, with a performance loss < 40 mV after 150K cycles (0.6 to 0.95 V).
In a PEM fuel cell, the catalyst ink formulation and mixing processes control catalyst layer coating quality, electrode morphology, and the resulting fuel cell performance and durability. Catalyst ink properties are a result of complex solvent-catalyst-ionomer interactions that depend on the mixing method employed. Here, we will compare the performance and durability of electrodes made from bath sonicated inks for ultrasonic spray coating vs. ball milled inks for Meyer rod coating. Ink rheology and catalyst particle size will be used to correlate ink properties to electrode morphology and structure and ensure consistency from batch to batch, and from small lab scale to subsequent scale-up. We will evaluate and discuss the challenges that arise when transitioning from spray coating catalyst ink on a small scale, directly on a membrane, to coating more viscous inks on gas diffusion layers (GDLs), and finally developing a roll-to-roll (R2R) fabrication process. The MEA performance and durability of the novel catalyst will be evaluated under heavy duty operating conditions. Finally, the electrode performance and durability of R2R fabricated GDEs will be tested, and compared to small scale GDEs made at Giner.
This work provides a comprehensive understanding of interactions between Pt, PtCo, carbon, ionomer, membrane, and GDLs and their impact on electrode structure, fuel cell performance and durability, as well as considerations for scale up to a R2R fabrication process. The attained information will be used to improve fuel cell electrode design, fabrication and scale-up.
Acknowledgement: The project is financially supported by the Department of Energy’s Fuel Cell Technology Office under the Grant DE-FOA-0002360.
A Systematic Investigation of Carbon Pretreatment for the Synthesis of Platinum Nano-Catalysts for Oxygen Reduction Reaction
Authors: Buchauer Fabian Luca , Cleemann Lars , Jensen Jens Oluf , Li Qingfeng , Brandes Benedikt Axel 
Published: July 2022

The synthesis of electrocatalysts for low- and high temperature fuel cells is dependent on many different factors that determine the activity of the produced catalysts. One important and highly underrepresented factor in literature are carbon pretreatments, which have a strong impact on the electrochemical activity of the produced catalyst. A web of science search showed that less than 1% of the articles working with the synthesis of Pt-based catalysts for the Oxygen reduction reaction (ORR) contain information on carbon pretreatments. In recent years no articles on the topic of carbon pretreatment for the synthesis of Pt-based ORR catalyst have been published.
However, different forms (as powder, nano tubes, etc.) of carbon are commonly used as support material for Pt-based catalysts. Previous work has shown the importance of pretreatment of carbon supports to change the surface-active groups, enhancing the dispersion and reducing agglomeration of Pt-nanoparticles [1]. Oxidizing treatments are known to change the surface groups and decreasing the BET surface area [2]. Furthermore, carbon pretreatments can effectively reduce impurities present in as-purchased carbon [3].
A systematic study of pretreatments of Vulcan XC72-R and Ketjen 300 have been carried out followed by the synthesis of supported Pt-nanoparticles using XPS, XRD, TEM, BET and RDE techniques. We found that the presence of sulfur in the surface strongly correlates with the ECSA of the supported Pt catalyst. This talk will elaborate on the effect of pretreatments on the carbon support, the synthesis of Pt nanoparticles and its impact on the resulting electrochemical performance: Compared to as received carbon, the Pt mass activity could be increased by a factor 4, exceeding the mass activity of comparable commercial Pt/C electrocatalysts.
[1] Bimetallic Pt–Sn catalysts supported on activated carbon I. The effects of support modification and impregnation strategy - A. Erhan Aksoylu; M. Madalena A. Freitas; Jose L. Figueiredo
[2] The effect of pretreatment of Vulcan XC-72R carbon on morphology and electrochemical oxygen reduction kinetics of supported Pd nano-particle in acidic electrolyte - Senthil Kumar, S. M.; Soler Herrero, Jaime; Irusta, Silvia; Scott, Keith
[3] Effect of the carbon pre-treatment on the properties and performance for nitrobenzene hydrogenation of Pt/C catalysts - Torres, G. C.; Jablonski, E. L.; Baronetti, G. T.; Castro, A. A.; De Miguel, S. R.; Scelza, O. A.; Blanco, M. D.; Peña Jiménez, M. A.; Fierro, J. L.G.

Figure 1