bluuebunny/crossref_metadata_2025 huggingface dataset:
Setting Development Targets for Fuel Cells and Systems for Heavy-Duty Trucks Using a Comprehensive Model-Based Approach
Authors: Watanabe Takao , Shibata Masao , Fukaya Norihiro , Nagai Tomoyuki , Suzuki Takahisa
Published: November 2022

For a carbon-neutral society to be realized, widespread use of fuel cells for transportation applications would be effective. The widespread use of fuel cells, in turn, requires improvements in the durability and energy conversion efficiency when fuel cells are used in high-load, long-time use applications, such as heavy-duty trucks (HDTs), construction machinery, railroads, and ships. Enhancing their durability and efficiency would require improving the performance of fuel cells and appropriately assigning performance targets to the hybrid system configuration, including batteries and radiators, and the control system. However, the performance target for each component remains unclear. This is due to the lack of a comprehensive study to reasonably assign the requisites for each component to achieve the system requirement, such as the durability and fuel economy targets of HDTs.

Few studies have comprehensively proposed how individual components should be developed to satisfy the fuel cell system requirements. Cullen et al [1] discussed the development targets of fuel cell materials from the HDT requirements. Additionally, performance targets of individual components must be set to minimize the total cost, including durability and replacement, total fuel, and initial costs. Furthermore, a comprehensive model that can calculate the total cost of HDTs while accounting for the efficiency degradation due to long time use of fuel cells is also required.

In this study, we propose a procedure to set the development targets of individual components by minimizing the total cost of HDTs. A mathematical model that combines a fuel cell performance model, degradation models, and a power management control model is employed to bridge the gap between the components’ properties and the system performance. Optimization using this model allows candidates to be found for the optimal I-V polarization curve, the system configuration of fuel cell stacks, batteries, and radiators, and their control algorithms. In the presentation, after showing the proposed procedure and the model, the development targets of the polarization curves, system configurations, and control specifications will be discussed.

Reference

[1] D. A. Cullen, et.al, NATURE ENERGY. 6, pp.462-474 (2021).
Synthesis and Characterization of a Polyaniline-Polyvinyl Alcohol (PANI-PVA) Composite As Anion-Exchange Membrane
Authors: Susana María Susana , Segura-Carvajal Nicolas , Sanchez Carlos Ignacio
Published: November 2022

Different polyaniline-polyanilylalcohol composites with different concentrations of constituent polymers and degrees of cross-linking were synthesized by chemical oxidative polymerization of aniline in an acidic medium. The electrochemical properties of the PANI/PVA composites were evaluated by electrochemical impedance spectroscopy (EIS), cell diffusion and sorption experiments. The following resistivity, permselectivity, permeability, ion exchange capacity, and chemical stability properties, were obtained and were used to estimate the diffusion coefficients across the membrane for Na+, Cl- and OH- ions. The PANI/PVA composites exhibited high conductivities, especially for higher PANI compositions, given the electrical properties of PANI. Also, although the degree of crosslinking provides higher resistance, it reduces the electrical properties of the membrane, also decreasing the mobility of ions passing through the membrane. Based on the results, potential applications of PANI/PVA in alkaline fuel cells and reverse electrodialysis technology are discussed. PANI base blends and composites have been widely reported due to their low cost and easy preparation through chemical and electrochemical routes. The properties and performance of the composite materials were compared with commercial and custom-made membranes.
Tuning the Rheology of Anode Inks with Aging for Low-Temperature Polymer Electrolyte Membrane Water Electrolyzers
Authors: Khandavalli Sunilkumar , Park Jaehyung , Rice Robin , Bender Guido , Myers Deborah J. , Ulsh Michael , Mauger Scott A
Published: November 2022

Low-temperature polymer electrolyte membrane water electrolyzers (PEMWE) are an attractive clean energy technology to produce hydrogen (H2), which is an energy carrier for several applications such as transportation and grid-scale energy storage and distribution (as supported by the US Department of Energy’s H2@Scale initiative). The catalyst layers -- composed of catalyst particles and ionomer, which acts as a binder for the catalyst and a proton conducting medium -- are key components of the PEMWE membrane electrode assembly (MEA). The catalyst layers are commonly fabricated by solution-processing an ink, which is a mixture of catalyst and ionomer often dispersed in a water-alcohol solvent mixture. Tuning the rheological properties of the anode inks (typically composed of iridium oxide catalyst, IrOx), particularly increasing their viscosity without significantly increasing the solids loading, to suit various scalable coating methods, is generally a challenge due to relatively low porosity and high density of the IrOx catalysts compared to the carbon-supported cathode catalysts. The typically low viscosities of the anode inks combined with high particle densities often cause stability/settling issues and challenges obtaining unform coatings, leading to inhomogeneous distribution of the catalyst that may have a negative effect on electrode performance. In this presentation we report on a dramatic enhancement in the viscoelasticity of the anode inks with aging, where the ink transitions from a liquid-like to a weak gel-like structure. The steady-shear and oscillatory shear rheology characterizations of the inks as a function of aging/time, the impact of formulation conditions (ionomer-to-catalyst ratio and dispersion media composition) on the viscoelastic enhancement with aging, and possible mechanisms for the observed behavior will be discussed. In addition to the rheological measurements, X-ray scattering characterization of the ink structure will be presented. The implications of the rheological changes on ink stability and processing will also be discussed. Additionally the impact of ink age on MEA performance will be presented.
Crown Ether As a Chemical Stabilizer for Enhanced Cerium Stability and Radical Scavenging in Proton Exchange Membranes
Authors: Agarwal Tanya , Komini Babu Siddharth , Sievert Allen , Park Andrew M , Hopkins Tim , Advani Suresh , Prasad Ajay Krishna , Borup Rod L.
Published: November 2022

Nafion is one of the standard proton exchange membranes that serves as the electrolyte membrane in fuel cells. However, it has been found to chemically degrade over time due to the generation of harmful peroxide and hydroxyl radicals. Attack by such radicals on the Nafion side chains causes polymer chain unzipping, and the membrane loses its mechanical integrity over time [1]. Cerium is proven to be an effective radical scavenger due to rapid transition between its +3 and +4 oxidation states and regenerates swiftly in the fuel cell environment. However, over time, cerium migrates due to the electrochemical potential, high water flux, and ionic diffusion [2] [3]. To resolve this issue, we functionalized a fraction of the side chains of Nafion with crown ether to complex with cerium and thereby prevent its migration. Crown ether has shown the ability to enhance cerium stability in recent studies [4] [5]. Cerium complex formation with crown ether was studied using UV visible spectroscopy, and enhanced retention was verified by testing drop in cerium concentration in the acidic medium, and migration of cerium under an external potential gradient. Membrane durability testing was conducted to verify that the stabilized membrane indeed shows higher lifetime in fuel cell operation.

[1] F. D. Coms, “The Chemistry of Fuel Cell Membrane Chemical Degradation,” ECS Transactions, 16(2): 235–255 (2008).

[2] S. M. Stewart, D. Spernjak, R. Borup, A. Datye, and F. Garzon, “Cerium Migration through Hydrogen Fuel Cells during Accelerated Stress Testing,” ECS Electrochemistry Letters, 3(4): F19–F22 (2014).

[3] Baker, Andrew M., et al. ''Cerium ion mobility and diffusivity rates in perfluorosulfonic acid membranes measured via hydrogen pump operation.'' Journal of The Electrochemical Society 164.12 (2017): F1272.

[4] Park, Junghwa, Yongman Park, and Dukjoon Kim. ''Chemical stability enhancement of crown ether grafted sulfonated poly (arylene ether ketone) fuel cell membrane by cerium ion fixation.'' Journal of Polymer Science Part A: Polymer Chemistry 57.2 (2019): 101-109.

[5] Tinh, Vo Dinh Cong, and Dukjoon Kim. ''Enhancement of oxidative stability of PEM fuel cell by introduction of HO• radical scavenger in Nafion ionomer.'' Journal of Membrane Science (2020): 118517.
Nanophase-Segregated Structures and Transport in Aquivion Membrane for Polymer Electrolyte Membrane Fuel Cell
Authors: Bazaid Mohammed Omar , Jang Seung Soon
Published: November 2022

In this study, molecular dynamic simulation method was employed to study the structure and transport properties of Aquivion in comparison to Nafion. From experimental and computational work, there is a general consensus that the favored properties of Polymer electrolyte membrane (PEM) system are a result of nano-phase segregation of hydrophilic clusters in a hydrophobic matrix. Aquivion has a similar chemical structure to Nafion with hydrophobic backbone and hydrophilic sulfonate group. As such, we investigate the structure formed by Aquivion, to check for the desired nanophase segregation, when simulated in conditions similar to fuel cell conditions of temperature and humidity. We also characterize water diffusion and proton transport in this segregated structure, and compared them with hydrated Nafion membrane system.
PEMFC Platinum-Based Catalysts Recycling Using an Electrochemical Process
Authors: Guillet François , Chatenet Marian , Druart Florence , Svecova Lenka , Dubau Laetitia
Published: November 2022

Hydrogen is one of the most promising energy carriers. Currently, the most used technology to produce electricity from hydrogen, particularly for green mobility, is the technology based on the use of Proton Exchange Membrane Fuel Cells (PEMFC). Platinum, pure or alloyed with another element, remains essential in the design of efficient catalysts either for anode or cathode catalytic layer in PEMFC. This metal is rare and expensive hence recycling it becomes an important issue for the hydrogen sector development.

Chemical ways to recover platinum from PEMFC have been already studied 1-2 based on Pt leaching using either a mix of HCl/HNO3 or HCl/H2O2. In our project, we investigate an electrochemical process to leach platinum contained in aged Pt based catalysts to further resynthesize catalysts from the recovered Pt salts. The electrodissolution of platinum becomes significant with the oxidation of the metal (around 1.1 V vs RHE) but particularly when the oxidized platinum is reduced (around 0.7 V vs RHE) 3. Moreover, the dissolution is enhanced when a complexing agent as chloride anion is introduced 4. The idea of our process is to study the impact of different protocol of steps between high potential (to oxidize platinum) and low potential (to reduce platinum oxide). The improvement of the process is linked to the upper and lower potential values, the number of steps and the nature of the electrolyte and the complexing agent. Our main parameter to monitor the dissolution is the changes in electrochemical real surface area (ECSA) associated to transmission electron microscopy (TEM) images of the catalyst at different stages of the protocol as illustrated in Figure 1.

In terms of methodology a model study on fresh commercial Pt/C catalyst has been first performed to determinate the optimal conditions of Pt dissolution followed by the application of the protocol on membrane electrode assemblies (MEA) aged in real conditions.

1 L. Duclos, L. Svecova, V. Laforest, G. Mandil, et P.-X. Thivel, « Process development and optimization for platinum recovery from PEM fuel cell catalyst », Hydrometallurgy, vol. 160, p. 79-89, mars 2016, doi: 10.1016/j.hydromet.2015.12.013.

2 L. Duclos, M. Lupsea, G. Mandil, L. Svecova, P.-X. Thivel, et V. Laforest, « Environmental assessment of proton exchange membrane fuel cell platinum catalyst recycling », J. Clean. Prod., vol. 142, p. 2618-2628, janv. 2017, doi: 10.1016/j.jclepro.2016.10.197.

3 S. Cherevko, A. R. Zeradjanin, G. P. Keeley, et K. J. J. Mayrhofer, « A Comparative Study on Gold and Platinum Dissolution in Acidic and Alkaline Media », J. Electrochem. Soc., vol. 161, n° 12, p. H822-H830, 2014, doi: 10.1149/2.0881412jes.

4 S. Geiger, S. Cherevko, et K. J. J. Mayrhofer, « Dissolution of Platinum in Presence of Chloride Traces », Electrochimica Acta, vol. 179, p. 24-31, oct. 2015, doi: 10.1016/j.electacta.2015.03.059.

Figure 1
Amino Functionalization Approach to Synthesis of Carbon Supported Intermetallic Platinum-Based Alloy Catalysts for Fuel Cell Application
Authors: Gong Qing , Zhang Qi , Zhang Hong , Cullen David A. , Jeon Sungho , Yu Haoran , Ren Yang , Yang Zhenzhen , Sun Chengjun , Stach Eric A. , Yu Yikang , Foucher Alexandre C. , Liu Ping , Xie Jian
Published: November 2022

Platinum (Pt) is a critical element in making electrocatalysts for oxygen reduction reaction (ORR) occurring at the cathode of polymer electrolyte membrane fuel cells (PEMFCs). To address the Pt abundance issue and to enhance Pt catalysis, Pt is often alloyed with another transition metal M (i.e. M = Fe, Co, and Ni). Ordered intermetallic PtM alloys are considered as one of the most promising candidates to achieve both high activity and stability in practical fuel cell applications. The transition metals in ordered intermetallic PtM alloys occupy specific sites, and are stabilized by both metallic and ionic bonding. Ordered intermetallic structures are formed via high temperature (>600 °C) annealing of disordered PtM alloys, as the atomic ordering is a thermodynamically driven process. However, the high temperature annealing inevitably leads to the migration and agglomeration of the nanoparticles forming randomly alloyed particles with poor dispersion and broad size distributions, due to weak adhesions to the carbon support under typical processing conditions. To prevent this coalescence during annealing, protective coating of the nanoparticles with inorganic shells or physical barriers has been suggested. However, these studies were limited to the synthesis of intermetallic nanoparticles on carbon supports at low metal loadings, or require an additional step of removing the coating layer from the surface of the nanoparticles to expose the active sites. Thus, it is essential to develop a general approach that can produce highly dispersed, structurally ordered nanoparticles while achieving controls over the size and size distribution. We propose to use the functionalized carbon supports to control PtM alloy nanoparticle size and prevent nanoparticles from aggregating during the high temperature annealing through improving the metal-support interactions. A strong electrostatic attraction between the negative charge from Pt precursor (PtCl6
2
-) and positive charge from the amino groups (C-NH2+) on the surface of the functionalized carbon will be established during the wet impregnation synthesis. Such bonds will help to make the PtM nanoparticle size smaller and more uniformly distributed over the surface of support. The ordered intermetallic 30 wt.% PtCo/KB-NH2 catalyst demonstrated an average size of 2.7 nm and uniform size distribution. In addition, 30 wt.% PtCo/KB-NH2 catalyst exhibited a mass activity of 535 A/gPt (H2/O2) and a rated power density of 1.05 W/cm2 at 0.67 V (H2/air), meeting the DOE targets.
Nitrogen-Doped Carbon Nanosphere Supports for Platinum-Decorated Oxygen Reduction Reaction Catalysts
Authors: Wang Hanson , Ly Alvin , Atanassov Plamen
Published: November 2022

Carbonaceous materials are widely used as supports for platinum-based oxygen reduction reaction (ORR) catalysts that are prevalent in proton exchange membrane fuel cells (PEMFC). In particular, a variety of carbon blacks are popular due to factors such as commercial availability and high surface area. However, as applications of PEMFCs shift towards heavy-duty vehicle deployment, durability of the supports has become an important criterion when evaluating materials. Carbon support corrosion can lead to Pt nanoparticle detachment and agglomeration, both of which decrease the electrochemically active surface area of the catalyst. Recently, nitrogen-doping of carbon supports has shown promising results towards improving stability in fuel cell operating conditions1. Graphitization is another strategy that mitigates carbon corrosion, as graphitic carbon is more resistant to oxidation than amorphous carbon2. In this work, we present a set of nitrogen-doped carbon nanosphere supports obtained via a one-pot colloidal synthesis and then decorated with Pt nanoparticles for ORR catalysis (Pt/NCS). The nitrogen-doped supports are monodispersed, contain a mesoporous pore structure, and show a higher level of bulk graphitization than commercial carbon blacks. Our work also elucidates how differences in certain nitrogen moieties on the carbon support’s surface impact catalytic activity. The Pt/NCS catalysts exhibit similar mass activity and improved specific activity in rotating disk electrode measurements compared to a commercial Pt/C catalyst at similar Pt weight loadings.

(1) Ott, S.; Orfanidi, A.; Schmies, H.; Anke, B.; Nong, H. N.; Hübner, J.; Gernert, U.; Gliech, M.; Lerch, M.; Strasser, P. Ionomer Distribution Control in Porous Carbon-Supported Catalyst Layers for High-Power and Low Pt-Loaded Proton Exchange Membrane Fuel Cells. Nat. Mater.
2020, 19 (1), 77–85.

(2) Yu, P. T.; Gu, W.; Zhang, J.; Makharia, R.; Wagner, F. T.; Gasteiger, H. A. Carbon-Support Requirements for Highly Durable Fuel Cell Operation. In Polymer Electrolyte Fuel Cell Durability; Büchi, F. N., Inaba, M., Schmidt, T. J., Eds.; Springer New York: New York, NY, 2009; pp 29–53.
Atomically Dispersed Co-Anchored N Rich Graphitic Carbon Network: A Highly Efficient Oxygen Reduction Electro Catalyst
Authors: Jha Neetu , Mane Rupali SHASHIKANT , Somkuwar Vaishnavi
Published: November 2022

Rational design of non-precious and highly efficient electrocatalyst for oxygen reduction reaction (ORR) is of great importance for sustainable energy exploitation to solve the energy crisis and environmental jeopardy. In this regard herein, we report work function tailored zeolite derived hierarchically porous and active site enrich electrocatalyst for ORR in acidic and alkaline medium. The electrochemical analysis proposes that the optimized electrocatalyst for surface area, porosity and active center density facilitate the electronic transfer from atomic Co to Nitrogen doped carbon framework and, further to antibonding oxygen state. The optimized catalyst shows the high ORR activity, remarkable onset potential (E onset acid- 0.89 V, E onset alkaline – 0.951 V) and large number of active site density (ASD acid -7.84×1023 /g, ASD acid - 1.51×1024 /g) with excellent stability and durability. It is proposed that the high performance of the catalyst is attributed to the reduction in work function (ф ZIF 67- 5.2 to ф optimized- 4.6) as an effect of temperature followed by post ‘acid leaching’ (AL) treatment to alter the surface area of the catalyst. Here, we represent a favorable strategy for highly efficient and durable ORR catalyst. This hybrid structure provides a new perspective to catalyst architectures.
Using 2D-Phthalocyanine Metal Organic Framework-Based Catalysts for Oxygen Reduction Reaction in Alkaline Media
Authors: Wei Lingze , Chen Gan , Hossain Md Delowar , Zamora Zeledon Jose Andres , Kreider Melissa E , Stevens Michaela Burke , Bajdich Michal , Bao Zhenan , Jaramillo Thomas F
Published: November 2022

Developing high performance electrocatalysts to improve the sluggish kinetics of oxygen reduction reaction (ORR) at the cathode is essential in expanding fuel cell applications. Metal organic frameworks (MOFs), given their high surface area, tunable pore size, and diverse metal choices, are promising candidates to catalyze such a reaction. Herein, we report a family of nine 2D-phthalocyanine MOF-based catalysts for alkaline ORR, where M = Co, Ni, Cu. Structurally, these bimetallic materials have two distinct metal sites, where M1 is a phthalocyanine moiety and M2 is a node, existing as M-N4 moiety. X-ray Diffraction (XRD) shows that all as-prepared MOFs have similar structures and inter-layer spacing. X-ray Photoelectron Spectroscopy (XPS) shows slight shifts in binding energy when the same element is placed in a M1 or M2 site, which indicates that the M1 and M2 sites are chemically distinct.

Through cyclic voltammetry we evaluate the role of the metal sites for ORR activity and selectivity in 0.1 M KOH. All materials are active for alkaline ORR, while Ni (M1) – Co (M2) has the best overall kinetic activity performance of - 5 mA cm-2 at 0.7 V vs. RHE. Cu – Cu, on the other hand, is the least active combination under the same testing conditions. Within composition series where M2 = Co, the activity trend for M1 is Ni > Cu ~ Co. From a 2-electron selectivity perspective, M1 = Ni > Cu > Co. From these general trends we hypothesize that Co M2 and Ni M1 sites are essential in promoting 4- and 2-electron selectively, respectively. On average we find a nominal ORR performance trend where M2 = Co > Cu > Ni. Interestingly, we note that the M1 identity also plays a non-linear role in activity and selectivity modulation. Though we identify one of the metal sites (M1 or M2) as the dominating site for activity and/or selectivity, the other site also contributes to the total performance. The density functional theory (DFT) calculation supports our experimental results and finds out that Ni as M1 is highly selective for H2O2 formation whereas Co as M2 shows excellent activity for ORR. Our predicted volcano plot shows that MOF with Ni – Co and Cu – Co combinations at Co active site offering lowest ORR overpotential among all other combinations, which is also in good agreement with experimental findings.

By evaluating different metal sites performance through electrochemical testing, we can better understand the active species in the MOF catalytic system. By pairing theory with experiment, we gain active site insight to design new specific enhanced active motifs. We believe that these performance trends can assist in better designing efficient MOF-based ORR catalysts that can lead to advances in clean energy technology for sustainable development.
New Insights into High-Temperature Anion-Exchange Membrane Fuel Cells
Authors: Dekel Dario R.
Published: November 2022

Until a few years ago, the operation of anion-exchange membrane (AEM) fuel cells (AEMFCs) at temperatures above 70 oC was a real challenge, mainly due to the temperature limitation of the AEMs. Recently, with the remarkable progress made in the development of stable AEMs, more and more AEMFC tests could be performed at higher cell temperatures, mainly at 70-85 oC. Very recently, very few studies even reported the operation of AEMFCs at 90-95 oC. In the past year, we presented the first results of what we call high-temperature AEMFCs (HT-AEMFCs) tested at cell temperatures above 100 oC. At these temperatures, we could obtain hydroxide conductivities close to 300 mS cm-1, the highest hydroxide conductivity ever measured for an AEM. The first HT-AEMFC results are very encouraging and represent a significant landmark for the research and development of fuel cell technology, opening a wide door for a new field of research - the HT-AEMFCs. At this initial stage, however, there are many open questions and unknowns, mainly regarding the stability of the polymeric materials under these high temperatures. In this talk, this topic will be discussed, and new exciting and surprising insights will be presented.

References

“A high-temperature anion-exchange membrane fuel cell”; John C. Douglin, John R. Varcoe, and Dario R. Dekel; J. Power Sources Advances 5, 100023, 2020.

“Quantifying the critical effect of water diffusivity in anion exchange membranes for fuel cell applications”; Karam Yassin, Igal G. Rasin, Simon Brandon, and Dario R. Dekel; J. Membrane Sci. 608, 118206, 2020.

“A High-Temperature Anion-Exchange Membrane Fuel Cell with a Critical Raw Material-free Nitrogen-doped Carbon Cathode”; John C. Douglin, Ramesh K. Singh, Saja Haj, Songlin Li, Jasper Biemolt, Ning Yan, John R. Varcoe, Gadi Rothenberg, and Dario R. Dekel; Chemical Engineering J. Adv. 8, 100153, 2021.

“A surprising relation between operating temperature and stability of anion exchange membrane fuel cells”; Karam Yassin, Igal G. Rasin, Sapir Willdorf-Cohen, Charles E. Diesendruck, Simon Brandon, and Dario R. Dekel; J. Power Sources Adv. 11, 100066, 2021.

“Magnetic-field-oriented mixed-valence-stabilized ferrocenium anion-exchange membrane”; Xin Liu, Na Xie, Jiandang Xue, Mengyuan Li, Chenyang Zheng, Junfeng Zhang, Yanzhou Qin, Yan Yin, Dario R. Dekel, Michael D. Guiver; Nature Energy, just accepted (https://doi.org/10.1038/s41560-022-00978-y) 2022.

“Non-Monotonic Temperature Dependence of Hydroxide Ion Diffusion in Anion Exchange Membranes”; Tamar Zelovich, Leslie Vogt-Maranto, Cataldo Simari, Isabella Nicotera, Michael Hickner, Stephen J. Paddison, Chulsung Bae, Dario R. Dekel, and Mark E. Tuckerman; Chemistry Mater., Chem. Mater. 34, 5, 2133-2145, 2022.
Evaluating Contributions of Pitch-Carbon Coating to Improved Stability of Si Anodes through Voltage-Resolved Multi-Phase Characterization
Authors: Fink Kae , Palmer Jack , Zweifel Christof , Schulze Maxwell , Carroll Mike Michael , Engtrakul Chaiwat , Han Sang-Don , Neale Nathan R. , Tremolet de Villers Bertrand J.
Published: November 2022

Silicon nanoparticles have emerged as a promising alternative to graphite to improve the energy density of next-generation lithium-ion battery anodes. Nano-sized Si domains facilitate rapid ion transport and minimize particle-scale mechanical degradation, but also exhibit increased (electro)chemical reactivity with Li-ion electrolyte components due to their high surface area. We have previously demonstrated that surface modification of Si nanoparticles with pitch-carbon is an effective strategy to reduce these parasitic reactions. In the present work, we holistically evaluate the mechanistic contribution of pitch-carbon coating to the observed stability improvement over uncoated Si. We utilize coupled in situ and ex situ methods to probe changes to solid-surface, volatile headspace, and gas-phase chemistry occurring during initial cycling. Measurements taken at targeted potentials associated with electrolyte species reduction enables the decoupling of specific reaction pathways tied to interfacial stability. Further, we demonstrate the non-trivial role of gas reconsumption in dictating the nature of the passivating surface layer evolved on both uncoated and pitch-coated Si. This multi-phase analysis offers insights into the mechanism of effective surface passivation, which may be applied to inform future Si material development.

Figure 1
Electrochemically Dealloyed 3D Porous Copper Nanostructure As High-Performance Anode Current Collector of Li-Metal Batteries
Authors: Ma Yifan , Zhang Guangxing , Ma Xuetian , Liu Zhantao , Chen Hailong
Published: November 2022

Li metal anode is the ultimate choice for Li batteries owning to its highest theoretical capacity (3806 mAh/g) and lowest redox potential (-3.04 V vs. standard hydrogen electrode) among possible candidates.[1] However, despite the advantages of Li metal anodes, a number of remaining challenges must be addressed before its commercialization: undesired dendrite growth of Li, and irreversible parasitic reactions between Li and electrolyte, etc.

Stabilization of Li metal is essential for commercial application of Li metal anodes. In the past few years, several strategies have been developed to suppress Li dendrite growth and stabilize SEI formation during Li plating/stripping processes. Among these strategies, 3D current collectors showed its high potential in Li anode stabilization due to its much larger surface area, which can provide much more Li nucleation sites, alleviate volumetric changes of Li anode, and decrease practical current density. Thus, compared to flat Cu foil used in commercial Li-ion batteries, 3D Cu current collectors can facilitate uniform Li deposition, mitigate Li dendrite growth, and enhance Li cycling stability.[2]

Our previous work reported a 3D porous Cu current collector fabricated via a facile one-step electrodeposition method directly on commercial Cu foil. [3] The fabricated 3D porous Cu current collector showed stable long-term cycling with a high areal capacity of 6 mAh/cm2 and no Li dendrite growth was observed during cycling process. However, for the one-step electrodeposition method, the thickness of the porous Cu deposition layer is limited. Thus, preparation of 3D porous Cu layers with both high thickness and high porosity is necessary to further improve the areal capacity of this current collector. Recently, we developed a new two-step electrochemical process to fabricate thick and porous Cu layer: a thick Cu-Zn alloy was first electrodeposited on commercial Cu foil, and Zn was then removed electrochemically, leaving a thick and highly porous 3D Cu layer. Compared to our previous method, this 3D Cu layer has a high thickness of ~14 um and porosity of ~72%. This new 3D Cu current collector can achieve stable Li cycling up to 230 h at high areal capacity of ~10 mAh/cm2 at a high current density of 10 mA/cm2, demonstrated its high commercial application potential in Li-metal batteries.

Tarascon, J.M. and M. Armand, Issues and challenges facing rechargeable lithium batteries. Nature, 2001. 414(6861): p. 359-367.

Yang, C.P., et al., Accommodating lithium into 3D current collectors with a submicron skeleton towards long-life lithium metal anodes. Nature Communications, 2015. 6.

Ma, X., Z. Liu, and H. Chen, Facile and scalable electrodeposition of copper current collectors for high-performance Li-metal batteries. Nano Energy, 2019. 59: p. 500-507.
Insights into the Na-Alloying Mechanism and Zintl Phase Transition of Lead-Based Anodes
Authors: Park Jehee , Han Jinhyup , Gim Jihyeon , Bak Seongmin , Ahmed Shabbir , Iddir Hakim , Garcia Juan , Kim Youngsik , Lee Eungje , Johnson Christopher S.
Published: November 2022

Sodium-ion batteries (SIBs) has been received growing attention in the electrical energy storage fields due to their low cost and earth-abundant sodium. [1] However, there has been a lack of new discoveries, growth directions, and real advancement with respect to Na-storage anodes. Despite the chemical similarities between sodium and lithium as alkali elements, the larger Na ion than Li ions (ionic radii of 0.98 Å and 0.68 Å, respectively) is limited to insertion into host materials and results in different phase transition behavior. [2] Among the available anode candidate materials for SIBs, lead (Pb), which has a large atomic size than other elements (e.g. Si, Sn), provides a big interstitial space to accommodate large Na ions by fast ionic diffusion, enabling reversible Na alloying/dealloying and exhibiting high volumetric capacity. [3] Furthermore, when Pb is used as anode with layered sodium transition metal oxide as cathode, the energy density of the pouch-type cell is estimated to be 549 Wh/L and the cost is lower than 63.5 USD/kWh according to the Argonne BatPac model. [4] Therefore, Pb-based materials have competitive potential as promising anodes and it is crucial to understand the electrochemical process from a fundamental perspective.

Here, we investigate a unique Na storage mechanism using a novel Pb-based carbon nanocomposite anode synthesized by a simple high-energy milling method. The electrochemical data show a decent cycle performance with a reversible capacity of 381 mAh/g. Nevertheless, the Na-storage performance of the Pb-based anode was not attractive compared to Li cells. In-situ X-ray diffraction and ex-situ X-ray absorption spectroscopy reveal the reaction mechanism and Zintl-phase formation that limits the Na storage, unlike the Li reaction. We expect these findings provide fundamental knowledge of Na-alloying reaction and guidance for designing anode materials for high-performance SIBs.

[1] K. Kubota and S. Komaba Journal of The Electrochemical Society, 2015, 162 (14) A2538-A2550

[2] M. Lao, Y. Zhang, W. Luo, Q. Yan, W. Sun, and S. X. Dou Adv. Mater. 2017,
29
, 1700622

[3] Chia-Yun Chou, Myungsuk Lee, and Gyeong S. Hwang, J. Phys. Chem. C 2015, 119, 27, 14843–14850

[4] P. Nelson, K. Gallagher, I. Bloom, Dennis Dees, and Shabbir Ahmed, BatPaC, Argonne National Laboratory. http://www.cse.anl.gov/batpac.
(Digital Presentation) H2o and CO2 Surface Contamination of the Lithium Garnet Li7La3Zr2O12 Solid Electrolyte
Authors: Li Yuheng , Prabhu Asmee , Choksi Tej , Canepa Pieremanuele
Published: November 2022

Garnet-type Li7La3Zr2O12 is a promising solid-state electrolyte for lithium (Li)-ion batteries, and it readily reacts with H2O and CO2 when exposed to ambient air. Such reactions form a contamination layer on Li7La3Zr2O12, which is detrimental to the battery operation. Here, using first-principles calculations, we investigate the adsorption and reactions of H2O and CO2 on a Li7La3Zr2O12 surface. We show that H2O reacts through the exchange of protons and Li+ and produces metal hydroxide species. At high H2O coverage, half of the H2O molecules dissociate, while the other half remain intact. CO2 reacts with the Li7La3Zr2O12 surface directly to produce carbonate species. We clarify that the individual reactions of H2O and CO2 with Li7La3Zr2O12 are thermodynamically more favorable than the co-adsorption of H2O and CO2. Finally, we demonstrate that low temperature and high partial pressure promote the reactions of H2O and CO2 with Li7La3Zr2O12. Our study provides guidance on processing conditions for the garnet Li7La3Zr2O12 solid electrolyte to minimize its surface contamination.
Moving Beyond Heat and Beat
Authors: Veith Gabriel M. , Malkowski Thomas F. , Chambers Matthew , Sacci Robert L
Published: November 2022

The synthesis of solid electrolytes is often described as the mixing of simple precursors (e.g. Li2CO3, La2O3, etc.), followed by extensive heating and regrinding to yield a single phase solid ion conductor. In this presentation we move beyond the traditional "heat and beat" approach to synthesis to a more nuanced approach more analogous to classic organic synthesis with the controlled and stepwise addition of reagents. We will show this approach produces a 500 fold increase in grain boundary conductivity of perovskite solid electrolytes and the complete synthesis of others in under 15 minutes and 200oC lower reaction temperatures. Through control of reaction energetics reaction selectivity can be enhanced offering unique opportunities to facilitate the properties of solid ion conductors.
Lithiation of an Agarose-Based Biopolymer Electrolyte for Li-S Batteries
Authors: Yu Xingwen , Tran Tam , Wang Yudong , Sun Yanhua , Zhou Xiao-Dong
Published: November 2022

Driven by the continually accelerating demand for energy storage, the development of batteries with high energy, high power, low cost, and high safety is an endless goal and eternally inspires researchers to pursue advanced energy storage technologies. Battery systems based on non-aqueous chemistry of lithium and sulfur have garnered overwhelming attention in the past decade. So far, many significant progresses have been made through rigorous research over the past decade. However, this battery technology still confronts considerably critical challenges. Due to their unique charge-discharge mechanism, electrochemical processes of a Li–S cell experience the formation of a sequence of soluble intermediate products existing in a variety form of polysulfides dissolved in the non-aqueous liquid electrolyte. Under the operating conditions of a Li-S cell, the solvated polysulfide species have a tendency to migrate from the positive electrode through the conventional porous separator to react with Li-metal anode. The shuttle of polysulfide can severely degrade the cell performance, lowers the cycling efficiency, and induces capacity fade during cycling. On the other hand, use of a lithium-metal anode in Li-S batteries would unavoidably lead to the additional persistent problem of Li dendrite with can easily penetrate a conventional porous separator and short the cell. These two problems — the polysulfide shuttle and lithium dendrites — are the most critical challenges for Li–S battery development. To overcome the above two issues, we present here a lithiated polymer membrane (as pictured in Figure 1a) which is developed from agarose (AG, with a unit molecular structure as displayed in Figure 1b) as a cation-selective electrolyte for Li–S batteries to suppress the polysulfide diffusion and to reduce the formation Li dendrite. Preliminary results of a Li ǁ AG ǁ Li symmetric cell showed that the membrane could sustain high-current-density operation with low overpotential (Figure 1c). The AG membrane exhibited amorphous structure (Figure 1d) and nonporous feature (Figure 1e). Our ongoing work includes the evaluation of dendrite-suppression capability and polysulfide-shuttle-inhibition function of the AG-based membrane, as well as the electrochemical performance of Li-S batteries with the AG membrane. In addition, ionic transport mechanism in the AG-based membrane will be presented as well.

Figure 1
The Effect of Pressure during Sintering on the Interface between Oxide Solid Electrolyte and Cathode in Solid State Lithium Batteries
Authors: Bae Youngjoon , Lim Sungjin , Kim Ryounghee , Kim Tae Young
Published: November 2022

Conventional Li-ion batteries (LIBs), which have been widely used as main power sources for various electronic devices, are facing huge challenges with the explosive growth of electric vehicles (EVs) market. The safety problems of LIBs in EVs causing fire incident mainly result from the use of liquid electrolytes which provide fuel for combustion. Therefore, solid state lithium batteries using a solid electrolyte are widely accepted as promising candidates for next generation energy storage devices with superior safety performances. However, solid state batteries have limitations that originate from solid-solid interfaces between electrode and solid electrolyte, hindering practical development of solid state batteries. Especially, compared to sulfide based solid electrolyte, oxide based solid electrolyte is rigid, resulting in difficulty in forming intimate contact between solid electrolyte and electrode materials. In this study, using lithium vanadium phosphate (Li3V2(PO4)3, LVP) and lithium aluminum germanium phosphate (Li1.5Al0.5Ge1.5(PO4)3, LAGP) as cathode material and oxide solid electrolyte model system, we demonstrate the effect of pressure during sintering on the contact between LVP and LAGP, and concomitant cell performance. In addition, we found that the crystallinity of solid electrolyte and the content of carbon conducting agent critically affect the contact. Without any complicated interfacial modification, we successfully made decent cathode-solid electrolyte interface with simple method for superior solid state lithium batteries.
Potency of Potassium Doping on Na-Ion Sites to Avert Phase Transition in P2 Type Sodium-Ion Battery
Authors: Banik Trapa , Bhattacharya Indranil
Published: November 2022

Sodium-ion battery (SIB) is acquiring considerable attention as a viable replacement to lithium-ion battery (LIB) technology in the ever-expanding energy storage market due to its attractive combination of homogeneous profusion in the earth and identical intercalation chemistry to LIB. However, SIB is still a laboratory child as SIBs exhibit slightly lower energy density as compared to those of LIBs. Hence, it is critical to determine a suitable cathode to facilitate facile Na-ion transport as cathode is the key factor affecting cycle life, energy density as well as safety. In case of SIBs, layered transition metal oxides are widely preferred as cathode material due to their excellent high specific capacity as well as their simple synthesis process. In this research, Manganese enriched P2 type quaternary Na0.6Fe0.48Mn0.5Ti0.01V0.01O2 (NFMTV) cathode material is studied which shows high capacity and high voltage (4.2V) along with reducing Jahn-Teller (JT) Effect. However, inferior reversibility and capacity fading have still been a challenge, particularly for higher voltage window as lower Na content during discharge process initiates the unavoidable phase transition. To preserve the lattice orientation, a feasible approach is demonstrated in this research by introducing potassium (K) ion into Na ion sites between transition metal oxide (TMO2) layers. This work explains that the K+ into Na+ ion layers serve as the supporting pillar to hold the stacking pattern intact even for very low Na content at higher voltage. As seen from the SEM and EDS analysis, no apparent alternation happened in surface morphology and crystal structure for a small amount of K doping. Furthermore, the XRD and Rietveld refinement results validate that emplacement of K+ ions in the Na sites in the NFMTV crystal structure. It also expands the Na+ ion diffusion path and substantially boosts the rate performance and reversibility. Besides, K+ ion doping halts the gliding phenomenon and hence, phase transition is impeded which is observed from the improved cyclability and capacity retention.
PGM-Free Catalysts and Electrodes for Anion Exchange Membrane Water Electrolyzers
Authors: Osmieri Luigi , He Yanghua , Yu Haoran , Cullen David A. , Zelenay Piotr
Published: November 2022

Recent progress in the development of anion exchange membranes (AEMs) with improved performance and durability has opened the way for the application of the AEM-based electrolyzers in low-temperature water electrolysis (LTWE),1 an important technology for producing “green” hydrogen.2 AEM-LTWEs can potentially operate on pure water, i.e., without highly concentrated and corrosive supporting electrolyte, and they allow for replacement of electrocatalysts based on platinum group metals (PGMs) with PGM-free ones, thus addressing the main drawbacks of the liquid-alkaline (LA) and proton exchange membrane (PEM) electrolyzers.3 Consequently, the development of PGM-free electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media is of primary importance for the deployment of AEM-LTWEs that has attracted significant attention of researchers.4–6 Besides improving the catalytic activity, the integration of PGM-free HER and OER electrocatalysts into electrodes for operation in AEM electrolyzers is crucial to achieving satisfactory electrolyzer performance and making them competitive with the LA and PEM systems.7,8

In this work, we measured electrocatalytic activity of a series of OER and HER catalysts in a three-electrode cell and then implemented these catalysts in electrodes for testing in an AEM electrolyzer. We investigated different classes of OER catalysts, including commercial IrO2 (a PGM ORR benchmark), LaxSr1-xCoO3-δ oxides, Ni-Fe nanofoam oxides, Ni-Fe aerogel-derived oxides, and MOF-derived Co oxides. In the HER-catalyst part of the study, we compared a commercial PtRu/C (a PGM HER benchmark) with an aerogel NiMo/C catalyst. Catalysts and electrodes before and after testing were characterized by XRD, SEM, EDS, and XPS.

In addition to exploring different catalysts, we investigated the impact of several fabrication variables such as the ink deposition method, amount of ionomer, incorporation of a binding agent, and the type of anode porous transport layer on performance. The tests were carried in an electrolyzer operating with pure water and two electrolyte solutions, 0.1 M KOH and 1% K2CO3. The results show that, in addition to the OER and HER electrocatalytic activity, the electrode fabrication is an important factor affecting AEM electrolyzer performance, especially in the pure-water operation mode, in which case assuring an effective transport of the OH– ions within the catalyst layer is especially challenging.

References

Y. S. Kim, ACS Appl. Polym. Mater. (2021).

C. Santoro et al., ChemSusChem, 202200027 (2022).

H. A. Miller et al., Sustain. Energy Fuels, 4, 2114–2133 (2020).

D. Xu et al., ACS Catal., 9, 7–15 (2019).

H. Shi et al., Adv. Funct. Mater., 2102285, 1–10 (2021).

H. Doan et al., J. Electrochem. Soc., 168, 084501 (2021).

N. U. Hassan, M. Mandal, B. Zulevi, P. A. Kohl, and W. E. Mustain, Electrochim. Acta, 409, 140001 (2022).

G. A. Lindquist et al., ACS Appl. Mater. Interfaces (2021).
The Impact of Multi-Layered Porosity Distribution on the Performance of Lithium-Oxygen Batteries with Organic Electrolyte
Authors: Lobachev Emil , Andrei Petru
Published: November 2022

Li-oxygen batteries have attracted much attention in the last few years because of their relatively high theoretical energy densities compared to other batteries and because of the recent advancements in material technologies. The high theoretical energy density of Li-oxygen batteries makes these batteries suitable for applications requiring light power sources such as portable electronic devices, unmanned aerial vehicles, and renewable energy storage. In this presentation, we investigate the impact of the porosity distribution on the performance of Li-air batteries with cathodes made of carbon nanotube foams. After presenting the transport model appropriate for such cathodes, we develop a mathematical optimization method to find the optimum 1-D porosity distribution inside the Li-air battery that maximizes the energy density of these batteries. Our preliminary results show that to maximize the energy density of Li-air batteries, it is better to use cathodes with spatially variable porosity, in which the porosity at the oxygen entrance is higher than near the separator. More details about the mathematical approach and preliminary experimental data will be presented at the conference.
3D-Structured Porous Carbon Host with Iron Nanoparticles for High Performance Sodium-Metal Batteries
Authors: Lee Kyungbin , Lee Young Jun , Kim Bumjoon J , Lee Seung Woo
Published: November 2022

Sodium (Na)-metal batteries have emerged as a promising alternative to lithium-metal batteries for next-generation batteries due to the low cost and natural abundance of Na. However, high reactivity of Na metal and uncontrollable growth of Na dendrites hinder the safe operation of Na-metal batteries. Several studies have been conducted to resolve those problems and regulating the initial Na nucleation is one of the promising methods for dendrite-free Na-metal anodes. Previous studies reveal that sodiophilic metal nanoparticles (Au, Ag, Sn, Sb, etc.) embedded 3D structures can induce the homogeneous initial Na nucleation and further guide uniform Na deposition. Herein, we newly develop a 3D nanostructured porous carbon particle containing carbon-shell-coated Fe nanoparticles (PC-CFe) as a highly reversible Na-metal host.1 PC-CFe delivers excellent cycling stability in asymmetric cells over 500 cycles with an average Coulombic efficiency of 99.6% at 10 mA cm-2 with 10 mAh cm-2 and in symmetric cells over 14,400 cycles at 60 mA cm-2. The role of carbon coating on Fe nanoparticles for enhanced sodiophilicity is also investigated by DFT calculations. Furthermore, the anode-free Na-metal batteries with a PC-CFe host and a high-loading Na3V2(PO)4 cathode shows an excellent capacity retention of 97% after 100 cycles at 1 mA cm-2. This work provides a novel approach toward the rational design of 3D hosts for next-generation Na-metal batteries.

References:

1. Lee, K.; Lee, Y. J.; Lee, M. J.; Han, J.; Lim, J.; Ryu, K.; Yoon, H.; Kim, B.-H.; Kim, B. J.; Lee, S. W. A 3D Hierarchical Host with Enhanced Sodiophilicity Enabling Anode-Free Sodium-Metal Batteries. Adv. Mater.
2022, 34, 2109767.