bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-Term, Non-Invasive Detection of Low-Dose Ionizing Radiation Exposure
Authors: Inman Jamie , Wu Yulun , Chen Liang , Ghosh Dhruba , Wan Kenneth , DeChant Jared , Obst-Huebl Lieselotte , Nakamura Kei , Ralston Corie , Celniker Susan , Mao Jian-hua , Holman Hoi-Ying , Zwart Petrus , Chang Hang , Brown James Ben , Snijders Antoine M
Published: August 2024

Ionizing radiation induces complex changes in cells and tissues. The conventional approach to biological dosimetry has been to integrate physical and clinical measurements to optimize dose assessment. Molecular biodosimetry is an effective strategy to monitor radiation exposure and hematologic, cytogenetic, protein and transcript-based approaches have been developed to increase dose estimation accuracy. However, these approaches are invasive, time-consuming, have limited effectiveness over time, and importantly do not accurately inform on low dose radiation exposures. Therefore, novel, non-invasive, biomarkers are required that can overcome these limitations. We developed a pipeline that employs Fourier transform infrared (FTIR) spectroscopy in the mid-infrared spectrum to identify a signature of low dose ionizing radiation exposure in mouse ear pinnae over time. Two cohorts of C57BL/6J and one cohort of BALB/c mice were followed for ninety days after total body X-ray exposures of 10, 50, 100 or 200 cGy. The stratum corneum layer of the ear pinnae were repeatedly measured with attenuated total reflectance - focal plane array (ATR-FPA)-FTIR at 5, 14, 21, 49 and 90 days after radiation exposure. We found statistically significant discriminative power for all doses and all tested time-points out to 90 days after exposure. Classification accuracy was maximized when testing 14 days after exposure (specificity > 0.9 with a sensitivity threshold of 0.9) and dropped by roughly 30% sensitivity at 90 days. Since only hundreds of samples were required to learn highly discriminative signatures, developing human-relevant diagnostic capabilities is likely feasible and this non-invasive procedure points toward future non-invasive biodosimetry applications at population scales.
Synthetic Chemistry and Microelectrode Arrays for Point of Care Diagnostics
Authors: Moeller Kevin D , Chang Yu-Chia , Huang Albert
Published: August 2024

Molecular diagnostics typically require a molecular interaction that identifies a specific target, a device that detects, quantifies, and records that interaction, and an interface between those two elements. Each feature is critical for the success of the device. Yet while the first two are matters of intense interest an research, the surface itself is often ignored. This is problematic because it provides the platform for the whole "experiment". For a "point-of-care" diagnostic, the surface on the device must be stable both in terms of chemistry and time while still allowing the signal from the molecular interaction to be sensed and recorded.

With this in mind, we have been focusing on the use of diblock copolymers as molecular surfaces for the construction of "point-of-care" diagnostics. We have developed a toolbox of chemical reactions that can be used site-selectively on such surfaces, and we have recently demonstrated that the approach taken is compatible with the use of DNA-aptamers to do multiplex sensing on a high density microelectrode array using a surface that is stable for a year. We have also illustrated how the quality of the signaling study conducted on an array is dependent on optimization of the chemical reaction.

But exactly how good are the chemical reactions employed on the arrays to build a surface in a site-selective manner? One can tell with the use of fluorescence based studies that reactions happen where you want then to happen, but are there background reactions that can be problematic for a multiplex sensing experiment, do the reactions happen in high yield, and how much of an expensive, difficult to obtain biological reagent might be lost due to the confinement strategy? Are some reactions better than others in this regard? In short, if we are to optimize the surfaces constructed on a diagnostic device, then we need not only have tools in place for conducting synthetic chemistry on the device, but also the tools in place necessary to analyze those reactions. Understanding the chemistry that can and/or does occur at any electrode in a high density array requires more than looking at pretty pictures of fluorescent spots. In the talk to be given, we will utilize a combination of a "Kenner-safety-catch" linker strategy and molecular biology techniques to answer key questions about the synthetic chemistry used to construct the DNA-aptamer based multiplex sensor mentioned above.
Effect of Experimental Parameters on the Electrochemical Current during Scanning Electrochemical Microscopy of Living Cells
Authors: Thomas Nikita , Lyu Mengzhen , Khouv Jadon , Lima Dhésmon , Trinh Dao , Kuss Sabine
Published: August 2024

Scanning Electrochemical Microscopy (SECM) is gaining popularity for its application to live cell imaging to monitor electrochemical processes occurring at the interface of living cells and electrodes. [1] Although many studies have been reported varying the instrumental parameters and using various probe designs, [2] the influence of experimental parameters on the electrochemical current must not be neglected, in order to generate reliable results. Our work explores parameters, such as temperature, light exposure and cell media during the SECM analysis of Adenocarcinoma Cervical cancer (HeLa) cells. The experimental and numerical studies with temperature variation revealed that temperature changes of 2ᵒC influence the reaction kinetics of single living cells. [3] Further, it was observed during light exposure that the electrochemical current becomes stabilized after 20 minutes of constant light environment compared to dark, where the standard deviation of the electrochemical current showed an increase in trend overtime. Furthermore, electrochemical current responses of HeLa cells in Phosphate Buffered Solution (PBS), Dubelcco’s Modified Eagle Medium (DMEM) and DMEM with 10% Fetal Bovine Serum (FBS) is being explored. These results will help to understand the origin of potential electrochemical current changes and the ideal experimental conditions to perform SECM measurements with living cells.

[1] I. Beaulieu, S. Kuss, J. Mauzeroll, M. Geissler, Biological scanning electrochemical microscopy and its application to live cell studies, Anal. Chem. 83 (2011) 1485–1492. https://doi.org/10.1021/ac101906a.

[2] D. Polcari, P. Dauphin-Ducharme, J. Mauzeroll, Scanning Electrochemical Microscopy: A Comprehensive Review of Experimental Parameters from 1989 to 2015, Chem. Rev. 116 (2016) 13234–13278. https://doi.org/10.1021/acs.chemrev.6b00067.

[3] N. Thomas, D. Lima, D. Trinh, S. Kuss, Temperature Effect on the Electrochemical Current Response during Scanning Electrochemical Microscopy of Living Cells, Anal Chem. 95 (2023) 17962-17967. https://doi.org/10.1021/acs.analchem.3c03716
Spectroelectrochemical Setup for Probing Reactions on Electrodes and in Electrolytes
Authors: Shilov Sergey
Published: August 2024

The combination of electrochemistry with vibrational spectroscopy is a powerful tool for studying electrochemical reactions, battery research, and failure analysis. Each molecule has a unique infrared and Raman signature providing great specificity in the analysis of the molecular change during electrochemical reactions.

An overview of the spectroelectrochemical accessories for probing reactions on electrodes and in electrolytes will be presented. The optimization of the setup and details of communication between the potentiostat and the spectrometer will be discussed. Examples of applications will include electro-oxidation of metal-organic complexes, carbon analysis in flexible electrodes, and chemical mapping of the solid electrolyte interface of lithium metal battery.
Electrochemical CO2 Reduction to Methane with Remarkably High Faradaic Efficiency in the Presence of a Proton Permeable Membrane
Authors: Pan Hanqing , Barile Christopher J.
Published: August 2024

The combustion of fossil fuels is a major contributor to rising levels of anthropogenic carbon dioxide (CO2) in the atmosphere. Due to the adverse effects of climate change caused in large part by CO2, new technologies must be developed that contribute to a global renewable energy supply. Electrochemical reduction of CO2 offers a viable pathway to generating value-added products and synthetic fuels to meet our future energy demands while decreasing greenhouse gas emissions. By constructing electrocatalysts capable of modulating proton transfer, we are able to tune product selectivity. Previous studies have demonstrated that two-electron products (CO and HCOOH) can be produced with high selectivity, but multiple-electron transfer products (CH4, CH3OH, and C2+ products) typically are produced at much lower Faradaic efficiencies. In this work, we construct polymer-modified Cu electrodes that exhibit extraordinarily high CH4 production (88% Faradaic efficiency). These electrodes afford a new strategy for increasing the selectivity of CO2 reduction electrocatalysts, an attribute that is key in developing industrially-relevant CO2 conversion devices. Nafion is a widely used fluoropolymer that is often mixed with electrocatalysts to facilitate proton transport. In contrast to these Nafion-catalyst composites, this work studies electrodes covered by Nafion overlayers for the CO2 reduction reaction. By varying the thickness, substrates, and voltage, we perform a detailed study of the effect of Nafion overlayers on metal and carbon mesh electrodes for CO2 reduction. Depending on the thickness of the Nafion membrane, CO2 reduction occurs at either the polymer–electrolyte interface or electrode–polymer interface. A Nafion overlayer of 15 μm on a Cu electrode enables an extraordinarily high yield of CH4 production (88% Faradaic efficiency) at a low overpotential (540 mV) via the stabilization of metal-bound CO intermediates. To the best of our knowledge, this yield is the highest for electrocatalytic CO2 reduction to CH4 production at room temperature reported.
Chemical-Free Stable and Multifunctional Electro-Based System for Treatment of Pesticides from Aqueous Solution
Authors: Gopal Venkateshwaran , Selvaraj Ambika
Published: August 2024

The usage of pesticides has become a common practice in modern agricultural systems to meet the growing demand for food production. However, the uncontrolled use of such chemicals results in the deterioration of natural ecosystems and living beings. Thus, herein, a hybrid treatment system performing the combined functions of electro- and photo Fenton was designed to treat aqueous pesticide solution. The anode was comprised of metal oxide-based electrode (MOx), whereas the cathode was comprised of N-doped carbon electrode (N-C). Both the electrodes consist of light-responsive photocatalysts, which facilitates the removal of pollutants by generating reactive radical species such as OH• and O2
•-. The application of external anodic bias helps to improve the photocatalytic activity by preventing the recombination of electron-hole pairs. In addition, N-C on the cathode helps to catalyze the reduction of O2 to H2O2, which further reacts with Fe2+ in the system to initiate the Fenton reaction. The hybrid reactor was further optimized to study the underlying mechanisms by varying the experimental conditions such as pH, current density, electrolyte concentration, and external H2O2 concentration.

Moreover, scavenging tests were performed using methanol and tertbutyl alcohol to identify the predominant radical species responsible for removing pollutants from the aqueous solution. Also, the reusability test showed that the prepared electrodes were stable for more than three successive cycles, thus offering sustainability. In general, the present study demonstrates the potential of hybrid treatment units for environmental applications and acts as a stepping stone for future endeavors in material synthesis and sustainable treatment solutions.
Electrodeposition of Amorphous and Nanocrystalline Ni-Co Alloys of Controlled Composition from Protic Ionic Liquid and Their Use for the Hydrogen Evolution Reaction
Authors: Vivier Vincent , Xie Yuelin , Turmine Mireille
Published: August 2024

In recent years, a growing interest has been paid in developing new and more efficient electrocatalysts for water splitting [1]. This study focuses on the synthesis of amorphous and nanocrystalline Ni-Co alloys through a one-step electrodeposition technique in pure ethylammonium nitrate (EAN), a protic ionic liquid. The use of ionic liquid prevents from the formation of oxide film during the electrodeposition of the metal [2]. However, only few studies involve protic ionic liquids and the use of EAN, in particular, the electrodeposition of Ni/Co-based materials is still scarce. In this work, the physicochemical properties of EAN with different concentrations of Ni2+ and Co2+ salts were investigated, along with the electrochemical behavior of these metal cations in the protic ionic liquid in an aerated atmosphere. Moreover, the redox reversibility of electrochemical systems involving Ni and Co ions were examined by cyclic voltammetry, revealing the formation of an oxide film or side-reactions in the presence of air during electrodeposition, showing the need to prepare these materials in an oxygen-free environment. The deposits have then been characterized by TEM (Figure 1). Nanocrystalline Ni-Co alloys with different atomic ratios were obtained depending on the deposition potential and ion concentrations. We showed that when a higher cathodic potential is applied (-1.3 V/Ag/Ag+), the amorphous Ni51.9Co48.1 alloy could be electrodeposited, instead of nanocrystalline alloys. The XRD and SEM analyses exhibited different morphologies and atomic structures of the synthesized alloys.

The electrocatalytic properties of the synthesized materials were investigated towards the hydrogen evolution reaction (HER). The results showed that the addition of Co in Ni-based alloys could enhance the HER, and notably, amorphous Ni-Co alloys exhibited lower overpotential, indicating better reaction abilities and faster reaction rates. The deposited Ni-Co alloys on Cu board also demonstrated good stability during the recycle measurement. This study provides a new pathway for preparing nanocrystalline and amorphous Ni-Co alloys with different ratios using protic ionic liquid, which can have practical applications and good performances in electrocatalysis such as water splitting.

[1] M. Zhao, K. Abe, S.-I. Yamaura, Y. Yamamoto, N. Asao, Chem. Mater. 2014(26) 1056-1061.

[2] M. Asnavande, C. Zhao, Chem. Mater. 26 (2014) 1056-1061. ACS Sustain. Chem. Eng. 2017 5 (1) 85-89.

Figure 1
Electrochemical Studies of Gold in Mops Buffer System
Authors: Cheek Graham , Dierickx Abram
Published: August 2024

Recent work in this laboratory has investigated interactions of L-cysteine with metal ions.1 For this purpose the MOPS [(3-N-morpholino)propanesulfonic acid] aqueous buffer system has been employed in order to minimize interactions between the metal ions and buffer anions.2 Gold electrodes are expected to be useful in the investigation of L-cysteine and related substances,3 so it is useful to ascertain the background behavior of gold in the aqueous MOPS buffer system. It is the purpose of the present work to determine the voltammetric features in this situation for use in amino acid/metal ion studies.

As shown in the accompanying figure, an initial positive-going sweep has a very small oxidation process at +0.45 V vs Ag/AgCl, presumably for the initial oxidation of the gold surface in pH 7.4 MOPS buffer. As this sweep continues, a much larger cathodic process corresponding to bulk gold oxidation is observed. On the return negative-going sweep, there is only a reduction process corresponding to the initial surface oxidation process. It is interesting to note that this reduction process is not observed upon reversing the sweep at only +0.50 V. On the second scan, the initial oxidation process has increased, possibly due to surface roughening in the first scan. Another investigation has involved addition of EDTA to the MOPS solution, resulting in an increase of the second (or bulk) gold oxidation process. This increase is apparently due to the ability of the EDTA to complex the gold cations formed in the oxidation process. This overall behavior is somewhat different compared to that found in other buffer systems such as phosphate,3 and contrasts to such behavior are planned for presentation in this talk.

T. Cheek and D. Peña, J. Electrochem. Soc.,
167, 155522 (2020).

M. H. Ferreira, I. S. S. Pinto, E. V. Soares, and H. M. V. M Soares, RSC Advances, 5(39), 30989 (2015).

G.T. Cheek and M.A. Worosz, ECS Trans., 72(27), 1 (2016). doi:10.1149/07227.0001ecst

Figure 1
An Analytical Model for an Anode-Supported Solid Oxide Fuel Cell
Authors: Salehian Shadi , Chuang Po-Ya Abel
Published: August 2024

This study presents a one-dimensional, non-isothermal, steady-state model to analyze performance of an anode-supported solid oxide fuel cell (SOFC). The modeling domain encompasses components including a NiO-YSZ support and functional layer forming the anode, a YSZ electrolyte, a GDC interlayer, as well as LSCF+GDC and LSCF constituting the cathode. The model distinguishes different types of electrode polarization resistances using experimental impedance data at various temperatures under open circuit voltage (OCV), employing a detailed equivalent circuit model to determine the temperature and partial pressure dependencies of electrode exchange current densities. Moreover, this approach serves as an efficient method for estimating the conductivity of both the anode and cathode. As a result, activation energies and ohmic overpotentials are derived, considering microstructural and geometrical aspects, which allows for accurate quantification of the ohmic resistance associated with ionic conduction.

The model incorporates coupled multi-physics elements, such as mass and charge transport, electrochemical reactions, and heat transfer. A notable feature of the model is its consideration of reaction zone layers near the electrolyte, where electrochemical reactions generate electrons, oxide ions, and water vapor. Enhancing prediction accuracy, the model applies multilayer discretization within the electrode and electrolyte to reflect actual material properties and localized conditions more accurately. The model predicts the performance of a single-cell SOFC using pure hydrogen at the anode and varying oxygen concentrations (100%, 50%, 20%, and 10%) at different operating temperatures (700°C, 660°C, 620°C, and 580°C) and design conditions. Simulated results are compared with experimental data, and the impact of various operating and design parameters on SOFC performance is examined. Findings indicate that kinetic and concentration overpotentials in an anode-supported SOFC are lower than ohmic overpotentials, even at higher current densities. Furthermore, ohmic overpotential is identified as the primary contributor to total cell potential loss, highlighting the need for its minimization to improve cell performance.
(Invited) Modeling of the Electric Double Layer (EDL) Structures of Localized High-Concentration Electrolytes (LHCE)
Authors: Qi Yue , Wu Qisheng , Hossain Md Jamil
Published: August 2024

Various electrical double layer (EDL) models have been proposed but mainly for homogenous solutions. Recently, the so-called Localized high-concentration electrolytes (LHCE) have shown many benefits to high-capacity electrodes. Recently, we have proposed micelle-like structures to enable a complete understanding of microstructures in LHCE, which contains a salt, solvent, and non-ion-solvating diluent, analogical to the roles of oil, surfactant, and water as in micelles. [1] As the solid electrolyte interphase (SEI) formation is sensitive to the EDL structure, [2] it is critical to understand the EDL structures for LHCE with heterogeneous structures.

Molecular dynamics simulations were performed in several electrolytes with heterogeneous structures on negatively charged surfaces. It was found the Stern model with an absorbed cation layer adsorption layer and a more diffused layer with cation, anion, solvent, and diluents, should be used to describe the EDL of this type of electrolyte.

For the system consisting of LiFSI salt, DME solvent, and TFEO diluent at a concentration of LiFSI-1.2DME-2TFEO, the heterogeneous micelle-like structures in LHCE are maintained in the EDL, with the Li+-rich salt-solvent clusters and the Li+-poor diluent regions. The diluent region contains Li+ near the negatively charged surface but does not have any ions in the bulk of LHCE. This is because TFEO cannot form a complete solvation shell in the bulk electrolyte due to the steric effect, however, only a partial solvation shell is needed in the Stern layer in the EDL. The appearance of Li+ in the diluent is also necessary for the EDL, as TFEO alone cannot screen the charge.

The chemical and concentration design space for the three components is very large. To obtain a more general picture, we also explored different salt-solvent ratios and different diluent-salt interactions. As the salt solvent ratio increases from low (LCE), to medium (MCE) to high concentration electrolytes (HCE), where all solvents are coordinated with ions, the salt-solvent structures evolve from fully solvated ions or ion pairs in LCE, 3D branched networks in MCE, to fully connected salt aggregates in HCE. The salt-diluent interactions and diluent concentration further modify the micelle-like structures. The EDL for both LHCE and LMCE are heterogenous.

[1] Nature Materials 22, 1531–1539 (2023)

[2] J. Am. Chem. Soc. 145, 4, 2473–2484 (2023)
Tailoring Solid-State Battery Performance through Computationally Tuning the Composition of LLZO-LCO Composite Cathodes
Authors: Garcia Oskar Kenyatta , Wang Bo , Wood Marissa , Heo Tae Wook , Adelstein Nicole
Published: August 2024

The composite cathode consisting of garnet-type solid-electrolyte Li7La3Zr2O12 (LLZO) and active material LiCoO2 (LCO) is one of the most promising solutions for the cathode design of all-solid-state lithium batteries. The transport properties of Li within the LLZO-LCO composite cathode are known to be sensitively dependent on the composition and microstructural features. This study focuses on computationally refining the performance of solid-state batteries by modifying the porosity and volume fractions of the LLZO-LCO composite cathode while considering the variations in the microstructural features. Various 2D and 3D microstructures were synthesized using a stochastic stacking particle model and the corresponding effective diffusivity of Li is calculated using a numerical homogenization method, which allows for a systematic assessment of the impact of composition on lithium transport within the microstructure. By identifying the optimal ratio between LLZO and LCO phases and porosity, this research yields crucial insights for improving the performance of solid-state batteries by tailoring the composite cathode.

Figure 1: A) An example 3-dimensional microstructure with 20.3% percent vacuum (white space) and 39.25% percent LCO (yellow) and 40.45% LLZO (orange). B) The highest effective diffusivity (purple) is found when the LLZO percentage is highest. Once the vacuum percentage is 30% or higher, minimal effective diffusivity (red) is observed.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Figure 1
Quantum-Chemistry Enabled AI for Materials Discovery for Energy Storage
Authors: Assary Rajeev S
Published: August 2024

A priori and reliable simulations can enable timely and cost-efficient design and discovery of materials for energy. Therefore, ‘Let’s Start from Computing’ is an optimal approach to initialize modern day R&D processes. In energy storage, beyond lithium-ion (BLI) research has the potential to revolutionize consumer electronics including portable and stationary power, transportation, and grid energy storage sectors. Multi-valent (Mg, Ca, Zn) energy storage or economically viable monovalent (Na, K) batteries, high-density metal-air, metal-sulfur batteries, or grid-storage systems are considered in the beyond lithium-ion research and development. All these R&D efforts require significant fundamental knowledge via a priori computations for materials discovery, property prediction, and optimization. Atomistic modeling when coupled with reliable Artificial Intelligence (AI) approaches can provide accurate insights to accelerate discovery of optimalelectrolytes, electrodes, and membranes for BLI systems to reduce the cost. Thus, coupled with AI and multi-scale simulations techniques, atomistic modeling can address prediction of molecular level properties of materials (redox potentials, solvation, spectroscopic, and reactivity) to down-select optimal materials or material combinations. In this presentation, I will describe some of our recent efforts in active learning coupled with large scale first principles simulations to down select/optimize desired molecules for flow battery technology. This concept can be utilized for design of experiments using autonomous experimentation. Additionally, I will describe some of our quantum chemistry-informed molecular property predictions redoxmers and liquid organic hydrogen carriers. In addition to molecules, I will present. A data driven approach to study longer time scale diffusion of ions for multivalent battery concepts.

Figure 1
(Invited) Unveiling Fundamental Reaction Mechanisms at the Electrochemical Interface by Ab Initio Simulations
Authors: Deissenbeck Florian , Wippermann Stefan , Todorova Mira , Neugebauer Joerg
Published: August 2024

Direct experimental exploration of atomistic mechanisms governing electrocatalysis or wet corrosion at the solid-liquid interface is notoriously difficult. While fully parameter-free ab initio calculations have the potential to accurately elucidate such mechanisms, they encounter substantial conceptual challenges. Recent methodological breakthroughs, including the advent of efficient computational electrodes and the development of effective thermopotentiostats, overcame many of these limitations thus providing new research opportunities. This presentation outlines the fundamental concepts underlying these innovative methodologies and demonstrates their application in performing fully explicit calculations of structure and chemical reactions at electrified solid-water interfaces. The power of this approach in discovering new mechanisms will be demonstrated for fundamental electrochemical reactions such as metal dissolution and the hydrogen evolution reaction (HER). The identified mechanisms challenge existing understandings and empfasize the active involvement of water molecules in electrochemical reactions, challenging the perception that they are passive bystanders.
Homogenized Modeling of CO2/CO Reduction Catalyst Microenvironments with Intermixed Hydrophobic and Hydrophilic Regions
Authors: Balaji-Wright Arunraj , Disselkoen Kyle , Khanwale Makrand , Kanan Matthew , Mani Ali
Published: August 2024

Electroreduction of CO and CO2 offer a pathway toward renewable-powered synthesis of hydrocarbon chemicals and fuels. Both the composition and the structure of cathodic catalyst microenvironments in gas diffusion electrodes play a dominant role in determining the product composition and efficiency metrics. Porous and hydrophilic copper environments are known to produce multi-carbon species and exhibit large active surface areas, but recent investigations have shown that the inclusion of sporadically-distributed porous hydrophobic regions creates additional pathways for the delivery of gaseous reactants, thereby mitigating transport limitations seen in pure Cu catalysts.

As the design space for catalysts has grown to include a wide variety of material and geometric parameters, accurate PDE-based modeling and simulation of such systems has become necessary to understand and optimize the coupled reaction and transport processes that determine cell performance. High fidelity models, however, pose immense computational challenges. Physical and chemical processes occur over a wide variety of spatiotemporal scales, ranging from pore-scale reaction and transport to device-scale gradients in species concentrations. Additionally, the spatial orientation of these features necessitates modeling in multiple dimensions, and transport occurs simultaneously through two phases located within randomly-intermixed porous regions. As a result of all these factors, numerical simulation of high fidelity models is prohibitively expensive.

In this work, we develop, numerically simulate, and validate a predictive model that efficiently incorporates a wide range of physical and chemical processes occurring in catalyst microenvironments with intermixed hydrophobic and hydrophilic regions. We employ homogenization as a means of model reduction, constructing a medium fidelity model that captures both microenvironment geometric scales and full device scales in 3D. Our model, coupled with the appropriate numerical methods for treatment of stiff and multi-dimensional problems, permits low-cost exploration of the high-dimensional parameter space associated with recently developed catalysts, offering quantitative insight into the optimal design of microenvironments for CO and CO2 electroreduction.

This work is supported by the United States Department of Energy under grant DE-SC0021633.
Probing the Depths of Electrocatalysis Systems: X-Ray Absorption Spectroscopy Reveals Catalyst Behavior
Authors: Liu Ershuai , Drisdell Walter S.
Published: August 2024

X-ray absorption spectroscopy (XAS) is a powerful experimental technique used to study the electronic structure and local environment of atoms in a material. It provides valuable insights into the chemical bonding, oxidation states, and coordination geometry of elements. XAS has been widely applied in various fields of electrochemistry, including popular topics like the hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and CO2 reduction reaction (CO2RR).Despite the growing recognition of the practical importance of XAS techniques, correlating experimental spectroscopy with the working mechanisms and deciphering the structure of the electrochemical interface under reaction conditions remains challenging. In the case of CO2RR, we utilized operando XAS to investigate multiple Cu-based catalysts in different cell configurations. Our findings revealed that altering the reaction environment can induce an alternative pathway for catalyst structural changes. Moreover, operando XAS demonstrated that the reduction of Cu oxide catalysts is not solely governed by applied potentials but is also influenced by mass transport and other parameters. For ORR, in situ XAS not only provides information about the local environment changes of Pt-based catalysts but also unveils surface properties through △μ-X-ray adsorption near-edge spectroscopy (△μ-XANES). This further aids in the discovery of degradation mechanisms in proton exchange membrane fuel cells (PEMFCs). In the case of HER, in situ XAS enables characterization beyond catalysts and extends to the electrochemical interface.

Overall, XAS techniques play a crucial role in understanding the electronic structure and local environment of atoms in electrochemical systems, shedding light on reaction mechanisms and catalyst performance under realistic conditions

Acknowledgement

The authors thank the funding source from Liquid Sunlight Alliance under the U.S. DOE, Office of Science, Office of Basic Energy Sciences, Fuels Award Number DE-SC0021266 and the Laboratory Directed Research and Development Program of the Lawrence Berkeley National Laboratory under the U.S. DOE Contract No. DE-AC02-05CH11231.
Table-Top Ultrafast Soft X-Ray Spectroscopy Toward Synchrotron-like in-Situ Photoelectrochemical Measurements
Authors: Nimlos Danika , Arellano Alejandro , Paradis-Fortin Laura , Lewis Kiara , Drisdell Walter , Cushing Scott K
Published: August 2024

Advancements in in-situ X-ray capabilities have enabled the measurement of electrochemical systems in more realistic operating conditions. While these measurements have progressed our understanding of electrochemical reactions from carrier dynamics to reaction mechanisms to degradation processes, they have mostly been limited to synchrotron facilities. However, performing in-situ table-top measurements has remained a challenge in the field. Table-top XUV spectrometers based on high-harmonic generation (HHG) are powerful tools for measuring ultrafast electronic and structural properties of photoelectrocatalysts ex-situ. However, extending the accessible energy range of HHG-based spectrometers beyond 300 eV is difficult due to inherent physical scaling laws. Laser-produced plasma sources can extend into the soft X-ray range to cover the water window. This capability could enable in-situ studies of photocatalysts, but their inherent source fluctuations have prevented ultrafast studies in the past. In this work, we employ methods pioneered by HHG-based setups to create a novel laser-produced plasma technique for table-top time-resolved measurements in the soft X-ray regime (200 – 1000 eV). We combine EMCCD detection, background-free self-referencing, edge-referencing analysis, amongst other advances, to reduce shot-to-shot noise so that sub-mOD signals are detectable. This presentation will also describe the technical advances pioneered at synchrotron sources that have enabled in-situ X-ray measurements of electrochemical systems. These advancements have inspired the effort to achieve the first table-top soft X-ray measurements in device-relevant liquid environments, enabling the correlation of photocatalyst properties, such as electron and hole energies and polarons, with photoelectrochemical product formation.
(Invited) Developing Lightweight Current Collectors and Separators for High-Energy Batteries via Scalable Manufacturing Methods
Authors: Fang Chengcheng
Published: August 2024

Improving energy density and thermostability is essential to achieve high-performance lithium batteries. Traditional copper (Cu) current collectors (CCs) made of metal foil possess high mass and cost. The unsatisfactory thermal stability of PP or PE-based separators necessitates the development of new separator materials. In this talk, I will demonstrate a fast and scalable chemical coating method for fabricating ultralight composite Cu CC with a thin Cu layer on an ultrathin polymer scaffold. I will also introduce a lignin-based, thin separator with outstanding thermostability via a dry processing method. The scalability of the chemical coating method for current collectors and the dry processing method for lignin-based separators provide promising solutions for the mass production of these important battery components.
Tuned Reactivity at the Lithium Metal – Argyrodite Solid State Electrolyte Interphase
Authors: Mitlin David
Published: August 2024

Thin intermetallic Li2Te–LiTe3 bilayer (0.75 mm) derived from 2D tellurene stabilizes solid electrolyte interphase (SEI) of lithium metal and argyrodite (LPSCl, Li6PS5Cl) solid-state electrolyte (SSE). Tellurene is loaded onto standard battery separator and reacted with lithium through single-pass mechanical rolling, or transferred directly to SSE surface by pressing. State-of-the-art electrochemical performance is achieved, e.g. symmetric cell stable for 300 cycles (1800 hours) at 1 mA cm-2 and 3 mAh cm-2 (25% DOD, 60 mm foil). Cryo-FIB sectioning and Raman mapping demonstrate that Li2Te–LiTe3 bilayer impedes SSE decomposition. The unmodified Li–LPSCl interphase is electrochemically unstable with geometrically heterogeneous reduction decomposition reaction front that extends deep into the SSE. Decomposition drives voiding in Li metal due to its high flux to the reaction front, as well as voiding in the SSE due to the associated volume changes. Analysis of cycled SSEs found no evidence for pristine (unreacted) lithium metal filaments/dendrites, implying failure driven by decomposition phases with sufficient electrical conductivity that span electrolyte thickness. Density Functional Theory (DFT) calculations clarify thermodynamic stability, interfacial adhesion, and electronic transport properties of interphases, while mesoscale modeling examines interrelations between reaction front heterogeneity (SEI heterogeneity), current distribution and localized chemo-mechanical stresses.
Selective Metal Recovery: Innovating Leaching from Lfp-NMC Cathode Mixtures in Lithium-Ion Batteries
Authors: Hubert Pierric , Chagnes Alexandre , Jradi Safi , Clerget Laure
Published: August 2024

Lithium-ion batteries lie at the heart of the energy transition and electric mobility. In the coming years, numerous gigafactories and recycling plants will be constructed worldwide to produce and recycle batteries for electric vehicles. While recycling plants currently focus on batteries for electric vehicle, there will also be a need to develop the recycling industry for smaller batteries, such as those used in electric bicycles, a market that is rapidly expanding. The chemical processes required to recycle these batteries may not necessarily be the same as those for batteries in electric vehicle due to differences in the composition of the materials to be processed. For electric vehicles, the composition will be well established as the materials will mainly come from either NMC (LiNixMnyCozO2) or LFP (LiFePO4) technologies. However, for batteries in electric bicycle and electric scooter, the materials to be processed will be a mix of NMC and LFP technologies. Therefore, it will be necessary to develop a flexible process capable of extracting metals from the feed which the composition will vary. Furthermore, the hydrometallurgical processes used to treat these materials must be capable of recovering cobalt, nickel, manganese, and lithium despite the presence of varying and significant concentrations of iron, which is generally challenging in hydrometallurgy.

This talk will demonstrate how we can take advantage of the physicochemistry of transition metals in the presence of phosphate to develop an effective leaching process that selectively dissolves cobalt, nickel, manganese, and lithium from mixtures of NMC and LFP, resulting in a sufficiently pure leachate to facilitate downstream purification steps through liquid-liquid extraction after leaching.
In-Situ Raman Spectroscopy of Li+ and Na+ Storage in Anodic Nanotubes
Authors: Kowalski Damian , Vincent Mewin
Published: August 2024

Anodizing is a high-voltage electrochemical conversion process that forms barrier-type oxide layers or self-organized nanoporous/nanotubular structures. So far, the Al2O3-like nanopores and TiO2-like nanotubes could be successfully synthesized on many valve metals and alloys.

Recently, it become possible to form nanotubular structures on iron and consequently control the ratio of hematite (Fe2O3) to magnetite (Fe3O4) by subsequent thermal treatment.1 Electrochemically active nanotubes, such as self-organized TiO2 are of high interest in the battery field due to a unique one-dimensional (1D) geometry offering high volume expansion tolerance and applications without binders and conductive additives. Herein, we report an in
-
situ Raman spectroscopy study under current control for a better fundamental understanding of Li+/Na+ storage in nanotubes and correlate the structural fingerprints with the electrochemical data on differential capacity plots of d(Q–Q
0) dE
–1.2 Real-time measurements revealed that the nanotubes had undergone two major phase transformations with increasing lithium content, disclosing the sequential steps of a lithium intercalation type of storage. In contrast, sodium-ion insertion induced no significant crystal structure modification but instead a slight crystallinity rupture, signifying a dominant nondiffusion-limited capacitive type of storage. The insight into the charge storage in a 1D material in relation to other nanostructures such as nanoparticles3 will be discussed.

1. L. Fadillah, D. Kowalski, M. Vincent, C. Zhu, S. Kitano, Y. Aoki and H. Habazaki,
ACS Applied Materials & Interfaces
, 2023, 15, 52563-52570.

2. M. Vincent and D. Kowalski,
ACS Applied Nano Materials
, 2023, 6, 6528-6537.

3. M. Vincent, S. S. Kumar and D. Kowalski,
Electrochimica Acta
, 2023, 469, 143161.

Figure 1
Benefits and Limitations of Encapsulating Platinum Electrocatalysts with Niobium Oxide
Authors: Hadley Annabelle M. K. , Gautam Sakshi , Gates Byron D.
Published: August 2024

The development of energy infrastructure based on renewable sources is vital to reduce our reliance on fossil fuels. Technologies such as hydrogen fuel cells and water electrolyzers are able to bridge the gap between the intermittency issues associated with green energy sources such as wind and solar, and the demand for reliable electricity by being able to convert between electrical and chemical energy. Nanostructured and mesoporous platinum (Pt) prepared by electrodeposition or sputter coating have been shown to have increased performance in hydrogen fuel cells compared to the industry standard of Pt nanoparticles supported on carbon.1,2 Over the lifetime of a fuel cell Pt nanostructures and nanoparticles are, however, known to restructure and lose their surface area by mechanisms such as Ostwald ripening, dissolution, and coalescence. Previously, thin film Pt catalysts have been shown to be stabilized by a nanoscale film of niobium oxide.3 Herein, nanoscale thin films of niobium oxide are investigated as a stabilizing material through use by encapsulating nanostructured Pt catalysts.

Nanostructured Pt catalysts were electrodeposited onto Pt-coated Si wafer substrates. Subsequently, niobium oxide films with thicknesses of 0.5 nm, 3 nm, and 4.5 nm were deposited onto the Pt catalyst using atomic layer deposition. X-ray fluorescence and conductive atomic force microscopy techniques were used to confirm the presence and coverage of the niobium oxide layer on the Pt catalyst. The performance of the encapsulated and un-encapsulated Pt catalysts as oxygen reduction reaction catalysts over the course of up to a thousand degradation cycles were evaluated using electrochemical techniques. The morphology of the catalyst before and after the degradation testing was also assessed using scanning electron microscopy techniques. Electrochemical impedance spectroscopy indicated that increasing the thickness of the niobium oxide layer increased the resistance of the catalyst towards the oxygen reduction reaction. The combined results of the analyses performed by electrochemical techniques and electron microscopy measurements revealed a range of film thicknesses for the niobium oxide that successfully stabilized the electrochemically active surface area and surface morphology of the Pt catalyst.

Paul, M. T. Y.; Gates, B. D. Mesoporous Platinum Prepared by Electrodeposition for Ultralow Loading Proton Exchange Membrane Fuel Cells. Sci Rep
2019, 9, 4161.

Debe, M. K. Tutorial on the Fundamental Characteristics and Practical Properties of Nanostructured Thin Film (NSTF) Catalysts. Electrochem. Soc.
2013, 160, F522.

Eastcott, J.; Gates, B. D. Nanoscale Thin Films of Niobium Oxide on Platinum Surfaces: Creating a Platform for Optimizing Material Composition and Electrochemical Stability. Can. J. Chem.
2017, 96, 260–266.
Programmable Oxygen Reduction Reaction Performance of Atomic Ir-Clusters Anchored Pd Nanoparticles on the Ni-Oxide Support
Authors: Tsai Cheng-Hung , Bhalothia Dinesh , Chen Tsan-Yao , Chen Pochun
Published: August 2024

Fuel cells is severely restricted by the sluggish oxygen reduction reaction (ORR) kinetics at the cathode side, which demands highly active and enduring catalysts for producing adequate rates. Herein, we report a systematic study to investigate the effect of structure configuration on the oxygen reduction reaction (ORR) activity of tri-metallic nanocatalysts (NC)s comprising atomic Ir-clusters (0.5 wt.% of Ir) anchored Pd nanoparticles on the tetrahedral symmetric Ni-oxide support (denoted as NPI). The electrochemical activities of NPI NCs are programmable via a temperature-controlled wet chemical reduction method. For the optimum condition when the Ni-crystal impregnation temperature is 40oC, the Ir-clusters decorated Ni@Pd nanoislands are formed (hereafter denoted as NPI-40), outperforming the commercial J.M.-Pt/C (20 wt.% Pt) catalyst by ~180-folds with an unprecedented high mass activity of ~12,000 mAmgIr
-1 at 0.85 V vs RHE in 0.1 M KOH. More importantly, NPI-40 NC retained 100 % ORR performance with no degradation up to 20k accelerated degradation test cycles, while only a 5 mV loss in half-wave potential (E1/2
) is observed after 30k ADT cycles. The results of physical structure inspections and electrochemical analysis suggest that such an exceptional ORR performance of NPI-40 NC originates from the potential synergetic effect between the high density of occupied Ir-d-orbital and adjacent compressively strained Ni-Pd interface. With this structure configuration, Ir-sites offer optimal adsorption energy for O2 splitting and Ni-Pd interface facilitates the subsequent desorption of hydroxide ions (OH-). We believe that the obtained results will open new approach for the design of Pt-free NCs for fuel cell cathode.

Keywords: Oxygen reduction reaction, Fuel cells, Mass activity, Ir clusters