bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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
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.
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.