bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Highly Active OER Electrodes Derived from Fe-Doped Ni Oxyfluoride Formed by Anodizing of NiFe Electrodeposits
Authors: Habazaki Hiroki , Yamada Naohito , Yato Yuya , Kowalski Damian , Kitano Sho , Aoki Yoshitaka
Published: July 2021

Because of the limited availability of fossil fuels and pertinent global environmental issues, hydrogen production via electrochemical water splitting using renewable resources is an important alternative for future energy economies. For efficient alkaline water electrolysis to produce hydrogen, we need to develop highly active and durable electrocatalysts, particularly for oxygen evolution reaction (OER) because of high overpotential. Anodizing of metals and alloys is a promising means of directly fabricating an OER electrocatalyst on a metallic current collector. Binder-free electrocatalysts are readily formed by anodizing. Since Fe-doped Ni oxyhydroxides and hydroxides are recently reported as highly active OER electrocatalysts in alkaline media. Here, we report anodizing of NiFe electrodeposits in fluoride-containing ethylene glycol electrolyte and the conversion of resultant nanoporous Fe-doped Ni oxyfluoride to highly OER active hydroxide during OER (1).

NiFe alloy films containing 7.2 – 21.1 at% Fe were obtained by electrodeposition on Ni substrate. Then, the alloys were anodized at 10 V in ethylene glycol electrolyte containing ammonium fluoride and water. The anodizing developed a porous layer consisting of crystalline NiF2 phase. XPS analysis revealed the presence of Fe and O as well as Ni and Fe. Thus, porous Fe-doped Ni oxyfluoride was developed by anodizing. The as-anodized NiFe alloys were initially less active for OER in 1.0 mol dm-3 KOH, but during potential cycling to OER potential, the OER activity was gradually enhanced. The enhancement was dependent upon Fe content, and the highest activity was obtained for the Ni-11.8 at% Fe. After activation, the porous layer was converted to amorphous hydroxide, and the fluoride content was highly reduced. Thus, anodically formed Fe-doped oxyfluoride on the NiFe electrodeposits is a suitable precursor of highly active OER electrocatalyst. The galvanostatic durability test exhibited the stable overpotential, disclosing the high durability of this electrocatalyst.

Reference

N. Yamada, S. Kitano, Y. Yato, D. Kowalski, Y. Aoki and H. Habazaki, ACS Applied Energy Materials, in press, doi.org/10.1021/acsaem.0c02362.
(Keynote) Decoupled Electrolysis for Water Splitting and Beyond
Authors: Symes Mark
Published: July 2021

The storage of renewably-generated energy as hydrogen via the electrolysis of water is a fundamental cornerstone of a sustainable hydrogen economy. Conventional electrolysers usually require stable power inputs in order to operate effectively and safely and so may be unsuited to harnessing renewable power, which is often intermittent and diffuse. Decoupled Electrolysis (see, for example: Nature Chem.
2013, 5, 403-409; Science,
2014, 345, 1326-1330; J. Am. Chem. Soc.
2016, 138, 6707–6710; Joule, 2018, 2, 1390-1395; Adv. Energy Mater.
2020, 2002453) has the potential to overcome some of the challenges surrounding electrolysis using low and/or sporadic power inputs (especially those related to gas crossover) as the decoupling of the two half reactions of water splitting allows the oxygen and hydrogen evolution reactions to be performed at different times, in different places and at rates that are not linked to each other. In this talk, we shall investigate these claims for decoupled electrolysis (Electrochim. Acta,
2020, 331, 135255) and also explore the use of decoupling agents in other contexts such as redox flow batteries (Nature Chem.
2018, 10, 1042-1047) and electrosynthesis (Chem. Commun.
2018, 54, 1093-1096).
(Invited) Highly Active Pt-Modified Catalyst for the Selective Electro-Oxidation of Saccharides
Authors: Coutanceau Christophe , Neha Neha , Baranton Stève
Published: July 2021

The increasing demand of energy and high value-added compounds, and the extinction of fossil resource reservoirs result in replacing fossil resources with biomass. Cellulose and hemicellulose represent 40 to 60 wt% of agriculture green wastes and can be considered as raw materials. After transformation of these biopolymers into saccharides, the latter can serve as platform molecules to produce chemicals with high value added and/or industrial interest. In that context carbohydrates need to be studied more deeply for obtaining every possible outcome. Focusing on environmental problems, electro-reforming can provide hydrogen together with a supplementary valuable industrial compound, but this last process must show very high selectivity and low cost to compete with classical biotechnological methods for sugar conversion.

monosaccharides, disaccharides and oligosaccharides are complex molecules bearing several oxygenated functions (primary alcohol, secondary alcohol, anomeric group) that are potentially electrochemically reactive. Therefore, it is needed to develop catalysts displaying very high activity at low potentials and very high selectivity towards a given compound. For this purpose, the synthesis and characterization of Pt-based binary catalysts will be presented and their electrocatalytic behavior towards the oxidation of saccharides (glucose and cellobiose bearing a reductive anomeric function, and methylglucoside and trehalose with a protected anomeric function) will be first studied by linear scan voltammetry in a classical three-electrode cell to evaluate their activity and by in situ infrared spectroscopy to determine reaction intermediates and products as a function of the electrode potential. Best candidates will be used as anode catalysts to perform the electroreforming of saccharides in a two-electrode electrolysis cell with simultaneous production of hydrogen at the cathode. Reaction products will be analyzed by HPLC, MS, and 1H and 13C NMR to determine the selectivity and the efficiency of the system.

From the electrochemical and analytical results, the high efficiency of the Pt9Bi1/C catalysts will be emphasized, the electro-reactivity of the different functions determined, and reaction mechanisms discussed.
(Invited) Benchmarking Oxygen Evolution Reaction Activity and Stability of Unsupported and Supported IrOx Nanoparticles
Authors: Ferreira da Silva Camila , Claudel Fabien , Abbou Sofyane , Chattot Raphaël , Scohy Marion , Martin Vincent , Dubau Laetitia , De Lima Fabio , Maillard Frederic
Published: July 2021

High investments and operational cost of proton-exchange membrane water electrolysers (PEMWE) devices are partly due to that of their constituting materials. In this context, research efforts are dedicated to minimize the content in iridium (Ir) used to electrocatalyze the oxygen evolution reaction (OER) at the anode. One possible materials’ strategy is to support iridium oxide nanoparticles (IrOx NPs) on a corrosion resistant support, such as antimony-doped (ATO), niobium-doped (NTO) or tantalum-doped (TaTO) tin oxide [1,2]. However, the Gibbs-Thompson effect, which controls the electrochemical stability of nanomaterials casts a doubt on the long-term relevance of this approach. To tackle these issues, we built a library of 18 supported and unsupported IrOx catalysts and established their stability number values using inductively-coupled plasma mass spectrometry (ICP-MS) and electrochemistry. Our results provide quantitative evidence that supported IrOx nanocatalysts are more active towards the OER but less stable than unsupported micrometer-sized catalysts. A large part of this instability comes from the metal oxide support which, by degrading, results in IrOx NPs being detached or electrically-disconnected (loss of doping element). In this respect, TaTO supports revealed substantially more stable than ATO supports [2]. Another reason for the drop in OER performance over the long term comes from the fact that IrOx NPs contain mixed valences including Ir atoms in (+III) oxidation state, which are highly active towards the OER but also prone to dissolve [1,3]. Similar to what was observed on extended surfaces, we report that mild thermal annealing (450°C) leads to lower Ir atom dissolution rate. Overall, the best compromise between OER activity and stability was obtained for unsupported porous IrOx microparticles after mild thermal annealing under air at 450°C [4].

Ackowledgements

This work was supported by the French National Research Agency in the frame of the MOISE project (grant number ANR-17-CE05-0033).

References

F. Claudel, L. Dubau, G. Berthomé, L. Solà-Hernandez, C. Beauger, L. Piccolo, F. Maillard, ACS Catal. 9 (2019) 4688-4698.

S. Abbou, R. Chattot, V. Martin, F. Claudel, L. Solà-Hernández, C. Beauger, L. Dubau, F. Maillard, ACS Catal.
10 (2020) 7283-7284.

M. Scohy, S. Abbou, V. Martin, B. Gilles, E. Sibert, L. Dubau, F. Maillard, ACS Catal. 9 (2019) 9859-9869.

C. Daiane de Ferreira, F. Claudel, V. Martin, R. Chattot, S. Abbou, I. Jiménez-Morales, S. Cavaliere, D. Jones, J. Rozière, L. Solà-Hernandez, C. Beauger, M. Faustini, J. Peron, B. Gilles, C. Beauger, L. Piccolo, F. H. Barros de Lima, L. Dubau, F. Maillard, submitted to ACS Catal.
Decoding Network Structure in Lab-on-Chip Cells with Synchronization of Electrochemical Oscillators
Authors: Kiss Istvan Z , Liu Yifan
Published: July 2021

The analysis of network interactions among dynamical units and the impact of the coupling on self-organized structures is a challenging task with implications in many biological and engineered systems. We explore the coupling topology that arises through the potential drops in a flow channel in a lab-on-chip device that accommodates chemical reactions on electrode arrays. The networks are revealed by analysis of the synchronization patterns with the use of an oscillatory chemical reaction (nickel electrodissolution) and are further confirmed by direct decoding using phase model analysis. In dual electrode configuration, a variety coupling schemes, (uni- or bidirectional positive or negative) were identified depending on the relative placement of the reference and counter electrodes (e.g., placed at the same or the opposite ends of the ow channel). With three electrodes, the network consists of a superposition of a localized (upstream) and global (all-to-all) coupling. The synchronization patterns and the network configuration are compared for the linear and the branched channel configurations. The networked, electrode potential (current) spike generating electrochemical reactions hold potential for construction of an in-situ information processing unit to be used in electrochemical devices in sensors and batteries.
(Invited) Peering into Electrochemically Active Polymers with Chemically Sensitive Synchrotron X-Rays
Authors: Su Gregory
Published: July 2021

The performance of electrochemically active materials, for example, ion-conducting polymer membranes, is defined by their unique molecular architecture and resulting hierarchical morphology across length scales that controls functional properties such as transport. Synchrotron X-ray probes have proven invaluable to reveal details into the chemistry and structure of electrochemical systems. Nevertheless, opportunities remain to uncover new structure-property insights with emerging synchrotron tools. Energy-resolved X-ray absorption spectroscopy coupled with resonant X-ray scattering can elucidate morphology with chemical sensitivity in heterogeneous polymer-based systems. These techniques are amenable to in situ and operando studies. Moreover, they are well-suited to probe thin films, enabling detailed interrogation of relevant interfaces, for example, membrane-electrode interfaces, and how interfacial molecular assembly impacts charge transport and overall electrochemical performance. Herein, we present examples of polymer morphology evolution, including perfluorinated ionomers with unique side chain architectures, leveraging the sensitivity of energy-resolved scattering to reveal detailed aspects of membrane phase separation. These studies highlight opportunities in synchrotron-based resonant scattering coupled with spectroscopy and other techniques to achieve new insights into the bulk and interfacial structure of membranes and other complex electrochemical materials.
(Invited) Elucidating Active Structures of 2D Metal Organic Framework Catalysts for Electrochemical Two-Electron Oxygen Reduction
Authors: Ross R. Dominic , Sheng Hongyuan , Jin Song
Published: July 2021

Hydrogen peroxide (H2O2) is a widely produced green oxidant with applications in paper bleaching, chemical synthesis, and disinfection. H2O2 could be electrochemically produced safely, rapidly, and on-demand by using catalysts that are highly selective for a two-electron oxygen reduction reaction (2e- ORR) pathway as opposed to the complete four-electron (4e-) pathway, though development of such catalysts has been hindered by lack of systematic design principles. Recently, well-defined crystalline two-dimensional conductive metal organic frameworks (2D-MOFs) with a square planar metal-nitrogen (M-N4) motif have shown selective 2e- ORR but the origins of the catalytic activity and selectivity remain unclear. Here, we use a combination of theory and experiments to show a 2D-MOF based on metal hexaaminobenzene (M-HAB) as a highly active and selective catalyst for H2O2 electrosynthesis. Furthermore, operando X-ray absorption spectroscopy reveals highly stable metal coordination sites and charging of the organic linkers that occurs during ORR that directly competes with the production of H2O2. These results confirm that the organic linker can act as the dominant active site during ORR in these MOF catalysts and reveal a unique interplay between the material’s catalytic and redox properties that can guide the future design of similar MOFs for enhanced catalytic performance.
New Screen-Printed Carbon Sensor for Trace Analysis of Thallium(I)
Authors: Kozak Jędrzej , Tyszczuk-Rotko Katarzyna
Published: July 2021

Thallium is an element classified as a heavy metal. In chemical compounds it occurs on +1 and +3 oxidation levels. In the context of the toxicity of this element, Tl(I) is most often referred to. The similarity of Tl+ ions to K+ ions is the basis of the mechanism of toxic action of Tl(I) on the human body. The main features of thallium poisoning in humans are gastroenteritis, polyneuropathy and alopecia Thallium in the environment comes from both natural and anthropogenic sources. Due to the high toxicity of thallium and its easy absorption by the human and animal organisms, it is extremely important to monitor the amount of this element, including in water.

The purpose of this work is to present a new method for determination of thallium in water samples using a screen-printed sensor with carbon working electrode modified with multiwalled carbon nanotubes and in-situ plated bismuth film. The measurements were carried out using square wave anodic stripping voltammetry (SWASV) method. Simultaneous deposition of bismuth and thallium took place at a potential of -0.9 V for 180 s. Under optimized conditions a linear calibration curve was obtained in the range of Tl(I) concentrations from 1·10-8 to 1·10-6 mol L-1. The procedure allows to achieve the limits of detection and quantification of Tl(I), 2.8 × 10-9 and 9.3 × 10-9 mol L-1 respectively. The method was applied for determination of Tl(I) in spiked water samples from Vistula river.

[1] Kozak, J., Tyszczuk-Rotko, K., Rotko, M. Physicochemical Problems of Mineral Processing
2019
, 55(6), 1422-1428.
Investigations on the Mechanism of Oxygen Reduction in Ca(ClO4)2/DMSO-Electrolytes
Authors: Hegemann Martina , Hegemann Martina
Published: July 2021

Within the context of our mechanistic research on processes in the Ca/ air battery, we studied in detail oxygen reduction using RRDE and DEMS. From an earlier DEMS study we know that on the Au electrode first a two electron transfer takes place and after that a one electron transfer. On Pt and GC electrode only the one electron process is taking place. [1] In Addition XPS – measurements show that a thin film was formed on the Au electrode. It was described, that the top layer of the film contains decomposition products but after Ar+ etching Ca(O2)2, CaO2 and CaO was found on the surface. [2] Here, we performed further measurements in this electrolyte system to clarify the mechanism which is taking place at the Au electrode. With the RRDE the ring potential was varied, the oxygen content in the electrolyte was varied and potential jump experiments were performed. To elucidate how many electrons are flowing not only during ORR, but also during product reoxidation, the DEMS measurement was repeated in our 6-electrode-thin-layer-flow-through-cell (flow rate of 5 µL/s) [3] to confirm the supposed reaction model. At Au-electrodes in Ca2+ containing DMSO we established the following reaction pathway: at low overpotentials oxygen is reduced to soluble peroxide, which can be reoxidized with two electrons; then, at higher overpotentials, a transition to a 1 electron transfer occurs with the formation of a thin (adsorbed) Ca(O2)2 layer a on the electrode. In Addition we used mixtures of TBA+ / Ca2+ and Li+/Ca2+ cations in DMSO to investigate the influence of the Ca2+ cation on the reduction of oxygen.

Acknowledgement:

The authors gratefully acknowledge the Federal Ministry of Education and Research (BMBF) for funding this work. This work is part of the MeLuBatt-project in the framework of the “Frischer Wind für Metall-Luftsauerstoff-Batterien”-initiative (03XP0110D).

[1] P. Reinsberg, C. J. Bondue, H. Baltruschat, J. Phys. Chem. C
2016, 120, 22179-22185.

[2] P. P. Bawol, P. H. Reinsberg, A. Koellisch-Mirbach, C. J. Bondue, H. Baltruschat, ChemRxiv (Preprint)
2020.

[3] C. J. Bondue, P. Königshoven, H. Baltruschat, Electrochim. Acta
2016, 214, 241–252.
(General Student Poster Session Winner - 3rd Place) Designing and Implementing a Tailored Alternative Data Analysis Algorithm (TADAA) to Evaluate Quasireversible Heterogeneous Electron Transfer Measurements By Square Wave Voltammetry
Authors: Haas Christian D , Coduto Joshua Richard , Leddy Johna
Published: July 2021

Square wave voltammetry (SWV) is used to investigate fast electron transfer kinetics across a wide range of redox active species. SWV is an inherently faster, frequency dependent method as compared to most potential sweep methods. Sweep methods commonly implement an applied potential as a staircase of small potential steps. The frequencies of SWV can be related to sweep methods as the product of SWV frequency and the potential increment at each staircase step.

Recent work in our group has shown that k0 measurements for tris-bipyridine transition metal complexes can be made using SWV as the wave morphology changes with k0. Heterogeneous electron transfer rates are not reliably measured at the slower voltage perturbations (scan rates) available with cyclic voltammetry (CV). The heterogeneous electron transfer rates k0 for M(bpy)3
z+ complexes, where M = Ru2+, Os2+, Cr3+, Co2+, Co3+, and Fe2+ are sufficiently rapid that k0 is not reliably measured by CV for most of these complexes. Analysis of the SWV data is possible but not as facile as analysis of CV data. To better evaluate k0 measurements, an alternative data analysis algorithm for quasireversible heterogeneous electron transfer is developed based on classical finite difference simulations. The algorithm can be envisioned as converting voltammograms between CV and SWV. Because CV and SWV both contain a potential parameter and a time parameter (mV/s in CV; frequency and step height in SWV), the algorithm uses a “universal scan rate” to convert between all of the other potential and time-dependent parameters. The purpose of the algorithm is to simplify quantitative SWV data analysis and present information in context of the more commonly used CV.
Wearable Chemical Sensor Badge
Authors: Chapman Kimberly , Cozy Alison , Jung Elijah , Locke Ed
Published: July 2021

Objectives

Under this program, a wearable chemical detection badge capable of detecting and alarming (visual + audible/vibratory) in the presence of relevant concentrations of toxic industrial chemicals (TICs) in air has been developed and demonstrated for ammonia, chlorine, hydrogen sulfide, and nitrogen dioxide. The badge will alarm via one of the user-chosen alarm modes in the presence of ½ Immediately Dangerous to Life or Health (1/2 IDLH) concentrations of these TICs in under 5 minutes. The technology operates in harsh environmental conditions (10-90% RH, -10 – 50 oC) and in the presence of interferents (e.g. smoke, fuels, bleach and diesel exhaust). The active sampling badge consists of a reusable detection device that is used in conjunction with a disposable colorimetric sensor coupon. The sensor badge is unobtrusive and can be worn in the breathing zone of the user with hands-free operation for up to 8 hours on battery power.

Results

Small prototype devices (2” x 2” x 0.5”) were manufactured based on feedback from expert first responder personnel. Key points from this feedback include:

Must have a low false alarm rate; no nuisance level alarms (e.g. PEL)

Alarm must be very visible/noticeable

Must be small and unobtrusive

Data logging would be beneficial for analysis at a later time

Prototype devices and associated sensor coupons were tested in the presence of PEL, ½ IDLH, and multiple IDLH concentrations of the target TIC analytes (ammonia, chlorine, hydrogen sulfide, and nitrogen dioxide) under harsh environmental conditions:

-10 oC, ~ 90%RH

23 oC, 10% RH/50% RH/90% RH

50 oC, 10% RH/50% RH/90% RH

and in the presence of environmental interferents including smoke (burning wood), diesel exhaust, diesel fuel and bleach. Utilizing four interrogation bands of the visible spectrum and combinatorial colorimetric response alarm criteria, the prototype badges performed well with no false positive or false negative alarms due to environmental interferent exposure, nuisance level (PEL) exposure, or harsh environmental conditions.

Conclusion/Significance

First Responders under duress need a simple, low-cost, rugged device capable of detecting the presence of harmful levels of Toxic Industrial Chemicals (TICs) with high fidelity while avoiding nuisance level alarms (e.g. OSHA PEL) and false alarms due to environmental contaminants (e.g. smoke, fuels, diesel exhaust). This prototype sensor technology fills an unmet need for the first responder and is adaptable for the incorporation of new sensors in the future.

Figure 1
How to Do Business with DHS S&T
Authors: Ervin Angela
Published: July 2021

Established by Congress in 2003 as the research and development (R&D) arm of the Department of Homeland Security (DHS), the Science and Technology Directorate (S&T) focuses on providing technology solutions and knowledge products to mitigate the adverse consequences resulting from the release of chemical, biological, and agricultural threats.

DHS S&T research areas include chemical and biological defense, borders and maritime security and port of entry screening, critical infrastructure and resilience, cybersecurity, explosives detection and aviation screening, first responders, unmanned aerial systems, and tests, evaluations, standards, and systems engineering. In addition, S&T partners with academic, national laboratory, and other research organizations to address specific homeland security topics and threats and funds DHS S&T Technology Centers with subject matter experts in sensors and platforms, modeling and simulation, data analytics, hazard awareness and characterization, biometrics and identity, social sciences, and interoperability and compatibility.

Innovation is the driving force behind S&T’s work. Because potential solutions may exist outside the homeland security arena, S&T casts a wide, inclusive net to find and use the best technology available. During her presentation, Dr. Angela M. Ervin will outline the current work of DHS S&T and explain the process for requirements gathering for initiation of projects and programs. She will also discuss opportunities available for academia and industry to work with S&T as well as mechanisms to apply for funding.
Electrical and Label-Free Detection of T-Cell Activation Against COVID-19: A Method Towards Point-of-Care Monitoring of Immune System
Authors: Nami Mohsen , Han Patrick , Hanlon Douglas , Yosinski Shari , Edelson Richard , Reed Mark
Published: July 2021

Despite great progress in biotechnology, COVID19 has revealed the inadequacy of current healthcare technologies to contain an infectious outbreak, specifically in rapid infection recognition to facilitate containment. Wide deployment of testing methods such as viral RNA (antigen) PCR and antibody detection have provided some relief in this regard; however, current technologies still require many hours to provide results. Thus, there remains a critical need for fast, sensitive, low-cost point-of-care (POC) biosensing assays to report on the infection status and immunity of patients. Emerging data on the importance of T-cell responses in generating long-term immunity against COVID19 has highlighted T-cell activation detection as a potential way for real-time monitoring native and acquired immunity. However, current approaches for T-cell stimulation monitoring are complex, laborious, time-consuming, and costly.

Here we provide proof-of-principle experiments which indicate that an electrical and label-free detection method based on CMOS-compatible silicon nanowire ion-selective field-effect transistors (SNW-ISFET) can act as a fast, sensitive, reliable, and low-cost approach to monitor T-cell response to pathogens such COVID-19. This technology enables direct detection of COVID-19-specific T-cells directly from patient blood, with potential utility as a POC diagnostic device. Detection of antigen-specific T-cell activation from clonal human T-cells lines utilizing CD8-restricted peptide-MHC complexes has been demonstrated using SNW-ISFET devices. The cell concentration was varied to achieve a clear understanding about the device sensitivity, detection limit, and reliability (Figure 1). SNW-ISFET structures were applied to detect T-cell activation in clonal T-cell lines and whole peripheral blood mononuclear cell (PBMC) with multiple cell concentrations (Figure 2). Reference experiments were applied to ensure the device reliability and sensing mechanism (Figure 3). These findings show that SNW-FETs platform are promising candidates for antigen-specific T-cell activation detection from whole blood.

Figure 1
Quantitative Failure Analysis for Battery Safety
Authors: Liaw Boryann (Bor Yann) , Zhang Yulun , Lin Yuxiao
Published: July 2021

Rechargeable Li batteries need better safety mitigations to ensure consumer acceptance. Conventional safety mitigation was constituted in the cell design and evaluated by abuse tests as part of the product acceptance. However, safety tests cannot warrant a consistency in meeting the codes and standards on safety regulations over a wide range of applications solely by testing. The process is costly and unreliable to some extent. To alleviate such concerns, a better evaluation technique by failure analysis should be considered. Here, we explain how to conduct a quantitative failure analysis using electrochemical analytic diagnosis. This method can separate the thermodynamic and kinetic attributes to failure of the batteries in a quantitative manner, which is verifiable with theoretical consideration and mechanistic understanding. We believe this approach could provide a much-improved capability to mitigate battery safety issues with diagnostic and prognostic that can provide identifiable and quantifiable information of the battery system.
Cross-Talk in Si Full-Cell with Various Cathodes
Authors: Kim Minkyu , Yang Zhenzhen , Bloom Ira
Published: July 2021

Crosstalk between cathode and anode in Li-ion batteries (LIBs) has been increasingly recognized in recent years as having a great impact on performance, safety and cycle life time. However, systemic understanding of crosstalk behavior in Si full cell with various cathode materials has not been studied. In this project, we investigated crosstalk behavior of a Si anode coupled with one of the following cathodes, LiCoO2 (LCO), LiNi0.5Mn0.3Co0.2 (NMC532), or LiFePO4 (LFP), in a full cell. For each system, we compared electrolyte decomposition products, solid electrolyte interface (SEI) chemistry, and degradation mechanisms of cells during cycling. From a very early stage of cycling, each system showed different crosstalk behavior, showing different electrolyte decomposition products and SEI chemistry on Si anodes. Especially, the SEI of the aged Si showed that decomposition of LiPF6 was more severe in the LCO/Si or the NMC532/Si cells than those containing LFP/Si. This can lead to an unstable SEI on Si anode, which can result in rapid degradation, such as significant Si pulverization and Li loss, in LCO/Si or NMC/Si system.

Acknowledgment

We gratefully acknowledge support from Brian Cunningham at the U. S. Department of Energy (DOE), Vehicle Technologies Office. The submitted manuscript has been created at Argonne National Laboratory. Argonne National Laboratory is operated for the DOE Office of Science by UChicago Argonne, LLC, under contract number DE-AC02-06CH11357.
Pulse Voltammetry Analysis of Li-Ion Battery Degradation
Authors: Kabra Venkatesh , Fear Conner , Northrop Paul , Cole James , Mukherjee Partha P.
Published: July 2021

Pulse voltammetry is a class of electroanalytical techniques which involve applying voltage pulses to understand the redox reaction in an electrochemical system. The advantages of such a technique is high sensitivity of pulse voltammograms towards kinetic and thermodynamic parameters. Here, a physics-based model is developed to simulate the Li-ion battery physics and the resultant pulse voltammogram for generic voltage pulses. We develop an in-situ diagnostic tool by combining it with a parameter estimation technique to accurately, rapidly and quantitatively capture the key parameters. A combined experimental and computational-modelling approach allows us to parametrize the state of Li-ion battery system. Degradation reactions such as solid electrolyte interphase growth, active material slippage, and loss have been considered to capture the pertinent degradation modes responsible for capacity fade under different experimental conditions. This method can be extended to integrate with battery management systems for state of health estimation and monitoring.

The objective of this effort is to quantitatively characterize battery properties in order to develop accurate physics-based models suitable for model-based development of fast charging protocols and accurate state-of-charge and state-of-health prediction. Pulse voltammetry analysis software and battery electrode characterization approaches provide the ability to determine quantitative values, with known confidence intervals, for input parameters of physics-based models describing battery performance. Pulse voltammetry characterization, in conjunction with physical analysis and complementary techniques such as galvanostatic intermittent titration (GITT) and electrochemical impedance spectroscopy (EIS) will be utilized to analyze the battery state. These quantitative methods enable the development and parameterization of predictive models for both battery performance and undesired processes, such as lithium plating, that limit charging rates and cycle life of lithium-ion batteries.

This presentation will focus on DPV data gathered periodically during cell cycling to identify the progression of capacity loss and degradation. The DPV analysis approach, which utilizes the experimental data to estimate kinetic and thermodynamic parameters of the model for battery performance, will be presented. The experimental characterization results will include example DPV measurements as a function of state-of-charge, cycling history, and operational temperature. Examples of data analysis to estimate model parameters with statistical confidence measures, and interpretation of the change in voltammogram response with cycling will be discussed.

Figure 1. Fitting model results with experimental differential pulse voltammetry data for parameterization

Figure 1
Simulation and Validation Testing of the Effect of Novel Electrolyte Design on Thermal Propagation of Lithium-Ion Batteries
Authors: Torres Gabriel , Raghunathan Aditya , Vaidya Rutvik , Moganty Surya
Published: July 2021

Lithium-ion batteries are an increasingly prevalent source of power in grid storage applications and electric powertrains, given its high energy density and extended cycle life. However, lithium-ion batteries carry significant safety risks and are a growing hazard due to possible fires that can be caused by overheating, physical cues (i.e., crushing or penetration of cell), overcharging and short-circuits. These risks are greatly increased when focus shifts from a single cell to either modules or packs, where an individual cell entering thermal runaway propagates to adjacent cells. In spite of multiple protections battery packs have in recent times been known to fail.

It is well understood that thermal runaway occurs when the self-heating rate in the cell exceeds the heat dissipation out of the cell. This self-heating is the product of undesired side-reactions in the cell which are onset by abuse conditions such as excess heat, internal short circuits, etc. The key to inhibiting thermal runaway is to modify the cell such that the self-heating rate under abuse conditions is significantly reduced. Reducing the self-heating rate is important when considering battery packs that consist of many cells as is the case in electric vehicles, so that if one cell fails in a pack the thermal runaway does not propagate to adjacent cells. Our approach therefore is to modify the electrolyte system to reduce the overall cell self-heating rate. This is a tunable, drop-in solution to addressing the need for improving battery safety.

The incorporation of NOHMs novel safe electrolyte formulation is shown to impact the abuse tolerance of cells on both the material level, i.e. the electrolyte-electrode interaction and on the cell level. The presented electrolyte systems demonstrate reduced overall energy and peak heat flow in the exotherm profiles of NMC cathode materials as well as lithiated graphite via differential scanning calorimetry (DSC). With this approach, we demonstrate significantly lower self-heating rates in an 18650 lithium-ion cell via an accelerating rate calorimeter (ARC).

Using the self-heating rate data produced via ARC testing we developed a thermal runaway model to simulate thermal propagation in battery packs consisting of seven 18650 lithium-ion cells arranged in a honeycomb configuration. The self-heating rate is translated into thermal power generation for individual cells surrounding a ‘trigger cell’, a cell that has entered thermal runaway. The model suggests that changes in the electrolyte system as measured by ARC mitigates cell-to-cell thermal propagation in event of an individual cell thermal runaway (Figure 1). This simulation is then validated with a real pack by inducing thermal runaway in the center cell with a nail penetration test. NOHMs novel safe electrolyte development carries significance in not only safer individual cells but also in safer overall battery packs.

Figure 1
Detection of First Venting in Battery Failures with Carbon Dioxide Sensors
Authors: Cai Ting , Tran Vivian , Engle Brian , Stefanopoulou Anna , Siegel Jason
Published: July 2021

Li-ion battery thermal runaway is a critical safety issue for large-scale battery packs. Upon battery failure, gas venting can occur when the cell's internal pressure exceeds a critical value and causes cell rupture and electrolyte leakage. The gas venting is usually categorized into first venting events and thermal runaway gas venting events (second venting). The first venting occurs around 120 °C and can be considered as a precursor to thermal runaway. The subsequent venting during thermal runaway is more aggressive and releases more vent-gas.

Detecting battery failures immediately after the first venting is critical to take action before the failure evolves into a thermal runaway event. Therefore, a gas detection method targeting first venting gas will be the focus. Early studies of first venting gas composition showed that CO2 is the primary gas component in battery overheating tests, nail penetration tests, and overcharging tests, while the gas composition in battery external short circuit tests was not revealed.

To this end, an external short circuit test for a pouch 4.6 Ah cell was performed in a non-sealed acrylic box, which has around 21.5 L volume. Shortly after the initiation of external short circuit, the battery expansion force rises due to gas generation inside the pouch cell. The force then dropped suddenly indicating a gas venting event, which occurred when the cell temperature reached 114 °C. A Non-Dispersive Infrared (NDIR) CO2 sensor was used. The CO2 sensor reading started to increase within 5 seconds of gas venting and reached a maximum of 1,500 ppm as shown in the figure.

To apply the gas detection strategies for first venting events, a detection threshold is required for different cells at different abuse conditions. To model the gas evolution process, the evolution of side reactions, mainly the SEI decomposition at high temperatures was considered. The released CO2 in first venting events can be estimated at different abuse conditions. The estimated CO2 amount can help determine the detection threshold of gas concentration for a given battery system.

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The Effect of Internal Pressure on Thermal Runaway Temperature
Authors: Lian Torleif , Troøyen Susanne Hansen , Forseth Sissel
Published: July 2021

Lithium-ion batteries have developed into one of the most popular secondary batteries on the market today due to high voltage, long lifetime and high energy density. However, lithium ion batteries may have safety issues, and several fires are reported. Thermal stability is one of many parameters used to evaluate the safety aspects of lithium ion batteries. Understanding thermal stability at material level is essential for the further development into safer lithium ion batteries.

Calorimetric methods are widely used in thermal stability tests for lithium-ion battery components. Accelerating rate calorimetry (ARC) is one of the most popular methods used to analyse full cells and differential scanning calorimetry (DSC) is the most common method for testing thermal stability of materials. DSC is however less sensitive than ARC, and uses smaller sample sizes in a fixed volume. This makes comparison between material samples and full cells difficult. Currently, there are no standard procedures for ARC tests on battery materials, and this work is an effort to standardize ARC lithium-ion material measurements.

The thermal stability of LiNi0.40Mn0.37Co0.23O2 fully charged cathode material from a commercial 8 Ah pouch cell with 1 M LiPF6 in EC/DMC (1:1) was studied by ARC. Four different calorimetry test setups were tested in order to understand the influences of the setup on the result. Regardless of the setup, the cathode/electrolyte mixture was found to have two stages of self-heating, where the rate of the first stage influenced the temperature at which thermal runaway (heating rate > 10°C min-1) occurred during the second stage. During the initial stage of self-heating (175–240°C), the setup was not found to impact the results. At temperatures above 240°C, the reactivity was found to be highly dependent on pressure. Samples at low pressure (near 1 bar) did not reach thermal runaway, whereas the samples in the higher-pressure setups all reached thermal runaway at 250–260°C. Figure 1 shows the ARC measurements of two NMC cathode materials mixed with electrolyte at approximately 1.2 bar and 3.9 bar at 315 °C.

It was concluded that the test setup is very important for the outcome of thermal stability measurements on fully charged LiNi0.40Mn0.37Co0.23O2 cathode material, and the reactivity of this cathode material is dependent on pressure. This is an important finding because most lithium-ion cells will have ventilated at temperatures above 150–200 °C and experience reduced internal pressure. DSC and ARC material measurements in closed containers with high pressure would not be representative for measuring lithium-ion cathode material reactivity.

Figure 1: Heat rates and pressure for two samples of LiNi0.40Mn0.37Co0.23O2 with 1 M LiPF6 in EC/DMC (1:1) in two different setups.

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Diagnosis of Remaining Useful Lifetime of Lithium-Ion Batteries for Prognosis Algorithms
Authors: Park Jaehyo , Seo Sang Won , Park Jong Woo , Jang Kwang Yeop , Jang Kyung Hoon , Kwon Wan Sung , Kim Dong Jin
Published: July 2021

Nowadays, lithium-ion batteries are the most promising candidate as the power source for electric vehicles and energy storage system. Unfortunately, the performance of lithium-ion batteries tends to degrade and their capacity declines after a number of charging and discharging process. Most of the lithium-ion batteries are considered to replaced or discard when the capacity or voltage drops 20% of its initial state. In order to predict the state, prognosis algorithms are necessary to screen out highly degraded batteries. In this paper, life prediction system equipped with prognosis algorithm is proposed for estimating the battery health and predicting it remaining useful life based on the non-linear slope of charge-voltage curve. In particular, the prediction of state-of-charge(SOC) is modeled by Backpropagation Neural Network algorithm, which is conducted by 6 coefficients and the prediction of state-of-health (SOH) is modeled by particle-filter algorithm in form of a probability distribution, which is carried out by Arrhenius electrochemical modeling. 10 sets of lithium-ion batteries were initially prepared with 18650 cells and degraded by repeating the 100 times of charging and discharging process in order to compare the experimental data with the modeled data. Both SOC and SOH error rate tend to decline when the gather input experimental data is increased. The average SOC and SOH error rate of 10 samples at 100th cycle with 4 input cycle data was 6.75% and 3.30% respectively, which correspond to the algorithm efficiency above 95%. For conclusion, the particle filtering method for predicting the residual life (SOL) is not only more accurate than the prediction by simple curve fitting, but also is very effective because it reflects the lack of data and uncertainty due to measurement in the confidence interval. In addition, the remaining useful life prediction of SOC and SOH by particle filtering and backpropagation neural network algorithm is a method of continuously updating the deterioration model coefficient in real time based on the measured data of the battery and modeling data.

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Designs to Prevent Thermal Runaway Propagation in Lithium-Ion Cell Shipping Packages
Authors: Jeevarajan Judith , Joshi Tapesh , Juarez Robles Daniel , Kathirvel Kanarindhana
Published: July 2021

Thermal runaway propagation in lithium-ion cells and batteries has been an area of intense study in the past few years based on the fires experienced with these cells and batteries during transportation as well as in field use. The UL team has worked on designs that will prevent the propagation of thermal runaway. Materials of different types and different designs of shipping packages have been studied to determine their effectiveness in preventing the propagation of thermal runaway. A single cell in a shipment package is triggered to go into thermal runaway and a baseline test with no mitigation designs will be compared to various materials and designs used to mitigate the propagation. The results of our test program will be presented.
Li-Ion Battery Deactivation through External Short Circuit
Authors: Tran Vivian , Cai Ting , Stefanopoulou Anna , Siegel Jason
Published: July 2021

While electric vehicle battery packs are designed to address safety issues, battery failures can still occur. Most prominently, electric vehicle fires can occur after accidents or from internal shorts due to defects, abuse, or accelerated aging. Battery fires can be difficult to manage due to the active lithium materials and the presence of both the fuel and oxidant produced by thermal decomposition. Typically, after extinguishing the original fire, the main priority is to cool the battery pack by applying a large and continuous volume of water directly to the pack. However, the fire may still reignite hours later, fueled by the remaining stored energy. This highlights the need for further investigation and discussion about how to effectively remove the stored energy from, or deactivate, batteries with the goal to prevent fire re-ignition in battery packs.

Batteries at a lower state-of-charge (SOC) are more thermally stable and have a lower energy release during thermal runaway than those at high SOCs. In addition, experimental results from single cells and small, multiple-cell configurations undergoing external short circuits show that thermal runaway (TR) events are rare, and the cell peak temperatures depend on the relative size of the external resistance to the internal cell resistance. To this end, this research aims to evaluate the use of high C-rate discharge and external short circuits to safely deactivate batteries while avoiding TR.

External short circuit testing was performed on 4.6Ah pouch cells at 15% and 100% SOC, with measurements of cell current, voltage, temperature, expansion force, and atmospheric CO2 gas concentration. At the end of the test, the cell initially at 15% SOC discharged to -10% SOC and reached a maximum temperature of 64℃. The cell had no visible damage afterwards. For the 100% SOC cell, it reached a maximum temperature of 120℃ and discharged to around 25% SOC at the end. In both cases, neither went into thermal runaway, but the first cell was able to discharge to less than 0% SOC in 5 minutes, while the 100%SOC cell took significantly longer to reach the low current cutoff. This is because during the gas venting process, electrolyte is lost, greatly increasing the internal resistance and increasing the discharge time. In addition, the lower peak temperature of the first cell indicates a reduced likelihood of thermal runaway propagation in a pack, and the lack of toxic and flammable vent gas and electrolyte leakage in the environment improves safety. In order to apply this at a larger level, we will investigate the appropriate external resistance to safely deactivate the cells without leading to hazardous conditions.

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