bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Sensors and Techniques for Redox Potential and Tritium Transport in a Neutron-Irradiated Molten Flibe Salt Loop
Authors: Vergari Lorenzo , Borrello Michael , Scarlat Raluca O. 
Published: November 2022

A consortium of the Massachusetts Institute of Technology, North Carolina State University, the University of California at Berkeley (UCB) and Oak Ridge National Laboratory have initiated a project to build a neutron-irradiated molten-salt forced-circulation loop at the MIT reactor. The loop will use FLiBe (Li2BeF4) salt and will duplicate thermal-hydraulics, chemical, and neutronics conditions in a salt reactor.
The SALT Lab at UCB is responsible for the design and application of electrochemical sensors and techniques for redox measurement and tritium transport within the loop. The proposed experiments will investigate redox measurements and control in the loop, tritium retention and diffusion in graphite, and tritium transport in the salt. Redox measurements and control studies will be performed to quantify the corrosive effect of neutron activation reactions and the effect of redox control agents in the loop. Tritium studies are being developed to quantify tritium uptake capacity in graphite, identify tritium desorption mechanisms, and measure tritium solubility, diffusivity, and speciation in the melt. To support these experiments, a variety of electrochemical probes are under development at UCB, including different size, shape, and material of the electrodes.
This talk will present the electrochemical probes under development and discuss the experiments that will be tested off-loop in the Be-gloveboxes of the SALT lab and then implemented in the loop.
Improvement of Corrosion Resistance of Stainless Steel Used in Nuclear Power Plant Cooling Water Components By Plasma Electrolysis
Authors: Heo Jun , Cho Sung Oh 
Published: November 2022

In this study, Plasma Electrolytic Oxidation (PEO) technology was adapted to stainless steel for improving its corrosion resistance. Stainless steel is widely used in various fields due to its remarkable properties including high corrosion resistance, excellent weldability, good performance at all temperatures, etc. Although, in the case of nuclear power plants secondary cooling water components, which mainly utilize stainless steel, aggressive environments are situated created. Plenty of corrosive and abrasive species from the coolants attack the component materials to initiate a wide range of corrosion problems such as general corrosion, pitting corrosion, crevice corrosion, and Stress Corrosion Cracking (SCC), etc. In order to protect the substrate from those corrosive environments, a pre-oxidized layer was deposited through an electrochemical process. The technology used in this study, namely PEO, is an advanced surface engineering method that can produce a protective film having an excellent hardness, heat resistance, and adhesiveness with a compact layer. PEO, which is a developed version of the anodization method, utilizes relatively high voltage with a pulse to enhance the properties of the ceramic layer on the surface by heating and quenching repetitive processes. PEO on stainless steel was conducted by cathodic process and plasma discharges were generated through vapor gas envelope insulating film. After the experiment, a variety of characterizations were conducted. Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were firstly utilized to check the surface morphologies and compositions. Then using hot mounting and polishing, the cross-section of the sample was examined to check the oxide layer thickness and chemical composition by depth. By using an X-ray Diffractometer (XRD), the exact crystalline structure of the fabricated film was characterized. The following characterizations were mainly focused on electrochemical corrosion resistance tests. A typical three-electrode cell system was used to conduct the Potentiodynamic Polarization (PDP) technique for evaluating the improvement of general corrosion resistance. With corrosion potential and corrosion current density parameters from the PDP technique, pitting potential was also evaluated to check the pitting corrosion resistance. Lastly, Electrochemical Impedance Spectroscopy (EIS) method was conducted to figure out the corrosion resistance mechanism of the fabricated protective film and support the numerical data from the perspective of corrosion resistance improvement.
PEO is a simple, fast, and relatively safe surface engineering method that can be applicated to various metal substrates. It is expected to improve diverse properties of the metal materials including corrosion resistance. It can be said that this technology can open a new era in material engineering in a wide range of industrial fields.
(Invited) Beyond Single Cell Characterization: Impacts of Module Configuration on Lithium-Ion Battery Performance and Degradation
Authors: Preger Yuliya , Mueller Jacob , Baker Gary , Fresquez Armando 
Published: November 2022

Batteries are commonly connected in series and parallel to form modules that meet the power and energy requirements of specific applications. However, conclusions about battery performance and degradation under different conditions are often based on single cell cycling results. In this study, we evaluate the performance of lithium-ion eight-cell modules in six different series-parallel configurations over the course of hundreds of cycles. Each cell was individually instrumented for voltage, current, and temperature monitoring. Current data were collected using closed-loop Hall effect sensors to provide accurate measurements of parallel branch currents without the influence of in-circuit shunt sensing elements. This cell-level data collection enabled calculation of the underutilization of individual cells and assessment of differences in energy lost to cell balancing for different configurations. We also evaluated current redistribution in parallel cells, which in some cases yielded transients with peak magnitudes more than twice the average expected cell current value. The capacity and energy fade of the full modules was compared to that of individual cells cycled under the same conditions. This module cycling study, one of the broadest reported to date, allows us to systematically evaluate the performance trade-offs and safety implications of different module configurations.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2022-5209 A
(Invited) Multifunctional Lithium Ion Battery Separators through Polymerization-Induced Phase Separation
Authors: Tenhaeff Wyatt 
Published: November 2022

In state-of-the-art lithium ion batteries, separators (microporous membranes) play a passive yet critical role – hosting liquid electrolyte and maintaining physical separation of the electrodes. However, as the demands on lithium ion batteries increase, with an emphasis on greater energy density, longevity (cycle/calendar life), and safety, engineering separators to take a on more active role in the cell (electro)chemistry is expected to be an important strategy. Myriad membrane materials and separator designs have been developed to impart additional functionality, for example, acid and/or transition metal scavenging, temperature responsiveness, enhanced thermal stability, increased ion dissociation, combustion suppression, and mechanical strength.
In this talk, I will preset my group’s approach to additive manufacturing of next-generation lithium ion battery separators. Our approach is based on polymerization induced phase separation (PIPS), wherein polymerizable monomers (or prepolymer resins) are mixed with porogen. Through rapid, low-cost, readily scalable photopolymerization, the monomers are converted to a crosslinked polymer network, which results in the porogen becoming immiscible and phase separating through spinodal decomposition. By tuning the thermodynamics of the polymer-porogen mixture and photopolymerization kinetics, the porosity and pore size of the resulting polymeric phase can be tuned. We have shown that ethylene carbonate (EC) mixed with common acrylate monomers, such as 1,4-butanediol diacrylate, is an effective porogen. Most importantly because EC is an indispensable component in liquid electrolytes, it does not need to be extracted from the separator prior to incorporation into the electrochemical cell.
By controlling the ratio of the 1,4-butanediol diacrylate (BDDA) monomer to EC, monolithic microporous membranes are readily prepared with 25 µm thickness and pore sizes and porosities ranging from 6.8 to 22nm and 15.4% to 38.54%, respectively. The optimal poly(1,4-butanediol diacrylate) (pBDDA) separator has a porosity of 38.5% and average pore size of 22 nm; uptakes 127% liquid electrolyte by mass, and has an ionic conductivity of 1.98 mS/cm, which is higher than that of Celgard 2500. Lithium ion battery half cells consisting of LiNi0.5Mn0.3Co0.2O2 cathodes and pBDDA separators were shown to undergo reversible charge/discharge cycling with an average discharge capacity of 142 mAh/g and a capacity retention of 98.4% over 100 cycles - comparable to cells using state-of-the-art separators. Furthermore, the pBDDA separators were shown to be thermally stable to 400°C, lack low temperature thermal transitions that can compromise cell safety, and exhibits no thermal shrinkage up to 150°C. I will also discuss my group’s efforts to engineer separators with additional functionality to improve cell performance under abuse conditions.
Development of a Framework for Modeling Protection Mechanisms Provided By Multi-Layered Organic Coatings Applied to Aerospace Al Alloys Via Finite Element Analysis
Authors: Vicente Moraes Carolina , Kelly Robert G 
Published: November 2022

Aluminum alloys, such as AA2024 and AA7050, are widely used in aerospace applications due to their high strength-to-weight ratio. However, because of the heterogeneous microstructure of these alloys, they are susceptible to microgalvanic corrosion and pitting in chloride-containing environments. The corrosion susceptibility is further increased when these alloys are in contact with more noble alloys, such as in locations near fasteners, where the galvanic interaction leads to accelerated corrosion attack of the less noble Al alloy. To protect these structures against corrosion attack, organic coatings are commonly used. Typical coating systems are usually composed of three layers: a conversion coating, a primer, and a topcoat. When the topcoat is breached, the primer can provide active corrosion protection by the release of inhibitors embedded in the primer. Depending on the type of inhibitor, it can provide chemical protection by the formation of a passive film on the surface of the exposed metallic area and/or provide cathodic protection by the preferential dissolution of sacrificial anodes.
The efficacy of the corrosion protection provided by the multilayered coating system to Al alloys in aircraft components exposed to atmospheric corrosion is affected by a large number of variables. The dynamic environment in which the component is exposed to (e.g., relative humidity, temperature, salt loading density), the geometry of the component, the chemistry of the primer, and the type of alloy are examples of important parameters that impact the corrosion and protection mechanisms. To unravel the impact of each one of these variables and/or the synergistic effects between them, a large volume of experimental work is needed, making the prediction of coating failure, corrosion damage, and, ultimately, component lifetime, remarkably challenging. In this context, the development of computational models that can simulate corrosion and corrosion protection mechanisms is attractive, as they can be used as tool to effectively assess the large parameter space and increase efficiency of experimental work.
This work focuses on developing a framework for modeling the protection mechanisms offered by chromate-based and Mg-rich primers via finite element analysis. Chemical and electrochemical protection mechanisms were modeled taking into consideration leaching of inhibitor from the primer, mass transport and the impact of the inhibitors in the electrochemistry of the Al alloys. The impact of environmental, geometric, and coating parameters on the effectiveness of the protection mechanisms was assessed. Ultimately, the framework developed will provide a better understanding of protection mechanisms of the organic coating systems and serve as a framework to study new coating systems.
Real-Time Imaging of Brass Cross-Section to Investigate Dezincification Corrosion Behavior during Electrochemical Measurement
Authors: Hoshi Yoshinao , Otake Yoshiyuki , Nishihara Yoshihiro , Watanabe Hikari , Shitanda Isao , Itagaki Masayuki 
Published: November 2022

The dezincification corrosion is a major limiting factor for use of brass in the plumbing system as it may cause the water leakage accident. It is well known that the porous copper rich layer is formed on the brass surface due to the dezincification corrosion, namely, the selective dissolution of zincoccurs on the brass surface1,2. We have developed the real-time surface observation system with channel flow double electrode to examine the dissolution behavior of copper and magnesium3-5. In the present study, a real-time cross-sectional surface observation system was developed to investigate the dezincification corrosion behavior of brass during electrochemical measurement.
An electrochemical cell was made using transparent acrylic plates. An electrochemical measurement was performed by a three-electrode system. The brass plate and the platinum wire were used as the working electrode and the counter electrode, respectively. A KCl-saturated silver/silver chloride electrode was used as the reference electrode. The electrolyte solution was 0.5 M NaCl containing 5 mM NaHCO3. The temperature of electrolyte solution was kept at 60 oC. The brass plate was fixed at wall surface of the electrochemical cell to record the video of the brass cross-section.
The video of the brass cross-section was taken by an optical microscope combined with a charge-coupled device camera under the galvanostatic polarization for 24 h. The brass cross-section under the galvanostatic polarization was successfully observed from the video recording, indicating that the dissolution of brass progressed inhomogeneously in the depth direction. We estimated the erosion depth from the cross-sectional surface images at each measurement time. The results demonstrated that the erosion depth was increased with time under galvanostatic polarization. The dissolution process involving preferential dissolution of zinc or the simultaneous dissolution of zinc and copper was discussed based on the video images and the potential changes of brass during the measurement.
References:
1) H.W. Pickering, C. Wagner, J. Electrochem. Soc., 7, 114 (1967).
2) Y. Hoshi et al., J Solid State Electrochem, 19, 3551 (2015).
3) Y. Hoshi et al., J. Electrochem. Soc., 164, C450 (2017).
4) Y. Hoshi et al., Surf. Finish. Soc. Jpn., 69, 34 (2018).
5) Y. Hoshi et al., J. Electrochem. Soc., 165, C243 (2018).
Assessing Electrolyte Transport through an Aircraft Coating System Using EIS
Authors: Policastro Steven A , Anderson Rachel M. , Hangarter Carlos M , Arcari Attilio , Iezzi Erick B. 
Published: November 2022

Electrochemical impedance spectroscopy (EIS) is frequently employed to nondestructively evaluate coating systems. However, there are several challenges associated with this approach. One of these challenges is associated with isolating the physical processes that are contributing to the measured impedance. We attempted to address this concern by measuring several of the coating system components before starting the exposures and attempted in-situ measurements of some properties during the course of the exposures.
In this work, we analyze impedance data obtained from a two-layer coating system that was applied to AA 2024 substrates that were subjected to either immersion and simulated outdoor exposure conditions. The impedance data from the full coating system is compared with data obtained from coating systems in which gold electrodes were inserted between the layers of the coating system that could be used to monitor changes in each coating layer. Several equivalent circuit models were evaluated before settling on a modified coatings equivalent model. Using this approach, we were able to estimate several coating system parameters, including electrolyte penetration depth as a function of temperature, and solution concentration from the values obtained from the equivalent circuit model.

Acknowledgments

The Department of Defense Strategic Environmental Research and Development Program (SERDP) sponsored this project under work unit 5399. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Office of Naval Research, the U.S. Navy, the Department of Defense, or the U.S. government.
Combining High-Temperature Cyclic Voltammetry and Electrochemical Impedance Spectroscopy in a Setup for the Controlled Oxidation of Copper
Authors: Stadt Michael Georg , Nelhiebel Michael , Larisegger Silvia , Fafilek Guenter 
Published: November 2022

Copper is utilized in a variety of industrial applications (e.g. heat conductors, electronic components, protective coating), where it is frequently exposed to high temperatures [1]. However, contact with the atmosphere at these high temperatures causes uncontrolled oxidation of the metal. Previous research investigated the oxidation mechanism by oxidizing at specific temperatures and then analyzing the oxide layers with a scanning electron microscope [2].
This work presents a new method for the simultaneous investigation of the oxide layer formation by electrochemical impedance spectroscopy and cyclic voltammetry. The high-temperature electrochemical polarization method allows a dynamic adjustment of the oxygen partial pressure on the surface of the copper, leading to oxide layers with different compositions in respect to their thickness and defect density. The common combination of a potentiostat and a frequency response analyzer (FRA) in a three-electrode setup suffers from bandwidth limitations and artifacts [3]. Therefore, a novel method developed by Fafilek in 2009 [3] for a potential controlled electrochemical spectroscopy was adapted to our high-temperature oxidation setup. Thereby the two measuring units, potentiostat and FRA are electrically separated with regard to their grounding. Cyclic voltammograms are obtained as the result of the polarization of a sputtered copper ring versus a reference electrode, while the impedance spectra are recorded between the same copper ring (large contact area) and a copper sphere (small contact area) as shown in Figure 1. The FRA has nearly no internal resistance which ensures that both samples are adopting the same potential during the potential sweep resulting in an equal oxide formation on them. As the copper ring shows a significantly larger area than the copper sphere, the current received by the potential sweep is assumed to stem from the copper ring. Conversely, it is considered that the impedance spectra originate from the copper sphere, since the impedance of the copper ring can be neglected due to its large size. The data obtained from the potential sweep, such as the oxide structure and film thickness, are combined with the electrical properties acquired by impedance spectroscopy. This allows accurate characterization of the oxide layer that forms during electrochemically controlled oxidation.
[1] Davis, J.R. ed., 2001. Copper and copper alloys. ASM international.
[2] Zhu, Y., Mimura, K. and Isshiki, M., 2002. Oxidation mechanism of copper at 623-1073 K. Materials transactions, 43(9), pp.2173-2176.
[3] Fafilek, G., 2009. A novel experimental method for potential controlled electrochemical impedance spectroscopy. Monatshefte für Chemie-Chemical Monthly, 140(9), pp.1121-1127.

Figure 1
(Corrosion Division Rusty Award for Mid-Career Excellence) Rust At a Glance: Electrochemical Thermodynamics and Kinetics of Porous Corroding Interfaces
Authors: Bastidas David 
Published: November 2022

The development of a rust layer is governed by physico-chemical processes at the electrode/electrolyte porous interface, including electrochemical thermodynamics and kinetics, as well as transport and reaction processes. While rust can be protective under passive and inert regions found on the Pourbaix diagram, it becomes interesting to see whether its stability is compromised under harsh conditions that lead to active dissolution of this porous interface.
Thermodynamics calculations can predict phase transformation, which nucleation and growth is governed by the chemical activity of the porous interfaces as well as by the saturation of the electrolyte solution. Understanding the electrochemical interface is a major challenge to unravel the corrosion mechanism of porous systems. The heterogeneous nature of the oxide structure as well as the development of amorphous gel regions influences the formation of active sites and point defects with a high lability for reacting with gas phases dissolved, entrapped, or occluded within interfacial substructures.
The stabilization and corrosion protection of the rust interface requires to understand the adsorption of corrosion inhibitors on the surface of the active site on the electrode ‒ creating a stable protective passive film. Enthalpy and entropy of the dissolution process can explain the spontaneous formation of a rust layer as well as the displacement of water molecules, which ultimately will result in the effective physico-chemical adsorption of the inhibitor molecules.
In summary, this communication is aimed to present the role of rust at a glance, and its implications on the electrochemical corrosion mechanisms on porous interfaces. The application of electrochemical fundamentals and first principles combined with state of the art electrochemical, chemical and surface characterization techniques provides a comprehensive vision and mission on current trends in corrosion and protection of steel in porous media.