bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of MoO3-Based Proton Batteries
Authors: Ikezawa Atsunori , Nishizawa Tadaaki , Koyama Yukinori , Arai Hajime
Published: November 2022

Aqueous rocking chair batteries have attracted attention as highly safe and inexpensive secondary batteries. Lithium and sodium ions have mostly been used as the mobile ions, whereas proton systems with potentially the highest mobility have rarely been reported. Recently, research on proton batteries has been conducted using concentrated sulfuric acid solutions as the electrolyte that can assist high-rate performance.[1] Stability under concentrated acidic conditions is required for the electrode materials, as well as the capability of proton accommodation. MoO3 has been reported as a stable negative electrode material for aqueous proton batteries,[2] while few positive electrode materials are known except for bulky organic[3] and Prussian-blue materials[4]. For achieving high energy density and long life, oxide positive electrode materials are desirable. Here we propose the application of MoO3 as the positive electrode material by optimizing the operating composition range. The potential values shown below are all shown versus SHE (actually measured with Ag/AgCl).

MoO3 showed a discharge profile at around 0.5 V with the maximum capacity of ca. 100 mAh g-1, as shown in the figure. This potential is sufficiently more positive than the redox potential of protonated MoO3 of around -0.3 V as the negative electrode. With the aid of operando X-ray diffraction analysis, it turned out that the discharge regions at 0.5 V and 0.4 V are respectively associated with a biphasic transition of MoO3/phase I (ca. 0 < x < 0.3 in H
x
MoO3) and a single-phase reaction of phase I (ca. 0.3 < x < 0.5 in H
x
MoO3). Deep discharging beyond this range results in the coexistence of phase I and phase III (ca. 0.5 < x < 1.5 in H
x
MoO3) and the proton extraction from phase III leads to the formation of phase II or phase IIa with its discharging potential of 0.0 V. Structural calculation based on the density function theory is employed to clarify the origin of this irreversible phase transition behavior. Different proton sites between these phases seem to be responsible.

An aqueous proton battery with a 7 mol dm–3 sulfuric acid electrolyte was constructed with H-inserted MoO3 and MoO3as the negative and positive electrodes, respectively, and was successfully discharged and charged repeatedly, with the operating voltage of ca. 0.6 V, indicating the launch of aqueous proton battery composed of oxide active materials.

Reference
s
:

[1] J. Li, H. Yan, C. Xu, Y. Liu, X. Zhang, M. Xia, L. Zhang, J. Shu, Nano Energy, 89 (2021) 106400.

[2] X. Wang, Y. Xie, K. Tang, C. Wang, C. Yan, Angew. Chem. Int. Ed., 57 (2018) 11569.

[3] X. Wang, J. Zhou, W. Tang, Energy Storage Mater., 36 (2021) 1.

[4] X. Wu, J. J. Hong, W. Shin, L. Ma, T. Liu, X. Bi, Y. Yuan, Y. Qi, T. W. Surta, W. Huang, J. Neuefeind, T. Wu, P. A. Greaney, J. Lu, X. Ji, Nat. Energy, 4 (2019) 123.

Figure 1
Near Infrared Spectroscopy of Fission Products in Alkali Chloride Molten Salt – Structural Interpretation and Analytical Use
Authors: Moon Jeremy , Chidambaram Dev
Published: November 2022

Advanced nuclear technologies using high-temperature molten salts are poised to increase the efficiency, flexibility, and acceptability of nuclear energy. To realize these advances, additional understanding of the chemistry and thermochemical and thermophysical properties of the molten salt mixtures is required. Additionally, methods to rapidly and non-destructively monitor and determine the concentration and chemistry of actinides and fission products must be developed. Electronic and vibrational spectroscopy are promising methods to both interpret the structure and speciation of dissolved species in molten salts and to determine concentrations of species of interest. We have determined the molar absorbance coefficients of selected absorbance features for several lanthanides of interest in the ultraviolet, visible, and near infrared ranges and show that some NIR absorbance features, which were previously neglected as a means of concentration determination, are analytically useful. In fact, these NIR absorbance features may have advantages over UV and visible range features for concentration determination in industrial systems. Additionally, we will present our analysis of the effects of the coordination environment on lanthanide electronic structure and transitions, yielding insight into the chemistry and coordination of these elements in molten alkali halide mixtures, which is crucial for understanding the corrosion issues in these salts amongst other requirements.

Acknowledgement:

This research is being performed using funding received from the DOE Office of Nuclear Energy's Nuclear Energy University Programs under award DE-NE0008889 and the US Nuclear Regulatory Commission (USNRC) under contract 31310018M0032. Dr. Kenny Osborne and Ms. Nancy Hebron-Isreal serve as the program managers for the DOE and NRC awards, respectively.

This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1447692. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, the U.S. Department of Energy, or the United States Government.
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.
The Effects of Sulfate on the Parameters for Maximum Pit Size Calculations on Stainless Steel 316L
Authors: Shehi Armando , Kelly Robert G
Published: November 2022

Dry storage canisters that contain radioactive waste containers in the United States are typically made of stainless steel such as 316L. The longevity of such canisters put into service around forty years ago is a primary concern to the United States Department of Energy. Due to their location, many of these canisters undergo fluctuations in relative humidity and temperature, as well as an accumulation of deliquescent salts on their surface. The nature of the anions present in these salts establishes whether or not proper conditions for pit propagation exist. In order to predict these canisters’ maximum pit size, computational models that employ input parameters on the pit kinetics can be utilized. Such kinetic parameters are the critical pit stability product (i·x)crit and the repassivation potential (Erp), as they are key to the anodic current demand in a pit and the cathodic current supply outside a pit, respectively. Previous models that focused on the effect of chloride concentrations on the maximum observed pit size have shown to be overly conservative. Therefore, to increase the accuracy of the model, a more complex solution that contains inhibiting ions, such as sulfates, should be considered. In this study, artificial 1-D pit electrochemical experiments were carried out in a 50.8μm diameter SS316L wire exposed to solutions containing different concentrations of magnesium chloride (MgCl2) and magnesium sulfate (MgSO4). Maximum pit size calculations were performed utilizing the kinetic parameters obtained from these experiments. A theoretical model that seeks to describe the formation and growth of a complex salt film precipitate at the bottom of the pit is presented as well.
Evaluating Localized Corrosion Susceptibility of Austenitic Stainless Steels Exposed to Varying Nitrate to Chloride Ratio Droplets
Authors: Katona Ryan Michael , Montoya Timothy , Snow Jason , Maguire Makeila , Bryan Charles , Schaller Rebecca Filardo
Published: November 2022

Austenitic stainless steels (SS), utilized extensively in coastal environments due to their enhanced corrosion resistance, are susceptible to localized corrosion and stress corrosion cracking (SCC) when exposed to chloride environments. One potential scenario under which SCC may pose a concern is the interim storage and the eventual transport of spent nuclear fuels (SNF) in SS canisters. The SS canisters may be subjected to marine sea-salts and elevated temperatures; however, assessing the current damage state on the surface of these canisters is difficult due to high radiation levels dictating confinement within a limited-access overpack. Hence, accelerated tests are needed in order to help predict potential materials degradation on the surface of these canisters. Another important factor related to SNF storage is the fact that the canisters are located in a variety of climates across the United States. Salt compositions and daily fluctuations of relative humidity (RH) and temperature differ widely by location. Of particular interest, inland sites have a higher nitrate concentration in comparison to coastal locations. One governing brine property for corrosion is the amount of nitrate present in the brine as this can serve to passivate a corroding alloy. Herein, we evaluate the influence of nitrate to chloride ratios on the pitting susceptibility of SS304L under full immersion and cyclic RH conditions. The results of this study are discussed in terms of potential canister degradation.

Acknowledgements

SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525. This document is SAND2022-3796 C.
Evaluation of Metal Oxide Coated Stainless Steel As a Potential Anode for Pyroprocessing
Authors: Moore Craig , Moon Jeremy , Howard Jerry , Chidambaram Dev
Published: November 2022

Pyroprocessing is a potential route to close the nuclear fuel cycle. Used nuclear fuel (UNF) is electrolytically reduced from UO2 to U0 at a stainless-steel cathode while oxygen evolution occurs at a platinum anode in a molten LiCl-Li2O environment. Platinum is consumed during this process as a result of the formation and spallation of lithium platinate. To increase the economic viability of pyroprocessing, alternative low-cost, electrochemically efficient materials are needed to replace platinum. In this study, metal-oxide coated 316L stainless streel rods were explored as potential replacements. The characteristics of these coatings in molten LiCl-Li2O was evaluated through electrochemical techniques. The surface chemistry of the coatings was explored through X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and scanning electron microscopy before and after exposure to molten salts to understand the degradation of the coatings. Results detailing the performance of the coatings will be presented.
(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.
(Invited) Wastewater Derived Cathode Materials for Aqueous Zn-Batteries
Authors: Nam Gyutae , Liu Meilin
Published: November 2022

While lithium-ion batteries (LIBs) have been widely used for portable devices and electric vehicles, it is highly desirable to develop safer and less expensive batteries as alternative to LIBs. In this regard, zinc (Zn) batteries have attracted much attention because of their excellent safety and low cost. However, one of the challenges is to develop cost-effective and highly efficient cathode materials for Zn-ion batteries (ZIBs) based on transition metal oxides. It would be more economical to recycle transition metals in order to reduce the fabrication cost. Co-precipitation method is widely used for synthesis of LIBs cathode materials, and large amount of wastewater would be produced during co-precipitation and battery production process. In this presentation, we will report a facile and general process for fabrication of cathode materials for aqueous Zn-ion batteries (ZIBs) by reusing wastewater from co-precipitation method. We have selected manganese rich phases with different ratio of nickel to cobalt precursors from co-precipitation wastewater, followed by a simple ball milling process, resulting in metal-hydroxide cathode materials (Mn0.6Ni0.1Co0.3OxHy, Mn0.6Ni0.2Co0.2OxHy, and Mn0.6Ni0.3Co0.1OxHy). Among them, the Mn0.6Ni0.1Co0.3OxHy cathode (with mass loading of 15 mg cm-2) exhibits an initial capacity of 263 mAh g-1 at a current density of 0.1 A g-1, as evaluated in an mixture electrolyte (2M ZnSO4 and 0.1M MnSO4). Furthermore, operando X-ray absorption spectroscopy analysis has revealed the role of each transition metal ions during insertion and desertion of Zn ions. It is found that the ratio of Ni to Co significantly influences ZIBs performances, providing important insight into rational design of more efficient cathode materials for aqueous Zn-ion batteries.

Figure 1
(Invited) Pathways Towards Practical Solid-State Batteries
Authors: Belharouak Ilias , Dixit Marm , Amin Ruhul , Parejiya Anand , Essehli Rachid , Muralidharan Nitin
Published: November 2022

Solid-state batteries are pivotal technologies for next-generation energy storage needs. However, they are plagued with various challenges from materials and interfaces all the way out to integration into devices. Herein, we discuss several new pathways that our team has evaluated to drive the research towards practical solid-state batteries. Initially, we highlight SolidPAC, which is an interactive experimental toolkit developed at Oak Ridge National Laboratory to enable the design of a solid-state battery for user-specified application requirements. The toolkit is flexible enough to assist the battery community in quantifying the impact of materials chemistry and fractions, electrode thicknesses and loadings, and electron flows on cell energy density and cost. The toolkit allows users to assess and extrapolate the impact of battery design and choice of cell components on cell-level energy density of a solid-state battery. Subsequently, we will discuss some key experimental strategies that leverage cheap and scalable electrochemical approaches towards the integration and on-line management of solid-state batteries. Specifically, these approaches are aimed to alleviate high interfacial resistances typically observed in some SSB configurations as well as to mitigate the growth of filaments within the solid electrolyte.
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.
Deconvoluting the Surface Area and Geometric Effects of Fastener Heads on Galvanic Corrosion Prediction through FEM Modelling
Authors: Kontopanos Victor
Published: November 2022

Galvanic couples are common in commercial and military aerospace applications and arise from a difference in the substrate and fastener materials. These couples are often formed between aluminum alloys (e.g., AA7075-T6) with stainless steels (e.g., SS316L) or Ti-6Al-4V and can cause extensive corrosion damage to occur. This work uses laboratory techniques, including polarization curves and rotating disk electrode testing, to determine the kinetics of the electrochemical reactions. Collecting over a range of revolution rates on the RDE allows for the determination of the dependence of limiting current density due to oxygen diffusion at variable water layer thicknesses. Constructing geometries in commercial software that will be comparable to aerospace structures, coupled with experimentally-determined boundary conditions, allows for quantification and prediction of galvanic corrosion in aerospace applications. With the wide array of fasteners used, many material and geometric combinations are possible. This work focuses on the deconvolution of the impact of surface area and geometry on the prediction of the galvanic corrosion through the FEM software to better understand their effects.
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).
(Digital Presentation) The Role of Steel Microstructures on Sweet Corrosion Scaling By in Situ Confocal Raman
Authors: Hassan Sk Mobbassar , Agrawal Surabhi , Casford Mike , Clarke Stuart M
Published: November 2022

Confocal Raman imaging and spectroscopy has been used in a custom-made flow-cell to map in-situ spatial and temporal growth of siderite and chukanovite on pipeline steel in a hot brine environment, under conditions typical of commercial interest (pH 6.8, temp 80oC, oxygen conc < 10 ppb, 0.5 M NaCl, open circuit potential (OCP)). Ferrite and pearlite domains are found to exhibit an interesting contrast (colour) inversion under sweet environmental conditions compared to their Nital etched contrast – confirmed by identifying the shapes and surrounding of the domains before and after exposure to two different conditions. Ferrite and pearlite phases are found to exhibit differing evolution of the corrosion scale mineralogy, and phase transformation. The process starts by revealing the microstructural phase constituents, significantly the interphase boundaries are identified as the primary sites for scale formation. The ferritic phase forms pure siderite scale while the pearlitic phase shows both siderite and chukanovite scales, with chukanovite transforming into siderite over time. LPR profiles reveal that for carbon steel with a higher pearlite fraction the initial corrosion rate is higher, followed by a faster drop when compared to steel with lower pearlite fraction!

Figure 1
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.
(Invited) Electrolytes and Additives to Enhance Low-Temperature Performance of the Lithium-Ion Battery
Authors: Liu Gao
Published: November 2022

We report the investigation of several electrolyte additives, which has the potential to enhance the low temperature performance of current lithium-ion rechargeable battery. Lithium-ion batteries (LIBs) power virtually all modern portable devices and electric vehicles, and their ubiquity continues to grow. With increasing applications, however, come increasing challenges, especially when operating conditions deviate from room temperature. While high-temperature performance and degradation has been extensively studied in LIBs, sub-zero Celsius performance has received less attention, despite being critical for batteries in transportation roles. Although many individual processes contribute to the capacity loss commonly observed in LIBs at low temperatures, most of them are governed to some extent by the non-aqueous liquid electrolyte present throughout the cell interior. Therefore, electrolyte engineering presents an unparalleled opportunity to study and address the fundamental causes of low-temperature failure. In this talk, we first outline recent literature on electrolyte-based strategies to improve said performance, including various additives, solvents and lithium salts. Then, we will detail the standard techniques and procedures we used to test the electrolytes and additives at sub-ambient temperature; and will discuss the results of the low temperature performance of new electrolytes and additives tested in our laboratory.
(Invited) Transition Metal Oxides and Sulfides for Supercapacitor Applications
Authors: Singhal Rahul
Published: November 2022

Energy produced by renewable energy sources need to be stored till required. Therefore, the development of high energy density energy storage systems is required to fulfil the energy needs around the world without any significant environmental impact. Recently, energy storage devices such as rechargeable batteries, fuel cells, and supercapacitors have attracted significant attention owing to their diverse applications in hybrid electric vehicles, energy management, and smart portable electronic devices. Rechargeable batteries such as lithium-ion batteries have been widely employed for various commercial application ranging from consumer electronics to hybrid electric vehicles. However, rechargeable batteries possess high energy density but often suffers from slow charging/discharging, limited cycle life, high cost of Li metal, low power density, poor cycle life, and environmental issues. Currently, supercapacitors are becoming more popular to overcome the issues raised by Li on rechargeable batteries such as low power density and limited cycle life.

Various transition metal-based materials such as oxides, sulfide, selenides, nitrides, phosphide are being used for supercapacitor applications due to their high theoretical specific capacitance abundant sources, and low cost. Transition metal oxides have attracted great attention of the researchers for supercapacitor applications because of their multiple oxidation states due to which multiple electrons transfer exists and discharge time extends, resulting in improving energy density in rapid Faraday redox reactions.

Our group is actively engaged in studying supercapacitor behavior of various transition metal oxides, sulfides, and their composites with carbonaceous materials such as carbon nanotube, graphene oxide (GO), reduced graphene oxide(rGO), and carbon nanotubes (CNT). We have synthesized pure MnO2 and CuS along with their composites with graphene oxide and multiwall carbon nanotube (MWCNT). It was reported that the specific capacitance of CuS and CuS-GO nanocomposite was found to be 158 F/g and 250 F/g, respectively, at a current density of 0.5A/g. The specific capacitance of MnO2 and MnO2/MWCNT nanocomposite was found to be as 124 F/g and 145 F/g, respectively, at a current density of 0.5A/g. The detailed studies on electrochemical performances of various transition metal oxide/sulfides and their composite with carbonaceous materials will be presented at 242nd ECS Meeting.
(Digital Presentation) The Effect of Tartaric-Sulfuric Acid (TSA) Anodizing on the Corrosion Resistance of the AA7475-T761
Authors: Araujo João Victor , Xavier Milagre Mariana , D Gabbardo Aline , Klumpp Rafael Emil , Costa Isolda
Published: November 2022

The microstructure of the high strength aluminum alloy, AA7475–T761, in the as-received condition was characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy, and statistical analyses of grain size and micrometer precipitates distribution and density were performed. An anodic aluminum oxide (AAO) film was potentiostatically grown on the alloy in tartaric sulfuric acid (TSA). The anodizing behavior of the alloy and the mechanisms of localized corrosion initiation and propagation in bare (not anodized) and anodized conditions were discussed. The alloy corrosion behavior was investigated in sodium chloride solutions using electrochemical techniques (cyclic potentiodynamic polarization) and the morphology and extent of corrosion propagation was investigated through optical microscopy, optical profilometry and scanning electron microscopy analyses. It was observed that the two alloy surface conditions (bare and anodized) play different roles in the propagation of the localized corrosion process. The bare alloy presented lower localized corrosion potentials and the propagation of the localized corrosion was shallower, but more heavily distributed, than in the anodized condition. However, the alloy in the anodized condition presented lower repassivation potentials due to the deeper pits formed. In addition, the variability of pitting potentials for the anodized condition was high, due to the heterogenous structure of the AAO film formed, and dependent on the time and drying storage conditions previous to electrochemical characterizations. The electrochemical results were correlated with the microstructural characteristics of the oxide surface film of the alloy in both conditions, bare (not anodized) and anodized.
Multichannel Electrochemical Impedance Spectroscopy and Equivalentcircuit Synthesis of a Kw-Scale Vanadium Redox Flow Battery
Authors: Trovo Andrea , Zamboni Walter , Guarnieri Massimo
Published: November 2022

An original multichannel Electrochemical Impedance Spectroscopy (EIS) system operating at high bias current and suitable for kW-class Vanadium Redox Flow Batteries (VRFBs) is presented. Power and signal connections, whose stray parameters affected measurements, required a careful optimization and calibration in the implementation of the measurement chain. In any cases, electromagnetic interferences set an upper limit to the applied stimulus frequency that limited the set of measurement data at each bias point. The work provides early results obtained with this EIS system, which were used to identify an equivalent circuit of the whole stack in which each cell is represented with a dynamic Thévenin equivalent, i.e. the series of a voltage source, a variable resistor and a variable RC loop. The dependence of the equivalent parameters on the operating conditions has been experimentally analyzed, confirming that only the RC-loop resistance is strongly affected by mass transport. In addition, more complex equivalent circuits have been proposed, i.e. a Randles cell modified with CPE, a Randles cell modified with CPE and Warburg element and a two-loop model of ZARC elements. The inclusion of the constant phase element constitutes a substantial improvement in the fit, Fig. 1. Conversely, the addition of the Warburg element, which aims to model the mass transfer in the electrochemical process, does not produce significant effects for the frequencies at which we have experimental data. To our knowledge, this is the first dynamic equivalent circuit of a whole stack that has been validated against EIS measurements taken on a real industrial-scale VRFB. Building on the measurement methodology here presented, advanced online state of health of industrial flow batteries can be developed and implemented.

References

[1] Trovò A, Zamboni W, Guarnieri M. “Multichannel Electrochemical Impedance Spectroscopy and equivalent circuit synthesis of a large-scale vanadium redox flow battery.” J Power Sources (2021) 493: 229703.

[2] Trovò A, Di Noto V, Epoupa M. J, Gamabaro C, Guarnieri M. “Fast Response of kW-Class Vanadium Redox Flow Batteries," in IEEE Trans Sustain Energy (2021), vol. 12, no. 4, pp. 2413-2422

[3] Sanchez-Diez E, Ventosa E, Guarnieri M, Trovò A, Flox C, Marcilla R, Soavi F, Mazur P, Aranzabe E, Ferreta R. “Redox flow batteries: status and perspective towards sustainable stationary energy storage.” J Power Sources (2021), 481: 228804.

[4] Guarnieri M, Trovò A, Picano F. “Enhancing the efficiency of kW-class vanadium redox flow batteries by flow factor modulation: An experimental method”, Appl Energy (2020), 262: 114532.

[5] Trovò A, Guarnieri M. “Standby thermal management system for a kW-class vanadium redox flow battery”. Energ Conv Manag (2021), 226: 113510.

Figure 1