bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Superstructure Controls First Cycle Voltage Hysteresis in O-Redox Cathode Materials
Authors: Bruce Peter G. 
Published: December 2020

The cathode is a major constraint on the energy density of Li-ion batteries. State-of-the-art materials, such as Li(Mn0.8Ni0.1Co0.1)O2, are limited in their ability to store charge by the amount of available transition metal redox. It is now known these limits can be surpassed by storing charge on the oxide ions (oxygen redox) in so-called lithium-rich transition metal (TM) oxides, e.g. Li[Li0.2Ni0.2Mn0.6]O2. However, such O-redox cathodes suffer from several problems one of which is that, in almost all known cases, the high voltage plateau associated with oxide oxidation is followed by reduction at a much lower voltage (1st cycle hysteresis) leading to a substantial drop in energy density. Here, we discuss the origin of 1st cycle voltage hysteresis and show that it can be controlled by the superstructure ordering within the TM layer.
We compare two layered Na-ion O-redox compounds as model systems with very similar compositions and structure but divergent 1st cycle voltage profiles. In P2-type Na0.75[Li0.25Mn0.75]O2 with honeycomb ordering of Li and Mn in the TM layer, present in almost all O-redox compounds, substantial voltage hysteresis is observed. Whereas, for P2-type Na0.6[Li0.2Mn0.8]O2 with unique ribbon ordering, reversible high voltage O-redox is realised. The origin of voltage hysteresis is shown to be rooted in the formation of molecular O2 on charge that is trapped in in the bulk of honeycomb ordered cathodes and which can be reduced on discharge. O2 formation can be suppressed with ribbon ordering in the TM layer. The implications for future O-redox materials will also be considered.

Figure 1
(Invited) Multiscale Modelling of Titanium Oxide Growth and Dissolution in Fluoride-Containing Electrolytes
Authors: Bojinov Martin S. , Betova Iva G. , Karastoyanov Vasil I. , Stancheva Mina J. 
Published: December 2020

Nanostructured valve metal oxides have been extensively investigated due to the variety of applications related to their valuable chemical and physical properties, including mechanical and thermal resistance, catalytic and photocatalytic activity, and biocompatibility. The technology to form well defined porous anodic oxides on titanium will strongly benefit from an optimization of the process parameters based on deterministic modelling. The relatively large number of adjustable parameters often precludes the unambiguous interpretation of steady-state and transient electrochemical data in terms of a unique kinetic model.
An approach to overcome this ambiguity by parameterization of the models of barrier film growth [1, 2] on Ti and its alloys (Figure 1) using a combination of in-situ EIS in a large frequency range, dynamic high-frequency impedance and photocurrent measurements, combined with ex-situ characterization of the oxides by X-ray photoelectron spectroscopy (XPS) is presented. Additional estimates of kinetic parameters are derived from density functional theory (DFT) modelling of adsorption of water and fluoride on Ti and TiO2 [3, 4]. Ways to extract information on the rate-limiting steps of the process of passive film formation, growth and restructuring are described and the significance of the obtained parameters for the kinetics of barrier film growth and dissolution is outlined.

Stancheva, M. Bojinov, Electrochim. Acta 78, 65 (2012).

Bojinov, I. Betova, V. Karastoyanov, Electrochim. Acta 344, 136137 (2020).

Stancheva, B. Diawara, F. Lebreau, M. Bojinov, J. Electrochem. Soc. 161, E3188 (2014).

Betova, M. Bojinov, V. Karastoyanov, M. Stancheva, Computational Mater. Sci.171, 109260 (2020).

Acknowledgments: The financial support of the National Science Fund of Bulgaria under contract ДН19/3-2017 „Modeling, optimization and modification of nanoporous anodic oxide films as catalysts for water photoelectrolysis“is gratefully acknowledged.

Figure 1
(Invited) Advanced Experimental and Modelling Approaches to Understand and Predict Better Corrosion of Metals
Authors: Terryn Herman Albert 
Published: December 2020

In the advanced materials industry, there is a clear trend towards more sustainable concepts, and this is certainly also the case for metals. They take a prominent position in the materials market thanks to their multifunctionality and structural and mechanical properties. However, metals are prone to corrosion, and therefore often organic coatings are applied to extend their lifetime. The search for organic coated metals with higher multifunctionality and extended lifetime goes together with the search for more sustainable material concepts in the context of the REACH regulation.
Nowadays, materials are developed for providing components with a lifetime ranging from 10 to 25 years. The lifetime of a material highly depends on its exposure to the environment inducing ageing processes. In the current state of the art, lifetime and ageing assessment are performed by means of experiments, combining accelerated and field testing. The limitation of the first is that the conditions of the accelerated tests are not representative for the real environmental conditions and that there is no proven relationship between accelerated laboratory tests and field performance data. The limitation of the second is that it takes several years (5 to 10 years).
The only way to realise a substantial decrease in the development time of new materials is to introduce modelling in the design cycle. What is needed to realize a breakthrough in this field is a tool that can predict quantitatively and dynamically the corrosion behaviour of (organic coated ) metals. The long term scientific motivation of our research is to build a knowledge and technology platform to enable the prediction of durability behaviour and the estimation of lifetime of (organic coated) metals under long-term environmental ageing and corrosion conditions. This requires advanced research because corrosion of a (organic coated) metal is the result of an intense interplay between several physical phenomena that need to be characterized in real conditions and modelled. Within VUB and TUDelft research we try to focus on both aspects bringing in new advanced combined electrochemical & in situ surface analysis, advanced finite element electrochemical modelling and more recently quantum chemical modelling. During the lecture an overview will be given on our state of the art in the different domains, emphasizing some success but also bringing bottlenecks when it really comes to predictions of corrosion.
Acknowledgements: all VUB-SURF and TUDELFT-CTE colleagues for the excellent collaborations.
(Invited) In-Situ Observation of Dynamic Electrochemical Interfacial Phenomena
Authors: Matsushima Hisayoshi 
Published: December 2020

Electrochemical interfacial phenomena play important roles for developing advanced nano-materials such as actuators, MEMS and catalyst. For advanced control, metal nucleation by electrodeposition is one of key technology, while the research for high durability of the nanomaterials will be an important issue in the future. It is necessary to understand the corrosion in the fine region. These processes are electrochemical-deposition and dissolution reactions of metals. Thus, the reaction is too fast to observe in real time. In this presentation, I would like to introduce some recent research on dynamic electrochemical interface phenomena using a high-speed probe microscope [1, 2] and a holographic interferometric microscopy [3, 4].
The Cu dissolution was investigated by HS-AFM (High-Speed Atomic Force Microscopy). The in-situ observation was conducted using an Au(111) single in 3 mM copper sulfate solution with 50 mM sulfuric acid. The HS-AFM operating in a dynamic mode can measure surfaces at frame rates up to 10 frame s−1. In the present experiment, the scan area range was in the range of 375–1000 nm2 and the scanning speed was 1 frame s−1. The dissolution process was observed at 0.05 V vs. Cu reference. The dissolution could be occurred as soon as the electrolysis was started. The dissolution rate was independent of the edge type. At 3 s, the effects of dissolution became clear and the step lines of the nuclei became uneven. Interestingly, as dissolution progressed beyond 5 s, some clusters [indicated by arrows in Fig.1] remained on the substrate briefly. This behavior had the appearance of small water droplets drying on a flat surface. The average size of the clusters was approximately 8 nm. After the large nuclei dissolved, these small clusters gradually dissolved.
In the interferometric microscopy, the ionic mass transfer phenomenon of Al3+ in a sulfuric acid (pH 1) was investigated. The investigation revealed the refractive index profile corresponding to the Al3+ concentration profile in the electrolyte. The thickness of the diffusion layer was proportional to the square root of time, which supported the reaction dominated by the mass transportation. The Al3+ surface concentration started to decrease at 20 s after starting electrolysis, probably because the Al dissolution reaction was hindered and the Al oxide layer formation progressed. This in-situ research might be a steppingstone in order to understand the mechanism of anodization of Al.
References
[1] T. Yoshioka et al., Electrochim. Acta, 302, 422 (2019).
[2]H. Matsushima et al., Faraday Discuss., 193, 171 (2016).
[3] A. Miki et al., J. Electrochem. Soc., 167, 062501 (2020).
[4] K. Nishikawa et al., Electrochim. Acta, 297, 1104 (2019).

Figure 1
(Invited) High Precision Corrosion Measurements from Flow Type Scanning Droplet Microscopy with Downstream Analysis By Inductively Coupled Optical Emission Spectroscopy or Inductively Coupled Mass Spectrometry
Authors: Hassel Achim Walter , Mardare Andrei Ionut , Mardare Cezarina Cela , Kollender Jan Philipp 
Published: December 2020

The oxide formation on valve metals such as Al, Nb, Ti, Ta has been studied for a long time. However one major drawback was always the unrealiability of the coulometric data. While the electrochemical current and thus the charge can be measured with very precision, it was simply not clear which reaction is actually consuming the charge or with which share are contributing concurrend reactions. The assumption of an almost complete consumption of the charge for oxide formation has often been read in papers. But especially the small losses which are usually neglected tell us a lot about the mechanism of oxide formation and lead to a modern basic understanding of the concurrent reactions.
High purity valve metals namely Al, Hf, Nb, Ta, Ti, Zr were anodised in voltage step experiments, in cyclic voltammetry or galvanostatically using a flow type scanning droplet cell microscope (FT-SDCM) with an ultra trace analytical downstream electrolyte analysis using an inductively coupled mass spectrometer. Experiments reveal that even the most corrosion stable element tantalum undergoes a measurable dissolution during anodisation which clearly scales with the field strength in the oxide and in the interface between oxide and electrolyte. This dissolution is roughly 10 times higher for niobium and 100 times for titanium. A comparison of the electrochemical current during titanium anodisation and the corresponding chemical current proves that the onset of oxygen evolution at some 3.5 V SHE is definitely not an ionic but an electronic current. However this electronic current can be driven only under high field conditions in which a significant number of ionic charge carriers act as stepping stones for electron movement in the oxide.
Spatial resolution and time resolution for these experiments are being analysed to put these method in the context of other corrosion evaluation tools. In particular when studying material libraries of laterally graded materials the spatial resolution of the FT-SDCM is of importance as it alloys allows adressing specific compositions.
(Invited) Analysis By Electrochemical Impedance Spectroscopy of Passive Film Properties of Additive Manufactured 17-4PH Stainless Steel
Authors: Barroux Adrien , Ducommun Nadège , Nivet Eric , Delgado Julien , Tribollet Bernard , Orazem Mark , Laffont Lydia , Blanc Christine 
Published: December 2020

Additive manufacturing is currently one of the most innovative processes to build metallic components, in particular because it allows to manufacture parts with new design out of reach of conventional processes. Among the various additive manufacturing processes, power bed technologies such as laser beam melting (LBM), also called selective laser melting (SLM), are certainly the most common and developed process at this time. The specific microstructures generated by LBM and the associated mechanical properties of the final parts have been well discussed in the literature for many types of materials. Nevertheless, these peculiarities can also affect the durability of such parts and specifically their corrosion behaviour.
The main goal of this work was to analyse the electrochemical impedance measurements performed on a 17-4PH martensitic stainless steel (MSS) manufactured by LBM. In this framework, LBM parts were built from 17-4PH MSS powder, using optimised machine parameters. Samples machined from a wrought cylindrical bar were studied as references. Differences between the impedance of the LBM samples and the references samples were observed; they appeared as a small shift in frequency on the Bode plots. The impedance of the passive layer was analysed in detail by using the Young impedance model; in this model it is also necessary to take into account the ohmic impedance [1] to perform the analysis in the entire frequency range. In agreement with TEM observations, an increase of about 40% of the film thickness was obtained for the LBM samples; but, for both samples the resistivity distribution was similar. In conclusion, electrochemical impedance spectroscopy appears as a powerful method to study passive film and better understand the corrosion behaviour of LBM 17-4PH stainless steel.
References
[1] O. Gharbi, A. Dizon, M. Orazem, M.T.T. Tran, B. Tribollet, V. Vivier, From Frequency Dispersion to Ohmic Impedance: A New Insight on the High-Frequency Impedance Analysis of Electrochemical Systems. Electrochimica Acta, 320 (2019) 134609.
(Invited) A High Throughput Screening Approach for Corrosion-Resistant Alloys
Authors: Melia Michael Anthony , Pegues Jonathan , Summers Kodi , Jones Morgan , Nation Brendan , Chidambaram Dev , Argibay Nicolas , Kustas Andrew 
Published: December 2020

Additive manufacturing (AM) is an attractive process for alloy development with some techniques having the ability to print a standalone part that spans a wide composition range. Fabricating compositionally graded parts allows spatially sensitive characterization techniques to perform property measurements across the composition gradient, providing high throughput testing of composition and phase space. This study utilizes an AM technique to make incremental additions of a single alloying element to a high entropy alloy (HEA), exploring how these alloying additions impact the HEAs microstructure and corrosion behavior. Specimens were produced with an in-house laser engineered network shaping (LENS) system capable of in-situ mixing of up to 5 metal powders. The equiatomic CoCrFeMnNi HEA is used in this study and compositionally graded with pure elements (Ti, W, and Nb). The susceptibility of the compositionally graded specimens to local corrosion initiation are tested using a micro (100 μm)-electrochemical cell and a scratch tester designed to measure repassivation kinetics. The efficacy of using this high throughput screening approach to develop alloys with superior corrosion resistance will be discussed.
SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.
(Invited) Are “Beyond Li-Ion” Batteries Only a Dream?
Authors: Mohtadi Rana 
Published: December 2020

Environmental pollution and resources scarcity are monumental challenges that face humankind. Indeed, rapid technical advances and industrialization of societies continue to push the boundaries of stresses that can be imposed on our planet and with these comes a realization that sustainable energy technologies produced from renewable resources and stored and harnessed in highly efficient and environmentally friendly ways are inevitable. Electrochemical energy storage devices have been and are expected to play a critical role in enabling these efforts, however they must meet a highly demanding set of performance metrics.
For over three decades, Li-ion batteries have offered a reliable and a relatively dense form of electrochemical energy storage and their enormous success is evident from their widespread use. Indeed, while these transformational technologies drove innovations in societal electrification and warranted a recent Noble Prize in Chemistry,1 the urge to enable batteries that allow for safer, cheaper, sustainable and more energy dense forms has been driving interests in batteries beyond Li-ion.2 Batteries that essentially use safer and more abundant active materials such as rechargeable magnesium batteries are in principle poised to meet these requirements.2,3 Nonetheless, despite tremendous breakthroughs that include demonstrating a rechargeable Mg battery prototype close to two decades ago, these batteries remain confined to research laboratories due to the absence of practical electrolytes and cathodes that can enable demonstrating competitive, energy dense systems.
However, over the past few years, scientific advancements have been producing more certainty in the potential of these batteries as manifested in the discovery of new classes of competent battery materials beyond classical state of the art and unraveling of associated underlying fundamental chemistries that take place; all of which have altered our understanding of these batteries and what an ideal material needs to be like. Herein, the concepts applied towards enabling a next generation Mg battery, which in its functionality mimic Li-ion, will be unveiled. This battery was made possible through coupling novel battery materials and isolating of true barriers that contributed thus far to the demise of these devices.

References

https://www.nobelprize.org/prizes/chemistry/2019/press-release/

Choi J. W. Aurbach D. Nature Reviews Materials 1, 2016, 16013, 1.

Mohtadi R., Orimo S., Nature Reviews Materials, 2016, 2,16091, 1311.

Mohtadi R., Mizuno F. Beilstein J. Nanotechnol. 2014, 5, 1291.
Effects of Applied Stress on Atmospheric Corrosion and Pitting Characteristics of 304 Stainless Steel
Authors: Plumley John Bryan , Alexander Christopher Lewis , Yu Zhenzhen , Kemp Nicholas A , Garzon Fernando H , Schindelholz Eric John , Schaller Rebecca Filardo 
Published: December 2020

The effects of applied stress, ranging from tensile to compressive, on atmospheric pitting corrosion of stainless steel 304L (SS304L) were analyzed through laboratory exposure and localized corrosion experiments. Pitting characteristics, analyzed through optical profilometry, scanning electron microscopy, and electron backscatter diffraction, were obtained after exposure for 50 days of an SS304L four-point bend bar to simulated seawater conditions at 50°C and 35% RH. Additionally, localized electrochemical measurements were carried out on an unexposed SS304L four-point bend bar to analyze the effects of applied stress on the corrosion susceptibility in analogous chloride solutions. In the tested, simulated seawater environment, the applied stress showed no effect on the pitting characteristics due to the aggressivity of the 4g/m2 loading of simulated seawater. Pitting depth, surface area, roundness, and distribution were found to be largely stochastic and rely on the available cathodic area and preexisting microstructure. However, through localized corrosion experiments in more benign environments, containing lower Cl- concentrations, the effects of stress on corrosion susceptibility start to become noticeable from the open circuit potential (OCP) measurements. A measurable decrease in the OCP indicated increased susceptibility to corrosion in the region of applied tensile stress as compared to the compressively stressed region. These findings indicate that stress may be less of a contribution to corrosion susceptibility than Cl- concentration under the exposure conditions examined.
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 US Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2020-4490 A
Effect of Zinc Addition on Electrodeposition of Fe-W Alloys
Authors: Park Jae-Hyeok , Hagio Takeshi , Kamimoto Yuki , Ichino Ryoichi 
Published: December 2020

Tungsten (W) and its alloys have been applied to various industrial fields for its excellent mechanical, tribological and chemical properties. Electrodeposition process is anticipated to be a economical and cost-effective method for preparing W-based alloys since W has the highest melting point among metals (3422 ℃). In general, electrodeposition of metal W from aqueous solution is difficult because it exists as oxyanions in a wide pH range. However, electrodeposition in the co-existence of iron group metals such as iron (Fe), nickel (Ni), and cobalt (Co), enables W to be reduced to metal state, which is so called the induced co-deposition. Recently, electrodeposited W alloys have gained increased attention due to their advanced properties such as high microhardness, thermal stability, wear resistance and corrosion resistance. Among them, binary Fe-W, Ni-W alloys have been most intensively studied. These alloys are expected to be promising substitute for hard chrome (Cr) plating due to its high hardness, abrasion resistance, heat resistance and corrosion resistance without the use of hazardous hexavalent chromium (Cr6+). Meanwhile, Ni has been reported as the one of the major elements in triggering skin allergies for humans. Therefore, we focused on Fe-W-based alloys that do not use Ni. Unfortunately, Fe-W alloys are reported to have inferior mechanical properties and corrosion resistance compared to Ni-W alloys. Thus, the addition of Zinc (Zn); an element that is widely used in anti-corrosion coatings, as a third element to the Fe-W binary alloy was considered for preparation of a ternary alloy with improved properties.
This study reports the first experimental results of electrodeposition of ternary Fe-W-Zn alloy by incorporation of Zn to Fe-W alloys. Ternary Fe-W-Zn plating was prepared in citrate-ammonia aqueous solution heated to 80℃ by potentiostatic elcecrolysis range from -1.1 to -1.4V (vs. Ag/AgCl). Ternary alloys with the compositions of Fe-(28.8 to 37.1 at.%) W-(1.7 to 6.5 at.%) Zn were obtained with maximum current efficiency of 42%. The corrosion properties of the prepared ternary alloys were compared with those of Ni-W and Fe-W platings by a potentiodynamic polarization test in deaerated 1M sulfuric acid solution and 3 mass% sodium chloride solution. Although Zn has lower potential than Fe, ternary Fe-W-Zn alloys with relatively low Zn contents of 1.7 to 2.6 at.% showed better anti-corrosion properties than Ni-20 at.%W and Fe-33 at.%W alloys in acidic media. Addition of a small amount of Zn was found to be effective in tuning properties of Fe-W alloys.

Acknowledgement

This work was partially supported by the JST-OPERA Program, Japan [grant number JPMJOP1843]