bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrosynthesis of Near-Neutral Ferrate Species for Drinking Water Treatment Using a Recirculating Batch Reactor
Authors: Bonakdarpour Arman , Cataldo Macarena , Mohseni Madjid , Wilkinson David P. 
Published: February 2020

High oxidation state iron species of ferrates (e.g., Fe (VI), Fe (V) and Fe (IV)) are very promising oxidants and are in particular excellent candidates for water treatment applications. Their advantages include, for instance, a higher redox potential (+2.2 V vs. SHE) than the commonly used ozone oxidant (+2.07 V vs. SHE), no production of carcinogenic and harmful disinfection by-products (DBPs – produced with disinfectants such as chlorine) and decomposition into benign ferric hydroxides which form excellent coagulants. Ferrates are known to remove many different types of pollutants, including organic matter such as biofilms, algae, and coliforms, and inorganic matter such as cyanide, heavy metals, and radionuclides, and bio-contaminants like viruses and chlorine-resistant bacteria. One approach in production of ferrates is oxidation of Fe3+-containing solutions using an inert anode electrode. The oxidation reaction can be expressed by:
Fe3+ + 4H2O → FeO4
2- + 8H+ + 3e- E0 = -2.2 V vs. SHE
On-site production of ferrates for drinking water treatment by electrochemical means avoids a number of challenges with respect to transport and storage of chemical ferrates and also allows for direct integration of the electrochemical process with the treatment chain. In earlier papers on electrochemical ferrates, we have reported on a novel analytical method of ferrate quantification, degradation of ferrate and production of ferrates in small batch-type reactors [1-3].
Here we present a semi-batch (2 L) reactor which includes recirculation, temperature control, lower cell resistance, excellent mixing, provision for the use of ion exchange membrane, and in-situ pH control. The reactor uses boron doped diamond (BDD), Fe (III) solution and can be operated with or without an ion exchange membrane. The impact of several variables including current density (5 - 15 mA cm-2), pH (5 - 9), concentration of the dissolved iron salts on the production of ferrates temperature (15 - 30 oC) and operation with/without membrane have been studied and will be presented. Current efficiencies of as high as 90% were reached for the first 20 minutes of operation using a 30 mM of Fe (III) feed and a current density of 45 mA cm-2. The recirculating reactor results were successfully interpreted by a simple model which considered first order kinetics for Fe (VI) generation.

References

[1] M. Cataldo Hernandez, A. May, A. Bonakdarpour, M. Mohseni, D.P. Wilkinson, Can J. Chem, 95 (1) 2016.
[2] M. Cataldo Hernandez, M. Stewart, A. Bonakdarpour, M. Mohseni, D.P. Wilkinson, Accepted for publication in the Canadian Journal of Chemical Engineering.
[3] M. Cataldo Hernandez, R. Govindarajan, A. Bonakdarpour, M. Mohseni, D.P. Wilkinson, Accepted for publication in the Canadian Journal of Chemical Engineering.

Figure 1
Enhanced Performance of Compact Electrolytic Cells through Optimization of Cell Structures and Components to Produce Chemicals from Brine for Use in Sequestration of Carbon Dioxide
Authors: Ha Heung Yong , Kim Jaewon , Park Su-Ryeon , Lee Ki Bong 
Published: February 2020

In recent decades, CO2 capture and utilization (CCU) strategy has been actively promoted because of the potential of CO2 to be used as a feedstock for producing useful organic and inorganic substances such as methanol, formic acid, and carbonates through biological, thermal, photochemical and electrochemical methods.
In this study, we report a development of compact continuous-flow electrochemical cells for an energy-efficient electrochemical splitting of brine (aqueous NaCl) to produce alkali (NaOH) and hydrochloric acid (HCl) that would be used to convert carbon dioxide into carbonate minerals at a subsequent stage. Cell structures and types of polymer electrolyte membranes (PEMs) have been explored for constructing energy efficient electrochemical cells in terms of reaction rates and caustic (Faradaic) efficiencies (CE). Two types of cell designs representing a first version (design 1, namely one-membrane cell) and an advanced version (design 2, namely two-membranes cell) are investigated.
The one-membrane cell consisted of a membrane sandwiched between an anode and a cathode. A feedstock comprised of a NaCl solution and H2 gas was supplied to the anode side while pure water was supplied to the cathode side. Upon applying a voltage of 1.5V between the two electrodes, the electrolytic reactions proceeded to produce HCl at the anode and NaOH and H2 at the cathode. In the case of two-membrane cells, two-membranes were used and a separator plate was placed between the two membranes and the NaCl solution was fed to the separator plate while H2 gas was fed to the anode.
The one-membrane cells show initial reaction rates as high as 400 mA/cm2 at an applied voltage of 1.5V. The reaction rate, however, drops rapidly due to the degradation of the anode catalyst by hydrochloric acid that is produced at the anode side during the reaction. On the other hand, the two-membranes cells show very stable performance over 200 hours though their reaction rates are kept below 80mA/cm2 at an applied voltage of 1.5V. In addition, we have tested various types of fluorine-based and hydrocarbon-based polymer electrolyte membranes. While two-membranes cells display definitely higher CEs than their counter parts, some membranes show comparable CEs even in a one-membrane cell. Therefore, development of PEMs suitable for this electrolytic cells is crucial in improving the cell performance. Optimization of the operating conditions, cell structures and types of membranes have been further carried out to enhance the reaction rates while maintaining the CEs high.
In conclusion, the two-membranes cells are estimated superior to the one-membrane cells because of their stability over long run though their reaction rates are somewhat lower than the latter.
Optimization of Mechanical Properties of Nickel-Cobalt Coatings from Sulphamate Baths
Authors: Karakaya Esra , Başkan Mertcan , Erdogan Metehan , Karakaya Ishak 
Published: February 2020

Nickel-cobalt alloys are important coating materials due to their magnetic properties [1-2],
wear resistance [3-4] and electrocatalytic properties [5]. Their deposition from sulfamate
electrolytes has many advantages including low internal stress, homogenous deposition at
high current densities, high current efficiencies and higher hardness as compared to the
conventional Watts electrolyte [6]. A statistical experimental design was used to study the
effects of boric acid and nickel chloride concentrations, bath temperature and applied current
density on nickel coatings in sulphamate baths. After the optimization of the electrolyte
composition, effects of pH and Co additions to the electrolyte were investigated. The coating
thickness and its distribution were measured by XRF techniques. Microhardness, surface
morphology and internal stress of coatings were also determined. It was found that Co
addition to the electrolyte and operation at higher pH yielded deposits of higher Co content
and enhanced hardness up to a certain point.
References
[1] A. Karpuz, H. Kockar, and M. Alper, J. Mater. Sci. Mater. Electron., 24 (2013) 3376-3381.
[2] G. Chatzipirpiridis, E. Avilla, O. Ergeneman, 50 (2014) 10-12.
[3] L. Xuewu, X. Yunhua, Q. Yi, and S. Lilong, Integr. Ferroelectr., 152 (2014), 144-151.
[4] L. Wang, Y. Gao, Q. Xue, H. Liu, and T. Xu, Appl. Surf. Sci., 242 (2005) 326-332.
[5] C. Hu, C. Tsay, and A. Bai, Electrochim. Acta, 48 (2003) 565-572.
[6] M. Saitou, S. Oshiro, and S. M. Asadul Hossain, J. Appl. Electrochem., 38 (2008) 309-313.
Profiled Anode Supported Solid Oxide Fuel Cells for Low Cost Stacks for Stationary Applications
Authors: Kluczowski Ryszard , Swieca Adam , Kawalec Michal , Kupecki Jakub , Krauz Mariusz , Naumovich Yevgeniy , Blesznowski Marcin , Zurawska Agnieszka , Skrzypkiewicz Marek , Motylinski Konrad 
Published: February 2020

This work presents the results of elaboration of technology dedicated to fabrication of anode supported solid oxide fuel cells (AS-SOFC) with profiled surface of the anode. Profile on anode support was designed as channels which allow to facilitate the fluxes of gaseous components to and from electrochemical reaction zone due to the decreased thickness on Ni-YSZ composites between ribs. Additionally profiling of the anode increases the active area and allows elimination of the profiled or corrugated interconnectors. At state-of-the-art, in order to collect current from the surface of AS-SOFC and to ensure proper distribution of the fuel flow, interconnects are made from special heat-resistant alloys with precise milled or stamped channels. Profiled anode supports will allow to distribute gaseous fuel and replace dual-side profiled interconnects by cheaper ones without introduction of additional treatments or parts.
In order to produce anode support with profiled surface without necessity of additional machining process of anode surface, the ceramic injection molding method (CIM) was used. This method significantly shortens the production time of the anode supports for AS-SOFCs, reduces its costs in comparison to commonly used techniques and is generates negligible amount of process waste material. This technique makes it possible to manufacture complex three dimensional ceramic components with tight dimensional tolerances. Cost-intensive post-processing can frequently be avoided, which allows high-scalable mass production of ceramic elements.
The mold for injection of anode support was designed to make an anode support of 50x50 mm with 1.4 mm of thickness. The profile consisted of 18 channels was fabricated along of one side of the support. Dimensions of each channel were 0.6 mm of depth and 1.5 mm of width (Fig. 1). The geometry of channels defined using numerical simulations and then adjusted to the technological requirements of CIM. Using this mold the anode supports consisted of NiO/8YSZ 66/34 wt.% with porosity of 25 vol.% were injected (Fig. 1). The screen printing method was used to print 3 µm thick NiO anode contact layer, 7 µm thick NiO/8YSZ 50/50 wt.% anode functional layer, 4 µm thick 8YSZ dense electrolyte, 1.5 µm thick Gd0.1Ce0.9O2 barrier layer and the 30 µm thick La0.6Sr0.4Fe0.8Co0,2O3–δ cathode with porosity 25 vol.%. Sintering conditions were adjusted to avoid the deformation of the anode
support.

Fig.1.

Schematic drawing of the profiled anode support (left) and the anode with fuel channels (right)

Fabricated AS-SOFCs were characterized by the microstructural analysis and electrochemical performance was measured.

Figure 1
In Situ TEM Observation of Dynamic Switching Behaviors in Vrram
Authors: Wu Min-Ci , Chen Jui-Yuan , Wu Wen-Wei 
Published: February 2020

Resistive random access memory (RRAM) is considered as a promising candidate for the next-generation nonvolatile memories (NVM) due to its high storage density, reduced power consumption, and fast switching speed. Transition metal oxides are widely utilized to RRAM as insulator, which exhibit stable structure, high endurance and retention, and shrinking ability under several nanometers.
In order to realize higher endurance and stability while reducing the size, knowing the mechanism of filaments formation and the interaction between adjacent nanodevices are essential. In this work, three-dimensional vertical RRAM (VRRAM) array architectures were built to access and organize data, which are expected to high density application potential. In our simple MIM structure, ZnO is the insulator, and Ag and Pt are served as active electrode and inert electrode, respectively. Each electrodes intersection contains two types of RRAM devices (Ag/ZnO/Pt, Pt/ZnO/Pt). By utilizing in-situ transmission electron microscope (TEM), we could observe the dynamic switching behaviors of two neighboring devices and realize the interaction between them. While the devices sizes scale down to few nanometers scale, the evolution of different types of filaments provides important information to improve the stability and performance of the devices.
Monte Carlo Model of Ion Conduction in Non-Arrhenius Glasses
Authors: King Clarence C , Beckman Scott P 
Published: February 2020

Ion conducting glasses are promising for use as electrolytes in all-solid-state batteries, which have the potential to both have higher volumetric energy density and overall safety than liquid electrolyte batteries. There are multiple studies that report non-Arrhenius conductivity in highly ionic conductive glasses. Although there are several theories proposed to explain this phenomena, as of yet, none of these have been verified.
Here we develop and deploy a Monte Carlo model of ion conduction to compare and contrast the theories of non-Arrhenius conductivity in glasses. In this relatively simple model ions hop between sites according Boltzmann statistics. The ions’ motion is coupled in the short range by geometrical factors, e.g., the network of interstitial sites and their occupancy, and in the long range by Coulomb interactions.
We further demonstrate that this model can be used to simulate the macroscale charging and discharging behavior of batteries. For these battery simulations, regions identified as cathode, electrolyte, and anode are identified. A jellium background charge is used in the electrolyte to maintain charge balance and used in the anode and cathode to account for the oxidation and reduction of the ions. This model accounts explicitly for the change in entropy during cycling and implicitly the overpotential that develops due to ion accumulation at the interfaces.
(Invited) How to Deal with Electrode Heterogeneity in Cell-Level Battery Modeling
Authors: Wheeler Dean R. 
Published: February 2020

As shown in Fig. 1, typical porous electrodes (in this case for a Li-ion anode) clearly have heterogeneity on the µm and smaller length scales. In addition, it has been shown that there is heterogeneity on mm length scale for even commercial quality electrodes [1]. This heterogeneity is a consequence of the particle-based manufacturing processes [2]. Furthermore, this heterogeneity is undesirable as it essentially requires that the electrodes be overdesigned to achieve adequate minimum performance.
The commonly accepted Newman-type model of the full-cell sandwich essentially averages over local heterogeneities in porous electrodes in order to make the system “macrohomogeneous.” The resulting model allows for uniform pathways for electrons and ions. Homogenization of the microstructure greatly decreases the computational cost of the model while retaining the essential physics of transport and reaction within the electrodes.
In this presentation I will discuss how one can measure heterogeneities as well as average values of electronic and ionic conductivities [1,3]. These can be compared to empirical correlations such as the Bruggeman equation. Our group has considerable experience in this area.
With respect to modeling, I will discuss strategies for dealing with heterogeneities in the context of Newman-type models. This can include using multiple particle types [4] as well as effective medium theories that allow one to average local values of physical properties to generate an overall or effective medium property. Lastly, I will discuss what effect such averaging has on predictions of the battery model.
This work was supported by the U.S. Department of Energy through the BMR program.
[1] Lanterman et al., J. Electrochem. Soc. 162, A2145 (2015).
[2] Forouzan et al., J. Power Sources 312, 172 (2016).
[3] Zacharias et al., J. Electrochem. Soc. 160, A306 (2013).
[4] Thorat et al., J. Electrochem. Soc. 158, A1185 (2011).
Fig. 1 SEM/FIB cross section of Li-ion anode showing local heterogeneity.

Figure 1
(Invited) Modeling Battery Performance Due to Volume Change in Porous Electrodes
Authors: Garrick Taylor R , Weidner John W. 
Published: February 2020

In order to accurately predict the behavior of electrochemical devices, it is necessary to develop sophisticated models that take into consideration transport processes, electrochemical phenomena, mechanical stresses, and structural deformations on the operation of an electrochemical system. Many different models exist that can predict the electrochemical performance of these devices under a variety of operating and design conditions. In many of these models, the porosity of a porous electrode is often assumed constant since the volume changes seen during the intercalation reaction can be small. However, electrode materials developed in recent years show significant volume changes during intercalation, which are unable to be accurately predicted using these constant porosity models.
Porosity and dimensional changes in an electrode can significantly affect the resistance of the battery during cycling and can cause premature failure of the battery due to generated stresses. Previously[1-5], we have shown the ability to incorporate dimensional and porosity changes in a porous electrode into a model to predict volume changes in the active material of a single electrode during intercalation through the coupling of porous rock mechanics and porous electrode theory. Many assumptions were used to obtain an analytical solution, including the assumption of bulk strain, uniform porosity, and uniform concentration across the electrode.[2] This model was extended to look at design considerations[5] as well as non-uniformity within a single porous electrode coupled to a lithium metal reference.[4] Here, we present a model that removes some of these assumptions and illustrates the coupling of porous electrode theory and rock mechanics in order to predict stress, strain gradients, and porosity gradients across a porous electrode during cycling in a battery containing a blended anode undergoing volume change coupled to a Lithium Nickel Manganese Cobalt Oxide (NMC) cathode.[6] In this model, we will examine separator deformation, volume change during high charge rates, and consider pressure generated in the cell due to restriction in a battery module.

P. M. Gomadam and J. W. Weidner, J Electrochem Soc, 153, A179 (2006).

T. R. Garrick, K. Kanneganti, X. Y. Huang and J. W. Weidner, J Electrochem Soc, 161, E3297 (2014).

T. R. Garrick, Y. Dai, K. Higa, V. Srinivasan and J. W. Weidner, Ecs Transactions, 72, 11 (2016).

T. R. Garrick, K. Higa, S.-L. Wu, Y. Dai, X. Huang, V. Srinivasan and J. W. Weidner, J Electrochem Soc, 164, E3592 (2017).

T. R. Garrick, X. Huang, V. Srinivasan and J. W. Weidner, J Electrochem Soc, 164, E3552 (2017).

K. Higa, S. Wu, D. Y. Parkinson, Y. Fu, S. Ferreira, V. Battaglia and V. Srinivasan, J Electrochem Soc, 164, E3473 (2017).
Modeling of Lithium Sulfur Battery with Microscopically Consistent Parameterization
Authors: Chung Jui-Hui , Chen Hsun-Yi 
Published: February 2020

Lithium sulfur (Li-S) batteries are considered a promising energy storage technology for that its theoretical specific capacity of 1.672 Ah g-1 is over five folds of currently commercialized lithium-ion batteries. The charge/discharge processes of Li-S batteries, however, involve complex reactions of sulfur species and are not yet fully understood. Physical models are crucial to elucidate these mechanisms occurring in Li-S batteries in assisting a multitude of experimental investigations.
However, previously developed models are usually overly simplistic and lack generality. The first one-dimensional Li-S model employed dilute solution theory including diffusion and migration, where transport properties base only on interactions between the solute and the solvent. In the case of multicomponent transport, ion pairing and ion association are important. Therefore, we integrate concentrated solution theory to the macroscopic model to incorporate effects of multi-valent states of sulfides.
Comparing our concentrated solution theory results to those of dilute solution theory, the discharge curves resembled one another, suggesting concentration polarization took little part in the overall potential loss under current parameterization. Thus, we investigate interrelated components of potential loss, namely the surface overpotential, ohmic potential drop, and concentration overpotential. Fig 1 shows that the modeled discharge rate capability is limited by the anode surface overpotential. This result is inconsistent with previous studies, where the low discharge rate has been explained in terms of mass transport limitation and slow charge transfer at the cathode due to precipitation of Li2S. We consider the lack of reliable parametrization is to blame for the inconsistency, and seek to resolve the parameter-prediction problems inherent in computational models.
To simulate multicomponent diffusion in concentrated solutions, we compute the full transport properties through the representation of Onsager coefficients matrix (Fig 2) and thermodynamic factors using equilibrium molecular dynamics (MD). In addition, we report a theoretical analysis of sampled-current voltammetry based on concentrated-solution to compute the exchange current density, which is not previously established. We emphasize the mathematical consistency among the formulation of modeling equations, experimental methods, and MD methods to achieve fidelity in simulations.

Figure 1
A Defect Density Profile Extraction Method for GaN Epi-Wafers
Authors: Kataoka Hiroaki , Hoshii Takuya , Muneta Iriya , Wakabayashi Hitoshi , Tsutsui Kazuo , Iwai Hiroshi , Kakushima Kuniyuki , Yamamoto Taiki 
Published: February 2020

Owing to the wide bandgap and high-mobility of GaN compared to that of Si, GaN power devices are expected to perform low on-resistance at high withstand voltage. However, due to the presence of defects in the crystal, GaN epi-wafers contain lots of traps sites which results in malfunction during the device operation; current collapse and so on [1]. As the defects are distributed in the whole epi-layer, it is difficult to extract the defect density profile from cyclic voltammetry. In this presentation, we propose a method to extract defect density profile in the GaN epitaxial wafer.
When a DC voltage (V) is applied to an Ohmic electrode connected to 2DEG at AlGaN/GaN interface, the entire epi-layer will depleted (t=0+) and a charge of Qcap
(=CcapV) will appear at both electrodes. At steady state (t=∞), the depletion layer shrinks back depending on the active defect concentration. The thickness of the depletion layer (z) can be extracted by the charges (Qdep
), which is the integral of current until the steady state is reached using the Cdep
=QdepV
-1 relation. Since we have the relation between V and z, the defect density profile at the position x, ρ(x), can be extracted using eq.1. Where q and ε are the elementary charge and the dielectric constant of GaN, respectively.
Figure 2 demonstrates the defect density profile extracted with the proposed method on AlGaN/GaN/buffer structure on a Si substrate. Here, buffer was used to reduce defect density. A distinctive change in the defect profile can be seen at x=4μm, which corresponds to the position where the epitaxial process has been changed.
In summary, a novel method to extract the defect density profile in the GaN epi-wafer has been proposed.
[1] T. Hashizume, etc., IEICE technical report, 104 (2004).

Figure 1