bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrodeposition of AuxAg1-X Alloys from Thiosulfate Solutions
Authors: Vasiljevic Natasa , Cruz-San Martin Vinicius , Sarua Andrei , Cattelan Mattia , Fox Neil A.
Published: December 2020

Silver (Ag) and gold (Au) are noble metals of particular interest for future plasmonic, and (bio)sensing applications due to their unique coupling with light in the visible range.[1,2] Recent studies suggest that AuxAg1-x alloy nanostructures of different geometry, composition and size can exhibit interesting new optical phenomena.[3,4,5] Therefore developing new environmentally-friendly (cyanide-free) electrodeposition route to fabricate AuxAg1-x alloys is desirable.[6] Thiosulphate-based solutions are less toxic, and this solution was previously studied for pure Au,[7] pure Ag [8] and recently for AuxAg1-x alloys.[6]

In this work, we will present a systematic study of electrodeposition of AuxAg1-x alloys from thiosulphate solutions on Au and indium-tin-oxide (ITO) substrates. Thin-film alloys (20 nm-100 nm thickness on Au on ITO) of different compositions were electrodeposited by variation of Ag+: Au+ ion concentrations in the solution. The structure of the deposited alloys was explored as a function of the electrodeposition potential and film thicknesses by Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM). Chemical composition of the electrodeposited alloys was determined using X-Ray Photoemission Spectroscopy (XPS).

The electrodeposition on the two substrates showed higher Ag content in the films than expected from the solution composition ratios. Comparison of the linear sweep voltammetry for deposition of alloys on Au and ITO show that the potential at which alloys start depositing for ITO is more negative than on Au. Stoichiometry of films varied between Au20Ag80 to Au50Ag50. Diffusion-limited deposition of alloys at lower overpotentials produced smooth, homogenous films on Au substrates; at potentials higher than 1 V vs MSE, hydrogen-evolution reaction assisted non-uniform growth and formation of instabilities at the surface in both substrates. The electrodeposited alloys were characterised by surface composition and structure sensitive UPD processes such as Pb UPD and Cu UPD. The results showed a correlation between the UPD peaks potential shifts and the UPD charge with alloy compositions.

References

[1] W. A. Murray, W. L. Barnes, Adv. Mat.,
19 (2007) 3771-3782.

[2] P.K. Jain, X. Huang, I.H. El-Sayed, M.A. El-Sayed, Acc. Chem. Res.,
41 (2008) 1578-1586.

[3] G. Guisbiers, R. Mendoza-Cruz, L. Bazan-Diaz, J. J. Velazquez-Salazar, R. Mendoza-Perez, J. A. Robledo-Torres, J. L. Rodriguez-Lopez, J. M. Montejano-Carrizales, R. L. Whetten, Jose-Yacaman, M. ACS Nano,
10, 1 (2016) 188-198.

[4] C. Gong, M. S. Leite, ACS Photonics,
3, 4 (2016) 507-513.

[5] G. Wang, X. Chen, S. Liu, C. Wong, S. Chu, ACS Nano,
10, 2 (2016) 1788–1794.

[6] D. A. McCurry, M. Kamundi, M. Fayette, F. Wafula, N. Dimitrov, ACS Appl Mater Interfaces,
3, 11 (2011) 4459-4468.

[7] A. M. Sullivan, P. A. Kohl, J. Electrochem.
Soc.,
144, (1997) 1686.

[8] V. Vandeputte, A. Hubin, J. Vereecken, Electrochem. Acta,
42, 23-24 (1997) 3429-3441.
The Effect of Leveler in Cu Electroplating Solution on the Bump Reliability of Flip Chip Packaging
Authors: Jo Yugeun , Lee Woon-Young , Lee Dong-Ryul , Jin SangHoon , Lee Min-Hyung
Published: December 2020

From the previous studies [1,2], it was well known that the voids at the interface of copper (Cu) and tin-silver (Sn-Ag) severely affects the bump reliability of flip chip packaging. And it was also suggested that impurity atoms existing in electroplated Cu film accelerate those voids formation [3]. So, in this study, we investigated the impact of leveler of Cu electroplating solution on the non-metallic impurities of electroplated Cu film and the voids at the interface of Cu and Sn-Ag solder was studied. We have found that the non-metallic impurity concentration was dominantly influenced by the adsorption characteristics of leveler. Fig. 1(a) shows the non-metallic impurity concentration in the electroplated Cu films using the electroplating solution containing different leveler. We can lower the total non-metallic impurity concentration to 14.9 ppm by changing the leveler. And we confirmed that 90% of voids at the interface of Cu and Sn-Ag solder can be reduced even after high temperature storage test at 150°C for 1000 hours, as shown in Fig. 1(b).

Reference

[1] C.Y. Liu, K.N. Tu, T.T. Sheng, C.H. Tung, D.R. Frear, P. Elenius, J. Appl. Phys. 87, 750 (2000)

[2] P.S. Teo, Y.-W. Huang, C.H. Tung, M.R. Marks, T.B. Lim, 50th Electronic Components and Technology Conference, Las Vegas, NV, USA, p. 33 (2000)

[3] T. Laurila, V. Vuorinen, J.K.Kivilahti, Mater. Sci. Eng. R, 49, 1 (2005)

Figure 1
Modelling Electrochemical Polishing of Additive Manufactured Parts. Limits of Secondary Distribution Model in Circulating Flow
Authors: Boucher Aurelien , Fedi Baptiste , Doche Marie-Laure , Hihn Jean-Yves
Published: December 2020

Additive manufacturing allows to design and to realize parts with complex geometries, which were difficult, even impossible, to obtain by conventional means. Nevertheless, the final surface finish obtained at the end of the 3D printing process do not fit with technological specifications especially due to high roughness levels. Thus, an additional finishing step must be implemented in order to get the expected surface finish. Electrochemical polishing is of great interest because it allows, as main advantage comparatively to tribological ones, to be able to deal with small parts exhibiting high complex shapes and/or material hard to be polished [1]. Electropolishing is an electrolytic process based on the anodic dissolution of the workpiece under constant current or potential [2]. As it is done for electroplating systems, it is nonetheless necessary to uniformize the current distribution lines in the treatment cell, in order to optimize the effect of the finishing on the whole surface of the parts. The ability to provide a relevant simulation of the processing by the help of an accurate modelling is a major issue to ensure its industrial deployment through the development of specific tools and the selection of relevant operating parameters [3]. These processes can be considered as a succession of unitary steps, in order to get the expected degree of surface state; and the simulation may be of great help in the design of the full treatment line-up. In this objective, the use of a secondary current distribution model is a useful first step and gives interesting results if special care is paid to the specificity of electropolishing processes. However, this approach faces limitations because of the agitation into the treatment cell which is not accounted for by the model. A correction is possible by integrating the influence of an average level of agitation on the polarization curves (current vs potential) used in the simulation. The present work describes this model based on secondary current distribution upgraded by considering a global agitation and presents comparison between experimental results and simulations. Eventually, even if the enhanced model improve the prediction ability of the model in term of dissolution rates and roughness reduction, some discrepancies confirms the need to reach a more accurate model, and the conclusion is that the local agitation knowledge at the surface vicinity of the surface to be polished is crucial.

[1] C. Rotty, A. Mandroyan, M-L Doche, J-Y Hihn, Surface & Coatings Technology 307, 125–135 (2016)

[2] P. A. Jacquet, Nature 135,1076 (1935)

[3] V. Urlea, V. Brailovski, Int. J. Adv. Manuf. Technol. 92, 4487–4499 (2017)

Figure 1
Electrolyte Solvation Chemistry for the Sustainable Lithium Metal Batteries
Authors: Lee Seon-Hwa , Sun Yang-Kook
Published: December 2020

The rechargeable battery using metallic Li as a counter electrode for Ni-rich Li[NixCoyMn1-x-y]O2 cathode (LMB) is strongly considered to be one of the most promising energy storage technology because of their high-energy density. Especially, LMB using commercial ester-based electrolyte, which appropriate for high-voltage application, has been widely studied to effectively increase the energy density. However, LMB have been plagued by the issue of rapid consumption of electrolyte and usable Li due to thermodynamically instability of Li metal anode. [1-3] Therefore, the key issue in developing a sustainable LMB lies in understanding how to improve the interfacial stability between anode and electrolyte. For the first time, here we propose the new effective solvation strategy in ester-based electrolyte enabled by Mg(NO3)2, which can alter the solvation structure of lithium ions and form a stable solid electrolyte interphase on the Li metal surface.

References

S.-J. Park, J.-Y. Hwang, C. S. Yoon, H.-G. Jung and Y.-K. Sun, ACS Appl. Mater. Interfaces
2018, 10, 17985.

S. H. Lee, J.-Y. Hwang, S.-J. Park, G.-T. Park and Y.-K. Sun, Adv. Funct. Mater.
2019, 29, 1902496.

J.-Y. Hwang, S.-J. Park, C. S. Yoon and Y.-K. Sun, Energy Environ. Sci., 2019,12, 2174.
(Battery Division Technology Award Address) Integrating Materials Science, Electrochemistry and Engineering in Energy Storage Technologies
Authors: Xiao Jie
Published: December 2020

Electrochemical energy storage has been a very hot topic in the last decade. Many efforts have been pursued in identifying new battery materials or technologies for a broad range of applications such as grid energy storage, vehicle electrification, mobile electronics and so on. This talk will highlight the importance of interdisciplinary research but also emphasize the urgent need to identify and address real challenges at relevant scales for battery systems. Three examples will be discussed: (1) Single crystal Ni-rich cathode for advanced Li-ion batteries, (2) next-generation of rechargeable lithium metal battery and (3) microbattery technologies for miniaturized sensors to encourage the integration of materials chemistry, electrochemistry and engineering to overcome the roadblocks for developing advanced battery technologies.
Electrochemical Manufacturing of a p-n Junction Employing Water Solutions
Authors: Felici Roberto , Carla Francesco , Fontanesi Claudio , Giaccherini Andrea , Russo Francesca , Di Benedetto Francesco , Innocenti Massimo
Published: December 2020

Our society relies on the use of semiconductor devices, which are, so far, fabricated using expensive and complex processes requiring ultra-high vacuum equipment. Here we report on the possibility of growing a p-n junction taking advantage of electrochemical processes based on the use of aqueous solutions. The growth of the junction has been carried out using the Electrochemical Atomic Layer Deposition (E-ALD) technique, which allowed us to sequentially deposit two different semiconductors, CdS and Cu2S on a Ag(111) substrate, using water based solutions containing Cd2+, Ag+ and S2- precursors [1,2]. The main problem, encountered when growing this kind of systems, is related to the unattainable electrochemical characterization of the deposition conditions for the different elements without altering the already deposited layers.

This problem was overcome by performing an in-situ x-ray characterization of the grown layers during the E-ALD process. By this procedure, we were able to find the conditions at which the deposition resulted in the formation of thin layers with crystallographic ordered structures and reduced surface/interface roughness. The electronic transport properties of samples, made of 9 nm of Cu2S on top of 10 nm of CdS, have then been determined ex-situ. The samples showed a good stability in air and the I-V characteristic, measured in several positions of the sample, to investigate the homogeneity of the response, is the one typical of a diode.

The present study is funded by the PRIN Project (“Progetti di Ricerca di Rilevante Interesse Nazionale”), “Novel Multilayered and Micro-Machined Electrode Nano-Architectures for Electrocatalytic Applications (Fuel Cells and Electrolyzers)”, grant number 2017YH9MRK.

References

[1] F. Carlà, et al., The Journal of Physical Chemistry C 118 (2014) 6132-6139

[2] A. Giaccherini, et al., Scientific reports 7 (2017) 1-10
Electrodes Two-Phase and pH Boundary Layers Multiphysics Modelling in a Hydrodynamic Alkaline Water Electrolyzer
Authors: Mandin Philippe , LE Bideau Damien , Sauvage Thierry
Published: December 2020

The presented work is a multiphysics calculation using Ansys-Fluent® CFD modelling of a hydrodynamic alkaline water electrolyzer. This work will start with an exhaustive review of the transport properties necessary for the multiphysics modelling of alkaline water electrolyzer. A recently published article provides experimental data and the correlations needed to calculate thermo-physical properties such as electrical conductivity, density, viscosity, heat capacity, heat and mass transfer diffusion coefficients as a function of temperature and electrolyte mass fraction for two classical alkaline electrolytes (KOH, NaOH). Different interpolation models from various authors are compared to raw experimental data. The goal of this work was to give to the modeler the correlations needed for the simulation of alkaline water electrolysis.

Thus, the two electrodes two-phase boundary layers can be calculated with precision. Calculations under discrete phase modelling (DPM) and Euler-Euler hypothesis have been performed and are presented.

Figure 1
Integrated Alkali-Electrochemical Process for Wastewater Treatment
Authors: Jafari Maasoomeh , Botte Gerardine G.
Published: December 2020

Solid waste mismanagement causes environmental contamination. Sewage sludge is the byproduct of the wastewater treatment process and contains pathogenic organisms (e.g Salmonella spp., Escherichia coli, etc.). Anaerobic digestion is widely used for sewage sludge treatment. However, the major drawback of this process is the sluggish rate of sludge biodegradation. Therefore, the retention time in the typical digester is long (between 20-30 days) which consequently results in substantial energy consumption. On the other hand, approximately 50- 60 % of the operational cost in the wastewater treatment plant is dedicated to the treatment and disposal of waste. Hence, it is essential to develop a treatment method to decrease energy consumption.

Alkaline treatment is an attractive process for sludge destruction and improvement in the sludge biodegradability. Furthermore, electrochemical oxidation of the organic materials is an environmentally friendly alternative pathway to disintegrate the sludge microbial cells and eliminate the pathogen bacteria from biosolid for safe disposal. Therefore, the combined alkaline electrochemical technique could expedite waste degradation by using the synergetic functions and increase efficiency of the treatment.

To overcome the challenges related to the conventional treatment method, our research group has developed a novel, energy-efficient mixed alkali-electrochemical sludge treatment in a membraneless electrochemical system at room temperature and low applied potential. In this study, the bimetallic (platinum-iridium) nanocatalyst was synthesized with modified polyol method. The thermal behavior of the raw sludge and the residue biosolid after electrolysis was evaluated by using thermogravimetric analysis (TGA). To determine the effect of electrolysis on the chemical structure of biosolid, the Fourier-transform infrared spectroscopy-Attenuated Total Reflection (FTIR-ATR) and elemental analysis techniques were applied. Ammonia was produced as a byproduct of the waste treatment which can be converted to hydrogen through electrolysis. A considerable amount of solid reduction was achieved by implementing a short electrolysis treatment which diminished the waste transportation and disposal cost to a large extend. Furthermore, the energy consumption was significantly lower than the previous research studies. In this presentation, results from this study including (i) the electrochemical performance of catalyst for sewage sludge treatment (ii) pathogen disinfection and (iii) biosolid characterization will be provided.
Mild Synthesis of Cyclohexanol and Cyclohexanone Via Electrocatalytic Reduction of Phenols Using Dispersed Metal Catalysts
Authors: Wijaya Yanuar Philip , Smith Kevin J. , Kim Chang Soo , Gyenge Elod
Published: December 2020

Cyclohexanol and cyclohexanone are industrially important chemicals for the synthesis of Nylon polymers. On the industrial scale, they are produced by thermocatalytic processes, either phenol hydrogenation (140–170 oC, 1 atm) or cyclohexane oxidation (140–180 oC, 0.8–2 MPa), which require high temperatures and external gas supply. This work demonstrates that electrosynthesis of cyclohexanol and cyclohexanone can be done at mild conditions using diverse aqueous electrolytes and dispersed metal catalysts (Pt/C, Ru/C, and Pd/C).

Electrocatalytic hydrogenation (ECH) of lignin-derived phenols (e.g., guaiacol and phenol) is performed in a stirred slurry H-cell under potentiostatic or galvanostatic control. Dilute mineral acid (H2SO4, HClO4), organic acid (CH4SO3), and inorganic salt (NaCl) worked efficiently as the electrolyte solutions. In the ECH of guaiacol at low temperatures (35–40 oC) and low Pt/C loading, high guaiacol conversions (83–96%) and Faradaic efficiencies (40–70%) were achieved with significant cyclohexanol selectivities (45–53%) after 4 h reactions. In the ECH of phenol, full conversion to cyclohexanol was achieved after 2 h with high current efficiency (90%). Remarkably, by pairing the NaCl catholyte and H2SO4 anolyte, the activity of Ru/C and Pd/C can be dramatically improved, showing the importance of electrocatalyst and electrolyte synergy in the ECH of phenolic compounds.

The stirred slurry catalyst allows the cell to operate at the industrially relevant current densities (in this work, between 100–300 mA cm-2). Dispersion of the negatively charged catalyst particles in the solution also facilitates the mass transfer between the organic molecules and chemisorbed hydrogens through physical collisions during the reaction, thereby improving the ECH efficiency. Mild electrocatalytic reduction of phenolic compounds represents a promising route for selective and efficient production of renewable chemicals from biomass.
Synthesis and the Cathode Properties of Na3Fe3(PO4)4 for Sodium-Ion Battery
Authors: Okada Masaki , Chiba Kazuyuki , Matsunaga Osamu , Kobayashi Wataru , Takahara Toshiya , Takahashi Kennichi , Okada Shigeto
Published: December 2020

Na-ion batteries (NiBs) are very attractive and promising for large scale electric power storage system because of the abundance for sodium source, the high cost-effectiveness and the long lifetime. Among the candidate of cathode active materials for NiBs, practical use of iron phosphate such as NaFePO4, Na2FePO4F, and Na3Fe3(PO4)4 [1] or carbonophosphate such as Na3FePO4CO3 [2] is expected from the viewpoint of cost and safety. In order to make full use of the resource and cost advantages of these materials, the raw materials used in the synthesis and the synthesis method are also important. In this presentation, we report the direct synthesis of Na3Fe3(PO4)4 by the hydrothermal method with mass productivity and the cathode properties.

Synthesis was carried out using ferrous sulfate hydrate (FeSO4·nH2O), phosphoric acid, and various sodium phosphate salts as sodium sources with various the raw material composition, hydrothermal treatment temperature, and reaction time. For the purpose of controlling the reaction, synthesis was performed under the condition that an oxidizing agent or a reducing agent was added. The obtained compounds were identified by powder X-ray diffraction measurement and Rietveld analysis.

Iron (Ⅱ) sulfate (FeSO4·7H2O), phosphoric acid (H3PO4), sodium dihydrogen phosphate (NaH2PO4·2H2O) and sodium persulfate (Na2S2O8) were used as raw materials, and hydrothermal synthesis was performed at 200 ° C for 16 hours. From the Rietveld analysis, the obtained compound was assigned to the layered structure Na3Fe3(PO4)4. This hydrothermal synthesis Na3Fe3(PO4)4 delivered initial discharge capacity of 160mAh g-1 between -1.2 and 1.3 V with a reference electrode of Ag/AgCl at 2 mA cm-2 in the 17 m NaClO4 aqueous solution (Figure 1). In the presentation, we will be reported the details of cathode properties of Na3Fe3(PO4)4.

References:

[1] G. S. Shinde, R. Gond, M. Avdeev, C. D. Ling, R. P. Rao, S. Adams, P. Barpanda, Mater. Res. Express, 7 (2020) 014001.

[2] B. Xie, R. Sakamoto, A. Kitajou, K. Nakamoto, L. Zhao, S. Okada, Y. Fujita, N. Oka, T. Nishida, W. Kobayashi, M. Okada, T. Takahara, Sci. Rep., 10 (2020) 3278.

Figure 1
Safe and Flexible Chitosan Gel Electrolyte Based Zn-MnO2 Alkaline Batteries
Authors: Madan Deepa , Negrete Karla , Poosapati Aswani , Vadnala Sudarshan
Published: December 2020

This work examines the use of naturally occurring chitosan with additives in a gel electrolyte and its efficient incorporation in safe, cost-effective, and rechargeable Zinc-EMD batteries. This study demonstrates (1) an energy and time efficient, scalable stage-wise preparation technique for achieving highly conducting (457mS/cm), flexible, electrochemically & thermally stable chitosan polymer electrolyte with PVA and KOH additives, along with their morphological and structural studies. This work also demonstrates (2) a robust and unique assembly technique employed to achieve good electrode/electrolyte interfacial contact when constructing a complete battery with the devised electrolyte to test its performance. (3) Employing a selective, limited potential window during galvanostatic charge-discharge tests; this work also achieved high specific capacity (310mAh/g) with good reversibility (170cycles) for Zn-EMD alkaline batteries using no cathode additives. The selective potential window approach helped utilize the available high capacity of EMD (γ-MnO2) through the two-step reduction process in addition to hindering the irreversible δ-MnO2 formations which usually hampers rechargeability in Zn-EMD alkaline batteries. The overall performance (70% capacity retention w.r.t initial, 97% and 110Wh/kg avg. energy density w.r.t cathode mass) recorded for the constructed battery with the devised gel electrolyte is comparable to the reported performances of Zn-EMD batteries with gel/liquid alkaline polymers in the literature. Culminating the electrochemical studies done on the assembled cell, it is possible to claim the successful rechargeability of our secondary batteries, which utilize novel alternative gel electrolyte fabrication methods that accommodate reversible zinc-reactions and novel cell assembly techniques.
(Invited) Fast Determination of Lithium Content and Failure Mechanism for NMC Cathodes
Authors: Ban Chunmei
Published: December 2020

The first demonstration of intercalation chemistry in transition metal dichalcogenides by Prof. Whittingham inspired enthusiastic research in developing electrochemical energy storage systems (such as lithium-ion batteries) and seeking new intercalation host materials such as transition metal oxides. Among transition metal oxides, cobalt-substituted series compounds with the general formula of LiNixMnyCozO2 (NMC, x+y+z=1) have been extensively studied as high-energy cathodes; and their efficient interaction reactions have led to their successful commercialization in lithium-ion batteries. As a complement to the study to further improve intercalation chemistry and surface stability, this presentation will introduce a new methodology to fast determine degradation mechanism and lithium ion content in aged NMC cathodes, without using the coupled plasma-mass spectrometry (which involves tedious procedures and error-prone preparation). When combining with in-situ characterization and electrochemical analysis, this presentation will also discuss possible degradation mechanisms at various operation temperatures and electrochemical methods for battery performance restoration.
Welcome Remarks - A01: Intercalation Chemistry for Electrochemical Energy Storage Technologies: In Honor of M. Stanley Whittingham
Authors: Xiao Jie
Published: December 2020

Welcome to A01: Intercalation Chemistry for Electrochemical Energy Storage Technologies: In Honor of M. Stanley Whittingham! Take a moment to listen to welcome remarks from the lead organizer, Jie Xiao.
Using Impedance to Quantify Transport Losses in Alkaline Water Electrolysis Electrode Catalyst Layers
Authors: Reumert Alexander Kappel , Sunde Svein
Published: December 2020

Anthropogenic climate change has brought on a global climate crisis and emergency. Increased levels of atmospheric carbon dioxide levels has brought with it undesirable changes to the world’s climate. To halt and eventually stop this trend the world needs to move to zero-carbon sources of electricity, transport and chemical production.

To offset the variability in zero-carbon electricity sources storage or usage of the excess energy is necessary. One of several technologies to achieve this is water electrolysis. A promising candidate of this field of study is Alkaline Water Electrolysis

The field of alkaline electrolysis have recently moved from a gap-based macro-material approach to a nanomaterials based membrane cell architecture.

Due to recent advances in membrane technology both ion-conduction and electrolyte solvating membranes allow for a zero-gap cell architecture. With this approach comes new engineering challenges. Bubble formation, -diffusion, -suppresion, and –transport are all phenomena that are relatively unexplored in the context of nanopowder-based electrodes in fully flooded aqeous KOH systems.

One of the ways of exploring this is the use of Galvanostactic Electrochemical Impedance Spectroscopy (GEIS).

Through GEIS investigations and Distribution of Relaxation Times of the electrochemical response of nano-powder based cathodes a Gerischer-like response can be observed indicating transport issues and a way of quantifying this.
The Application of Indirect Impedance to Monitor Corrosion Rates of Inhibitor-Impregnated External Post-Tensioned Tendons
Authors: Silnutzer Justin , Alexander Christopher Lewis
Published: December 2020

An indirect electrochemical impedance spectroscopy method was previously explored as a potential nondestructive method for detecting corrosion of steel in post-tensioned tendons which are used as reinforcing structural elements in segmental bridge construction. The tendons are composed of a grout-filled cylindrical plastic duct that contains high-strength steel strands. A proof of concept was demonstrated by experiments performed on tendons with passive and corroded strands and through finite-element simulations of the indirect impedance response.1 Further work showed that the indirect impedance method was sensitive to local corrosion in field tendons if the measurement is obtained near the corroding region.2

This work expands the application of the indirect impedance methodto corrosion monitoring of inhibitor-impregnated post-tensioned tendon sections. A corrosion inhibitor that is injected into the tendons through the interstitial space of the strands may be capable of preventing or stopping corrosion. The sensitivity of indirect impedance measurements to changes in both electrical properties of the grout and the corrosion rate of the steel is assessed by comparison to traditional measurements of the impedance in which direct contact is made to the steel. Additionally, further assessment of the indirect impedance method is made by relating the analysis results to the actual corrosion damage obtained by autopsies of the tendon sections.

C. L. Alexander and M. E. Orazem. "Indirect Impedance for Corrosion Detection of External Post-tensioned Tendons: 2. Multiple Steel Strands." Corrosion Science 164 (2020): 108330.

C. L. Alexander and M. E. Orazem. "Indirect electrochemical impedance spectroscopy for corrosion detection in external post-tensioned tendons: 1. Proof of concept." Corrosion Science164 (2020): 108331.
(Invited) Development of Polymer Electrolyte Membrane Fuel Cell Models for Transportation Applications Using Sequence of Direct Simulation Methods
Authors: Shimpalee Sirivatch , Satjaritanun Pongsarun , Dutta Sandip , Van Zee John William , Weidner John W. , Hirano Shinichi
Published: December 2020

Augmentation of fuel cell performance at high current densities, particularly under automotive application, is important to improve the overall power density and to reduce the cost of proton exchange membrane fuel cell (PEMFC) systems. Primarily, the fundamental non-linearity of the equations governing PEMFC performance on a three-dimensional model necessitates iterative solutions. As of now, mass transport over-potential is a major barrier to achieving high performance at a high current density. Condensed water, specifically in the gas diffusion layer, decreases oxygen transport to the oxygen reduction reaction area. Experimental investigations of oxygen transport are limited by an inability to resolve the water saturation-dependent properties.

The alternative approach to comprehend and overcome transport resistances, predominantly inside the gas diffusion layer, is to use advanced mathematical modeling. The timeline of direct simulation techniques using in PEMFC will be presented including the Lattice Boltzmann method (LBM) which is an alternative advanced modeling technique [1-12]. This LBM can be implemented into existing models to visualize the transports inside the structure of microscale geometries, such as: a gas diffusion layer (GDL), micro porous layer (MPL), and catalyst layer (CL). The study where the goal was to couple the conventional computational fluid dynamics (CFD) model in the macroscale geometry and LBM in the microscale geometry using the technique called co-simulation will be presented. The understanding of local kinetic activity inside nanoscale CL implemented into the model will also be discussed. The completion of this model development can enhance the potential capability of a model-based investigation of mass and heat transports to find solution of designs and operational conditions in the PEMFC for automotive applications.

References:

S. Dutta et al., J of Applied Electrochemistry, 30, 135-146, 2000

S. Shimpalee et al., J. of Power Source, 135, 79 – 87, 2004.

S. Shimpalee et al., J. of Power Sources, 160, 398-406, 2006.

S. Shimpalee et al., Int. J. of Hydrogen Energy, 32/7, 842-856, 2007.

S. Shimpalee et al. Electrochemica Acta, 54, 2899-2911, 2009.

S. Shimpalee, J. of Electrochem. Soc, 161(8), E3138-E3148, 2014.

V. Lilavivat et al., Electrochimica Acta,174,1253–1260, 2015.

S. Shimpalee et al., J. of Electrochem. Soc., 164(11), E3073-E3080, 2017.

P. Satjaritanun et al., J. of Electrochem. Soc., 164(11), E3359-E3371, 2017.

P. Satjaritanun et al., J. of Electrochem. Soc., 165(13), F1115-F1126, 2018.

S. Shimpalee et al., J. of Electrochem. Soc., 166(8), F534-F543, 2019.

P. Satjaritanun et al., J. of Electrochem. Soc., 167(1), 013516, 2020.
Unified Framework for the Finite Element Modeling of Li-Based Batteries with Liquid Electrolyte
Authors: Andrei Petru , Tan Kenley
Published: December 2020

Despite the high demand for accurate electrochemical simulations tools that can compute the d.c. (charge and discharge), a.c. (i.e. electrochemical impedance spectroscopy), and transient characteristics of electrochemical devices, there is currently a lack of such simulation environments in the literature. Most often, the different research groups and institutions are writing their own custom simulators that usually work only for specific battery configurations and chemistries. Even more advanced commercial simulators, such as Comsol Multiphysics, have a few modules that can simulate batteries, however, these modules can simulate only specific chemistries such as Li-ion or Li-air batteries and do not have a more general electrochemical device simulator that can simulate any general, user-designed device.

In this presentation, we summarize our efforts to build such a tool, starting from the numerical implementation of the transport models to problems associated with the discretization and numerical solution of transport equations. We focus on how to design a unified framework for designing electrolytes, modeling ion transport in the electrolyte and electron transport in the electron conductive materials, and interface phenomena such as double layer effects, SEI layers, and the multitude of possible chemical and electrochemical reactions that can take place once the system is designed. In our tool, the transport in the electrolyte is governed by a modified concentrated solution theory written in the form of a generalized Nernst-Planck model. The a.c. analysis is performed by linearizing the discretized system of differential equations and using the linear perturbations theory on the finite element grid. More details about the formulation of the mathematical model, state variables, electrochemical reactions, microstructure modeling, and numerical implementation will be discussed at the conference. Specific examples for the simulation of Li-ion, Li-air, Li-S and other Li-based systems (symmetric and asymmetric cells) will also be presented.
(Invited) Application of Microelectrode Technique to Battery Materials Study
Authors: Nishikawa Kei , Shinoda Keisuke , Kanamura Kiyoshi
Published: December 2020

Li-ion batteries use the “composite electrode” which includes active materials, conductive agents, binder, and current collector. In general, the electrode characteristics is affected by not only the active materials property but also the state of “composite”. The state of “composite” has many parameters, for examples, mixing ratio, tap density, thickness, and so on. In order to understand the electrochemical characteristics of an active material, the microelectrode technique is very important. Under microscope observation, the microelectrode is contacted to one active material particle by using micromanipulator. Then, we can evaluate the electrochemical characteristics of one particle. In this presentation, we will introduce the results of “single particle measurement” for Si, LiCoO2, LiNi0.5Mn1.5O4, and so on.

In addition, microelectrode technique is also useful for the study of Li metal electrode. Li metal electrode is suffered from dendrite growth during charging, and dead lithium formation during discharging. These phenomenon are mainly induced non-uniformity of the current distribution. In addition to that, SEI (solid electrolyte interphase) should play an important role for the morphological variation of the electrodeposited Li metal. Many researches were conducted based on the surface chemistry in order to reveal the relationship between the nature of SEI layer and the morphology of electrodeposited Li metal. However, the localization of the electrodeposition sites is an obstacle for the quantitative analysis in order to discuss the dendrite initiation and growth. In our study, microelectrode was utilized to observe the morphological variation of the electrodeposited Li metal. Constant current electrodeposition was conducted to observe the electrodeposited Li metal. After the electrodeposition, the microelectrode was transferred to FE-SEM or TEM with transfer vessel without air exposure. Ex-situ SEM and TEM observation was done to discuss the electrolyte effects to the morphology of electrodeposited Li metal. We also would like to introduce the typical results of the morphological variation and SEI nature of the electrodeposited Li metal.

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Transmission Line Model of Battery Cell's Impedance: Theory Vs. Experiments
Authors: Moskon Joze , Drvarič Talian Sara , Dominko Robert , Gaberscek Miran
Published: December 2020

Electrochemical impedance spectroscopy (EIS) is arguably the most accurate electrochemical technique. It often appears as the main or, more commonly, an additional approach in experimental investigation of advanced batteries. To a large extent, the popularity of impedance technique is probably due to fully automized, easy-to-use modern devices and, also, due to user-friendly softwares that facilitate the basic analysis of measured spectra in terms of equivalent circuit fitting. On the negative side, the final result of such a standard approach is a set of parameters (resistors, capacitors, inductors) which are difficult to interpret in terms of physical processes occurring in the measured cell. In the worst case, assignment of equivalent circuit parameters to physical processes is carried out arbitrarily which frequently leads to erroneous intepretation of cell’s physics.

Interpretation of measured EIS spectra gets much more reliable if instead the equivalent circuit approach one relies on physical-chemical models that describe transport and reaction phenomena in given cell. The linearized physical-chemical models of electrochemical cells can be solved in three ways: (i) by finding an analytical solution, (ii) using conventional numerical procedures, (iii) using the transmission line approach which transcribes the physical equations into a large number of spatially distributed discrete visual elements that resemble the usual resistors and capacitors.

In this presentation we will demonstrate the power of transmission line approach when trying to resolve the physical meaning of measured impedance features of advanced battery cells. After explaining the transmission line methodology on conventional battery electrodes, such as LiCoO2, NMC, LiFePO4, the general applicability of the approach will be demonstrated on state of the art electrodes such as sulfur cathode, lithium rich fcc and magnesium batteries. In all cases discussed we will compare the actual measured spectra with theoretical predictions of the corresponding transmission line model. We will show that the latter is able to accurately predict the trends in both sizes and shapes of measured spectra when changing the experimental conditions (electrode thickness, concentration of salt, state of charge, cycle number, surface treatment of electrode, porosity of electrode etc.). Furthemore, the proposed model is also able to capture peculiar small details of measured impedance responses, some of which will be discussed and explained in order to further elucidate processes taking place in modern battery components.
Electrodeposited Zinc-Based Films As Anodes for Aqueous Zinc Batteries
Authors: Fayette Matthew , Chang Hee Jung , Rodriguez Perez Ismael , Li Xiaolin , Reed David
Published: December 2020

In the past thirty years, there has been significant development in the search for alternative energy sources such as secondary battery systems. Zinc (fourth-most mined material) has attracted much attention due to its abundance, low-cost, and recyclability. More-over, as Zinc-based batteries can be manufactured with aqueous-based electrolytes, this allows for competition with Lithium-ion batteries, but with the advantage of enhanced safety. Zinc-based batteries (MnO2/Zinc) have been previously commercialized and are one of the dominant technologies in the battery market. However, the alkaline MnO2/Zinc battery is not currently considered re-chargeable due to the formation of zinc-dendrites, passivation of Zn metal, and cathode poisoning. In contrast to the alkaline system, the mild acidic system does not suffer from zinc passivation as there is negligible generation of zinc oxide/zinc hydroxide.

In this work, we report a proof-of concept work where electrodeposited zinc-based anodes (zinc and copper-zinc) are used in mild aqueous zinc batteries. The study provides a comparison of commercial zinc foil, and electrodeposited zinc/copper-zinc in a mild aqueous zinc battery. Prior to this comparison, electrodeposition conditions are determined by cyclic voltammetry. The three anodes are further compared structurally through X-ray diffraction and scanning electron microscopy. Further electrochemical characterization was carried out in coin cells as symmetric/asymmetric and full cells to evaluate the feasibility of each anode. The electrodeposited zinc-based anodes exhibit low electrode polarization (~0.025V), and stable cycling performance from 0.25-10 mA cm-2 compared to commercial zinc foil. Coulombic efficiencies at 1 mA cm-2 were over 98% for the electrodeposited zinc-based materials and were maintained for over 100 cycles. Furthermore, full cells with an electrodeposited zinc and brass anode, EMD MnO2 cathode, in 1M ZnSO4 + 0.1M MnSO4 delivered capacities of 96.3, and 163 mAh g-1, respectively, at a 100 mA g−
1
compared to 92.1 mAh g-1 for commercial zinc. Lastly, the zinc-based anodes also show better rate capability at a current density of up to 3 A g-1.
(Invited) Multivalent Battery Chemistries: Anodes, Cathodes, and Electrolytes
Authors: Gewirth Andrew A. , Ta Kim , Zhang Ruixian
Published: December 2020

Multivalent batteries based on Mg2+, Al3+, Ca2+, or Zn2+ may have advantages over traditional lithium ion batteries, particularly in the area of volumetric capacity. Each of these chemistries, however, presents challenges which inhibit implementation. In this talk we discuss aspects of each chemistry. With regard to Mg and Ca, we discuss the essential features of electrolytes that support reversible cation deposition and stripping. The crucial feature is the presence of electrolyte components which depassivate the electrode. In the case of Mg, this depassivation is typically provided by Cl-. In the case of Ca, depassivation comes from hydride formation at the interface. In both cases, the necessity to form a depassivation product leads to altered deposition kinetics.

For Al and Zn we discuss cathodes. For Al, we report a new C3N4-based cathode, and on the mechanism of Al interaction with it. In particular, Al associates with C3N4 not as bare Al3+, but rather as a AlCl4
-. For Zn, we report a new series of spinels -- ZnAlxCo2-xO4 and ZnNixMnxCo2-2xO4 -- and discuss their utility as cathode materials for non-aqueous Zn-ion battery. The data show that the Zn2+ ions reversibly intercalate into the spinel structure during the charge/discharge processes, a compositional transformation directly correlated with a multiply reversible conversion between Co4+/Co3+ or Co4+/Co3+, Ni4+/Ni3+/Ni2+ and Mn4+/Mn3+ oxidation states within the lattice. The data suggest that Mn, Ni co-substitution for Co in ZnCo2O4 is an efficient method to facilitate Zn-deintercalation and enhance discharge capacity.
Highly Energy-Efficient Vanadium Redox Flow Batteries with Thermo-Chemically Activated Graphite Felt Electrodes
Authors: Neburchilov Vladimir , Tsay Ken , Fatih Khalid , Neagu Roberto , Kodra Oltion , Kjeang Erik , Vinicios Juvencio da Silva Caio
Published: December 2020

The Vanadium Redox Flow Battery (VRFB) is a promising energy storage technology for large scale stationary applications that require a long cycle life of over 10 years. The specific feature of VRFB is the slower kinetics of redox reactions (V2+/V3+) on the negative electrode (NE) as compared to the kinetics of the redox reaction (VO2
+ /VO2+) on the positive electrode (PE) and poor kinetic reversibility.. The commonly used electrodes for VRFBs are graphite felt electrodes (GFE). One of the main challenges facing these GFEs is their activation that enhances a rate of redox reactions due to the increase of GFE wettability and surface area. Another challenge is capability to maintain GFE activation over cycling.

In this work, we report on thermal and thermo-chemical activation of GFEs which leads to the formation of functional groups (carboxyl C=O, phenolic C-O, and adsorbed O or H2O for the enhancement of the electrode wettability and active surface area. The physicochemical characterization of the activated GFEs was performed using X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The electrochemical study was conducted by cyclic voltammetry (CV) measurements in 0.2M VOSO4/2M H2SO4 at 1 mV/s and cycling tests (50 cycles, three tests for every GFE) in a commercial 9cm2 VRFB ( Standard Energy Corp.) using a charge/discharge current density of 80 mA/cm2 at 20oC and a commercial vanadium electrolyte 1.6M [V]/2M H2SO4. The increase of temperature of GFE heat treatment of GFEs from 400 to 500oC resulted in the growth of the energy efficiency (EE) of VRFBs with such electrodes from 81.3 to 87.2%, respectively, due to the increase of adsorbed oxygen or water from 1.6 to 8.72% and C-O (C-OH) groups from 0.49 to 2.09%, respectively and wettability (contact angle (CA) decreases from 78.7 to 65.1o). Analysis of CVs of the redox reaction VO2
+ /VO2+ shows the decrease of the peak of potential separation ΔEp (Epa-Epc) from 0.357 to 0.345 V and the peak of current ratio (Jpa/Jpc) from 1.406 to 1.26, indicating lower polarization due to the increase of the electrode surface area, acceleration and reversibility of these redox reaction, respectively (Table 1). The proposed additional treatment of the heat treated GFE at 400oC (GFE400) in strong oxidants H2O2, H2SO4 and HNO3 for the decomposition of C=O and the enhancement of the content C-O groups and GFE wettability didnt result in the performance improvement (VRFB with GFE400+10%H2O2 - energy efficiency of 78%).

The thermal treatment of GFE at 500oC demonstrated improvement of VRFB cell performance, namely growth of energy efficiency to 87.2% and VE to 90.1%, % due to the increase of wettability and active surface area of GFEs.

Figure 1