bluuebunny/crossref_metadata_2025 huggingface dataset:
In Situ Characterization of Gassing Processes in Lithium-Ion Batteries By Dems-Deirs
Authors: Berkes Balázs B. , Schiele Alexander , Michalak Barbara , Sommer Heino , Brezesinski Torsten , Janek Jürgen
Published: February 2020

Gas evolution has a profound effect on the functioning of state of the art lithium-ion batteries. On the one hand, it is the natural concomitant of SEI formation; on the other hand, because of the demand for high terminal voltages, it is the consequence of electrolyte or electrode material oxidation. This happens on the expense of the efficiency. Furthermore, the presence of gases in the cell raises safety problems.

In general it is important to understand gas formation processes. First, to be able to develop novel electrolyte mixtures or tailor electrolyte additives that form a stable SEI. Second, to optimize the surface and/or structure of cathode materials to influence both their bulk oxidative properties upon delithiation and electrocatalytic activities. Differential electrochemical mass spectrometry (DEMS) is one of the most appropriate tools to qualitatively elucidate gas evolution reactions in electrochemical systems.

Herein, we report on the in situ gas analysis by means of differential electrochemical mass spectrometry and infrared spectroscopy (DEMS-DEIRS) of various battery systems. We analyze the SEI formation on different anode materials and the influence of various electrolyte additives. The impact of temperature and constant voltage/OCV periods on the first charge cycle (so-called formation process) is investigated. Their effect on both the gassing and electrolyte salt decomposition is described.

The stability problem of the most common electrolytes at high voltages is discussed through the example of either NMC (LiNixMnyCozO2) type materials or with high voltage spinels (LiNi0.5Mn1.5O4). The electrocatalytic activity of the individual active material particles seems to play a decisive role in the oxidative decomposition processes. Through the application of modified cathode surfaces a relation between surface activity and the amount of produced gases is revealed. Beyond the decomposition of the electrolyte, oxygen evolution is the crucial factor at high cathode potentials. This effect is particularly apparent for overlithiated and high Ni content materials. Monitoring gassing over 20 cycles uncovers interesting changes being only recognizable in “long term” tests. We demonstrate the importance of potentiodynamic cycling in addition to the traditional galvanostatic test with DEMS-DEIRS in the exploration of reaction mechanisms. Pressure measurements complete the analysis in terms of validation of gas amounts.
Direct Observation of Electrophoretic Flow of Solvent Molecules with Lithium Ions By NMR Imaging
Authors: Kawamura Junichi , Iwai Yoshiki , Endo Shotaro , Kuwata Naoaki , Takekawa Reiji , Ohzu Masato
Published: February 2020

Lithium ion transport in the organic liquid electrolyte is a key process in conventional lithium ion batteries, where the lithium ion shuttles between the positive and negative electrodes while the charging and discharging process. The translational motion of the lithium ion in the liquid electrolyte is accompanied by the coordinating organic solvent molecules such as EC, DMC etc., which must be detached from the lithium ion at the electrodes by the desolvation process. On the other hand, the counter anions such as PF6
- is thought to move opposite direction, although the local concentration is the same to that of lithium cation in order to keep the electroneutrality condition.

Although this picture is based on many evidences by electrochemical measurements, the direct observation of the correlated motion of the lithium ions and solvated molecules has not been reported.

In this paper, we first demonstrate the direct observation of the translational motion of solvent molecules (EC,DEC) with the lithium ions by using NMR micro-imaging technique.

NMR microimaging is observed by Avance 400 spectrometer equipped with mini-Imaging probe by Bruker Co. The 1H and 19F NMR imaging are observed in this measurement. Model cell is constructed in NMR spectrometer, which is composed by LiMn2O4 cathode, lithium metal anode and liquid electrolyte of EC/DMC+LiPF6. The cell is connected to an electrochemical charge-discharge set-up to operate the cell. Small desolution of Mn2+ from the cathode acts as a contrast agent to enhance the flow image of the cell.

Some vertical images of the cell in a charge-discharge process are shown in Fig. 1, where the LiMn2O3 positive electrode is located at the bottom and the lithium metal anode is on the top. Constant current mode of 25 mA is used. While the charging current is set upward from LiMn2O3 cathode to the lithium anode, namely the Li+ cations move upward, then the proton NMR imaging observing the motion of the EC and DMC molecules is confirmed to upward, which is the same direction as that of the Li+ ions. Moreover, the flowing current of the solvent moves toward left and right directions near the lithium anode, where the EC and DMC should release the Li+ to the anode and move aside. This continuous flow generates an electroconvection which can be seen in Fig. 1 as a vortex curling from center to the side wall.

On the other hand, when the current is reversed to discharge, the flow of the solvent changes its direction from the top (anode) to the bottom (cathode), which generate the reverse vortex as shown in Fig. 1.

Figure 1
(Electrodeposition Division Research Award) Using Liquid Metals for Advanced Electrodepositions
Authors: Maldonado Stephen
Published: February 2020

This presentation will summarize the recent development of the hybrid electrodeposition process known as electrochemical liquid-liquid-solid (ec-LLS) crystal growth by our group. Three aspects will be covered in this presentation. First, the general premise behind ec-LLS and how ec-LLS melds conventional electrodeposition and melt growth for the purposes of controlled and low-temperature growth of crystalline inorganic solids. Second, the status of ec-LLS as a method to produce Group IV (Ge, Si, and alloys thereof) and Group III-V (GaAs, GaSb, InAs, InSb, and alloys thereof) semiconductor crystals will be presented. Special emphasis will be given to the deposition of nanowires, microwires, and epitaxial films. Third, a general outlook on the possibilities ec-LLS offers as a unique electrodeposition method will be given. Specifically, opportunities for quantitative melt crystal growth studies, the synthesis of other inorganic materials, and the prospects for ec-LLS as a means to produce directly functional devices will be discussed.
In-Situ Microfluidic Study with Kinetic-Monte Carlo Simulations to Investigate Zn Electroplating Morphology at High Overpotentials
Authors: Gupta Tanya , Davies Greg , Park Jeung Hun , Steingart Daniel A
Published: February 2020

Despite the low cost and high energy density, use of Zinc anode in secondary batteries is limited due to the associated shape change of Zn during cycling. Vast literature on morphological studies of Zn in alkaline electrolyte indicates formation of varied structures ranging from mossy, to boulder-like and dendritic morphologies,1 primarily depending on the plating potential.

Recently, Zinc plating at extremely high overpotentials 2 is shown to form a highly porous, conductive, ramified foam like morphology, called Hyper Dendritic Zinc (HD Zn). HD Zn has been demonstrated to act as an efficient secondary anode, with improved cycle life and kinetics 3. The fine (~60 nm) needle-like crystallite core microstructure that forms the dendrite makes this morphology unique. An important distinguishing feature from the previously known morphologies is that it grows in conformal layers, giving it an appearance of dense branching morphology, but instead of DLA like motifs it has Dendritic motifs.

In this work, in-situ microfluidic studies coupled with Kinetic-Monte Carlo simulations are used to investigate plating and cycling behavior of HD Zn. While Monte Carlo simulations have been implemented in the past 4 to show growth of DLA like structures, we extend these to incorporate effect of crystal anisotropy in electrochemical systems. We hypothesize that growth at high overpotentials leads to the formation of a space charge region at the electrolyte/electrode interface due to high potential gradient. This space charge region is where migration becomes important. The migration length along with high concentration gradient built at the growth overpotentials gives rise to the HD Zn morphology.

1. Naybour, R. D. et al. Electrochimica Acta 13.4 (1968): 763-769.

2. M. Chamoun et al., NPG Asia Materials, 7, e178 (2015).

3. T. Gupta et al., J. Power Sources, 305, 22–29 (2016).

4. Erlebacher, J. et al. Physical review letters 71.20 (1993): 3311.
In-Situ Stress Measurements during Cobalt Electrodeposition
Authors: Stafford Gery R. , Bertocci Ugo
Published: February 2020

Electrodeposited Co has attracted much attention over the past several decades owing in part to its interesting magnetic properties. These properties are largely dependent upon the structure and morphology of the electrodeposit, which can vary dramatically with overpotential, electrolyte pH, and the presence of strongly adsorbing anions. For example, solutions with a pH < 2.5 will generally result in a mixture of both face-centered cubic (fcc) and hexagonal close-packed (hcp) Co on Au, while more alkaline solutions yield nearly pure hcp Co. The evolution of residual stress during thin film growth also depends on deposit microstructure and growth conditions, making in situ cantilever curvature measurements a nice complement to traditional electrochemical measurements during electrodeposition. This talk will examine the surface and growth stress associated with the electrodeposition of Co films onto (111)-textured Au cantilever electrodes from dilute Co2+ aqueous electrolyte. We have measured the stress response as a function of overpotential in films measuring less than 25 nm in thickness, from 0.1 mol/L NaClO4 + 0.001 mol/L Co(ClO4)2 (pH = 4.8) and at Co current efficiencies ranging from 65% to 90%. XRD analysis indicates that under these deposition conditions the Co is face-centered cubic and maintains the (111) texture of the Au substrate, suggesting epitaxial but not pseudomorphic growth on the Au. The stress-thickness product is compressive in the first monolayer followed by increasing tensile stress as the film thickens. The initial compressive stress is most likely due to surface and interface stresses that dominate at submonolayer coverage. Steady state tensile stress, ranging from 0 to +450 MPa, developed in continuous Co films and showed a strong dependence on electrode potential. However, over this potential range there is no change in grain size or growth rate, factors typically associated with tensile stress. We attribute the tensile stress and its potential dependence to the formation of hydrogen stabilized vacancies, defects found to be quite stable in fcc Fe-group metals and alloys deposited under conditions of H+ discharge.
Effect of Amine Additive on Properties of Electrodeposited Nickel
Authors: Kim Hyoung Chan , Lee Wook Jin , Lee Sang Joon , Kim Yang Do
Published: February 2020

Nickel and its alloys are commonly used as materials for electroforming process, and the electroforming of nickel alloys has been conducted to manufacture three-dimensional micro-structures and micro-components with high precision. Many studies have been performed to minimize internal stress of the electrodeposited nickel layer using pulse plating and/or various additives, as the internal stress and the hardness of the nickel layer are very important factors. This study was performed to investigate changes in the internal stress and the hardness of the electrodeposited nickel layer by amine additive.

Effect of amine additive was investigated using in-situ measurements of pH values adjacent to the electrode surface with a gold mesh electrode in the nickel sulfamate electrolyte. The internal stresses of the nickel layer from the same electrolyte were measured with bent strip test. Polarization curves and adjacent to surface pH values showed that the amine additive provided hydronium ion to lower the pH value adjacent to the electrode surface in the electrolyte. The zero internal stress of the nickel layer could be obtained with a small amount of amine additive. The hardness of the nickel layer also increased up to 550 Hv. X-ray diffraction and transmitted electron microscope analyses were adopted to evaluate the microstructure of the nickel layer.
Electrochemical Codeposition of Cobalt and Ruthenium from Acidic Chloride Electrolytes
Authors: Mech Krzysztof , Mech Justyna , Zabinski Piotr , Kowalik Remigiusz , Wojnicki Marek
Published: February 2020

CoRu/Ru alternate nanostructures exhibit giant magnetoresistance (GMR). Enormous research effort is turned toward low-cost and simple preparation methods of materials, which display GMR. Position of cobalt and ruthenium on  –logi0-dGM-H dependence allows on assumption that CoRu alloys can exhibit also high catalytic activity for hydrogen evolution reaction (HER). Generally CoRu alloys are obtained by physical (PVD) or chemical (CVD) vapor deposition techniques [1]. Electrodeposition of pure Ru as well as Ru containing alloys is quite complex process. The redox potentials of Ru are: 0.25V and 0.46V vs SHE for Ru3+(aq)/Ru2+(aq) and Ru2+(aq)/Ru(s), whereas of Co in acidic solution: +1.81V and –0.28V vs SHE for Co3+(aq)/Co2+(aq) and Co2+(aq)/Co(s), respectively [2]. The CoRu alloys deposited from sulphate-sulphamate electrolytes were reported by Juzikis et al. [3, 4]. In the work of Laszlo et al. one can find an informations concerning co-deposition of Co with Ru from chloride-sulfate bath [5]. In this work chloride complexes were used for the first time for RuCo codeposition. The work describes the mechanism responsible for formation of CoRu alloys through electroreduction of aquachloro complexes of Co(II) and Ru(III) in an aqueous acidic chloride electrolyte of pH=3. Identification of electrode reactions was performed based on voltammetric and electrogravimetric tests. Potential range for  alloy deposition and current efficiency of electrolysis were determined by EQCM and voltammetric tests, respectively. UV-Vis spectrometry was used to examine electrolyte stability. The influence of concentration of various forms of Co(II) and Ru(III) complexes Σ[CoClx(H2O)6-x]2-x (x=0,1,2) (10–100 mM), Σ[RuCly(H2O)6-y]2-y(10 mM) as well as applied potential (from –0.5 to –0.9V vs Ag/AgCl), pH of electrolyte (1–3) and temperature range (25–70°C) were examined towards composition, structure and morphology of deposited CoRu alloys. The performed structural analysis showed a high influence of the synthesis conditions on the structure and morphology of the obtained alloys.

 References

1. Zoll, S., et al., Competing Anisotropies and Magnetization Processes in Epitaxial Co/Ru Asymmetric Sandwich Structures. Journal of Magnetism and Magnetic Materials, 1995. 148(1-2): p. 145-147.

2. Antelman, S.M., The Encyclopedia of Chemical Electrode Potentials. 1982, Plenum Press: New York.

3. Juzikis, P., L. Gudaviciute, and E. Matulionis, Ruthenium-Cobalt Alloy Electrodeposition. Platinum Metals Review, 1995. 39(2): p. 68-71.

4. Juzikis, P., et al., Electrodeposition of Ru/Co compositionally modulated multilayers. Journal of Applied Electrochemistry, 1997. 27(8): p. 991-994.

5. Fesharaki, M.J., et al., Anomalous codeposition of cobalt and ruthenium from chloride-sulfate baths. Journal of Solid State Electrochemistry, 2012. 16(2): p. 715-722.
(Invited) Pulsed Electrodeposition of Metallic Nanoparticles for Energy Conversion and Storage Applications
Authors: Karimi Shahram
Published: February 2020

Metallic nanoparticles, including platinum, nickel and copper, were deposited on carbon substrates and titania nanotubes (TNTs) using a pulsed current electrodeposition technique with very low duty cycles, high peak current densities, and pulses delivered in both milli- and nano-second range employing triangular and ramp-down waveforms. The presence of nanoparticles, ranging from 2-50 nm in diameter, were confirmed by scanning electron microscopy and X-ray powder diffractometry. Further electrochemical characterization was performed utilizing cyclic voltammetry and frequency response analysis.

A simple yet robust mathematical model was developed to predict the influence of different electroplating parameters, including peak deposition current density, pulse waveform, pulse on-time and pulse off-time, on the size and catalytic activity of the resulting nano-catalyst layers. The model is based on progressive nucleation and considers contributions from both nucleation and growth currents. The model was further refined by considering all contributing factors towards growth current, including diffusion, ohmic and charge transfer phenomena as well as changing diffusion coefficients, during electrodeposition. According to the model, at high peak deposition current densities and low duty cycles, the ramp-down waveform yielded the highest nucleation rates, confirming the experimental findings in which nanoparticles generated with the above waveform produced the smallest average grain size, ranging from 2 to 5 nanometer in diameter for platinum nanocatalysts on carbon cloths and TNTs and 10 to 50 nm in diameter for nickel and copper nanoparticles deposited on TNTs.
Electrodeposited ZnO Nanostructures Onto Transparent Metallic Web Electrodes for Photocatalytic Applications
Authors: Matei Elena , Diamandescu Lucian , Enculescu Monica , Zgura Irina , Enculescu Ionut
Published: February 2020

Electrodeposition of ZnO is a process with a history of almost two decades and leads towards the straightforward fabrication of nanostructures with easy tunable properties[1,2]. Using metallic webs as working electrodes the electrodeposition from an aqueous bath results in the formation of hierarchical structures nanofiber/nanostructure with tailored morphology. Thus, an interesting combination of fibers/nanostructures is obtained in a straightforward manner. Taking advantage of the flexibility of the process one can easily design the desired properties by choosing the appropriate experimental parameters.

We employed metallic webs fabricated by the electrospinning of polymer fiber webs and subsequent metal sputter deposition as electrodes for the electrodeposition of ZnO. The electrodeposition parameters were tuned for controlling the morphology of the oxide nanostructures which further influence specific properties including optical, electrical or even the wettability [3,4]. Moreover the system of hierarchical fiber/nanostructures presents important photocatalytic properties which are strongly influenced by the morphology opening the way towards applications such as self cleaning surfaces.

References

[1] S. Peulon, D. Lincot, Cathodic electrodeposition from aqueous solution of dense or open‐structured zinc oxide films, Adv. Mater. 05 (1996) 166–170. http://onlinelibrary.wiley.com/doi/10.1002/adma.19960080216/full (accessed September 29, 2014).

[2] M. Izaki, T. Omi, Transparent zinc oxide films prepared by electrochemical reaction, Appl. Phys. Lett. 68 (1996) 2439. doi:10.1063/1.116160.

[3] E. Matei, I. Enculescu, Electrodeposited ZnO films with high UV emission properties, Mater. Res. Bull. 46 (2011) 2147–2154.

[4] I. Enculescu, M. Sima, M. Enculescu, M. Enache, V. Vasile, R. Neumann, Influence of geometrical properties on light emission of ZnO nanowires, Opt. Mater. (Amst). 30 (2007) 72–75. doi:10.1016/j.optmat.2007.01.002.
Silver Electrodeposition Based Multicolor Electrochromic Cell Toward Energy Saving Applications
Authors: Kobayashi Norihisa , Nakamura Kazuki , Hong Jineui , Tejima Riho
Published: February 2020

Electrochromism (EC) is defined as a reversible color change by electrochemical redox reaction and has several features such as color variation, memory property and so on. Multifunctional electrochromic materials which control multiple colors, various color density, and specular reflection are expected to be potential candidate for light-modulation device such as smart window and novel reflective display device such as e-paper.

Electrodeposition is an attractive method to create colors because silver (Ag) nanoparticles exhibit various optical states based on their localized surface plasmon resonance (LSPR). LSPR bands of metal nanoparticles are affected by the size and shape. The control of LSPR, therefore, must enable dramatic changes in color for the surface where nanoparticles are deposited. We successfully demonstrate the first LSPR-based multicolor EC device enabling reversible control of six optical states such as transparent, silver mirror, cyan, magenta, yellow and black, which is attractive for smart window as well as color e-paper application. We will discuss the mechanism of electrodeposition and a wide range of its applications.
Flexible CIGS Thin Film Solar Cell from Electrodeposited Precursors
Authors: Kim Youngho , Kim Daejung , Oh Hyunpil
Published: February 2020

At present, CIGS thin film solar cell industry needs to overcome various hurdles including efficiency improvement, low cost fabrication, and long term reliability to survive in the market dominated by crystalline Si solar cell.

Since the efficiency enhancement of a solar cell asks considerable time and efforts, it is hardly accomplished to get an immediate and straightforward solution for CIGS.

Then, a viable way to last for the time being is creating a niche market with specific advantages of CIGS such as flexibility, light-weight, and esthetic value so on.

In addition, an economic process of manufacture to mass production in good yields is another matter of concern and this problem could be solved by the electrodeposition thanks to its rapid roll to roll processing, high material utilization, and low waste emissions.

Cu/In/Ga precursors were electrodeposited on flexible STS/SiOx/Mo substrates and processed to CIGS devices in this study and their physiochemical properties and performances were discussed.
An Electrochemical Study of Sb and Ni Doped SnO2 Electrodes for Ozone Electrolysis
Authors: Sandin Staffan , Bäckström Joakim , Cornell Ann
Published: February 2020

Electrochemical formation of ozone as an alternative to gas phase formation via the corona discharge process (CDP) has been investigated for several decades. Most anode materials show very low current efficiency at room temperature[1] because of the competing oxygen formation reaction. Up until ten years ago, the most promising material in this respect was PbO2 coated anodes, reaching a current efficiency of ~13% at room temperature[2]. Boron doped diamond (BDD) as electrode coating has also shown promising results for the ozone formation reaction[3]. Ten years ago Wang et al.[4] discovered that antimony doped tin oxide (ATO) additionally doped with nickel (NATO) could produce ozone at high current efficiency at low overpotentials. Since then, current efficiencies as high as ~50% at room temperature have been reached, enabling the process to be as, or more energy efficient than CDP[5] while avoiding the expensive BDD and toxic PbO2. In the studies concerning ozone formation on NATO, SnCl4.5H2O has been used as the source of tin. This is a very volatile specie, making the composition of the oxide coating unpredictable and potentially very different from the precursor solution used for preparation. In this study, SnCl2.2H2O has been used as an alternative source of tin. Because of its lower volatility, the electrode coating can be made with a much higher deposition efficiency, thus yielding a cheaper and faster preparation process. As most previous studies have optimized the precursor solution composition based on tin tetrachloride, we suspect that the dopant concentrations in the final coating have been underestimated. We have here varied the concentrations of antimony and nickel in relation to tin, and compared to our previous study of SnO2 from the two different tin sources. To evaluate the kinetics and selectivity, the electrodes were examined by polarization curves and cyclic voltammetry as well as in situ ozone measurement during potential sweep and galvanostatic electrolysis.

[1] Y-H Wang and Q-Y Chen. Journal of Electrochemistry, 2013:1-7, 2013.

[2] P.C. Foller. Journal of The Electrochemical Society, 129(3):506, 1982.

[3] P-A. Michaud. Journal of Applied Electrochemistry, 33(2):151-154, 2003.

[4] Y-H Wang et al. Journal of The Electrochemical Society, 152(11):D197, 2005.

[5] P.A. Christensen et al. Ozone: Science and Engineering, 31(4):287-293, Jul 2009.
Paired Electro-Synthesis of PbO2 and Pb As Lead Storage Battery Active Materials Using Pb(NO3)2 as a Precursor
Authors: WANG Yaqiong , LI Baotong , Xu Wenlin
Published: February 2020

The preparation of PbO2 and Pb as lead storage battery active materials were investigated by paired electro-synthesis method, using lead nitrate (Pb(NO3)2) as a precursor , which was converted from waste lead-acid battery pastes.

Lead oxides, such as PbO and PbO2, present as important components in waste lead-acid battery pastes, and together account for up to 50% of the paste by weight. The principle is based upon the solubility of PbO in aqueous nitrate acid solution. The paste was treated by nitrate acid leaching to convert PbO to Pb(NO3)2 and Pb(NO3)2 can be isolated from the waste battery paste as raw material by the nitrate acid leaching and refining process. The paired electro-synthesis of PbO2 and Pb as the lead storage battery active materials using Pb(NO3)2 as a precursor was investigated and the optimal synthesis conditions were determined by investigating the effect of the concentration of Pb(NO3)2, current density, temperature, and operating time. Experimental results have shown that lead can be recovered effectively as Pb(NO3)2 , and the precursor can be readily converted to PbO2 and Pb for directly making lead-battery pastes by controlling the electrochemical process

The route is suitable for large scale operations which in turn entail large scale movement of battery waste materials. The process can avoid smelting, desulphurisation and electro-winning, and achieve lead recovery simultaneously.

Key words
: paired electro-synthesis, lead nitrate, lead monoxide, lead dioxide, lead storage battery
Paired Electro-Synthesis of PbO2 and Pb As Lead Storage Battery Active Materials Using PbSO4 As a Precursor
Authors: WANG Yaqiong , Zhao Xuan , Xu Wenlin
Published: February 2020

Given the toxicity and economy of lead, it is important to achieve good recovery in the recycling of waste lead storage batteries. Lead sulfate (PbSO4), which plays an important part in reactions of the lead storage battery, is formed in accordance with Faraday's law during discharge.

PbSO4, is the main component in a waste battery paste and account for up to 50% of the paste by weight. PbSO4 can be isolated from the waste battery paste as raw material by the nitrate acid leaching-ammoniacal ammonium sulfate leaching-refining and solid-liquid separation process. First, the paste was treated by nitrate acid leaching to convert PbO to lead nitrate (Pb(NO3)2), then leach residue containing lead sulfate and lead dioxide was leached with ammoniacal ammonium sulfate, based upon the solubility of PbSO4 in aqueous ammoniacal ammonium sulfate solution. After solid-liquid separation the solution is then purified, PbSO4 was obtained by removal of free ammonia and heating. The paired electro-synthesis of PbO2 and Pb as lead storage battery active materials using PbSO4 as a precursor was investigated. Optimal synthesis conditions were determined by investigating the effect of the particle diameter and distribution of the precursor, current density, temperature, and operating time. Experimental results show that lead can be recovered effectively as PbSO4, and as a precursor, can be readily converted to PbO2 and Pb for directly making lead-battery pastes by controlling the electrochemical process and the particle diameter and distribution of the precursor in microscale powders.

Results in this work are used to underpin the development of a new process that can be used for recovering lead from lead battery pastes. The route is suitable for large scale operations which in turn entail large scale movement of battery waste materials. The new process can avoid both smelting, desulphurisation and electro-winning. PbSO4, as a precursor, can be readily converted to PbO2 and Pb for directly making lead storage battery pastes for achieving lead recovery simultaneously.

Key words
: paired electro-synthesis, lead storage battery, lead sulfate, lead monoxide, lead dioxide
(Invited) Thermoelectrochemical Impedance Method Fundamental Aspect and Applications
Authors: Aaboubi OMAR
Published: February 2020

In previous works we have shown the great importance to control of solution temperature (isothermal process) or the working electrode temperature (non-isothermal process) what has led us to develop a new transfer function based on the sine wave modulation of the electrode temperature [1, 2]. Thus the thermoelectrochemical (TEC) transfer function has been experimentally measured and compared with theoretical models for mass transport controlled systems and charge transfer controlled system involving adsorbed species (i.e. nickel electrodeposition from Watts solution or silver electrodeposition from nitric and tartaric bath (Fig. 1)) [3]. In addition, the use of a superimposed thermal gradient should be able to give further information about the whole electrochemical process, since the TEC method has revealed its ability, as well as a technique of mass-transport analysis, as for the determination of characteristic parameters of adsorption or kinetic process [4, 5].

Fig. 1. TEC transfer function diagrams measured at various polarizations DEp for silver electrodeposition.

 (¡) Ep = 0.39 /V vs SCE; (u) Ep = 0.365 V/SCE; (o) Ep = 0.34 /V vs SCE and () Ep = 0.29 /V vs SCE. DT = 2 K; C* = 0.01 mol dm-3 and Tb= 298K.

[1] P. Grundler, A. Kirbs, L. Dunsch, “Modern Thermoelectrochemistry” ChemPhysChem, 10 (2009) 1722.

[2] Z.A.Rotenberg, Russ. J. Electrochem., 37 (2001)113.

[3] A. Olivier, E. Merienne, J.-P. Chopart, O. Aaboubi, Electrochim. Acta, 37 (1992) 1945.

[4] I. Citti, O. Aaboubi, J.-P. Chopart, C. Gabrielli, A. Olivier, B. Tribollet, J. Electrochem. Soc. 144, (1997) 2263.

[5] O. Aaboubi, A. Housni, J. Electroanal.Chem., 677-680 (2012) 63–68.
(Invited) EIS Analysis of the Water Uptake Process in Model Epoxy Coatings and Free Films
Authors: Vosgien Lacombre Coralie , Bouvet Geoffrey , Trinh Dao , Mallarino Stéphanie , Touzain Sébastien
Published: February 2020

Electrochemical Impedance Spectroscopy (EIS) is a widely used technique to study the organic coatings degradation. Thanks to capacitance measurements in the high frequency (HF) domain, EIS allows measuring the water uptake into the coating, using different models. Usually, a three electrodes cell is used to perform such measurements but if the sole HF domain is considered to assess the water uptake during the beginning of the immersion period, then the reference electrode (RE) can be deleted and a two electrodes cell can be used.

In this work, model epoxy coatings (DGEBA/DAMP), with or without pigments (TiO2), were prepared as free films or were applied onto steel panels (Q-Panel). The different samples were immerged in a NaCl 3 wt% saline solution and water uptake was followed by EIS using a two or three electrodes cell. EIS spectra obtained without RE show new time constants in the HF domain which can be related to intrinsic properties of the system. This leads to a better understanding of the water uptake phenomenon into organic coatings and offers the possibility to modify well-known water uptake models.
Gentle, Nondestructive Monitoring of Wound Healing in Cell-Based Assays Using Electrochemical Impedance Spectroscopy
Authors: Wanzenboeck Heinz , Bertagnolli Emmerich
Published: February 2020

Electrical impedance spectroscopy is a soft analysis methods for living cell cultures, that is non-destructive for cell cultures and allows continuous measurement of cellular changed in real-time. In this work we report on an in vitro impedimetric sensors that measures the confluence and the density of human epithelial cell layers. A mechanically inflicted damage in a confluent cell layer leads to a reduction of the impedance, while the healing of the cell layer was closing the holes and increased impedance. The entire healing process could be tracked in real time via the impedance.

To advance existing in vitro cell impedance spectroscopy we have not only used opwn metal electrodes but also electrically insulated interdigitated microelectrodes. The influence of the insulation on sensor performance is experimentally and theoretically analyzed A circuit model was established. In a comparison between open (not passivated) electrodes was made. The best setup for sensitivity and repeatability, which are crucial parameters for cell analysis, will be presented. The presented novel sensor design allows for the integration of alternative electrode materials such as aluminum. This enables cost-effective fabrication of large-volume sensor arrays.
(Invited) Effect of Mechanical Stress on the Passivity of Steel
Authors: Thierry Dominique , Nazarov Andrej , Vivier Vincent
Published: February 2020

The influence of the elastic and plastic tensile stress on the electrochemical properties of mild carbon steel and austenitic stainless steel was studied using Scanning Kelvin Probe (SKP) and Localized Electrochemical Impedance Spectroscopy (LEIS) techniques. These two methods give complementary information on the surface of the stressed electrode. SKP characterizes the thermodynamic (surface potential) and LEIS is informative on the conditions of the passive oxide (capacitance of the film).

The Volta potential and the admittance were mapped across an area with stress concentrator (notch) “in situ” under load. It was found that the elastic deformation slightly influences both the potential and the capacitance. The plastic strain decreases the potential measured in the lab air for both steels by 150 to 300 mV. LEIS shows an increase of the capacitance measured in borax electrolyte above the yielded surface in the notch relatively to the surrounding surface. Thus, the change inf the potential is reciprocal to the change of the capacitance.

After straining, in load free conditions, stainless steel saved low potentials in the area containing residual stresses. It corresponds to LEIS data that shows an increased capacitance. In opposite, unloading of strained mild steel redistributes the surface potential. Mainly the surface increased the potential showing the passivation. However, low potential locations related to residual stress were also found by SKP. Mapping of the capacitance by LEIS also shows partial passivation of the steel. Thus, locations with concentrated stress, which are prone to localized corrosion can be recognized using local electrochemical techniques.

After experiments, the strained surfaces were characterized by XPS and AFM. The effect of the plastic tensile strain was explained by the formation and emerging of dislocations and dislocations pile-ups. The dislocations rupture the oxide film making it more defective that weaken the steel passivity. On the other hand, the formation of the stepped surfaces decreased the potential that decreased the activation energy of anodic dissolution of the steel.
Broadband Spectroscopic Characterization of Hybrid Low-k Dielectric Thin Films for Micro- and Nanoelectronic Applications
Authors: Obeng Yaw S. , Okoro Chukwudi A. , Montgomery Karl R. , Amoah Papa K. , You Lin , Kopanski Joseph J. , Obrzut Jan
Published: February 2020

Broadband Spectroscopic Characterization Of Organic and Hybrid Dielectrics Thin Films for Micro- and Nanoelectronic Applications

Yaw S. Obeng*, Chukwudi A., Okoro, Karl R. Montgomery, Papa K. Amoah, Lin You, Joseph Kopanski, Jan Obrzut

Engineering Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899

Micro- and nanoelectronic devices use materials of varying dielectric constants for specific applications1, 2, as in electrical insulation and isolation; however the matching of materials to applications has is frequently guided by intuition3.  The electrical performance of the materials, e.g., dielectric constant, is frequently evaluated by measuring the metric such as impedance measurements on metal-insulator-metal (MIM) capacitors, and by assuming that the MIM devices are ideal4. However, as we have shown elsewhere, these devices are imperfect, and the chemistry and physics of the materials also play crucial roles in their application utility, especially in low operating voltage devices5, 6. Thus, material selection based on such characterization frequently result in sub-optimal choices.

In this paper, we discuss the use of broadband microwaves (MW) (up to 20 GHz) characterize organic and hybrid silicon-organic thin films meant for insulation applications in micro- and nanoelectronic devices. Specifically, we will take advantage of MW propagation characteristics7, to extract and examine the relationships between electrical and mechanical properties, and the chemistry of prototypical materials. The impact of moisture on the electrical behavior of any material defects will be evaluated from the impact of thermal anneal at modest temperatures on the samples.  These studies will shed light on the chemical changes that occur within the dielectric films that could impact the performance and reliability, as well as provide basis for rational selection of organic dielectrics for integrated device.

1.            R. P. Ortiz, A. Facchetti and T. J. Marks, Chemical Reviews 110(1), 205-239 (2010).

2.            W. Volksen, R. D. Miller and G. Dubois, Chemical Reviews 110(1), 56-110 (2010).

3.            V. Sharma, C. Wang, R. G. Lorenzini, R. Ma, Q. Zhu, D. W. Sinkovits, G. Pilania, A. R. Oganov, S. Kumar, G. A. Sotzing, S. A. Boggs and R. Ramprasad, Nat Commun 5(2014).

4.            E. Verrelli, N. Kemp, M. O'Neill, F. Cheng, F. A. Alharti and S. M. Kelly, SID Symposium Digest of Technical Papers 44, 108-111 (2013).

5.            Y. S. Obeng, C. A. Okoro, P. K. Amoah, R. R. Franklin and P. Kabos, ECS Journal of Solid State Science and Technology 5(4), P3025-P3030 (2016).

6.            C. A. Okoro and Y. S. Obeng, Thin Solid Films 520(15), 5060-5063 (2012).

7.            J. Obrzut, ACTA IMEKO 4 (3), 42-46 (2015).
Deposition and Electrical Characterization of CaCu3Ti3FeO12 Thin Films
Authors: Skaria Giji , Nehate Shraddha
Published: February 2020

There is an increased interest in very high dielectric constant (high-k) material studies due to their potential applications in energy storage elements. In this aspect, the perovskite materials seem to achieve very high-k values [1]. In this study, the focus has been to deposit thin films of CaCu3Ti3FeO12. These films are deposited by RF magnetron sputtering process using CaCu3Ti3FeO12 target. The films are deposited under varies deposition conditions that include argon gas flow ratios, process pressures and RF power. Metal–insulator–metal (MIM) structures have been fabricated using aluminum film as the electrodes. The electrical properties of the films have been characterized and reported as a function of deposition parameters for the above MIM structures.
ALD for Functional Devices Based on TiO2 Nanotube Arrays
Authors: Zazpe Raul , Prikryl Jan , Sopha Hanna , Macak Jan M.
Published: February 2020

Synthesis of highly-ordered nanostructures of valve metal oxides has recently attracted huge scientific and technological interest motivated by their possible use in many applications.

It is the nanotubular TiO2 that has received the highest attention after porous Al2O3, motivated by its wide range of applications, including photo-catalysis, solar cells and biomedical uses. However, the TiO2 nanotube potential for a range of advanced devices, in particular when considering all possible shapes and geometries, has not at all been exploited. One of the major issues to extend the functional range of nanotubes is to coat homogenously tube interiors by a secondary material, potentially until the complete tube filling. Efforts based on electrochemical deposition, chemical deposition and spin-coating led only to limited success with a narrow range of materials.

The presentation will therefore focus in detail on the coating of secondary materials inside the nanotubes by means of ALD. The deposited materials influence strongly optical, electrical and mechanical properties of nanotubes. Experimental details and some very recent results demonstrating unprecedented ability of nanotube functionalization by ALD will be presented and discussed [1-3].

References:

1] J.M. Macak, Chapter 3: Self-organized anodic TiO2 nanotubes: functionalities and applications due to a secondary material in monograph Electrochemically Engineered Nanoporous Materials: Methods, Properties and Applications. Editors: A.Santos, D. Losic. Springer, 2015. ISBN: 978-3-319-20345-4, Vol. 220.

2] J. M. Macak, J. Prikryl, H. Sopha, and L. Strizik, Phys. Status Solidi RRL, 9, 516 (2015).

3] R. Zazpe, J.M. Macak et al. Adv. Mater. Interf., under review

Figure 1
Improved Activity and Stability of TiO2-Coated Co/C Catalysts for Electrochemical Application
Authors: Kim Hyung Ju , Jackson David H. K. , Kuech Thomas F. , Huber George W.
Published: February 2020

In this work we demonstrate the preparation, characterization and testing of a highly active and stable TiO2 coated Co/C catalyst for the electrochemical water oxidation. This non-precious metal catalyst is over 3 times more active than the traditionally used Pt based catalyst. The TiO2 coating was added by atomic layer deposition (ALD). The TiO2 overcoat increased the stability of the cobalt particles and the catalytic activity of the cobalt metal. The improved activity for water oxidation of these catalysts is probably associated with the role of ALD(TiO2) in promoting the oxidation of surface Co oxide. The formation of Co-O-Ti configuration on the ALD(TiO2)-Co/C catalysts may also change the surface binding energy of O or OH species on the catalyst surface. Therefore, the ALD(TiO2) overcoating on Co/C could change the nature of the active sites, thereby facilitating the formation of O-OH (known as the rate-limiting step for the reaction) more effectively, which could improve the water oxidation activity. In addition, the stability of the ALD(TiO2)-Co/C catalyst was enhanced compared to the Co/C catalyst. This work shows how the ALD synthesis technique can be used to improve the catalytic activity and stability of non-precious metal based catalysts like Co/C for electrochemical water oxidation.
High Aspect Ratio through Silicon Via Filling By Nickel-Tungsten Alloy Using Graphene As a Conducting and Barrier Layer
Authors: Huang Yen-Cheng , Zeng Wei-Yang , Chang Shih-Cheng , Dow Wei-Ping
Published: February 2020

Recently, three-dimensional (3D) chip stacking becomes more and more important because of “More than Moore” story. Through silicon via (TSV) technology is one approach to achieve the target of “more than Moore”. However, the coefficient of thermal expansion (CTE) of copper filled in the TSV may lead to failure of the TSV interconnects because the copper CTE is much higher than that of silicon. The packaging materials with different CTEs will induce large stress at interfaces of materials. To overcome this problem, we choose nickel to substitute copper as a filling material of TSV since the nickel CTE is lower than copper CTE. To further decrease the CTE of the filling material, a few tungsten whose CTE is similar to that of silicon is codeposited during filling plating.

Graphene has drawn extensive attention due to its outstanding electrical and thermal properties. In addition, graphene can be used as a barrier layer of copper diffusion. Also, the CTE of graphene is similar to that of silicon. Hence, we use graphene to replace the TiN barrier layer and the copper seed layer, which was used in the traditional TSV process.

The filling performance is evaluated by examining vertical cross-sections and top-down cross-section of the filled TSVs by using optical microscope (OM). The Ni-W pillar is examined by scanning electron microscopy (SEM). The thermal reliability of the fully filled TSV is evaluated after a thermal annealing process. The CTE of the filled Ni-W is measured by thermomechanical analysis.
Using Reduced Graphene Oxide (rGO) As a Conducting Layer on a Polyimide Flim for Cu Metallization
Authors: Zhang Yu- Zhen , Dow Wei-Ping
Published: February 2020

Polyimide (PI) film is an insulator and has been commonly used as a dielectric layer of a flexible printed circuit board (FPCB) due to its high thermal stability, well mechanical strength and excellent chemical resistance. For FPCB fabrication, the dielectric layer surface, PI surface, has to be metallized. Herein, we proposed an all-wet process to fabricate a copper diffusion barrier layer, avoiding Cu diffusion into the PI and a conducting layer, that is, a reduced graphene oxide (rGO) grafted on the PI surface. For a copper diffusion barrier layer, rGO has great electrical and thermal properties, and easy process than Ni barrier deposited by electroless plating. Owing to graphene oxide has a lot of carboxyl functional groups that forms carboxylate anions, it can ligand with the cations on the PI surface after the PI went through a chemical grafting process step. In this work, we successfully utilized rGO as a conducting layer on the PI surface, which can conduct copper plating on the PI surface. Furthermore, we demonstrated that rGO changed PI surface roughness by using an atomic force microscope (AFM).

Keywords

Reduced Graphene Oxide, Polyimide, Copper Electroplating

References

[1] Wei-Ping Dow, Guo-Liang Liao, Shang-En Huang and Sinn-Wen Chen, “Modification of Cu nanoparticles with a disulfide for polyimide metallization”, J. Mater. Chem.
(2010) 20, 3600-3609

[2] T. Osaka, S. Wakatsuki, T. Masuda, M. Yoshino, N. Yamachika, J. Sasano, I. Matsuda, Y. Okinaka, “A Wet Process for Forming an Adhesive Copper Layer on Polyimide Film”, Electrochemistry, 76, 191 (2008).

[3] Songfeng Pei, Hui-Ming Cheng, “The Reduction of Graphene oxide”, Carbon, 2012, 50, 3210-3228
Using Reduced Graphene Oxide As Conducting Layer of Plating through Holes of a Printed Circuit Board
Authors: Chang Shuo-Wen , Zeng Wei-Yang , Dow Wei-Ping
Published: February 2020

Graphene is a popular material because of its unique two-dimensional (2D) structure and intrigued physical and chemical properties. Graphene materials, including single layer and multi-layer graphene sheets, have recently drawn extensive attention due to their outstanding electrical and thermal properties. In the traditional metallization process of through holes of printed circuit boards (PCBs), copper electroless deposition process has been commonly used. It has environmentally unfriendly characteristics because it contains precious metal (i.e., Pd), formaldehyde and chelating agents. In contrast, reduced graphene oxide (rGO) has no these issues and can replace the copper electroless deposition of PCBs because the rGO process for copper metallization is simpler than that of copper electroless deposition. Herein, we used rGO process to replace the copper electroless deposition process in order to achieve a green fabrication process.

In this study, the effect of different conditioners for uniform adsorption of graphene oxide (GO) on the sidewalls of through holes of a PCB was investigated. We used different conditioners to chemically modify the substrate surfacefor uniform adsorption of GO. Following the GO adsorption, the adsorbed GO was reduced to rGO on the substrate surface. Then, the rGO-coated sidewall becomes conductive to replace the copper seed layer by electroless deposition. Finally, the rGO-coated through holes were successfully plated in an acidic copper bath with a high throwing power and these through holes could pass thermal shock reliability test.