bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Scanning Tunnelling Microscopy Study of Early Stages of Intergranular Corrosion of Copper
Authors: Marcus Philippe , Bettayeb Mohamed , Klein Lorena , Lapeire Linsey , Verbeken Kim , Maurice Vincent
Published: February 2020

Electrochemical scanning tunnelling microscopy (EC-STM) was used to investigate in situ and locally the topographical alterations of copper surfaces under electrochemical control. The aim of this work was to better understand the early stages of intergranular corrosion and the relationship between local structure of grain boundaries emerging at the solid/liquid interface and corrosion properties. A prerequisite for this approach is the use of a high purity material, in order to exclude the segregation of impurities, such as sulphur, at grain boundaries, which would strongly affect the intergranular corrosion behaviour and prevent us from studying the intrinsic effect of grain boundary structure This was achieved in this work by using high purity cast electrolytic tough pitch (ETP-) Cu, cryogenic rolled and post-annealed at relatively low temperature (200°C). This process also produces a grain size compatible with the limited field of view of STM, as confirmed by electron back scatter diffraction (EBSD) analysis.

 EC-STM data obtained in situ after a surface preparation producing oxide-free surfaces with emerging grain boundaries show that performing cycles of anodic dissolution in the absence of any surface oxide reveals a grain boundary structure-dependent corrosion behaviour. Localized attack is initiated at grain boundaries that can be assigned to either random-type boundaries or non-coherent coincidence site lattice (CSL) grain boundaries whereas, under the same conditions, coherent twin grain boundaries are not attacked. Direct coupling of EC-STM and EBSD, using a re-positioning procedure allowing the analysis of the same local surface area by both techniques, show that even for the corrosion resistant coherent twin grain boundaries, the intergranular corrosion behavior measured at the emergence of the grain boundaries at the solid/liquid interface is dependent on the local surface structure. Further combined EC-STM and EBSD analysis will be discussed to link grain boundary type, local surface structure and susceptibility to intergranular corrosion.
Au@SiO2 Nanoparticles Sheathed W Nano-Tips for Local Electrochemical and SERS Applications
Authors: Zhang Mengyuan , Ling Yunhan , Yu Siqi , Zhang Zhengjun , Gu Yanhong
Published: February 2020

Simultaneous acquisition of information on electrochemistry and phase composition is of great concern in diagnosis and detection of localized corrosion, which is calling for spatial resolution and phase recognition with improved accuracy. In this work, a new structure of Au@SiO2 nanoparticles sheathed W nano-tips for local electrochemical and SERS measurements is proposed, by which W nano-tips are prepared by improved direct current electrochemical etching, followed by coating with Au@SiO2 nanoparticles. The influence of the etching solution composition, voltage and the depth of immersion on the surface structure, tip apex radius and aspect ratios of W nano-tips has been investigated. Gold nanoparticles are prepared with chemical reduction method and the size is controlled via adjusting the molar ratio of sodium citrate to chloroauric acid. By measuring the TEOS and ammonia, the layer of SiO2 is attached onto gold nanoparticles with different thicknesses to produce Au@SiO2 core-shell nanoparticles. The microstructures, morphologies and composition are characterized using TEM, HRTEM and EDX, respectively, while the SERS effect is detected using Rhodamine 6G (R6G) as probe molecules. It was found that the enhancement on both SERS and spatial resolution of electrochemical measurement could be obtained by optimal diameter manipulation of tip apex and Au NPs. This work provides a convenient way to prepare new functional electrodes with the high sensitivity and stability for local electrochemical detection and SERS application.
EIS Study on Detection of Corrosion Site of Reinforced Concrete By Two Sensing Electrodes
Authors: Hoshi Yoshinao , Koike Taisuke , Tokieda Hiroyuki , Shitanda Isao , Itagaki Masayuki
Published: February 2020

A reinforced concrete has been used for the civil engineering and construction in the whole world. In order to obtain the real-time information of reinforced concrete, Dawson et al. 1) attempted to investigate the electrochemical behavior of reinforced concrete by an electrochemical impedance spectroscopy (EIS). John et al. 2) proposed the equivalent circuit to interpret the impedance spectrum of reinforced concrete. Though these methods can be applied to the investigation of conditions of reinforced concrete, an electrical connection of reinforced concrete to the measurement device is required. Keddam et al. 3) proposed the concept of floating electrode for contact-less electrochemical measurement of reinforced concrete. In this method, a four-electrode probe was set on the reinforcement, and the capacitive loop related to the double-layer capacitance at the cement-rebar interface was measured 3).

In the present study, a new method to detect the corrosion site of reinforced concrete was proposed by using two sensing electrodes. The sensing electrodes were placed on the surface of reinforced concrete as working and counter electrodes. The electrochemical impedance measurement was performed in this setup. The impedance related to the corrosion site of steel rebar in concrete with different cover thickness is measured by proposed method. In addition, the current and voltage distributions between sensing electrodes set on the concrete surface were discussed by a finite element method.

Reference:

1. J. L. Dawson, L. M. Callow, K. Hladky and J. A. Richardson, Corrossion/78, No-125(1978).

2. D. G. John, P. C. Searson, J. L. Dawson, Br Corros J, 16, 102-106 (1981).

3. M. Keddam, X. R. Nòvoa, V. Vivier, Corros. Sci., 51, 1795-1801 (2009).
Electrical Characteristics of Dual Layered Tunnel Barrier with High Speed and Good Retention for Charge Trap Flash Memory
Authors: Choi Jae Ho , Jung Il Sub
Published: February 2020

In this paper, we investigate the electrical characteristics of SiO2/ZrO2 hybrid tunnel oxide in MAONOS structure in an effort to improve program and erase speed as well as retention endurance. Inserting ZrO2 into the conventional MAONOS structure increased the programmed Vth variation to 5.8 V, and increased the erased Vth variation to -3.2 V at 15 MV/cm. The results can be understood in terms of reduced the F-N tunneling barrier due to high-k ZrO2 in the tunneling oxide. In addition, Zr diffusion in SiO2 caused the formation of ZrxSi1-XO2 at the interface region, which reduced the energy band gap of SiO2. The retention property of the hybrid tunnel oxide varied depending on the thickness of SiO2. For thin SiO2 less than 30 Å, the retention properties of the tunneling oxides were poor compared with those of the SiO2-only tunneling oxides. However, the hybrid tunneling oxides with SiO2 thickness thicker than 40 Å yielded improved retention behavior compared with those of the SiO2-only tunneling oxides. The detailed analysis in charge density of ZrO2 was carried out by ISPP test. The obtained charge density was quite small compared to that of the total charge density, which indicates that the inserted ZrO2 layer serves as a tunneling material rather than charge storage dielectric.
Electroless UPD Monolayer Deposition - a Prelude to Highly Selective Electroless Atomic Layer Deposition Process
Authors: Solanki Dhavit , Wu Dongjun , Joi Aniruddha , Dordi Yezdi , Brankovic Stanko
Published: February 2020

The improved understanding of nucleation kinetics has led to various discoveries in which the thin film growth was manipulated to enhance the evolution of atomically flat epitaxial overlayers. Exploiting some of these results has led to invention of several new methods and protocols for electrodeposition where underpotentially deposited (UPD) monolayer is used as a mediator, surfactant or sacrificial template. The one successful example is so called “deposition via surface limited redox replacement (SLRR) of UPD monolayer,” which gained a lot of applications for synthesis of noble metal thin films with different functionalities. This protocol/method represents the combination of the potential controlled step (formation of UPD monolayer) and the electroless step (SLRR of UPD monolayer by more noble metal ions, i.e., galvanic displacement). However, our studies show that there is still a lot of room left for improvements and further simplifications. These should expand application of this deposition protocol in many areas where traditional atomic layer deposition (ALD) process has been used.

In this talk we present results demonstrating an electroless ALD process in which a Pb UPD monolayer is used as a reducing agent and sacrificial material in SLRR reaction with noble metal ions such as Pt, Pd, and Ru and Cu. The full deposition cycle involves sequential exposure of the substrate such as Cu and Ru to the solution for electroless Pb UPD monolayer deposition and then to the solution for SLRR reaction and noble metal deposition. This results in an overall deposition of controlled amount of noble metal which is the function of the areal density of deposited Pb monolayer and stoichiometry of the SLRR reaction. Therefore, the process mimics, to a great extent, the standard ALD cycle where adsorption of the metal precursors and surface catalyzed reaction are replaced by electroless Pb UPD monolayer deposition and SLRR reaction. If the two-step SLRR cycle is repeated an arbitrary number of times, a highly compact, smooth, and conformal noble metal thin film can be grown. The deposition process is highly selective to the metal substrates at which Pb forms an UPD monolayer providing an advantage when certain integration requirements are considered. The process is designed for (but not limited to) aqueous solutions with fairly simple and stable chemistry that can be easily scaled up to any size and shape of the substrate surface. Results demonstrating details and underlying phenomena controlling this process will be discussed. In addition, an example of a high quality of Pt, Pd, Cu and Ru films grown on Cu and Ru substrate will be shown, as well as the applications of this process for metallization of structures relevant to semiconductor device fabrication.
(Invited) In-Situ Studies of Alloying and Alloy Surfaces in the Electrochemical Environment
Authors: Lucas Christopher , Grunder Yvonne , Fogg Joshua , Vasiljevic Natasa
Published: February 2020

The development of new functional materials is transforming many technological areas of great interest from electronics and catalysis to detection and bio-sensing. Surface alloying and self-organization phenomena, driven by the surface stress and elastic interactions in metals, are key to these developments. While much has been done theoretically and explored experimentally in ultra-high vacuum (UHV), very little has been exploited in practical applications. Electrochemistry is the ideal science to exploit the physics and chemistry of such functional materials. Alloying between two components in general is driven by negative enthalpy of mixing and the lowering of surface free energy. However, when confined to a few surface layers, it can be observed even in systems that do not form alloys in the bulk phase (so called immiscible systems). UHV studies at elevated temperatures have found that the formation of immiscible surface alloys is a rather common phenomenon in systems with large lattice mismatch and that it is driven by surface stress relaxation and elastic energy.

In this talk in-situ surface x-ray scattering studies of alloy formation and alloy surfaces will be presented. This will include alloys prepared by UHV methods, in particular both bulk and surface Pt3Sn(111) alloys, and alloys prepared directly in the electrochemical environment, Pb-Au(111). For the Pt3Sn system, of interest in electrocatalysis due to its tolerance towards CO poisoning, the surface has been studied under UHV conditions and during the adsorption of water and the results are compared to measurements of bulk Pt3Sn alloys in 0.5 M H2SO4 electrolyte under potential control. For the Pb-Au(111) system, resonant x-ray scattering methods are used to identify the onset of surface alloying and correlate the changes in surface stress with the out-of-plane atomic structure.
(Invited) Interpretation of Certain Features of the Interface Stress Vs. Electrode Potential Curves of Gold with the Help of Dual Dynamic Voltammetry
Authors: Lang Gyözö G. , Kovacs Noemi , Dankhazi Zoltan , Vesztergom Soma , Ujvari Maria
Published: February 2020

It is a widespread opinion that the electrochemical behavior of gold in aqueous media has been thoroughly studied, and the interface stress changes of gold can be explained by monolayer oxide formation/removal and adsorption phenomena. However, there are some peculiarities to consider. For instance, a sudden change in the slope of the interface stress vs. electrode potential curve recorded during the negative-going scan of the cyclic voltammogram can be observed in the oxide reduction region of gold in sulfuric acid solutions (Fig. 1).

The method of dual dynamic voltammetry, i.e. the simultaneous application of dynamic potential programs to the generator and the collector electrodes of a generator-collector system, is a promising new method for studying the mechanisms of electrochemical processes [1-3]. By applying this method to a gold/gold rotating ring-disk electrode (RRDE) it could be shown that the sharp change in the slope of the surface stress vs. potential curve recorded in the oxide reduction region of gold in sulfuric acid solutions [4] is accompanied by the formation of soluble, electrochemically reducible gold species which can be detected at the ring electrode.

References:

[1] S. Vesztergom, M. Ujvári, G.G. Láng, Electrochemistry Communications, 19, 1–4 (2012).

[2] N. Kovács, M. Ujvári, G.G. Láng, P. Broekmann, S. Vesztergom, Instrumentation Science and Technology, 43, 633–648 (2015).

[3] S. Vesztergom, N. Barankai, N. Kovács, M. Ujvári, P. Broekmann, H. Siegenthaler, G.G. Láng, Electrochemistry Communications, 68, 54–58 (2016).

[4] G.G. Láng, C.A. Barbero, „Laser Techniques for the Study of Electrode Processes”, Springer-Verlag, Berlin, Heidelberg, 2012.

_

Figure 1
Superconformal Cobalt Fill through the Use of Sacrificial Oxidants
Authors: Rigsby Matthew , Brogan Lee , Doubina Natalia , Spurlin Tighe , Zhou Jian , Reid Jonathan
Published: February 2020

As interconnect dimensions continue to decrease, the extendibility of conventional copper damascene processing becomes increasingly problematic. Small feature openings can lead to agglomeration of the thin seed that is required to avoid pinch-off, and this can then lead to poor nucleation during the electrodeposition process. Electromigration performance also suffers from the decrease in line dimensions. In addition, the increase in line resistance with shrinking dimensions means that the barrier is consuming valuable space within the feature. To address these extendibility issues, alternative metals, such as cobalt, are being actively explored.

Conventional damascene electroplating utilizes a combination of organic additives, namely, a suppressor, an accelerator, and a leveler, to achieve superconformal fill of interconnects. An alternative mechanism for superconformal cobalt fill is presented here. This mechanism, the Differential Current Efficiency Fill (DCEF) mechanism, utilizes sacrificial oxidants to achieve void-free superconformal fill. In the DCEF mechanism, the presence of a sacrificial oxidant promotes a difference in metal deposition rate between the field and the feature bottom. Addition of a single suppressor-type additive may assist in driving the plating rate differential. By appropriately selecting the sacrificial oxidant, the waveform, and the rotation rate, void-free superconformal fill can be achieved.

Figure 1 shows an example of the superconformal cobalt fill that can be achieved. Here, the rate and degree of fill are modulated by changing the rotation rate during the electrodeposition. Electrochemical polarization and current efficiency experiments are useful in determining appropriate process conditions, and these data will also be discussed.

The DCEF mechanism presents a new approach to achieving superconformal fill and will be important in extending electroplating to increasingly smaller interconnect dimensions. While the DCEF mechanism has been shown to work for superconformal cobalt fill, the concept may be applicable to other metals as well.

Figure 1: Superconformal cobalt fill: 1mA/cm2 240s, varied rotation rate

Figure 1
1D Core-Shell Nanostructures Formed By Electrodeposition of Metals and Metalloids in Anodic TiO2 Nanotubes
Authors: Kowalski Damian
Published: February 2020

The anodizing is a high-voltage electrochemical conversion process that forms barrier-type or nanoporous/nanotubular oxides on valve metals and alloys, mainly depending on the composition of electrolyte used.[1] The key to achieve the ordered nanoporous/nanotubular structures is a displacement of the film material above the original surface position due to synergistic effect of pits generation (field assisted oxide dissolution), stress generated at the metal-oxide interface including electrostriction and plastic oxide flow switching the growth of the barrier-film to nanotube/nanopore. Typically, the TiO2nanotube array formed in organic electrolytes such as glycerol, dimethyl sulfoxide, ethylene-glycol is obtained in the form of close packed structure in which the nanotubes nearly stick together with the tube walls. A fundamentally different nanostructure from that is obtained in diethylene-glycol electrolyte. The nanostructure is characterized by free standing nanotubes separated by an interconnecting space much bigger than the thickness of nanotube wall. [2,3] Such geometry gives possibility for deposition of secondary materials using electrochemical processes in view of improved wetting behavior of the nanostructure. [4] Herein we report on how to control the electrodeposition process to achieve unique core-shell geometries. We discuss on wetting behavior and nucleation-growth on such porous structures, a key points to achieve controlled electrodeposition. An examples of composites formed between oxide layer and Si, CdSe, Au, Pt will be demonstrated.

References:

[1] D. Kowalski, D. Kim and P. Schmuki, Nano Today, 8(2013) 235.

[2] D. Kowalski, J. Mallet, J. Michel, and M. Molinari, J.Mater.Chem.A
3(2015) 6655.

[3] D. Kowalski, J. Mallet, S. Thomas, J. Rysz, B. Bercu, J. Michel and M. Molinari, Electrochim. Acta, 204(2016) 187.

[4] D. Kowalski, and P. Schmuki, Chem. Comm., 46(2010) 8585.

Fig. 1 Core-shell structures formed by means of electrodeposition of Si and Au. STEM image (left) shows 60nm thick silicon layer electrodeposited from ionic liquid electrolyte on the outer-shell of TiO2 nanotube. Back scattering electron image (right) shows gold electrodeposited in-between the bottoms of TiO2 nanotubes.

Figure 1
Cost of Renewable Energy
Authors: Newman John
Published: February 2020

To switch from conventional fossil fuels to renewable energy is a huge undertaking. Before starting this costly exercise, the community should assess what is involved, how much it will cost, and by how much the standard of living will be reduced.

It is not complete to focus on efficiency, and certainly not reversible energy efficiency. In one example, emphasizing minimizing overall energy efficiency leads one to conclude that building a photovoltaic device and an electrolyzer in a single unit is the correct approach. However, this raises the total cost significantly over what could be accomplished when the photovoltaic and the electrolyzer can be kept separate and each optimized separately. Then the PV can be run at its maximum power, and the electrolyzer can be run at a different temperature and at a significantly higher current density, at the optimum governed by a trade-off between capital and operating costs.

To bring a new product to market requires careful planning to insure that the product is useful and at an attractive price. Even more so when you are contemplating changing the whole energy infrastructure.

Perhaps cheaper than clean renewable energy like wind, geothermal, or solar would be to continue to burn fossil fuels but to capture and sequester the carbon dioxide produced and thereby mitigate climate change. It surprised me how much more attractive this method could be.
Ruthenium Electrodeposition from Deep Eutectic Solvents
Authors: Bernasconi Roberto , Magagnin Luca
Published: February 2020

Ruthenium is one of the most promising materials for the realization of barrier/seed layers in low-k copper interconnects technology. It is a possible candidate for the substitution of materials like Ta/TaN or TiN. This metal presents interesting properties like a reasonably low resistivity (7.1 µΩcm in bulk), a high melting point and high mechanical properties. Moreover, it presents almost no solubility with copper, preventing thus interdiffusion [1]. Finally, ruthenium can be directly plated with copper [2], avoiding the deposition of seed layers.

Ruthenium can be easily PVD deposited on Si, obtaining ultrathin barrier layers suitable for the most advanced patterning techniques. However, PVD deposition presents some major disadvantages like high cost, limited productivity and a significant difficulty in uniformly plating vias and trenches having high aspect ratio (this effect is known as shadowing). Alternative techniques, including wet metallization, can overcome these limitations. Electrodeposition in particular proved to be able to provide uniform metallization even in very high aspect ratio features, like in the case of copper superfilling [3].

Ruthenium tends to oxidize in aqueous solution, and for this reason electrodeposition from standard electrolytes can present technological problems. Alternative solvents have been proposed in the past to solve this issue, the most notable being ionic liquids like BMIPF6 [4]. Another possible alternative are deep eutectic solvents, which are characterized by interesting properties like water stability, high conductivity and the absence of harmful chemicals (which make them suitable also for employment in the green chemistry field).

The present work describes the electrodeposition of ruthenium thin films for microelectronic applications from a deep eutectic solvent. Metallic layers are deposited and characterized from the electrical and morphological point of view to evaluate their possible use as barrier layers in microelectronics industry.

[1] R. Chan, T. N. Arunagiri, Y. Zhang, O. Chyan, R. M. Wallace, M. J. Kim and T. Q. Hurd, Electrochem. Solid-State Lett., 7, G154 (2004)

[2] Y. Zhang, L. Huang, T. N. Arunagiri, O. Oieda, S. Flores, O. Chyan, and R. M. Wallace, Electrochem. Solid-State Lett., 7, C107 (2004)

[3] D. Josell, D. Wheeler and T. P. Moffat, Electrochem. Solid-State Lett., 5, C49 (2002)

[4] O. Raz, G. Cohn,W. Freyland, O. Mann, Y. Ein-Eli, Electrochim. Acta, 59, 6042 (2009)
(Invited) Molten Sulfides for Metal Electrodeposition
Authors: Allanore Antoine
Published: February 2020

Molten sulfides are known to electrochemists for energy storage applications, but remain an understudied medium in which metal electrodeposition reactions can be conducted. Our research group has been investigating such opportunity in the context of novel processes to extract metals from sulfide ores. During those developments, alkaline and alkaline-earth based sulfide electrolytes have been designed and investigated to operate in a broad temperature range. This presentation aims to provide an overview of the performances and challenges of molten metal sulfide electrolytes in the context of the decomposition of metal sulfide compounds, including Cu, Zn, Mo, Re and Ag sulfides. Results obtained using AC voltametry techniques as well as electrolysis experiments will be presented, highlighting the physical and chemical questioning that arise when considering the use of molten sulfides for electrodeposition.
Experimental and Modeling Studies of Neodymium Electrodeposition from High-Temperature Chloride-Based Molten Salts
Authors: Shen Dai , Akolkar Rohan
Published: February 2020

Electrowinning and electrorefining of rare earth lanthanides using molten salt electrolytes is of interest because these technologies offer the potential for energy-efficient and low-cost recovery and reuse of these strategically important elements. However, efficient electrochemical processing of rare earth elements such as neodymium (Nd) is hindered by its multivalent nature. Specifically, the existence of Nd3+ and Nd2+ redox-active species can substantially lower the overall current efficiency of Nd electrorefining [1]. In the present talk, we will report on experimental and modeling investigations into the electrodeposition of Nd metal from NdCl3-containing halide melts (eutectic LiCl-KCl). We will discuss how cyclic voltammetry studies and diffusion-reaction modeling help unravel the thermodynamic, kinetic and mass transport properties associated with the multivalent redox transitions prevalent during Nd electrodeposition. Furthermore, we will discuss how these properties can be used to design efficient Nd electrowinning and electrorefining processes. The broad applicability of our design approach will be discussed in the context of electrodeposition of other multivalent rare earth metals and alloys.

1. L. Feng, C. Guo, and D. Tang, J. Alloys Compd., 234, 183 (1996).

Figure 1
Electrochemical Nucleation and Growth of Metals in Molten Salts
Authors: Suzuki Yuta , Yokota Masayuki , Sakanaka Yoshihide , Fukunaka Yasuhiro , Goto Takuya
Published: February 2020

Investigation of electrochemical nucleation and growth mechanism is of great significance for controlling morphology of elctrodeposited metals on substrate. However, information concerning nucleation and growth mechanism in molten salts has not been sufficient, although it is necessary to understand growth processes of electrodeposition of metals in molten salt for realizing practical process. In particular, investigation of electrodeposited metals at early stage is expected to give us new information about morphogenetic process during electrolysis in molten salts.

From the background, molten chloride salts containing silicon ions was used for studying electrochemical nucleation and growth mechanism of metallic silicon by using electrochemical techniques combined with micro-spectroscopic techniques. After conducing electrolysis for one second, hemispherical nucleated Si was observed by SEM, and process of agglomeration was also observed as time proceeded. The effect of time evolution on growth process has been also studied by conduction potentiostatic electrolysis. The growth mechanisum from the experiments will be presented at the symposium.
Effect of Magnetic Field on Al Electrodeposition in Ionic Liquid
Authors: Takahashi Hitomi , Matsushima Hisayoshi , Ueda Mikito
Published: February 2020

1.Introduction

　Aluminum is a very important material because of its distinctive features of a bright silvery appearance, light weight and high corrosion resistance. Also, it is used as a base in light-emitting diodes owing to its high reflectance of more than 90% in the visible light region. We have previously carried out Al electrodeposition with additives and reported a shiny coating under the control of a stirred flow [1]. In that work, the surface roughness and glossiness was drastically improved by increasing the stirring rate.

　To pursue a novel convection method, we consider that the superimposition of a magnetic field, B, is a possible solution. Lorentz force occurs when a magnetic field is applied perpendicular to current, and a convection caused by the power is called MHD convection [2]. Therefore in an ionic liquid which consists of only ion species, the MHD convection can expect to act more effectively as compared with an aqueous solution system. In this report, Al films were electrodeposited in EMIC-AlCl3 ionic liquid under a uniform magnetic field, whereupon their morphology and crystal orientation were analyzed by scanning electron microscopy and X-ray diffractometry.

2.Experimental

　Electrodeposition was carried out with a three-electrode system. The electrolyte used was EMIC-AlCl3 (1:2). The cathode was a Cu plate and the anode was an Al plate. All experiments were conducted in a glove box purged using by Ar gas at 60°C. The Al electrodeposition was conducted galvanostatically until the amount of electrical charge reached 29 C cm−2, which corresponds to a deposition 10 µm thick. A static and uniform magnetic field of 0.3 T was applied parallel to the electrode surface. The surface morphology of the electrodeposited Al films was observed using SEM, while the crystal orientation was measured by XRD using the Cu-Kα line.

3.Results and discussion

　In the galvanostatic electrolysis experiment, potential shifted to the noble direction by applying a magnetic field, and when current density was enlarged, the difference appeared more notably. The magnetic field also affected the orientation of deposition, and a (200) plane orientated priority. These are considered that the stirring effect by a MHD convection is involving. The SEM images show that the crystal grains change remarkably in the presence of a magnetic field, where a typical morphological variation is shown in Fig. 1. Fig. 1(a) shows angular deposits around 1.0 µm in size, and a surface covered with fine irregular grains. The application of magnetic field, however, created large grains with tabular-facet planes 2–4 µm in size (Fig. 1 (b)), although no additives were used in the present experiments.

[1] H. Takahashi, C. Namekata, T. Kikuchi, H. Matsushima and M. Ueda, Journal of the Surface Finishing Society of Japan, 68, 208 (2017).

[2] A. Bund, S. Koehler, H. H. Kuehnlein and W. Plieth, Electrochimica Acta, 49, 147 (2003).

Figure 1
Improving Li/Solid Electrolyte Interfacial Contact and Performance By Evaporating a Conformal Lithium Layer
Authors: Frisco Sarah , Whitacre Jay
Published: February 2020

In solid polymer electrolyte/lithium metal based batteries, the interfacial integrity of the lithium metal/polymer interface is critical, and the imperfect, non-uniform initial contact of lithium foil pressed into electrolyte worsens with cycling. This leads to increased impedence at the interface and declining cell performance. To address this issue, we are assessing the impact of depositng a conformal layer of lithium via evaporation onto the electrolyte surface prior to the application of a lithium foil bulk electrode. This approach yields initially enhanced interfacial area due to the improved contact from this conformal coating, which should lead to improved cycling behavior. Electrochemical data in the form of galvanostatic cycling and electrochemical impedence spectroscopy will be discussed in the context of nano-resolution X-ray radiographs and SEM. Data from commercial and lab created solid electrolytes, including PEO and other polymer electrolytes will be shown. Discussed will be the relative performance of solid-state lithium metal cells with a simple lithium foil anode versus a combined lithium evaporated layer/lithium foil anode. Furthermore, the propensity for dendritic failures in PEO electrolyte systems will be examined.
Imaging Li and Resolving the Degradation Mechanism of All-Solid-State Li-Ion Batteries
Authors: Gong Chen , Jadidi Zinab , El Gabaly Farid , Fuller Elliot James , Talin Albert Alec , Leite Marina S
Published: February 2020

All-solid-state Li-ion batteries (SSLIBs) with enhanced safety are a promising candidate for large-scale energy storage applications, such as hybrid vehicles. However, further improving the electrochemical performance requires controlling and suppressing the degradation mechanism for SSLIBs upon cycling. To reveal the nature of the irreversible reaction that takes place in SSLIBs, we combine scanning/transmission electron microscopy (S/TEM), X-ray photoelectron spectroscopy (XPS), conductive atomic force microscopy (c-AFM), and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). We directly image Li ions within each battery component during charging/discharging for SSLIBs with Al and Si anodes. We observe the formation of an Al-Li-O complex capping the AlLi alloy on the strain-free surface of the Al anode using S/TEM and XPS [1, 2]. We found that this layer is insulting through c-AFM and therefore retards electrons to flow in and out of the anode, ultimately leading to the poor capacity retention. For comparison, we fabricate SSLIBs with Si anodes, a high-capacity material. We identify the electrical property of the Si anode remaining intact after cycling by c-AFM. This battery shows a Coulombic efficiency of ~98% after 100 cycles, see Fig. 1.

To further investigate the irreversible lithiation process of Si anode SSLIBs, we directly map Li ions by ToF-SIMS. We determine the Li distribution within all active layers (anode, electrolyte, and cathode) at three state-of-charge: pristine, charged, and cycled. We demonstrate a remarkable spatial variation of Li concentration within the anode upon the first charging, later the ions are trapped and cannot be fully extracted from the anode during subsequent cycles. The accumulation of foreign ions within the Si anode is detrimental to the structure integrity, resulting in the capacity loss after cycling the device [3]. Moreover, we identify “hot spots” of Li ions within the LiPON electrolyte, which could be ascribed to the amorphous nature of LiPON. Overall, we provide critical information about how the capacity fades and where the irreversible lithiation happens. Our results will undoubtedly contribute to the design of energy storage devices with enhanced performance.

[1] M. S. Leite et al., J. Mater. Chem. A
2014,
2, 20552. i-­Cover

[2] C. Gong et al., ACS Appl. Mater. Interfaces
2015,
7, 26007. ­Cover

[3] C. Gong et al., In preparation
2017

Figure 1
Superior Shelf Life and Moisture Tolerance of ALD-Coated Cathode Materials As Important Aspect of ALD-Based Improvements of Li-Ion Cell Cycle Life
Authors: Venkat Maithri , Dahlberg Kevin , King David M , Meyer Harry M , Ruther Rose Emily , Wood David L , Stevenson Lisa , Townsend Dennis
Published: February 2020

Lithium-ion battery-based energy storage is widely regarded as the best technology to realize affordable electrification of automobiles (hybrids and EVs), buses, and ships. However, strategies to realize higher energy density and lower cost come at the expense of cell lifetime and safety. Extensive effort has been devoted to studying the effects of ALD coatings on cathode materials, with varying reports of the impact on full cell cycle life. The changes in surface chemistry of ALD-coated cathode particles and their specific effects on electrochemical performance have not been studied in detail. Unmodified particle surfaces contain active oxygen, LiOH, and Li2CO3 species. The chemistry of these species during delithiation and interaction with the electrolyte can introduce components of impedance that can limit the capacity and rate capability of the material. Moisture adsorption can occur over time which can interact with and generate more of these species, causing a further deterioration of capacity. We have shown that important functions of ALD are to “clean” the particle surfaces, decreasing the content of LiOH and moisture, and forming a barrier to water adsorption and further generation of these species. Thus an important mechanism of ALD enhancement of cathode materials in full cells is demonstrated. This understanding should be applied to past and future studies, and represents a powerful new strategy to mitigate the effects of moisture.
(Invited) HQ Characterisations Techniques for Li-Ion and Solid State Batteries
Authors: Zaghib Karim , Hovington Pierre , Wen Zhu , Trudeau Michel , Paolella Andrea , Vijh Ashok , Guerfi Abdelbast , Julien Christian M , Mauger Alain , Armand Michel
Published: February 2020

In these presentation, we will present the data and movies of several an operando techniques to study lithium ion and solid state batteries such in situ SEM, In situ TEM, in situ Raman spectroscopy , in situ X-ray diffraction and in situ UV visible. These studies help to understand several mechanism such volume expansion of anodes such lithium metal (20 %), Graphite (10 %), LTO (0 %) and another example the measurements of the thickness of anode, cathode and electrolyte during charge discharge. The mechanism of lithium dendrite was also study and details will be shown during this presentation.

Bleand Lithium/solid polymer electrolyte (SPE)/sulfur cells were studied in operando by two techniques: Scanning Electron Microscope (SEM) and ultraviolet-visible absorption spectroscopy (UV-vis). During the operation of the cell, extensive polysulfide dissolution in the solid polymer electrolyte (cross-linked polyethylene oxide) leads to the formation of a catholyte.

A clear micrograph of the thick passivation layer on the sulfur-rich anode and the decreased SPE thickness by cycling confirmed the failure mechanism; the capacity decays by reducing the amount of active material, and by contributing to a charge inhibiting mechanism called polysulfide shuttle. The formation of elemental sulfur is clearly visible in real time during the charge process beyond 2.3 V. The non-destructive in operando UV-vis study also shows the presence of characteristic absorption peaks evolving with cycling, demonstrating the accumulation of various polysulfide species, and the predominant formation of S4
2- and of S6
2- during discharge and charge, respectively. This finding implies that the charge and discharge reactions are not completely reversible and proceed along different pathways.
Electrochemical Cells for Operando Time-of-Flight Neutron Diffraction Study of Li/Na-Ion Electrode Materials
Authors: Bobrikov Ivan A. , Ivanshina Olga Yu , Sumnikov Sergey V , Samoylova Natalia Yu , Balagurov Anatoly M.
Published: February 2020

In-situ and operando neutron powder diffraction are well established methods for studying structural changes in Li-ion electrode materials in real time during battery operation. Quality of diffraction data obtained in operando experiments depends on characteristics of diffractometer (brightness, space resolution) and design and assembly of electrochemical cell. Operandoneutron diffraction experiments can be successfully performed with real batteries; however using special designed electrochemical cell allows us to exclude some undesirable reflexes of battery components from diffraction pattern, use Li-metal as counter electrode, decrease background from incoherent scattering elements, be almost independent from commercial machines for battery preparation and considerably reduce a mass of investigated materials.

In this report we present special designed electrochemical cells developed for operando study of Li-ion electrode materials at time-of-flight neutron diffractometers at the IBR-2 neutron source (Dubna, Frank Laboratory of Neutron Physics). The cells are easily assembled in a glove box and demonstrate the excellent parameters of cyclabilities (with graphite electrodes, more than 700 cycles) and absence of leakage current. In dependence of scattering properties of studied materials the measured diffraction patterns can be analyzed by Rietveld method or Peak’s profile data analysis. Several successful operando experiments on Li-ion electrode materials using these cells have been performed. In particular, investigation of LiNi0.8Co0.15Al0.05O2(NCA) cathode material in the electrochemical cell allowed us to reveal the microstructural reasons of phase separation that occurs in cycled NCA during the first charge.

[1] A. M. Balagurov, I. A. Bobrikov, N. Yu. Samoylova, O. A. Drozhzhin, E. V. Antipov, RUSS CHEM REV. 2014, 83(12), 1120–1134
Thermal Conductivity Study on a Working Li-Ion Battery Cell
Authors: Cao Lei , Hartig Julia , Santhanagopalan Shriram
Published: February 2020

Lithium-ion batteries have been popular powering mobile electronics and electric vehicles owing to its high energy density and good electrochemical performance. However, thermal transport performance, especially in cross-plane direction, is not on a par with electrochemical ones. Poor thermal transport may result in overheating and even thermal runaway while there’s still a lack of methods studying battery electrode thermal conductivity under working condition1. Previous efforts provide measurement on either dry battery electrodes or reassembled electrodes with electrolyte but not being able to charge and discharge2, 3. Current study demonstrates a new method measuring thermal conductivity of a working battery cell through flash diffusivity technique. By minimizing contact resistance between electrode sample and holder, the work can contribute to comprehensive study of a working battery cell for better thermal performance.

1. V. Vishwakarma, C. Waghela, Z. Wei, R. Prasher, S. C. Nagpure, J. Li, F. Liu, C. Daniel, and A. Jain, Journal of Power Sources,
300 123-131 (2015).

2. H. Maleki, S. A. Hallaj, J. R. Selman, R. B. Dinwiddie, and H. Wang, Journal of The Electrochemical Society,
146 (3), 947-954 (1999).

3. S. C. Nagpure, R. Dinwiddie, S. S. Babu, G. Rizzoni, B. Bhushan, and T. Frech, Journal of Power Sources,
195 (3), 872-876 (2010).
Effects of Additives on Copper Layer Stress Electroplated on Polyimide
Authors: Lin Liang-Jie , Dow Wei-Ping
Published: February 2020

Flexible printed circuit board (FPCB) made of polyimide film as an insulator with a low dielectric constant, good mechanical strength and excellent chemical resistance has been widely applied to complicated electronic devices and products such aschip on flexible printed circuit (COF) and laptops. Because of economic advantage, we developed an all-wet process to metallize polyimide film. In this work, electroless Ni was predeposited on the polyimide as seed and barrier layer, and then followed by copper electroplating. The copper electroplating bath contained chloride and acidic copper sulfate as well as a suppressor and an accelerator. We used various copper electroplating formulas in the plating bath to reduce the surface roughness and intrinsic stress of the electroplated copper film on the polyimide film for a high reliability, such as high adhesion and good thermal reliability. The intrinsic stress, preferred crystalline orientation and surface morphology was analyzed by the Bent Strip Method (Deposit Stress Analyzer System), measured by an X-ray diffraction (XRD), and examined by scanning electron microscope (SEM), respectively. As a result, we found that the peel strength between the plated copper film and the polyimide depends on the copper plating formula.
High Speed Blind Via Filling By Copper Electrodeposition
Authors: Lo Chun-Hsiang , Dow Wei-Ping
Published: February 2020

Blind vias filling by direct-current copper electroplating is widely used in printed circuit boards (PCBs) to increase input/output (I/O) density due to high density interconnection. The blind vias of a PCB can be filled perfectly by copper electroplating using organic additives such as suppressor, leveler and accelerator in a copper plating bath. However, the current density cannot be raised too high because a void is easily formed at the blind via after filling plating at a high current density. Therefore, this work is to adjust the ratio of organic additives to fill the blind vias of a PCB by copper electroplating at 25℃~30℃ and at a high current density (i.e., 5 A/dm2). The filled blind vias were examined by cross-sectional analysis using an optical microscope (OM) and a scanning electron microscope (SEM). In addition, synergistic effect of organic additives on copper deposition was analyzed by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) to explain how did these additives work for superfilling of the blind via at the high current density.
A Self-Forming Membrane for Advanced Electrochemistry-Based CO2 Capture
Authors: Zhang Peng , Tong Jingjing , Huang Kevin
Published: February 2020

The presentation describes a new type of low-cost and easy-to-fabricate mixed e- and CO3
2- conducting membrane for advanced high-flux and selective electrochemical CO2 separation from flue gas. The membrane is consisted of a CO3
2--conducting molten carbonate phase and an e--conducting lithiated Ni-oxide interphase formed in situ during operation. The testing results explicitly show that the membrane exhibits a CO2 flux density >1.0 mL min-1 cm-2 at 850 oC with a selectivity of 100-500 and excellent stability for 450 hours. Compelling experimental evidence is also provided to support that the self-formed interphase Li0.4Ni1.6O2 is highly electronic conducting and responsible for providing electrons to the co-reduction of CO2 and O2 into CO3
2-. Given the performance level demonstrated, this low-cost and easy-to-fabricate membrane is superior to the conventional “size-sieving” inorganic and “dissolution-diffusion” organic counterparts, promising it to be a very competitive technology for future advanced CO2 capture from flue gas.
Investigation on the Performance of Electrolytic Processing of Kraft Pulping Black Liquor
Authors: Cloutier Jean-Noël , Paris Jean , Savadogo Oumarou , Perrier Michel , Labrecque Raynald , Champagne Pascal
Published: February 2020

The bio refinery initiative in the pulp and paper industry aims at diversifying their product offering including value added biomaterials from lignin. As an alternative to the chemical method using carbon dioxide and sulfuric acid, we have developed an electrochemical approach to precipitate lignin from black liquor while recovering caustic. Our approach, which is based on electrolysis of black liquor, reduces its alkalinity electrochemically to the point of lignin precipitation. It does not require any chemicals from an external source and generates no additional effluent complying with sustainability development. The technology offers an increased production capacity for a Kraft mill limited by the recovery boiler capacity or the recausticizing system. In this study, we investigated the fundamental electrochemical phenomena involved and the the effect of variables on the process performance in order to determine the best operating conditions in terms of current efficiency, energy consumption and caustic production.