bluuebunny/crossref_metadata_2025_split huggingface dataset:
Texture Evolution during Zinc Electrodeposition
Authors: Orme Christine , Keist Jayme , Wright Paul K , Evans Jim W 
Published: February 2020

This talk investigates the impact of additives and ionic liquids on the stability of zinc interfaces by measuring the temporal evolution of the surface roughness. Experiments are designed to quantify the morphological evolution during charge and discharge cycles in battery electrolytes. We use of in situ electrochemical atomic force microscopy and in situ ultra-small angle x-ray scattering (EC USAXS) to track surface morphology during zinc electrodeposition from two electrolytes: alkaline potassium hydroxide and an ionic liquid, 1-butyl-3-methyl-imidazolium trifluoromethanesulfonate (BMIM OTF). Images are used to quantify the temporal evolution of lateral correlations and surface roughness as a function of deposition thickness.
Zinc growth within BMIM OTF displays a surface morphology that has not been described for zinc before; the surface organizes into domains of parallel platelets with the prism facets perpendicular to the surface. Because of this textured morphology, the surface roughness stops growing under some conditions. This cessation of roughening is counter to current models of surface evolution. The coarsening of the grains and the evolution of the roughness are quantitatively described using scaling exponents. The goal of our project is to link early time nucleation events with the onset of large-scale instabilities such as dendrites.
Auspices: Portions of this work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Additives for Suppressing Zinc Dendrites in Rechargeable Zinc Metal Batteries
Authors: Banik Stephen J , Akolkar Rohan 
Published: February 2020

Rechargeable zinc-based battery systems hold great promise for future energy storage devices due to their low cost and high theoretical energy density.1 However, the development of portable or stationary rechargeable zinc batteries has been hindered by several critical issues. The key issue has been the evolution of dendritic zinc electrodeposit morphology during battery charging,2,3leading to battery capacity fade and cell shorting.
In this work, we focus on the use of organic electrolyte additives to suppress zinc dendrite growth. We examine both acidic and alkaline electrolytes, which are relevant to acidic zinc-halogen flow batteries and alkaline zinc-metal batteries, respectively. To study zinc dendrite propagation, we employ in-situ microscopy during growth of the electrodeposit.4 To study the mechanism by which organic additives modulate the dendrite propagation rate, we utilize classical polarization measurements on a rotating disc electrode. For acidic zinc electrolytes, we studied numerous additives (Figure 1) and their dendrite suppression efficacy. We observed that strongly polarizing additives suppress zinc dendrites more than weak polarizers. For zinc electrodeposition from an alkaline electrolyte, we identified that polyethylenimine (PEI) enables near-complete dendrite suppression,5even at low concentrations (~50 ppm, see Figure 2). Figure 2 also shows electrochemical polarization measurements on a rotating disk electrode, which confirm the polarizing effect of the PEI.
The aforementioned characterization techniques, together with electrochemical quartz crystal microgravimetry, ex-situscanning electron microscopy, and various ‘additive-injection’ tests, provide insights into the mechanism by which additives suppress dendritic growth of zinc. Additives are believed to adsorb onto the zinc surface and suppress zinc electrodeposition kinetics locally, thereby inhibiting activation-controlled dendrite propagation. In the talk, we will develop the mechanistic understanding further and provide guidelines for judicious selection of the additive chemistry for dendrite-free zinc electrodeposition in acidic and alkaline systems.

References:

[1]: Y. Li and H. Dai, Chem. Soc. Rev., 43, 5143 (2014).
[2]: K. Wang, P. Pei, Z. Ma, H. Xu, P. Li, X. Wang, J. Power Sources, 271, 65 (2014).
[3]: C. P. de Leon, A. Frias-Ferrer, J. Gonzalez-Garcia, D. A. Szanto, and F. C. Walsh, J. Power Sources, 160, 716 (2006).
[4]: S. J. Banik and R. Akolkar, J. Electrochem. Soc., 160, D519 (2013).
[5]: S. J. Banik and R. Akolkar, Manuscript submitted to Electrochimica Acta, October 2014.

Figure 1
Effect of Additive on the Formation of Cusn Alloy Nano-Trees Formed with DC Electroplating
Authors: Shingubara Shoso , Shimizu Tomohiro , Kaneko Naoto , Tada Yoshihiro 
Published: February 2020

We have found nano-tree of CuSn alloy by DC electroplating with a constant potential mode. The plating bath contained copper-sulphate, tin-nitrate, citric acid, and additive (PEG). Substrate was Pt thin film sputtered on a Si substrate. Nano-trees have many branches which separate from trunk perpendicularly, and sub-branches grow perpendicular from them also. The electroplating condition to grow nano-tree structure is limited in the very narrow window of cathode potential. From TEM-EDS analysis, it was clarified that each branch of nano-tree is single crystal having orthorhombic structure. Diameter of branch distributes between a few tens of nm to a few hundreds of nm.
There is a significant effect of additive (PEG) for the formation of nano tree structure as shown in Fig.1. If there is no addition of PEG, deposited Cu-Sn alloy has a round rock shape only (Fig.1-a). However, when adequate amount of PEG is added to the plating bath, a very interesting nano-tree structure grows almost perpendicularly to the substrate (Fig.1-b). The top view of the nano-tree clearly shows branches are formed with 4-fold symmetry.
Nano-tree has a huge ratio of surface area to its volume, and is regarded as a typical three-dimensional nano-porous structure. The nano-tree may have a high potential to be used for electrode of Li-ion batteries, as well as chemical sensors when it is oxidized.
Further studies are in progress to clarify the effect of the additive for the growth of nano-tree structure.

Figure 1
Gravitational Level Effects on Coupling Phenomena Between Morphological Variations of Electrodeposited Film of ZnO and Mass Transfer Rates
Authors: Osaki Hiroshi , Wakatsuki Takao , Homma Takayuki , Fukunaka Yasuhiro 
Published: February 2020

Coupling Phenomena between morphological or microstructural evolution rate of electrodeposited film and mass transfer rates must be well understood in order to tailor the unique physical properties of nanostructured films. It is well known microstructure of electrodeposited ZnO film is drastically influenced by the adsorption phenomena of surfactant molecule. However, the mass transfer rate of surfactant has been seldom discussed, especially when natural convection accompanying oxide layer synthesis reaction is induced in an electrolytic cell. The surfactant concentration is significantly influenced at the liquid/soli. interface. Now it is discussed how gravitational level influences the nucleation and growth phenomena of electrodeposited ZnO.
ZnO electrodeposition onto FTO/ITO substrate is firstly performed in 0.1MZn(NO3)2-LiNO3 aqueous solution (pH=5.1) at 70°C without addition of surfactant molecule. The substrates were ultrasonically cleaned sequentially in acetone, ethanol and deionized water for 15 min., respectively. The counter electrode was a sheer of pure zinc (Nilaco Corp.). Effective surface of workin and counter electrodes were 10x10mm. They were embedded in each side of channel walls. Ag/AgCl was used as a reference electrode. The cell was arranged in two different configurations: (1) a horizontally installed cathode facing downward over a horizontal anode (C/A) and (2) an anode over a cathode (A/C). No natural convection is principally expected under the former configuration.
Current transients were measured at various electrode potential. No apparent differences were observed between -0.85 and -0.8V. Below -0.9V, they were categorized into four stages.
Stage 1: Double layer charging and start of NO3
-reduction
Stage 2: Induction time for nucleation
Stage 3: ZnO nucleation and growth
Stage 4: Transport limited
The initial three stages can be described by a model including progressive nucleation and kinetically controlled 3D growth. Surface OH- concentration during the nucleation period was estimated by using a simple model. We assume ZnO nucleation can be caused by the production of precursor like Zn(OH)4
2-. Surface morphology and XRD spectrum are changed by the gravitational field direction. The effect may be attributed to natural convection, eventually, concentration of reactant near the substrate cathode surface during electrodeposition.
Microvia Filling in an Acidic Copper Planting Bath with Insoluble Anodes
Authors: LIU CHU-CHI , Dow Wei-Ping 
Published: February 2020

Microvia filling of a printed circuit board (PCB) by acidic copper electroplating has been widely used in electronic industry. The filling mode of copper electrodeposition in microvia must be bottom-up form. Moreover, bottom-up filling phenomenon is believed to be related to the properties and interaction of plating additives. Especially, the interaction of three (accelerator, suppressor, leveler) components have significantly effect on copper filling performance. It was confirmed that soluble anodes (i.e., P-doped Cu anode) have disadvantage when they were used in the acidic copper plating bath. For instance, the shape of the soluble anodes are changeable with operating time, which may causes non-uniform current distribution to form unequal copper thickness on substrate. Therefore, a special functional insoluble anode was used to replace the soluble anode and conventional dimensionally stable anode (DSA) to maintain better bath stability. The disadvantage of soluble anode can be improved by using the novel DSA. In this work, a planting formula which was composed of chloride ions, suppressor (polyethylene glycol), leveler (quaternary ammonium species) and a novel accelerator instead of bis(3-sulfopropyl) disulfide (SPS). SPS is not appropriate for DSA system because of easy breakdown; therefore, we develop a novel accelerator, ACC, which has a longer lifetime and better performance for acceleration on copper deposition than SPS. Using DSA instead of P-doped Cu anode has another important contribution, that is, SPS reacts with the copper anode to produce Cu(I)-thiolate. The Cu(I)-thiolate is a strong accelerator in the presence of chloride ion. Cu(I)-thiolate will be accumulated in the copper plating bath to destroy the synergy between the suppressor and accelerator. DSA has no this issue because DSA has no copper. Herein, we will show that ACC combining with DSA can perform excellent copper fill in microvia.
Screen-Printed Silver Source-Drain Electrodes for a Solution-Processed Zinc-Tin-Oxide Thin-Film Transistor
Authors: Kwack Young-Jin , Choi Woon-Seop 
Published: February 2020

As a first step to achieve all-printing-processed oxide thin film transistors (TFTs), we prepared solution-processed zinc-tin oxide (ZTO) TFTs by screen printing electrodes for the first time. The source and drain were silver nanoparticles, and the channel length was patterned by using screen printing technology. Different silver nanoinks and process parameters were tested to find optimal source and drain contacts. A finely patterned channel layer of 100 μm in channel length was defined with a 4 μm thickness. The electrical characteristics of solution-processed ZTO with screen-printed source-drain electrodes were comparable to those of solution-processed ZTO with vacuum-deposited electrodes. Relatively good electrical properties of screen-printed solution-processed oxide TFT were obtained: a mobility of 2.3 cm2/V s, an on-off current ratio of 106, a Vth of 17 V and a subthreshold swing of 3.2 V/dec. The bias stability was also characterized. Because of the microstructure of the device, water and oxygen adsorption from the atmosphere affected the Vth shift and the subthreshold slope change under a gate bias stress.
Electrohydrodynamic (EHD) Jet Technique for Indium-Zinc-Oxide (IZO) Thin-Film Transistors
Authors: Kwack Young-Jin , Choi Woon-Seop , Kim Hunho 
Published: February 2020

Many studies have reported that oxide TFTs for printed electronics can be processed using solution methods. Printed electronics can circumvent time consuming-, expensive-, and chemical waste-photolithography process for patterning. One of the issues in solution processed oxide TFTs is that a high temperature annealing process is needed to remove organic residues because they can deteriorate the electrical characteristics. For a low temperature process, many studies have examined a variety ways to reduce the reaction under 200oC but retain excellent performance. Another issue is to apply a printing process for fine patterning. Most studies of solution-processed oxide semiconductors were carried out by spin coating or ink-jet printing. The electrohydrodynamic (EHD)-jet printing process is unique technique that can overcome these limits. In the case of a paste, transpiring is possible by setting a high voltage because inks are forced down by the electric field between the nozzle and substrate. The ink can form a drop to spray configuration under a range of bias voltages. Electrohydrodynamic (EHD) jet-printed indium- zinc-oxide thin-films transistors (TFTs) were prepared at various annealing temperatures. The EHD jet was achieved by optimizing the process parameters; such as the precursor viscosity, driving voltages, and substrate temperatures. The EHD jet-printed IZO films were characterized using a range of analytical methods. Metal oxide formation was confirmed by X-ray photoelectron spectroscopy. The EHD jet-printed IZO TFTs showed good electrical properties: mobility of 4.8 cm2/Vs, threshold voltage of 8.4 V, on-to-off current ratio of 107, and a subthreshold slope of 1.2 V/dec at 400oC. The positive and negative bias stability were also analyzed.
Ultrathin Pd Films on PBI-HFA Membranes for Selective Hydrogen Separation
Authors: Choi Sun Hee , Kim Da Hye , Yoon Chang Won , Ham Hyung Chul , Kim Hyoung-Juhn , Nam Suk Woo , Lim Tae Hoon , Han Jonghee 
Published: February 2020

A polymeric gas separation membrane utilizing polybenzimidazole (PBI) based on 4,4'-(hexafluoroisopropylidene)bis(benzoic acid) (HFA) with an effective permeating area of 8.3 cm2 and a thickness of 30(± 2) mm was prepared and its gas permeation properties were investigated using H2, CO2, CO, and N2 at various temperatures ranging from 24 to 200 oC. The PBI-HFA membrane not only exhibited excellent H2 permeability, but it also displayed superior gas separation performance particularly for H2/N2 and H2/CO2. The permeation parameters for both permeability and selectivity ( PH2 and α(H2/N2); PH2 and α(H2/CO2)) obtained for the new material were found to surpass those reported by Robeson in 2008. The gas permeation properties of the prepared membrane were found to be dependent on trans-membrane pressure difference as well as temperature.
A gas-tight palladium (Pd) membrane was fabricated on a PBI-HFA membrane by a vacuum electroless plating technique (VELP). The thickness and effective permeating area of the Pd/PBI-HFA membrane were estimated in the range of 228–261 nm, and 8.3 cm2, respectively. The Pd membrane prepared using the VELP technique had a more uniform microstructure than those manufactured by a conventional electroless plating method (CELP), with no delamination or agglomerated Pd particles observed. The gas permeation properties of the prepared Pd membranes were evaluated using H2, N2, CO2, and CO as functions of:35 to 200 °C temperature, 0.4 to 0.8 MPa pressure difference, and membrane preparation methods including CELP, VELP, and VELP following a H2O2 surface treatment (H-VELP). The Pd film fabricated by the H-VELP method showed superior performance, and proved to be impermeable to nitrogen as well as carbon monoxide. Additionally, the Pd membranes prepared by H-VELP with a 228 nm thickness also demonstrated an excellent gas tightness with an infinite H2/N2 permselectivity, and its separation performance was above the Robeson’s 2008 upper bound.
Investigation of Zinc Whisker Growth from Electrodeposits Produced Using an Alkaline Non-Cyanide Electroplating Bath
Authors: Wu Liang 
Published: February 2020

Metal whiskers are spontaneous growths protruding from metal surfaces. It has been observed that tin, zinc and cadmium surfaces, especially their electroplated coatings are prone to develop whiskers. Many electrical and electronic failures have been attributed to the presence of these small metallic filaments. During the past 70 years, researchers have been striving to address the problems induced by metal whisker growth. However, most research effort has been focused on tin whiskers, whilst very little attention was paid to reliability issues associated with zinc whiskers. Only a few previous studies have been carried out to investigate the growth mechanisms of zinc whiskers, but the results of such studies are often conflicting and there is, at present, no widely accepted growth mechanism in place.
The current study focuses on whisker growth from zinc coatings on mild steel substrates electrodeposited from a commercial alkaline non-cyanide electroplating bath. Experimental work has been undertaken to investigate the effect of deposition parameters and storage conditions on whisker growth, and also to understand the formation and growth mechanism. Scanning electron microscope (SEM), focused ion beam (FIB), energy dispersive x-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD) have been used to characterise the as-deposited structure of the zinc coatings and to evaluate whisker growth.
Analysis showed that, for samples stored at room temperature, whiskers were present on samples deposited at current densities in the range of 20 – 50 mA cm-2 within 4 weeks of electroplating. However, electroplating at low current densities significantly reduced whisker growth and no whiskers were observed on samples deposited at 5 mA cm-2 after 12 months. Also, it was found that short period of post-electroplating heat treatment at high temperatures markedly reduces zinc whisker growth. In terms of the mechanisms for zinc whisker growth, our experimental data indicated that hydrogen evolution reaction that occurs on the steel, due to the low overpotential, was closely associated with zinc whisker growth. In addition, recrystallisation of the as-deposited columnar structure occurred at the whisker root.

Figure 1
Structural and Optical Characterization of Electrodeposited Black Chrome-Graphite Encapsulated FeCo Nanoparticles Composite Solar Selective Coatings
Authors: Harinipriya S , Usmani Belal 
Published: February 2020

Abstract

Black Chrome-graphite encapsulated FeCo nanoparticles (BC-GE FeCo NPs) composite based solar selective coatings were prepared on substrates such as stainless–steel, Cu and Ni-coated Cu employing electrodeposition technique. Electrodeposition was done by addition of three different weight proportions of GE FeCo NPs (0.025, 0.05, and 0.1) in the electrolyte bath. X-ray diffraction, Atomic Force Microscopy, UV-Visible and FTIR spectroscopy were used to characterize the structural and optical properties of these coatings. The major content of the deposited film is contributed by Cr (ICDD 74-7045), Fe-Cr (ICDD 34-0396), Fe2AlCr (ICDD 54-0387) and FeCr0.29Ni0.16C0.06 (ICDD 33-0397) as deduced from XRD. Spectral reflectance of the selective surface is observed to be low in UV-Visible region even after the addition of GE FeCo NPs. The low surface reflectance in the near infrared region due to the addition of GE FeCo NPs indicates increase in the absorptance of the selective surface in near infrared region. Atomic Force Microscopy indicated that film smoothness increases and grain size decreases with decrease in the weight percentage of GE FeCo NPs. Hardness and Young’s modulus were found to decrease with decreasing weight percentage of GE FeCo NPs.

Keywords:

Electrodeposition; Black Chrome; Graphite encapsulated FeCo NPs, solar selective coatings
Recovery of Rare Earth Metals By Electrodeposition from Ionic Liquids
Authors: Stevenson Keith J. , Redman Daniel 
Published: February 2020

Rare earth elements have become increasingly important to modern life as they are used in nickel-hydride batteries in current hybrid vehicles, as phosphors in fluorescent and LED lighting, and magnets used in computer hard disks and various automotive subsystems.1 In recent years the prices of the many of these elements have increased drastically due to reduced exports.2 Developing recycling methods for these elements is becoming a necessity for meeting future demands. Electrodeposition is a low-cost technique that could prove exceedingly useful to recover these elements from various sources. Traditional aqueous electrolytes are unsuitable for the electrodeposition of rare earth elements because they lie outside the electrochemical window of stability. This requires alternative electrolytes. Ionic liquids have received considerable attention as alternative electrolytes for electrodeposition due to several of their interesting chemical and physical properties. The large electrochemical windows of ionic liquids allow for the electrodeposition of electropositive elements, such as rare earth metals. In addition, the low volatility and high thermal stability of these solvents allows higher temperatures to be used in electrochemical processes.
Recently, our group has used ionic liquids to electrodeposit various elements and compounds, including Ge, Se, GeSx, and MoSx.
3,4,5 This was done by finding and synthesizing appropriate elemental precursors and ionic liquids for electrochemical deposition. This same strategy has been employed for the electrodeposition on rare earth metals. A number of precursors have been synthesized and investigated for electrodeposition. The effect of temperature on the electrodeposition was investigated. In addition, several ionic liquids were employed to investigate the effect of the cation and anion on the deposits.

References

1.) Van Gosen, B.S.; Verplanck, P.L.; Long, K.R.; Gambogi, J.; Seal II, R.R. The Rare-Earth Elements – Vital to Modern Technologies and Lifestyles. United States Geological Survey, USGS Mineral Resources Program. Reston, VA. November 2014.
2.) Rare Earth Elements: A Review of Production, Processing, Recycling, and Associated Environmental Issues. Environmental Protection Agency, National Risk Management Research Laboratory. Cincinnati, OH. December 2012.
3.) Murugesan, S.; Kearns, P.; Stevenson, K.J. Langmuir. 2012, 28(13), 5513-5517.
4.) Murugesan, S.; Akkineni, A.; Chou, B.P.; Glaz, M.S.; Vanden Bout, D.A.; Stevenson, K.J. ACS Nano. 2013, 7(9), 8199-8205.
5.) Redman, D.W.; Murugesan, S.; Stevenson, K.J. Langmuir. 2014, 30, 418-425.