bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Studies of a Redox Responsive 4 H-Bond Array Capable of Self-Dimerization
Authors: Darzi Ghazwan M , Smith Diane K.
Published: February 2020

Supramolecular structures can change in response to external signals, such as change in pH, temperature, or voltage of an electrode. This is important for many applications such as self-healing polymers and gels, triggered release of entrapped molecules for drug delivery, and smart material. Ureidopyrimidinone (UPy) array with an alkyl-pyridinium (RP) redox center has been synthesized for this study. This array prefers the tautomer that presents an ADAD H-bond motif in the starting oxidation state. Due to electrostatic repulsions and unfavorable secondary H-bond interactions, this motif would form a dimer with relatively weak H-bonding. Upon 2e- reduction, where 1e- is gained per R-pyridinium redox center, the H-bond strength should increase due to the loss of the repulsive charges, making the nitrogen a stronger hydrogen acceptor. Because the nitrogen is now a better hydrogen acceptor, there could be a possibility of an intermolecular proton transfer. This would encourage the tautomer to have an AADD motif that will make the H-bonding stronger by increasing the favorable secondary H-bond interactions.

The UPy(RP) array is not soluble in dichloromethane using the NBu4PF6 electrolyte, but it is soluble in acetonitrile. The concentration dependent 1H NMR spectra suggest that UPy(RP) is a monomer in acetonitrile. The cyclic voltammetry scans of the UPy array in CH3CN show three reductions. The first occurs at a potential very similar to that seen with simple model compounds. The second is considerably positive of that observed for the model compounds and the third is very close to the second reduction peak of the model compounds. The first reduction is reversible if the scan direction is switched immediately after the peak, but irreversible if the scan direction is switched after the second reduction peak. As the scan rate increases, the second reduction peak disappears. An oxidation peak at far positive potentials starts to appear only after going through the second and third reduction. DFT calculations suggest the preferred tautomer changes upon reduction, and this may explain the unexpected voltammetry observed in acetonitrile where the compound is not dimerized. To improve the solubility of the UPy array in methylene chloride, TFAB was used as a counterion instead of the PF6. The CV’s of UPy/TFAB array in methylene chloride show similar behavior to that in acetonitrile with an additional fourth reduction wave observed at far negative potential. 1H NMR spectrum of UPy/TFAB at room temperature suggests the presence of two tautomeric forms in methylene chloride. However, at low temperatures, only one tautomer is observed in 1H NMR spectrum that’s believed to be the dimer. Further studies to help elucidate what is actually happening in this system will include taking CV’s at low temperatures in CH2Cl2, and conducting UV-Vis spectroelectroanalytical experiments for the system.
Self-Organized TiO2 Nanotubes: Influence of the Ti Microstructure on the Nanotube Growth
Authors: Sopha Hanna , Macak Jan M.
Published: February 2020

The 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. The most established member of this group of materials is nanoporous Al2O3, which has been prepared two decades ago by anodic oxidation of Al into perfectly ordered, honeycomb-like porous structures employing suitable electrochemical conditions [1]. Owing to the flexibility of the pore diameter/length and the relative ease of the Al2O3 dissolution, its porous membranes have been since than widely used as template material of choice for a range of materials [2-4].

Recently, TiO2 has received the highest attention after Al2O3 motivated by its range of applications, including photocatalysis, water splitting, solar cells and biomedical uses. Very significant research efforts have led to reproducible synthesis of self-organized TiO2 nanotube layers by means of anodic oxidation, during which the starting Ti substrate is converted into a highly-ordered nanotubular layer by anodization in suitable electrolytes [5-7]. Although advancements in the anodic synthesis of self-organized TiO2 nanotube layers have been presented over the past years [8], the degree of ordering has not reached so far the level known from porous alumina [1]. Numerous factors influence the ordering and the homogeneity of the TiO2 nanotube layers.

In the presentation, we demonstrate significant advancements in the understanding of the influence of Ti substrates on the TiO2 nanotube growth compared to the recent state-of-art. Using SEM, AFM, GDOES and optical measurements we will show how to obtain a high degree of ordering, uniformity and homogeneity in the nanotube structure of TiO2 by tailoring the anodization protocol [9, 10]. Furthermore, based on SEM, EBSD and TEM measurements, we will demonstrate how the Ti grain structure influences the lateral uniformity of the nanotube layers [11].

References

1. H. Masuda, K. Fukuda, Science, 268 (1995) 1466.

2. K. Nielsch, F. Müller, A.-P. Li, U. Gösele, Adv. Mater. 12 (2000) 582.

3. H. Asoh et al., J. Electrochem.Soc. 148 (2001) B152.

4. J. Kolar, J. M. Macak, K. Terabe, T. Wagner, J. Mater. Chem. C, 2 (2014) 349.

5. J. M. Macak, H. Tsuchiya, P. Schmuki, Angew. Chem. Int. Ed. 44 (2005) 2100.

6. J.M. Macak et al., Curr. Opin. Solid State Mater. Sci. 1-2 (2007) 3.

7. K. Lee, A. Mazare, P. Schmuki, Chem. Rev. 114 (2014) 9385.

8. J.M. Macak, S. P. Albu, P. Schmuki, Phys. Stat. Sol. (RRL) 1 (2007) 181.

9. H. Sopha, L. Hromadko, K. Nechvilova, J.M. Macak, J. Electroanal. Chem. 759 (2015) 122.

10. H. Sopha, A. Jäger, P. Knotek, K. Tesar, M. Jarosova, J.M. Macak, Electrochim. Acta 190 (2016) 744.

11. J.M. Macak, M. Jarosova, A. Jäger, H. Sopha, M. Klementová, Appl. Surf. Sci., 371 (2016) 607.
Advanced Photoelectrocatalysts for TEMPO-Mediated Alcohol Oxidations
Authors: Chadderdon David J , Wu Ivy , Panthani Matthew G , Li Wenzhen
Published: February 2020

The transformation of primary alcohols to carbonyls or acids is a fundamental chemical process of interest from both academic and industrial viewpoints, but typically requires stoichiometric oxidants which are costly and generate potentially toxic waste. As an alternative approach, conversion of biomass-derived alcohols in a photoelectrochemical (PEC) cell is a promising environmentally-friendly route, which takes advantage of renewable carbon feedstocks, renewable solar energy, and renewable electricity from wind, geothermal, or photovoltaic sources. In this talk, we will share our recent progress in designing semiconductor / electrocatalyst composite photoanodes made of earth-abundant elements for photoelectrochemical alcohol oxidation.

Previously, we have studied selective electrocatalytic oxidation of biomass-derived alcohols and 5-hydroxymethylfurfural (HMF) on noble metal catalysts.1-2 Electroactive homogeneous catalysts such as (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) represent an alternative to expensive metal catalysts.3 Furthermore, it was recently reported that the electrode potential required to drive TEMPO-mediated alcohol oxidation can be significantly reduced in a PEC reactor, where solar energy is harvested with a bismuth vanadate (BiVO4) semiconductor electrode.4 However, significant electron-hole recombination and efficiency losses due to the competing oxygen evolution reaction (OER) make BiVO4 a poor electrode material for TEMPO oxidation. While it is common to modify semiconductor electrodes with electrocatalysts to enhance OER, such strategies to selectively promote TEMPO oxidation have not been explored.

We present the first composite photoanode for enhanced TEMPO-mediated alcohol oxidation. BiVO4 modified with a cobalt-based electrocatalyst layer facilitated TEMPO oxidation at potentials >400 mV lower than unmodified BiVO4 by enabling facile charge transfer across solid–solid and solid–electrolyte interfaces. The competing OER was completely suppressed, allowing nearly 100% faradaic efficiency for TEMPO oxidation. In this talk, factors that tune the competition between TEMPO oxidation and OER, including photoanode structure, applied potential, and other reaction conditions will be discussed.

References:

(1) Chadderdon, D. J. et al., Green Chem. (2014), 16 3778–3786.

(2) Chadderdon, D. J. et al., ACS Catal. (2015), 5 6926−6936.

(3) Rafiee, M.; Miles, K. C.; Stahl, S. S., JACS (2015), 137 14751−14757.

(4) Cha, H. G.; Choi, K. S., Nature Chem. (2015), 7 328–333.
Metal Alloy ICF Capsules Created By Electrodeposition
Authors: Horwood Corie , Stadermann Michael , Bunn Thomas
Published: February 2020

Metal capsules for inertial confinement fusion (ICF) experiments are currently produced using micromachining (MM) or physical vapor deposition (PVD). These time and labor intensive methods have failed to yield capsules that meet the exacting standards for smoothness, purity, thickness uniformity and shape required by the National Ignition Facility (NIF). Electrochemical deposition (ED) has the potential of rapidly producing a full density capsule without seams or inclusion of unwanted atomic constituents, the current shortcomings of MM and PVD, respectively. There are, however, specific challenges to ED such as the contact point for applying an electric potential.

We will present our ED approaches to enable high quality metal coatings such as Pt, Au, Ag, Cu and their alloys on spherical mandrels by enabling temporary contact with a working electrode and constant, random motion of the mandrels. Our plating technology has been demonstrated to work well for metal and metal-flashed bead and shell mandrels independent of mandrel density. We will report on ED coating quality metrics including density, surface roughness, and porosity as well as thickness uniformity and sphericity.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Effect of Composition and Temperature on Current Efficiency for Aluminium Electrolysis from Cryolite-Based Molten Alumina Electrolytes
Authors: Morishige Taiki , Haarberg Geir Martin , Gudbrandsen Henrik , Skybakmoen Egil , Solheim Asbjørn
Published: February 2020

Aluminium smelting from molten cryolite alumina electrolytes is the industrial production process known as the Hall-Héroult process. The current efficiency for aluminium electrolysis in modern cells can be as high as 96 %. The main reason for loss in current efficiency is the socalled back reaction between dissolved aluminium and the anode product of CO2as the following reaction:

Al(diss) + 3/2 CO2 = 1/2 Al2O3+ 3/2 CO

The current efficiency can be improved by suppression of metal dissolution from deposited metal. Decreasing temperature of the cell may also give higher current efficiency. Addition of LiF leads to decreasing the liquidus temperature and also to decrease the metal solubility into the electrolyte. However, low superheat may cause solidification of melt. A laboratory cell to determine the current efficiency was recently modified to obtain more reliable results. The base composition of the electrolyte was Na3AlF6-11.55wt.%AlF3-5wt.%CaF2-4wt.%Al2O3 and electrolysis was conducted at 965 ºC. Electrolysis was performed at constant current density (~0.9 A cm-2) and the current efficiency was determined from the weight of deposited aluminium. The current efficiency at the base condition was 95% in this study. Effects of electrolyte composition by some percent of LiF addition on the current efficiency was studied. The current efficiency and the metal shape on the cathode was changed by the addition of LiF. The loss in current efficiency is strongly related to the content of dissolved aluminium in the electrolyte. Realistic values for the current efficiency were obtained.

References

[1] J. Thonstad, P. Fellner, G.M. Haarberg, J. Híveš, H. Kvande and Å. Sterten. Aluminium electrolysis: Fundamentals of the Hall-Héroult process 3rd edition, Aluminium-Verlag, Düsseldorf (2001). ISBN 3-87017-155-3

[2] P.A. Solli, T. Haarberg, T. Eggen, E. Skybakmoen and Å. Solheim. Light Metals 1994, 195-203 (1994).

[3] X. Wang, R.D. Peterson and N.E. Richards. Light Metals 1991, 323-330 (1991)

[4] E.W. Dewing. Metall. Mater. Trans. B., 22B, 177-182 (1991).
Electroless Deposition of Iron–Phosphorus on Copper: Experimental and Modeling Studies of the Critical Role of Substrate Activation By Palladium
Authors: Blickensderfer Jacob , Akolkar Rohan
Published: February 2020

Electroless deposition of amorphous iron-phosphorus (Fe–P) is investigated. Fe–P is a potential benign alternative for replacing nickel-phosphorus films commonly used in electronics and surface finishing applications. In the present talk, the role of substrate (Cu) activation by palladium (Pd) in enabling electroless Fe–P deposition will be discussed. Specifically, it will be demonstrated that a critical Pd surface coverage is essential for spontaneous electroless Fe–P deposition to commence. Below this critical Pd coverage, the surface is catalytically inactive for Fe–P deposition. A mechanistic model that incorporates surface heterogeneity due to partial Pd coverage of Cu and the effect of this heterogeneity on electrocatalysis of the reductant oxidation reaction during electroless deposition will be presented. Model predictions will be compared to experimental observations of the electroless surface mixed potential to gain insights into the mechanism by which Pd coverage affects the efficacy of electroless Fe–P deposition. Implications of the findings to the optimization of pretreatment and activation processes commonly used in electroless deposition systems will also be discussed.
An Electrochemical Procedure to Form Metal Powders from Recycled Hard Particle Embedded Composite Cutting Tools
Authors: Altunbasak Tansu , Kul Mehmet , Karakaya Ishak
Published: February 2020

Recycling of waste has become an important issue considering the depletion of natural sources and discarded valuable particles and metals. Industrial diamond and other valuable particle embedded into metal matrix cutting tools are manufactured by powder metallurgy techniques [1,2]. They have been widely used in cutting, polishing and grinding of hard metallic and nonmetallic materials like stone, marble and other materials. During its lifetime, a saw blade normally processes around 400 m2of stones [3]. This number corresponds to consumption of only about 60 % of composite cutting tools. Therefore, there are plenty of residual hard particles and combined agents in waste cutting tools [4].

Currently, the general processes of recycling cutting tools involve acid dissolution and separation processes that adopt the principle by utilizing the insoluble characteristics of diamond and tungsten carbide, while dissolving metals. After the filtration of valuable particles, the solution that carries dissolved metal ions are discarded [5,6]. This study offers not only recovering diamond and other valuable particles, but also recycling of metals by co-deposition of metal powders. The waste cutting tools used as anode dissolves in relatively weaker acidic electrolytes and metalic parts are collected as powders at the cathode while hard particles sink to the bottom of electrolyte when power is applied. Temperature, current density, acid concentration and CuSO4concentration of electrolyte are the process parameters to optimize microstructure, density and surface area of metallic powders. It was found that decreasing current density resulted in a more compact and dense powders as it can be seen in Figure below.

References

[1] M. Jeenings, D. Wright, Ind. Dia. Rev. 49 (1989) 70.

[2] M. Meszaros, K. Vadasdi, Process and equipment for electrochemical etching of diamond containing Co–WC tools and recovery of diamond from used steel tools, Int. J. Refrac. Met. Hard Mater. 14 (1996) 229.

[3] A.L.D. Skury, G.S. Bobrovnitchii, S.N. Monteiro, C.C. Gomes, Recovery of synthetic diamonds from scrapped sawblades, Separation and Purification Technology 35 (2004) 185–190

[4] D. Yuan, Method for regenerating diamond with waste material, Chinese Patent Number CN1253116, 2000.

[5] X.D. He, X.Y. Guo, P. Li, K. Huang, and K.H. Xu, Recovery of nickel, cobalt and m anganese from waste acid solution from synthesis of artificial diamond, Hydrometallurgy of China, 2005, 24 (3): 150.

[6] L.H. Guo, and S.T. Cheng, Study on selective leaching and recycling technology of waste diamond tools, Sichuan nonferrous metals, 1996, (1): 19.

Figure 1
Microfabrication and Characterization of Concentric Nanodes for Brain Chemical Sensing
Authors: Yin Haocheng , Dutta Gaurab , Arumugam Prabhu
Published: February 2020

Understanding the function of human brain is one of the most scientific challenges of the 21st century. Recent studies show the critical role of neurochemicals in several brain disorders such as Epilepsy, Parkinson’s Disease, Alzheimer’s disease and Schizophrenia. Developing advanced chemical sensor technologies that can detect multiple neurochemicals, neurotoxins and local field potentials with high spatial-temporal resolution is urgently needed to better understand the underlying mechanisms. Current chemical microsensors foul quickly and lack sensitivity in long-term use. They also are bulky and lack multiplexing, multimodal capability. In recent times, there is an enormous interest in the use of band, disc and hemispherical nanoelectrodes for novel electroanalytical applications. Albeit their advantages in terms of enhanced analyte transport, low charging currents and high signal-to-noise ratio, they do not provide a 3D electrode geometry that are more suitable for interrogating cells and tissues and are difficult to fabricate multiple nanoelectrodes onto a single cylindrical probe. In this work, we design, fabricate and characterize a novel ring-shaped nanoelectrode “nanode” for brain chemicals of importance. Gold nanodes are micro fabricated on to silicon micropillars and are characterized using SEM, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The nanode’s general electrochemical behavior will be studied in standard redox species. We report the effect of Atomic Layer Deposition coated passivation layers and their thickness on electrical cross talk. Using multiple concentric nanodes (e.g. Au, Pt and boron-doped nano diamond), improvements in chemical signal amplification from dopamine and lead will be discussed.
Electrolytic Deposition of Doxorubicin-Chitosan Composites on Post Hydroxyapatite Coated Titanium Alloy for Localizing Tumor Treatments
Authors: Yen Shiow Kang , Hsu Shin- Ru , Cheng Yu- Mei , Lai Yu-Liang , Lin Chien- Chung
Published: February 2020

In order to reduce the side effects caused by the chemotherapy of cancer, various target treatments and drug-delivery systems have been investigated. In this study, the doxorubicin-chitosan composite was deposited on the post hydroxyapatite coated Ti alloy for the tumor treatment by sustaining release of localized drug to achieve the inhibition or apoptosis of cancer cells. In the experiment, cathodic polarization tests coupled with electrochemical reactions were analyzed to speculate the deposition mechanism of doxorubicin, UV-visible spectrometer to measure the doxorubicin loading and release, field emission scanning electron microscope (FESEM) to observe the surface morphology, Fourier transform infrared spectroscopy (FTIR) to characterize the chemical bonds of composite, and X-ray diffractometry (XRD) the crystal structures. The MTT assay was carried out to analyze the toxicity of the drug to cells. It is concluded that doxorubicin-chitosan composites can be successfully deposited on the titanium alloy by the electrochemical method, while the post hydroxyapatite coated specimen with high porosity can enhance the drug loading and reveal the complete drug release. Besides, the electrochemical deposition does not vary any chemical bonding or destroy any medical function of doxorubicin, revealing a practical method for drug loading.

Keywords: Doxorubicin, Chitosan, Hydroxyapatite coated Ti alloy, Localize, Tumor.
Evaluation of Microbial Fuel Cells with Graphite Plus MnO2 and MoS2 Paints As Oxygen Reduction Cathode Catalyst
Authors: Jiang Bolong , Muddemann Thorben , Kunz Ulrich , Bormann Hinnerk , Haupt Dennis René , Niedermeiser Michael , Schlaefer Ottmar , Sievers Michael
Published: February 2020

For the improvement of microbial fuel cell (MFC) performance in real wastewater it is necessary to implement catalysts on the cathode. Graphite, MnO2 and MoS2 fulfill the requirements with respect to costs and activity and were evaluated in this work. These materials were prepared by dispersion of MnO2 and/or MoS2 and graphite in a solution of celluloid using butanone as solvent. The mixture is than painted on the surface of stainless steel cathode carriers. The individual maximum output power densities of MFCs were evaluated in dependence of time, see figure (left). Comparing with graphite plus MnO2 coating, the graphite plus MoS2 paint shows a lower power density but much higher long-term stability than graphite plus MnO2 coating. Therefore, the combination of different catalysts (MnO2 and MoS2) is necessary for further improvement of power density. The power density performance of MFCs with different MnO2 plus MoS2 proportions is shown in figure (right). The data suggested that the MFC with mixed catalysts with graphite plus MnO2 plus MoS2 proportion of 20:1:1 possessed the highest power density during experiments (125 mW/m2 at 5th day). The power density of a MFC with mixed catalysts with graphite plus MnO2 plus MoS2 proportion of 30:1:2 possessed the value of 85 mW/m2 at the beginning and descended rapidly after starting operation. By comparing the MFC with mixed catalysts with graphite plus MnO2 plus MoS2 in proportion of 30:2:1, with the power density of the MFC with graphite plus MnO2 plus MoS2in proportion of 20:1:1 it was shown, that the later one is the optimal mixing proportion in our experiments.

A RHE is also used in our experiments for measuring the potential of single electrodes. The data are shown in figure (right). It can be seen that the cathode potential of the cell descended significantly during the measurement, while the potential of the anode changed only slightly. These reveals clearly, that the cathode is the rate limiting electrode. Therefore, new forms of cathodes have to be further developed to improve the performance of MFC.

Figure 1
Fabrication and Characterization of Ni-GDC/GDC Half-Cell Manufactured By Tape Casting and Reactive Magnetron Sputtering Processes As Half-Cell for SOFC
Authors: Hernandez Londono Carlos
Published: February 2020

In this work, anode-supported solid oxide fuel cells (SOFCs) has been manufactured by tape casting and co-sintering technique. NiO and GDC (10% Gd), used for the anode-supported (as) and the anode functional layer (afl) powders, with an initial size of -40 mesh and -100 mesh particle size respectively, were milled by using zirconia balls in a Turbula-(System Schatz from WAB) times up to 24 to 48 hours. Half-cell, 28 mm of diameter, Ni-GDC10 composite anodes have been elaborated by slurry based tape casting method for anode supported solid oxide fuel cell. The chosen ceramic powders in suspension were prepared with the mass ratio of 65:35 for NiO to GDC10. The microstructural morphological /porosity/surface features of the half-cell were analyzed by Scanning Electron Microscopy (SEM), XRD and 3D profilometry before and after different annealing treatment. Pycnometry and porosimetry techniques were primarily used to determine pore size and pore volume by equation Washburn and Ideal gas law-method. Depending on the results, work on the support anode (AS) Ni-GDC will continue in particular to avoid the presence of the residual phase of carbon resulting from the use of an agent poro formers with graphite. The obtained cell after sintering was seen without any deformation or crack. One of the ways followed to remove the residual graphite is increase of the temperature and / or sintering time.The pre-sintered anode green tape was coated with a GDC electrolyte film by reactive magnetron sputtering using PEM techniques. An Alcatel SCM650 sputtering chamber was used for synthesizing the dense GDC layers. A Ce-Gd metallic target (90-10% at) was powered by a pinnacle + pulsed current generator from Advanced Energy. The structural, microstructural and morphological features of the half-cells were determined by XRD, SEM and 3D profilometry as deposited and after different annealing treatments. Finally, the EIS measurements were performed on Ni-GDC/GDC half-cells under 60 sccm nitrogen by the means of a Solartron SI 1260 impedance / gain analyzer from 20 MHz to 0.1 Hz with 11 points per decade.
Using Data Science to Improve Battery Performance: How Data Analytics Can Help Drive Design and Use Decisions
Authors: Dawson-Elli Neal , Subramanian Venkat R.
Published: February 2020

Batteries are complex electrochemical devices whose short-term and long-term operational lives are highly dependent on their construction, materials, and use cases. Models have been developed and used to improve the performance of batteries by providing different material design, model based control and model based battery management systems1.

There is a recent trend in data-science-based approaches for modeling different devices and processes2,3. In this talk, we will review different data science methods and approaches in the context of parameter estimation, optimal control and mechanism elucidation for lithium-ion batteries.

In particular, we will discuss opportunities and challenges in applying the same for battery models – for model reduction, data set training, online estimation and control. It has been demonstrated that using machine learning techniques can retain 99.9% of the accuracy of a complex model while improving solve time by four orders of magnitude, which can allow for the use of high accuracy models in a real-time control scenario3. We will be attempting to demonstrate that this is true for battery models as well, which typically have large cpu time requirements.

Real-time model-based control has demonstrated significant improvements in time remaining, state of charge, and state of health, even using simple equivalent circuit models4. By reducing the order and solve time of higher complexity models, we believe that better predictability is possible.

Acknowledgments

The authors thank the United States Department of Energy (DOE) for the financial support for this work though the Advanced Research Projects Agency – Energy (ARPA-E) award #DEAR0000275.

 

 

References

 

1. Y. Dai, and V. Srinivasan,. J. Electrochem. Soc., 163, A406 (2016).

2. D. A. C. Beck, J. M. Carothers, V. R. Subramanian, and J. Pfaendtner, “Data science: Accelerating innovation and discovery in chemical engineering,” AIChE J., vol. 62, no. 5, pp. 1402–1416, May 2016.

3. Blake R. Hough, author. Jim Pfaendtner, degree supervisor. 2016 Thesis (Ph. D.)--University of Washington,2016.

4. Williard, Nick, Wei He, and Michael Pecht. "Model Based Battery Management System for

Condition Based Maintenance." Technical Program for MFPT 2012, The Prognostics and

Health Management Solutions Conference - PHM: Driving Efficient Operations and

Maintenance, 2012
Ceramic Additive Manufacturing of Solid State Electrochemical Devices
Authors: Benavidez Angelica D , Cook Adam , Tsui Lok-kun , Evans Lindsey , Garzon Fernando H
Published: February 2020

The additive manufacturing of electro-ceramics is a major technological challenge with many possible applications. The technology can prototype and produce in small volume production, custom dielectric, piezoelectric and solid state ionic devices. Sandia National Laboratories was the birthplace of modern, 3-D ceramic additive manufacturing. The newly developed manufacturing methods are considered to be the foundation of 3-D printing via particulate slurries and our spin off company Robocasting Enterprises, is commercially producing dense ceramic and composite parts. These parts are used in various applications including complex geometry catalyst supports and casting filters. This technique is based on the layer-by-layer deposition of highly loaded colloidal slurries that are extruded through a small nozzle. The rheology of the slurry is crucial in order to maintain the structural integrity of the part being built, as Robocasting does not rely on polymerization reactions or solidification to retain shape after extrusion. Since this process is essentially binderless, a dense ceramic part can typically be freeformed, dried, and sintered in less than 24 hours.

Although Robocasting is a highly useful technique, it has been optimized for ceramic and composite materials. More recently there has been some work on expanding this technology for use in printing electrode materials. Printing conductors and other structures for electrochemical and electronics using direct write technology gives the potential to reduce production time and reduce waste of expensive material. We have demonstrated that this direct write manufacturing technique can produce Multi-Chip Modules (MCM) by depositing silver and gold on Low Temperature Co-fired Ceramics (LTCC). We have also applied this additive manufacturing technique to our unique design of electrochemical gas sensors. These multi-component mixed potential sensors consist of solid electrodes and a porous electrolyte. In order to expand the versatility of this manufacturing method to be used in solid state ionic devices, slurries of solid electrolytes and electrode materials with specific rheological properties were developed. Another challenge was controlling the residual stress and shrinkage through the material properties of various components. These devices are capable of detecting NOx, hydrocarbons, and NH3 at concentrations on the order of parts per million. The additive manufacturing technique allows for the rapid prototyping of these devices and low volume production of custom devices optimized for specific applications.

Figure 1
(Invited) Electrochemical Atomic Layer Deposition: Metal Deposition One Atomic Layer at a Time Enabled By Potential Pulsing & Self-Limiting Growth
Authors: Akolkar Rohan , Dordi Yezdi , Joi Aniruddha , Venkatraman Kailash , Gusley Ryan
Published: February 2020

Many important technological applications, including nano-electronics, photovoltaics and electrocatalysis, critically depend on the ability to fabricate materials with precise, atomic-level control over structure and properties. Traditionally, fabrication of atomic-scale materials has been achieved through vapor-phase atomic layer deposition (ALD); however, this process has several drawbacks such as the use of unstable precursors which decompose yielding contaminated deposits. An alternative approach, using liquid-phase precursors and electrode potential manipulation, termed electrochemical atomic layer deposition (e-ALD), allows atomic-scale deposition of metals such as copper (Cu) and cobalt (Co). In this approach, underpotential deposition first forms a monolayer of a sacrificial metal such as zinc (Zn). The Zn adlayer then undergoes spontaneous surface-limited redox replacement by a nobler metal such as Cu or Co. This sequence is repeated to build multi-layered metal deposits one atomic layer at a time. Unlike vapor-phase ALD, e-ALD does not use unstable precursors and thus provides high-purity deposits. Prior e-ALD formulations have used toxic chemicals and necessitated frequent electrolyte switching; however, our e-ALD approach uses benign chemicals and eliminates electrolyte switching through the use of optimized potential pulsing sequences. This talk will highlight advantages of our e-ALD approach for applications in nano-fabrication and semiconductor interconnect metallization.
Pulse Reverse Plating of Zn-Ni on Aluminum and Steel
Authors: Xu Jing , Hall Timothy D , Inman Maria , Taylor E. J. , Snyder Stephen
Published: February 2020

Cadmium has been one of the top choices for corrosion resistant coatings in aerospace, electrical, and fastener industries due to its excellent corrosion resistance, lubricity, electrical conductivity, and an ability to withstand thermal and electrical shock. However, cadmium is a known carcinogen, and it is deposited from a cyanide plating bath, and cyanide waste treatment1 is very expensive. These environmental concerns and performance limitations mandate the need for alternatives to cadmium coatings. Numerous efforts have been made worldwide to develop alternate, non-cyanide baths for cadmium plating, based on sulfamate, fluoroborate and chloride.2,3,4 Therefore, Cd replacement alternatives are being investigated to satisfy mission critical performance standards. Of these replacements, Ni-Fluorocarbon (SAE AMS-2454), Zinc-Nickel (ASTM B841, AMS 2417), Aluminum (Mil-DTL-83488), Zn, and Tin-Zinc have been recently evaluated. Each of these potential Cd replacements have shown potential to replace Cd for specific applications but only alkaline Zn-Ni has shown the most promise due to its conductivity, corrosion resistance, low hydrogen embrittlement (LHE), and the lack of cyanide and borate in the electrolyte.

This paper will discuss ongoing efforts by Faraday to optimize the deposition conditions for an adherent LHE Zn-Ni alloy coating on aluminum and steel connector surfaces. We will present data on the performance of the alkaline ZnNi process using direct current baseline conditions, while also evaluating the potential to improve coating properties using pulse reverse plating parameters. Specifically, our focus is on improving adhesion of the coating to the substrate, reduction of hydrogen embrittlement challenges, characterization of the functional properties of the coatings, and development of a preliminary technology transition plan. The following material property tests may be evaluated over the course of the program: 1) visual examination (AMS 2460), 2) thickness (ASTM B487 / AMS 2460), 3) adhesion (ASTM B571), 4) hydrogen embrittlement (ASTM F519), 5) corrosion (ASTM B117). This work will help facilitate adoption of alkaline Zn-Ni plating processes as a functional Cd replace for coating DoD mission critical components like electrical connectors and back-shells.

Acknowledgement

This material is based upon work supported by an SBIR from the US Air Force under Grant No. FA8501-16-P-0047 References:

1 W. H. Safranek, Plat. Surf. Finish., 84(8), 45 (1997).

2 D. Altura, F. Mansfield and L. P. Streett, Plating, 61, 850 (Sept., 1974).

3 A. J. Boehm , Plat., Surf. Finish., 80, 52 (1970).

4 James A. Bates, Plat. Surf. Finish., 4, 36 (1994).
Pulse Reverse Electrolysis with Mg/Pt Electrode Promoting Simultaneous Removal of Ammonia and Phosphate from Wastewater
Authors: Quan Guoqing , Ding Wenchuan , Li Xiaoyu , Li Chaohui , Zheng Liangqiu
Published: February 2020

The main objective of this study is to develop an innovative electrolysis system to improve the removal of ammonia and recovery of nutrient elements from water. The system consists of a Magnesium (Mg) electrode, a Platinum (Pt) electrode and a pulse reverse power. When the voltage between Mg and Pt electrode was positive, the sacrificial magnesium anode released Mg2+ which reacted with ammonia and phosphate in solution to generate struvite precipitation. However, when the voltage between Mg and Pt electrode was turned negative, ammonia was removed by electrochemical oxidation. The duty of cycle, electric voltage, frequencies of pulse reverse and the molar ratio of N/P are the main effect factors on the treatment efficiency. The experimental results showed that the removal rate of ammonia in wastewater could reach 88.5%, meanwhile, about 98.2% the phosphate was recovered after 3.0 h reaction at electrolysis parameters of 14.0V, 0.04 Hz, and 45% duty cycle. The precipitate in solution was analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). This pulse reversed system, which provided cathodic and anodic pulse voltage, can increase ammonia removal dramatically in comparison to conventional electrochemical process.
(Invited) Interfacial Modification of Heterojunction Metal Oxide Photo Anodes for Efficient Solar Water Splitting
Authors: Mathur Sanjay , Gonullu Yakup , Fischer Thomas
Published: February 2020

Photoelectrochemical splitting of water to produce hydrogen is a viable approach to transform sunlight into chemical energy, which has triggered a quest for suitable photocatalysts. Among different semiconductor metal oxides, hematite (α-Fe2O3) has emerged as a promising photo-anode material for water oxidation since it is cheap, abundant, non-toxic and stable under photoelectrochemical conditions. Although it promises high theoretical photocurrent densities (11–14 mA/cm2), corresponding to a solar-to-hydrogen (STH) efficiency of 14-17 %, these values can hardly be attained since hematite suffers from high resistivity,] short lifetime of the photoexcited charge carriers, and short hole diffusion length (2-4 nm). Few of these limitations can be overcome by optimizing the nanostructure and electronic properties, as recently shown in a number of studies.In this study, we have focused on Interfacial modification of α-metal oxide multilayer photoanodes deposited by plasma enhanced chemical vapor deposition (PE-CVD). Different mechanisms such as heterostructuring (Fe2O3//TiO2), nano-structuring, patterning of multilayering with different structure (bar structure or line structure) or graphene supporting were examined in this study. The bilayer electrode exhibited enhanced PEC responses in terms of a lower onset potential and a higher photocurrent density when compared to the single layer α-Fe2O3 electrode. This enhancement was observed to be due to synergistic light absorption with the bilayer electrode, although charge carrier recombination occurred faster due to interfacial defect states. The incorporation of a graphene layer between the α-Fe2O3/TiO2 double layer and the FTO substrate resulted in a doubling of the photocurrent, but lead to a loss of the synergistic effect between the two active metal oxide layers. However, depositing the graphene between the two metal oxide layers resulted in an even higher photocurrent, while retaining the enhanced onset potential of the double layer electrode. This enhancement was observed to be due to either the passivation of the oxide defect states or enhancement of the charge transfer between the two oxide layers.
Elimination and Quantification of Oxidation Induced Interstitial Injection via Ge Implants
Authors: Martin Thomas P , Jones Kevin Scott , Camillo-Castillo Renata A , Hatem Chris , Xin Yan , Elliman Robert G
Published: February 2020

The presence of Silicon-Germanium (SiGe) alloys at the Si/SiO2 interface during an oxidation is known to suppress the injection of silicon self interstitials that normally accompanies silicon oxidation and leads to observed effects such as Oxidation Enhanced Diffusion (OED) and stacking fault growth. To measure interstitial injection, a layer of implantation induced dislocation loops was introduced and the interstitial fluxes measured via quantitative plan-view TEM. Germanium was introduced via a second implant at 3keV over a range of doses between 1.7 x1014 cm-2 and 1.4 x1015 cm-2. We show that partial suppression can be observed for sub-monolayer quantities of germanium, and that more than three monolayers of SiGe are necessary to suppress interstitial injection below the detection limit during oxidation. This study shows that low energy implantation of germanium can be used to eliminate or modulate injection of interstitials. Additional results suggest the mechanism is related to stopping interstitial formation, not migration.

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Comparative Investigation of Graphene Quantum Dots and Graphitic-phase C3N4 Nanosheets in Terms of Photoluminescence Properties and Biomedical Imaging
Authors: Dong Jian , Zhao Yanli , Wang Kaiqi , Dong Lifeng
Published: February 2020

In recent years, fluorescent nanomaterials have attracted great attention due to their broad applications. Extensive efforts have been made on the development of novel metal-free fluorescent nanomaterials. Among these nanomaterials, graphene quantum dots (GQDs) have demonstrated chemical inertness, photostability, low cytotoxicity and favorable biocompatibility. Due to their excellent quantum confinement effect and edge effect, GQDs are usually characterized with distinct photoluminescence (PL) behaviors for biomedical imaging. Similar to GQDs, graphitic-phase C3N4 (g-C3N4) nanosheets have also exhibited high biocompatibility, low toxicity, and unique optical properties. Both GQDs and g-C3N4 nanosheets have been extensively investigated as potential biomedical imaging candidates. However, there are very few systematic comparative studies on GQDs and g-C3N4 nanosheets in terms of photoluminescence properties and biological imaging characteristics. Therefore, in this study, we mainly focus on investigating these differences. Highly water-dispersible GQDs and g-C3N4 nanosheets were prepared by a similar top-down process, chemically oxidizing thermally exfoliated graphite oxide and bulk g-C3N4 with concentrated nitric acid, respectively. UV-Vis absorption and photoluminescence spectral analyses were used to compare their optical properties. Compared to GQDs, g-C3N4 nanosheets demonstrate higher photoluminescence quantum yield. Cytotoxicity measurements indicate that both GQDs and g-C3N4 nanosheets are of low cytotoxicity with favorable biocompatibility. The remarkable performances of GQDs and g-C3N4 nanosheets in biomedical imaging are demonstrated by a simple incubation study with HepG2 cells. All these studies suggest that both GQDs and g-C3N4 nanosheets prepared by the above method have low cytotoxicity and are greatly promising for biomedical applications, such as in vitro and in vivo imaging studies.
(Invited) Bringing III-Vs into CMOS: From Materials to Circuits
Authors: Czornomaz Lukas , Deshpande Veeresh Vidyadhar , O'Connor Eamon , Caimi Daniele , Sousa Marilyne , Fompeyrine Jean
Published: February 2020

High-mobility channel materials such as InGaAs and SiGe alloys are considered to be the leading candidates for replacing strained Si in future low power/high performance logic circuits. However, the integration of InGaAs on Si and the co-integration of InGaAs devices with SiGe devices are extremely challenging. On the one hand, the large lattice mismatch (8 to 10%) and the potential formation of antiphase domains at the polar/non-polar III-V/Si crystalline interface typically hinder the integration of high quality InGaAs crystals on Si. On the other hand, InGaAs and SiGe require very different processing conditions in terms of thermal budgets, dry and wet chemistries, passivation schemes and contacting schemes which complexifies the realization of CMOS circuits.

Recently, tremendous progress were achieved as a result of innovation at the material and device levels. Latest technology developments yielded the first demonstration of InGaAs/SiGe CMOS inverters and dense SRAM arrays on Si, fabricated with InGaAs selective epitaxy and standard front end of line processes in a 2D co-planar configuration. This novel and scalable CMOS integration scheme enables InGaAs nFET fabrication in close proximity to SiGe pFETs (down to 25 nm spacing), resulting in 6T-SRAM arrays having a minimum cell size below 0.45 μm2. This scheme can be combined with any bulk Si or SOI-based planar or fin technology, and is compatible with standard large-area Si substrate.

Furthermore, progress on 3D Monolithic integration showed that this integration scheme not only an opportunity for further density scaling, but it also offers unique advantages for solving the integration of high mobility materials for 3D CMOS and stacking of functional layers on top of standard CMOS circuitry.
Electrolyzed Sulfuric Acid Application in Semiconductor Cleaning Processes: An Advanced Substitution of SPM Cleaning
Authors: Ahn Jin-hyun , Kim Pyung Dae , Hwang Seong Cheol , Seo Jinyoung , Lee Sungjin , Ogawa Yuichi , Ida Junichi , Sasaki Yuya , Nagai Tatsuo , Otsu Toru
Published: February 2020

SPM cleaning, a mixture of Sulfuric Acid and Peroxide, is a commonly used cleaning method in the semicondutor industry. The main purpose of the SPM cleaning is remove unwanted metal and organic contamination by oxidation process. The removal rate of both metal and organic contamination depend on the density of peroxide. As the semiconductor technology node shrinks, processes require less amount of metal loss, while the removal of organic contamination is relatively maintained. It is impossible to meet the demand with the conventional SPM cleaning, in which the density of peroxide do not take part in improving the metal, polymer selectivity.

Instead of using conventional SPM cleaning, where peroxide produces Caro's acid taking the main part in the oxidation process, electrolytic Sulfuric Acid is introduced. Electrolytic sulfuric acid produces Persulfate ion, which is more powerful oxidizer compared to peroxide used in conventional SPM cleaning. We used the Kurita's “Green Sulfaceed KD”(GS-KD) Module to supply the electrolytic sulfuric acid into the DNS batch type FC-3100 system.

Electrolytic Sulfuric Acid, compared to conventional SPM Cleaning, showed improvement in the metal, organic removal selectivity. In this paper, cases of process integration challenges concerning the metal, organic removal selectivity are reviewed. In case of a metal residue removal process with metal disclosure, minimum removal is required, however excess metal removal results in contact disconnection. In case of a implant dosed photo resist residue stripping process with danger of metal disclosure, low peroxide SPM cleaning is required however it is insufficient to strip the photo resist residue. Using the Electrolytic Sulfuric Acid, it was possible to meet the requirements of the processes, removing the unneeded residues while maintaning the metal underlayers. The improvement in the removal selectivity became the key factor in overcoming the technical challenges in the processes.