bluuebunny/crossref_metadata_2025 huggingface dataset:
Interconnected Nickel Nanowires – the Missing Link between Metallic High Surface Area Catalysts and High Porosity Foams
Authors: Zankowski Stanislaw Piotr , Vereecken Philippe M.
Published: February 2020

Porous and electrically conductive materials having extended surface area are attractive for wide range of applications, such as catalysis, sensing or energy storage. High surface area of the material provides higher reaction rates and lower electrode resistance. For instance, metallic sponges such as Raney nickel, having surface areas up to 100 m2/g show high catalytic activity during water electrolysis or heterogenous organic synthesis. However, low porosity and small average pore diameter limit their application for devices utilizing additional functional layers (e.g. active electrode materials in batteries). On the other hand, highly porous nickel foams are commonly used as current collectors for Ni- and Zn-based batteries, where sufficient loading of active material can be realized inside of the porous network. However, the surface area of such foams is more than three orders of magnitude smaller than that of the metallic sponges, lowering the potential for e.g. high rate operations of their parent devices.

In this talk we will present a recently developed material composed of interconnected nickel nanowires of controllable diameter and distance. The nanowires assembly offers a unique combination of high surface area of metallic sponges and high porosity of metallic foams. The material is conveniently obtained by cheap and up-scalable electrochemical techniques. The unique nanostructural properties of the interconnected nanowires allow for high flexibility of the material and applications in e.g. flexible electronics or wearable sensors. As a proof-of-concept, we will present the performance of our structure for hydrogen generation during water electrolysis. Compared to nickel foams, the high surface area interconnected nanowires offers significantly higher hydrogen evolution currents, showing their potential for next generation electrolyzers and energy devices.

Figure 1
(Invited) Electrochemically Synthesized High Density Chemical Sensor Arrays
Authors: Myung Nosang Vincent
Published: February 2020

Electronic detection of molecules is rapidly emerging as an alternative to the tranditional optical and electrochemical methods because of the small size, low-power consumption, improved sensing performance and most of all possibility of developing high density arrays for simulatenous analyses of multiple species in small sample volumes. Recently, one-dimensional nanostructures (e.g., carbon nanotubes (CNTs), inorganic, and organic nanowires) as conduction channels of field effect transistors (FETs) have been developed for detection of a variety of gaseous molecules with excellent low detection limit, sensitivity, and selectivity. These features are a consequence of dramatic decrease in characteristic length and increase in the ratio of surface to volume atoms, allowing for rapid diffusion into the bulk and for a more significant fraction of the atoms to participate in surface processes such as chemical and biochemical binding interactions. One-dimensional geometries also enhance response times by virtue of their two-dimensional mass transfer profile. Furthermore, nanowires are heralded for device miniaturization and sensor arrays, enabling duplicate elements to reduce false positives/negatives and pattern recognition systems termed electronic noses where each sensor in the array has a unique response to every analyte creating a fingerprint type response that increases sensitivity and selectivity. Finally, sensors are also attractive for their proven commercial viability, as this approach uses a single material behaving as both the sensitive layer and transducer to directly covert chemical information into an electronic signal without the need for labels, allowing for real-time, continuous monitoring.

In this presentation, synthesis, functionalization, and assembly of various nanoengineered materials including CNTs and conducting polymer nanowires will be discussed to create “true” high density gaseous sensor arrays with superior sensing performance in cost-effective manner. Finally, Android based smartphone integratable sensor will be demonstrated.
(Invited) The Role of Pyridine Derivatives in the Formation of Anisotropic Gold Nanoparticles
Authors: Burgess Ian James
Published: February 2020

It is appealing to develop and understand new approaches to generate anisotropic metal nanoparticles (NPs) owing to their application in optical-based sensing platforms. Empirically, the formation of anisotropic NPs is typically back-rationalized by speculating that shape-directing ions or molecules preferentially adsorb on different crystallographic facets of the growing particle. An alternative strategy is described herein whereby electrochemical measurements of pyridine-derivative adsorption on different low index single crystal surfaces conclusively demonstrate preferentially adsorption on Au(100} surfaces. This serves as a starting basis for developing rational approaches to generate homogeneous and heterogeneous anisotropic NPs through chemical and electrochemical reduction of AuIII precursors. The pyridine derivatives are shown to play a critical role in the formation of Au nanopods and nanodaggers. Electrochemical evidence is provided of a two-step reduction of tetrachloroaurate involving a pyridine-stabilized AuI species which plays a key role in producing anisotropic structures. Both electrodeposited and suspended NPs have surface plasmon resonances that extend well into the near IR (λmax ≈ 1000-1350 nm). Near-IR Raman sensing applications are demonstrated using FT-Raman with 1064 nm excitation. Electrodeposited nanodaggers provide SERS enhancement factors greater than 106 for monolayers of 4-aminothiophenol (4-ATP).
(Invited) Guided Growth and Smooth Deposition of Lithium Metal Film through Electrolyte Strategy
Authors: Xu Wu , Ding Fei , Zhang Yaohui , Qian Jiangfeng , Ren Xiaodi , Li Xing , Zhang Ji-Guang
Published: February 2020

Lithium (Li) metal batteries have been regarded as the most promising candidate for next generation energy storage because Li metal as anode has extremely high theoretical specific capacity (3860 mAh g-1), the lowest negative electrochemical potential (-3.040 V vs. the standard hydrogen electrode) and low density (0.534 g cm-3). However, the safety concerns and the short cycle life due to Li dendrite growth and low Coulombic efficiency (CE) hinder the development and practical applications of rechargeable Li metal batteries. During the past four decades, several approaches have been reported to suppress the Li dendrite growth and improve the stability of Li metal anode, including using Li alloys, solid-state electrolytes, polymer electrolytes, ionic liquids, highly concentrated liquid electrolytes, additives, protecting layers, interlayers between Li and separator, nanoscale design, selective deposition, Li-reduced graphene oxide composites, and so on. However, the improvement on Li anode as far is still unsatisfactory. In the past six years, we at PNNL systematically investigated various strategies to suppress Li dendrite growth, increase Li CE and enhance Li structural stability through electrolyte formulations, separator modifications, 3D structured Li hybrid anodes, and so on. In this talk, the electrolyte strategy to guide uniform growth and to form smooth deposition of Li metal film will be discussed and the details of the investigations will be reported at the presentation.

Acknowledgement

The research has been supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy (DOE) through the Advanced Battery Materials Research (BMR) Program.

Figure 1
(Invited) Electrodeposition in Li in Non-Aqueous Solution
Authors: Fukunaka Yasuhiro , Homma Takayuki , Nishida Tetsuo , Nishikawa Kei
Published: February 2020

Dendrite growth was observed during Li electrodeposition in Ionic Liquids as well as Organic solvents. Effect of current density, cation and anion on dendrite behavior was investigated.
(Invited) Observing the Overgrowth of a Second Metal on Silver Cubic Seeds in Solution By Surface-Enhanced Raman Scattering
Authors: Qin Dong , Zhang Yun , Wu Yiren
Published: February 2020

Bimetallic nanocrystals have received ever-growing interest owing to their properties often superior to the monometallic counterparts. Among various methods, seeded overgrowth has emerged as the most powerful route to the synthesis of core-frame or core-shell bimetallic nanocrystals. However, it simply cannot be applied to two metals with built-in galvanic replacement between them. In the past, we successfully demonstrated the galvanic replacement-free deposition of Au on Ag nanocrystals by introducing an additional reducing agent that can quickly reduce the metal precursor before it undergoes galvanic replacement with the seeds. In this talk, by building upon the prior success, we report our progress to turn the successful synthesis into a model system for investigating the fundamentals involved in the heterogeneous nucleation and overgrowth of metal nanocrystals. We hypothesize that the vibrational frequency of a metal-sensitive molecular probe can serve as a distinctive reporter for the metal being deposited on the surface of a Ag nanocrystal, with a detection limit well below one monolayer. To validate our hypothesis, we develop a novel class of fingerprint probes based on isocyanide compounds (R–NC) for the in-situ characterization of the heterogeneous nucleation and early-stage deposition of a metal, such as Pd, Pt, Ir, Rh, or Ru, on the edges of Ag nanocubes by surface enhanced Raman scattering (SERS). This research will create new foundation for the design and rational synthesis of bi- and multi-metallic nanocrystals sought for a variety of applications.
Annealing-Free Copper Foil Due to Ultra-Large Grain Sizes after Electroplating
Authors: Dow Wei-Ping , Chan Po-Fan
Published: February 2020

Copper electroplating has been widely used in the fabrication of electronic products. For semiconductor fabrication, damascene copper process needs copper electroplating;1 for IC chip packaging, 2.5D, 3D TSV and FOWLP need copper electroplating;2 for HDI PCB fabrication, microvias and through holes also need copper electroplating.3 Regarding the 3D IC chip packaging and FOWLP, copper pillars are necessary components, which are used as conducting pillars or heat conductors. Currently, copper pillars are made by electroplating, so that they are a polycrystalline structure. In other words, there are many grain boundaries in the copper pillars, which lead to a high electric resistance and, usually, need to be annealed at high temperature to obtain large grain sizes and reduce their electric resistance simultaneously. Moreover, if the copper pillar is polycrystalline, it is easily to form IMC with tin-containing solder and induce Kirkendall voids.4, 5 Many papers have demonstrated that the formation of Kirkendall void depends on the grain boundary of the electroplated copper. The more grain boundaries in the electroplated copper, the more Kirkendall voids will be observed.5 Impurities from plating additives, empty space between two grains and active copper atoms exist at the grain boundaries will lead to vacancies. Once these vacancies aggregate together, voids will be observed. Therefore, if there is no grain boundary instead of nano-twinned boundary or single crystal without boundary after copper electroplating, no void will be observed even after a long ageing time at a high temperature. Herein, a copper foil is obtained by electroplating and it has an ultra-large grain size (i.e., 10~20 μm) after electroplating. Hence, it needn’t annealing after electroplating. Of course, there is no Kirkendall void at the interface between copper/tin joint for a long ageing time at a high temperature.

References:

1. P. C. Andricacos, C. Uzoh, J. O. Dukovic, J. Horkans and H. Deligianni, IBM Journal of Research and Development, 42, 567 (1998).

2. V.-H. Hoang and K. Kondo, J. Electrochem. Soc., 164, D795 (2017).

3. T.-C. Chen, Y.-L. Tsai, C.-F. Hsu, W.-P. Dow and Y. Hashimoto, Electrochimica Acta, 212, 572 (2016).

4. T. C. Liu, C. M. Liu, Y. S. Huang, C. Chen and K. N. Tu, Scripta Mater., 68, 241 (2013).

5. L. Yin and P. Borgesen, J. Mater. Res., 26, 455 (2011).
Copper Electroplating with Polyethylene Glycol and Chloride: Modeling, Experimental Analysis and Parameter Determination
Authors: Yang Hongliu , Krause Robert , Scheunert Christin , Liske Romy , Uhlig Benjamin , Preusse Axel , Dianat Arezoo , Bobeth Manfred , Cuniberti Gianaurelio
Published: February 2020

Additives play an important role in electrochemical deposition and understanding their working mechanism is a great challenge. In cyclic voltammetry measurements of copper deposition, a complex hysteresis behavior is ubiquitously observed. In previous models a common assumption to explain the hysteresis is the consumption of additives during copper deposition. However, second-ion mass spectrometry measurements often detected comparatively low levels of impurities in deposits. We proposed recently an alternative mechanism for explaining hysteresis without invoking additive consumption. By assuming for instance a conformation change in the adsorbed PEG layer and an additional activation of additive desorption by copper deposition, the new model can reproduce characteristic features of cyclic voltammograms measured under vastly different conditions and exhibiting pronounced hysteresis. In parallel to that, we examined experimentally the process behavior of the additives PEG (polyethylene glycol) and chloride ions over a wide range of parameters relevant for production-like conditions. Moreover, we fitted crucial parameters of our model from the experimental data. The quantitative agreement of performed simulations of CV scans with the measured scans demonstrates the quantitative predicting power of the proposed model. Equipped with the determined parameter set, the model may help to optimize the copper plating process in industrial applications.
Electrolyte and Electrode Design for Dynamic Windows Based on Reversible Metal Electrodeposition
Authors: Strand Michael , Hernandez Tyler , Slotcavage Dan , Barile Christopher J. , McGehee Michael D.
Published: February 2020

Dynamic windows, which allow electronic control over light and heat flux, enable responsive environments free of glare and unwanted heat. Electronic control over traditionally static performance characteristics like visible light transmittance and solar heat gain coefficients will allow dynamic windows to be integrated with algorithms to optimize for energy efficiency and comfort. Dynamic windows based on reversible metal electrodeposition (RME) represent an exciting, new class of electrochromic devices. Metals are ideal light-modulators for dynamic windows because they can be color neutral, inert, photostable, and opaque at 20-50 nanometer thicknesses. Our team recently demonstrated metal-based dynamic windows that boast cheap processing, fast switching, and stable performance over thousands of cycles on the 25 cm2 scale.

Several technical challenges hinder further scalability of the technology. Indium tin oxide (ITO), the most ubiquitous transparent conductor, has a relatively high sheet resistance. By Ohm’s Law, maintaining a uniform current density across ITO electrodes necessitates a voltage drop proportional to the electrode area. Large-scale RME windows must be engineered with a tolerance to the voltage drop across the transparent electrodes in order to maintain optical uniformity. Additionally, undesired side reactions like the hydrogen evolution reaction (HER) set strict limits on the potentials that may be applied in aqueous electrolytes. The ideal system will enable uniform nucleation and growth of metal films over the potential range set by side reactions inherent to aqueous electrolytes, and the voltage drop inherent to transparent conductors.

Prudent design of electrode structure and electrolyte composition enable uniform and reversible electrodeposition over large areas. First, we demonstrate a scalable, self-assembly process to fabricate transparent electrodes functionalized with Pt nanoparticles. The nanoparticles enable site-selective control over nucleation of metal deposits. Second, we establish selection criteria for the use of polymeric levelling agents in reversible metal electrodeposition systems. By understanding the binding affinity between levelling agents and metal ions in our system, we access a range of electrodeposit morphologies that offer tunable control over optical properties. Finally, we demonstrate 100 cm2 RME-based dynamic windows that switch uniformly from a clear state (60% transmission) to an opaque state (<5% transmission) in less than one minute.

Figure 1
Effects of Microstructure of Nickel Electrodeposits on the Growth of Tin-Nickel Intermetallic Compound and Joint Reliability
Authors: Park MiSeok , Ryu TaeSeon , Lee SunSoo , Kim KangSoo , Kwon HyukSang
Published: February 2020

The mechanical breakage and electrical open failure of the flipchip bump interconnection are main issues that retarding the scale shrinkage of the 3D interconnections.

In this study, the effects of the microstructure of the nickel electrodeposits on the growth of Sn-Ni intermetallic compound (IMC) and on the electro-migration (EM) reliability were investigatged. The crystal structure of the Ni diffusion barrier can be controlled by addition of additives in electroplating bath. When both coumarin and cis-2-butene-1,4-diol were contained in the bath, extremely fine grain Ni electrodeposits were deposited by the synergistic effects of the additives. The growth rate of Ni3Sn4 IMC formed on the interface between the extremely fine grain structured Ni layer and Sn solder is higher than that of the IMC formed on the interface between the large grain structured Ni layer and Sn solder. The EM failure stage corresponds to large void propagation at the Sn-Ni3Sn4 interface due to volume consumption of Sn for IMC formation. The results of STEM analysis in an early stage of the heat treatment of the solder demonstrated that substantial quantities of Ni atoms were dominantly dissolved into the liquid Sn layer. Ni3Sn4 IMC was mainly formed on the finely grained Ni layer due to the high dissolution of Ni atoms into the solute Sn during the reflow process. IMC growth was suppressed at the interface between the large and fine grain structured area. This study suggests a robust concept of the vertical structure of Ni diffusion barrier having a multi layered Ni microstructure, which can reinforce an adhesion property as well as diffusion barrier properties

Figure 1
A Yolk/Shell Strategy for Improvement in Thermal Conductivities in Microencapsuted Phase Change Materials
Authors: Chung Feng-Ju , Chueh Yu-Lun , Lu Ming-Chang , Hsu Ting Heng
Published: February 2020

Solar thermal energy has been considered as one of the most promising energy source because of its inexhaustible feature. Solar thermal power generation system is designed for using and storaging sunlight and turning it into electricity. However, the amount of power generation is limited by the working fluid’s heat capacity and thermal conductivities. Enhancements in solar thermal storage induced by latent heat have been demonstrated by adding phase-change materials (PCM) into working fluids. In this study, we introduce yolk/shell structure, which represents a new class of special core/shell structures with a distinctive core @void @shell configuration. We successfully encapsulated Sn microparticles with protective carbon shell to prevent oxidation. And with this yolk/shell strategy, the voids between the yolk and the shell could serve as a buffering space for the volumetric changes of the Sn cores during the phase transition process, resulting in high stability. The Sn coated with carbon yolk/shell microparticles possessed high thermal conductivity and heat capacity. Furthermore, the appropriate doping proportion of PCMs with Hitec salt has also been tested without sacrificing viscosity of working fluids. This study provides a new strategy for microencapsulated particles and carbon shell have high thermal conductivity and thermal stability. With the low-cost synthesis process and superior thermal properties, Sn encapsulated with carbon shells have potential applications in energy storage enhancement in thermal energy systems.
Understanding the Effects of Sulfate/Bisulfate Ions on Electrolytes for Vanadium/Sulfuric Acid Redox Flow Batteries
Authors: Donnelly Daniel J , McDonnell Elias , Lawton Jamie S. , Arruda Thomas M
Published: February 2020

Redox flow batteries are a promising utility scale energy storage technology, recognized for the safe storage of surplus energy harnessed by wind and solar. Of particular promise is the all vanadium redox flow battery (VRFB) which relies on two redox couples of VO2
+ (V5+)/VO2+(V4+) on the cathodic side and V3+/V2+ on the anodic side. Significant efforts in recent years have focused on the optimization of operating conditions of VRFBs required for widespread commercialization. However many of these endeavors rely on incomplete or inappropriate data applied to specific systems, (e.g. wrong diffusion coefficients under specific conditions) which is necessary for a more complete and robust model.

One such phenomena inherent to the operation of a VRFB is proton and vanadium ion crossover.1–4 Proton transport is a requirement for the electrochemical reactions and to maintain charge balance. However, in practice vanadium ions also transport across the membrane causing parasitic and other unknown effects. For example, it is difficult to monitor changes to proton concentration (e.g. pH) as chemical treatment (titration) is clouded by the precipitation of VO(OH)2, and pH measurements under operational conditions are impossible or impractical.

This presentation will report our fundamental measurements of VRFB electrolytes by first investigating concentration effects of SO4
2-/HSO4
- to gain insight on the discharged (VO2+) electrolyte and the chemical equilibrium with a goal of being able to identify proton concentration. This understanding will allow for the determination of proton concentrations of the charged electrolytes and shed light on vanadium crossover which has occurred during charging. Those data will be compared to our experimental electron paramagnetic spectroscopy EPR vanadium crossover data.

J. S. Lawton, A. M. Jones, Z. Tang, M. Lindsey, and T. Zawodzinski, J. Electrochem. Soc. , 164, A2987–A2991 (2017) http://jes.ecsdl.org/content/164/13/A2987.abstract.

J. S. Lawton et al., J. Electrochem. Soc., 163, A5229–A5235 (2016).

R. A. Elgammal, Z. Tang, C.-N. Sun, J. Lawton, and T. A. Zawodzinski, Electrochim. Acta, 237, 1–11 (2017) http://linkinghub.elsevier.com/retrieve/pii/S0013468617306138.

R. M. Darling, a. Z. Weber, M. C. Tucker, and M. L. Perry, J. Electrochem. Soc., 163, A5014–A5022 (2015) http://jes.ecsdl.org/cgi/doi/10.1149/2.0031601jes.
Intermediate Temperature Na-ZnCl2 Battery
Authors: Lu Xiaochuan , Chang Hee Jung , Bonnett Jeff F , Canfield Nathan L , Jung Keeyoung , Sprenkle Vincent , Li Guosheng
Published: February 2020

Sodium-metal halide (Na-MH) batteries have been considered as one of the most attractive energy storage systems for stationary applications. Significant progress has been achieved in the Na-MH technologies during the past a few of decades. However, the batteries are still facing challenges in battery performance and cost. Recently, we have been working on advanced planar type Na-MH batteries with operating temperatures below 200oC. It was found that the low-temperature operation dramatically improved the battery performance (e.g., cycle life). Meanwhile, we have put efforts to replace the major cathode component of Ni in the Na-NiCl2 chemistry with Zn, which potentially can cut down around 46 and 20% of the cell material and overall battery costs. In this study, we further investigated the performance of the Na-ZnCl2 battery at intermediate-temperatures (e.g., 190oC). It was found the Na-ZnCl2 chemistry has significant higher rate capability over the Na-NiCl2 counterpart under similar operating conditions. The mechanisms for the higher rate capability could be related to the improved mass or charge transfer rate in the Na-ZnCl2 cathode. We believe this high-performance, low-cost, and safe Na-ZnCl2 battery will bring it one-step closer for broad market penetration of the Na-MH technologies.

Figure 1
A High-Voltage Aqueous Flow Battery Based on Highly Soluble Organometallic Materials
Authors: Li Bin , Hollas Aaron , Nie Zimin , Wei Xiaoliang , Wang Wei , Reed David , Sprenkle Vincent
Published: February 2020

Redox flow batteries (RFBs) systems, as one of the most promising electrical energy storage systems, provide an alternative solution to the problems of balancing power generation and consumption. These batteries are not only able to provide energy where and when it is required but also reduce the high capital cost of managing peak demands on the grid as well as large investments in grid infrastructures. Cost, reliability and safety are the most important factors to be considered to develop these systems. Because of good safety characteristics and high power densities (e.g., VRBs), aqueous systems have attracted widespread interest. The most widely studied redox species, vanadium, is expensive and toxic in its oxidized form. Therefore, organic or organometallic redox species could be used since they can offer more flexibility to tune the redox activity, redox potential, solubility, and stability.

Here, we will introduce a new low-cost aqueous redox flow battery system based on organometallic redox species. The theoretical energy density of this system can reach 90 Wh/L. Fig. 1(a) and (b) show the typical charge-discharge curves of this system (before and after electrolytes optimization) and cell efficiency performances over cycling, respectively (after optimization). It can be seen the open circuit voltage (OCV) increases from 1.52 V to 1.83 V and the system shows a very stable cell performance. The underlying mechanisms will be discussed.

Figure 1
Development of Advanced Electrokinetic Process for Brackish Water Desalination
Authors: Pan Shu-Yuan , Snyder Seth , Lin Yupo , Tseng Po-Chih , Chiang Pen-Chi
Published: February 2020

This paper first explores the current state-of-the-art in the removal of ions from brackish water using electrokinetic processes, as well as identifying emerging technologies and potential advances via materials science, process engineering, and system integration. Then, we focus on two major types of electrokinetic processes for brackish water desalination: electrodialysis (and electrodeionization) and capacitive deionization. Lastly, we discuss the balance between energy efficiency and throughput in the context of large-scale deployment of a desalination plant to address the associated challenges in water and energy nexus.
Blackwater Disinfection Using Potentiodynamic Methods and Surface-Modified Electrochemical Packed Bed Electrode Materials
Authors: Thostenson James O. , Mourouvin Rayane , Hangarter Carlos , Ngaboyamahina Edgard , Hawkins Brian T. , Sellgren Katelyn L. , Rossman Carolyn , Parker Charles B. , Deshusses Marc A. , Stoner Brian R. , Glass Jeffrey T.
Published: February 2020

The present work investigates the use of an electrochemical packed bed reactor (EPBR) for improving the energy efficiency of disinfecting human-generated blackwater. Potentiostatic and potentiodynamic treatment methods are used to compare packed-bed electrodes of magnelli-phase titanium-oxide, granularized activated carbon (GAC), and surface modified forms of both.

Our results highlight the differences in energy expenditure, oxidant generation, and EPBR operating conditions, as well as time needed for disinfection of blackwater as a function of packed bed electrode material and potentiometric treatment method. It is proposed that potentiodynamic treatment methods offer a more energy efficient and practical solution to treating blackwater than potentiostatic methods. Moreover, the benefits and drawbacks of using magneli-phase titanium oxide compared to common granularized carbon electrode materials are highlighted by correlating disinfection to energy expenditure and electrochemically generated oxidants. Reactive oxygen species, such as H2O2, and chlorine containing species, such as Cl2, are quantified and correlated to the reduction of bacterial concentration for each electrode material and treatment method. Lastly, the effects of flow-rate, particle size, and blackwater composition are correlated to the optimal conditions for blackwater disinfection.
Is There Room for Theory in Data Science? Encoding Physics into Machine Learning Algorithms
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. 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.

When data science techniques, and machine learning in particular, are implemented in battery systems, they are typically used as black boxes to predict battery behavior4. In this talk, we will highlight why this approach is ill suited for use in physics-based battery models, which are highly nonlinear, and how an understanding of the system can improve the result of the machine learning effort for use in optimization and control, while still allowing for the prediction of important internal states. Additionally, we will highlight ways to employ the flexibility of machine learning algorithms to allow for more accurate state estimation and voltage prediction.

Real-time model-based control has demonstrated significant improvements in time remaining, state of charge, and state of health, even using simple equivalent circuit models5. 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, as well as the Clean Energy Institute (CEI) through the DIRECT program at the University of Washington.

References

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

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.

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

J. Liu, A. Saxena, K. Goebel, B. Saha, and W. Wang, “An Adaptive Recurrent Neural Network for Remaining Useful Life Prediction of Lithium-ion Batteries,” NATIONAL AERONAUTICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER, Oct. 2010.

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
Electrochemical Properties of Anatase-Type TiO2 Nanoparticles with Different Morphology
Authors: Juhasz Gergely
Published: February 2020

Yamauchi and her group recently showed that anatase type TiO2 electrodes can be used for electrochemical reduction of carboxylic acids to alcohols [1]. So far this reaction was demonstrated only for oxalic acid with an efficiency very sensitive to the preparation conditions of the anatase electrode. One possible explanation of such sensitivity electrochemical activity to preparation conditions is that the morphology of the surface has deep impact on the electrochemical processes. To improve the efficiency as well as to understand what factors limit the reduction of other acids, we studied the effect of morphology on the electronic structure of anatase nanoparticles using Density Functional Tight Binding (DFTB) method. Since only nanoparticles of anatase up to 5 nm are thermodynamically stable, we focused on nanoparticles of 2-4 nm and assumed that morphological differences of the electrodes can be described with the help of such particle models.

The edges and peaks of nanoparticles contains of 4- and 5- coordinated Ti ions, which can be responsible for smaller band gap and strong reactivity of the particles. We performed extensive calculations to study the water and acid absorption on the edges and faces of nanoparticles to identify the most probable coordination environment of these Ti ions. We also studied the energy and overlap between LUMO (conduction band) of the nanoparticles and substrates, as these orbitals play important role in electrochemical reduction reactions. Our computational work offers new understanding for optimization of titania electrode surfaces for electrochemical reaction.

The work was supported by CREST, JST and the computations were partially performed using Research Center for Computational Science, Okazaki, Japan.

Reference:

[1] R. Watanabe, M. Yamauchi, M. Sadakiyo, R. Abe and T. Takeguchi, Energy Environ. Sci., 2015, 8,

1456–1462

Figure 1
Charge Transport and Stability of a Semiconductor-Solution Interface Under Electrical Bias from First Principles
Authors: Campbell Quinn , Dabo Ismaila
Published: February 2020

Solar energy is the most abundant energy source available to humankind; this energy cannot be harnessed on demand, however, due to the variability of sunlight. Artificial photosynthesis offers a sustainable way to overcome that variability through the photocatalytic conversion of solar power into chemical fuels at a semiconductor–electrolyte interface. Although considerable progress has been made in simulating the bulk properties of semiconductors from first principles, much less has been done to address the electrochemical response of semiconductor–electrolyte interfaces under realistic environmental conditions. We present broadly applicable and highly transferable computational techniques to simulate semiconductor–electrolyte interfaces. By introducing a continuum model of the semiconductor and electrolyte regions surrounding the quantum-mechanical interfacial layer, our model enables the self-consistent determination of the electrical response of a semiconductor-solution interface, including the atomistic effects of charge trapping at interfacial surface states. Using this, we develop a new description of the semiconductor-solution interface allowing us to predict the electrical response, stability, and equilibrium Schottky barrier of a photoelectrode as a function of different surface chemistries. This allows researchers to optimize materials selection for both charge transport and stability, leading to more efficient and practical artificial photosynthesis systems.

Reference:

Campbell and Dabo, Physical Review B 95, 205308 (2017).
Modeling Lithium Growth in Symmetric Cells
Authors: Chen Jerry , Subramaniam Akshay , Lee Seong Beom , Geise Natalie R , Kasse Robert M. , Toney Michael F , Subramanian Venkat R.
Published: February 2020

Lithium-metal batteries are receiving great attention in recent years as an anode material. It has a higher theoretical specific capacity (3860 mAh∙g-1) compared to the graphite (372 mAh∙g-1) used in conventional Lithium-ion batteries.1 However, the capacity fade resulted from unexpected dead lithium, and dendrite growth is a major issue that causes shorter cycle life and possible internal short circuits during operation.

The purpose of this study is to develop a continuum model that captures the dynamics of lithium metal deposition and stripping during repeated cycling of a lithium-metal cell. The repeated deposition and stripping of Lithium accounts for the presence of a heterogeneous growth of Lithium foil (anode) in a battery electrode. One can take advantage of the simplicity of symmetric cells to understand electrodes and electrolyte in a controlled applied potential.2 The symmetric cell consists of the same materials on both electrodes, so the average potential of the system is zero. This study will compare the continuum model with experimental data for a Li/Li symmetric cell.

The mathematical model used in this study is based on the concentrated solution theory models developed by Newman and coworkers.3-5 The mass transport of the Li-ion in the electrolyte, neglecting migration, is governed by Fick’s law. A modified Ohm’s law for the liquid electrolyte phase is considered and the Butler-Volmer equation is accounted for lithium metal deposition and stripping at the electrode.

The system will be studied with one-dimensional modeling coupled with a moving boundary representation of lithium stripping and plating.6 Some experimental variations such as high current density cases will also be considered. The one-dimensional model will then be extended to two-dimensional modeling to understand the trend of heterogeneous plating/growth of Lithium metal.

Acknowledgements

The authors would like to thank for the financial support of this work by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the DOE through the Advanced Battery Material Research (BMR) Program (Battery500 consortium) and the Clean Energy Institute (CEI) at the University of Washington and the Washington Research Foundation (WRF) for their partial monetary support during this work.

References

J. Qian, W. A. Henderson, W. Xu, P. Bhattacharya, M. Engelhard, O. Borodin and J.-G. Zhang, Nature communications, 6 (2015).

J. C. Burns, L. J. Krause, D.-B. Le, L. D. Jensen, A. J. Smith, D. Xiong, and J. R. Dahn. J. Electrochem. Soc.,
158, A1417-A1422 (2011).

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V. Srinivasan and J. Newman, J. Electrochem. Soc. , 151, A1517–A1529 (2004)

S.-L. Wu, A. E. Javier, D. Devaux, N. P. Balsara, and V. Srinivasan, J. Electrochem. Soc. , 161, A1836–A1843

Q. Zhang and R. E. White, J. Electrochem. Soc. , 154, A587–A596 (2007)
Estimation of Transport and Kinetic Parameters of Vanadium Redox Batteries Using Static Cells
Authors: Lee Seong Beom , Pratt Harry D. , Anderson Travis M. , Mitra Kishalay , Chalamala Babu R. , Subramanian Venkat R.
Published: February 2020

Redox Flow Batteries (RFBs) are receiving significant attention as a promising technology for grid storage applications.1 While there has been great progress in experimental aspects of flow battery technology, there is a lack of modeling approaches to rapidly evaluate system performance. For example, a common practice has been to determine parameters in mathematical RFB models either through conducting experiments or based on the information available in the literature.2,3,5 However, it is not easy to investigate all parameters for models through this way, and there are occasions when important information, such as diffusion coefficients and rate constants of ions, is not studied. In addition, the parameters needed for modeling charge-discharge are not always available.

In this presentation, we demonstrate that an optimization-based robust modeling framework, which is based on a physics-based electrochemical engineering model and parameter estimation techniques,2-5 is useful in studying and analyzing RFB systems. We have studied aspects of capacity loss/fade, kinetics, and transport phenomena of the system and further optimized our model using a laboratory-scale all-vanadium redox static cell setup. The practical impact of this work will be reviewed by providing executable files that enable to identify the performance of redox batteries without the need for software installation and a priori programming knowledge.

Acknowledgements

This work was supported by the Clean Energy Institute located in University of Washington, Seattle and Washington Research Foundation. The battery experimental work has been supported by program manager Dr. Imre Gyuk through the U.S. Department of Energy, Office of Electricity Delivery and Energy Reliability. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

References

K. T. Cho, P. Ridgway, A. Z. Weber, S. Haussener, V. Battaglia, and V. Srinivasan, Journal of The Electrochemical Society,
159 (11), A1806-A1815 (2012)..

K. Knehr, E. Agar, C. Dennison, A. Kalidindi, and E. Kumbur, Journal of The Electrochemical Society,
159 (9), A1446-A1459 (2012).

A. Shah, R. Tangirala, R. Singh, R. Wills, and F. Walsh, Journal of the Electrochemical society,
158 (6), A671-A677 (2011).

A. Tang, J. Bao, and M. Skyllas-Kazacos, Journal of Power Sources,
196 (24), 10737-10747 (2011).

P. A. Boettcher, E. Agar, C. Dennison, and E. C. Kumbur, Journal of The Electrochemical Society,
163 (1), A5244-A5252 (2016).
(Invited) Extending Advanced CMOS Scaling with SiGe Channel Materials
Authors: Carter Rick J , Sporer Ryan , Triyoso Dina H , Child Amy , Mulfinger George Robert , Wahl Jeremy A , Mcardle Timothy J , Kluth George J , Fronheiser Jody , Holt Judson Robert , Punchihewa Kasun , Vanamurthy Laks , Beasor Scott , Rana Uzma , Sohn D K
Published: February 2020

Advanced CMOS Scaling has benefited from the introduction of novel materials and integration techniques over the past two decades. Consumer demand for more connectivity and real-time information continues to drive the need for product solutions with advanced power management and increased functionality while maintaining low cost. New device architectures such as FINFET and Fully Depleted Silicon-On-Insulator are part of the solution, however these device architectures still rely on advanced channel strain engineering to meet power, performance, and scaling requirements. The use of SiGe as a channel material is attractive due to enhanced mobility and compatibility with standard CMOS processing. PFET drive current enhancement has already been realized to enable platforms based on high performance planar FDSOI devices, while SiGe as part of the channel is also a top solution to enable next generation FINFET and Gate-All-Around devices. In this invited paper we will provide an in-depth look into the device benefits and challenges of SiGe as a channel material.
Model Based Corona Charge - Kelvin Probe Characterization of Patterned Structures
Authors: Marinskiy Dmitriy , Lagowski Jacek
Published: February 2020

Corona – Kelvin characterization of semiconductor materials is now a common technique that is used as a non-contact replacement of contact CV measurements [1,2]. Traditionally it is applied to planar structures such as an oxide – semiconductor structure or similar. Deposition of corona charge ΔQCORONA causes a change in surface voltage, ΔV = ΔVSB + ΔVD, which includes voltage drop across the semiconductor space charge layer, ΔVSB, and across the dielectric layer, ΔVD. The differential capacitance is calculated as C = ΔQCORONA/ΔV. The incremental charging-measuring cycle gives the non contact CV characteristic and also charge-voltage characteristic, QV, where Q = ΣΔQ, and V = ΣΔV.

In this work we applied the Kelvin-corona method to a patterned structure, which represents a grid of 2 or more locally adjacent elements having different properties (Figure 1). Elements of the structure can constitute a planar structure (Figure 1A) or a non-planar three dimensional structure (Figure 1B). In both cases, the elements of the structure have dimensions smaller than the size of the Kelvin probe, such that at least one cycle of the pattern structure is within the Kelvin probe diameter.

A model based analysis of corona charge – Kelvin probe data (QV data) was developed which is based on the geometrical dimensions, electrical parameters of elements of the patterned structure, and response of each element to corona charging. The effective voltage measured by the Kelvin probe follows: Veff=Σ(aiVi)/Σ(ai), where ai is the area of an element i, and Vi is the voltage in the area ai. The surface voltage for each element of the structure depends on electrical properties of the structure, Vi=f(φMS, CD, QD, DIT), and responds to corona charging according to its electrical properties.

Examples of experimental and simulated data will be presented for a type 1B structure. The simulated data allow quantification of electrical parameters of each element of the structure such as interface properties at the SiO2 / silicon interface, including the interface trap density, DIT, and the flat band voltage, VFB.

The results are of importance for the rapid characterization of 3D structures, such as STI, FinFET, etc. where the electrical properties vary between elements of the structure. The model based QV method enables extraction of electrical parameters that are different for the elements of the structure.

References.

K. Schroder, Meas. Sci. Technol., 12, R16 (2001).

Wilson, D. Marinskiy, A. Byelyayev, J. D’Amico, A. Findlay, L. Jastrzebski, and J. Lagowski, ECS Trans., 3(3), 3 (2006).

Figure 1
(Invited) Enhanced Light Output Power from Eu-Doped GaN Narrow-Band Red Light-Emitting Diodes By Actively Controlling Photon Fields
Authors: Fujiwara Yasufumi , Inaba Tomohiro , Shiomi Keishi , Tatebayashi Jun
Published: February 2020

While InGaN/GaN blue and green light-emitting diodes (LEDs) are commercially available, the search for an efficient red LED based on GaN is ongoing. This is essential for the monolithic integration of the three primary colors and the development of nitride-based small-size, full-color, high-resolution displays. We have succeeded in the realization of a red LED using Eu-doped GaN (GaN:Eu) grown by organometallic vapor phase epitaxy [1]. Making use of the intra-4f shell transitions of Eu3+ ions, our LED features an ultra-narrow linewidth of less than 1 nm at room temperature, and unprecedented thermal stability of 1 pm/K. By gradual optimization of the Eu excitation mechanism, we have increased the light output power above 1 mW at 20 mA [2].

One of limiting factors for enhanced light output power is the relatively long radiative lifetime of the Eu emission in GaN:Eu (∼300 µs). According to the Fermi’s golden rule, modifying the spontaneous emission rate of Eu ions can be achieved by increasing the photonic density of states (PDOS) at the frequency of spontaneous emission, as already demonstrated with a planar Fabry-Perot cavity. We have boosted the output power by actively manipulating radiative recombination probability at the atomic level of the Eu ions, which can be achieved through control of their photon fields in micro- and nano-cavities. In a GaN:Eu layer embedded in a microcavity consisting of an AlGaN/GaN distributed Bragg reflector (DBR) and a Ag reflecting mirror, a 21-fold increase of the Eu emission intensity was obtained under optical pumping at room temperature [3]. Furthermore, in a preliminary LED with a microcavity consisting of ZrO2/SiO2 and AlInN/GaN DBRs, the output power was enhanced by 5 times [4]. In this talk, current status of the red LED and strategies for further enhancement of the light output power are reviewed.

A. Nishikawa, T. Kawasaki, N. Furukawa, Y. Terai, Y. Fujiwara, Appl. Phys. Exp. 2, 071004 (2009).

B. Mitchell, V. Dierolf, T. Gregorkiewicz, and Y. Fujiwara, submitted to J. Appl. Phys.

T. Inaba, D. Lee, R. Wakamatsu, T. Kojima, B. Mitchell, A. Capretti, T. Gregorkiewicz, A. Koizumi, Y. Fujiwara, AIP Adv. 6, 045105 (2016).

T. Inaba, K. Shiomi, J. Tatebayashi, and Y. Fujiwara, in preparation.