bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Plating Additives on Microstructure and Properties of Electrodeposited Ni-Fe Alloy
Authors: Hung Mao-Chun , Chan Po-Fan , Dow Wei-Ping , Lee Hsiao-Yen , Lin Yi-Sheng , Yang Ping-Feng
Published: February 2020

With the evolving technology, the frame mounted design of electronic components has increasingly become high-density, which leads to the electronic elements that are inevitably vulnerable to electromagnetic interference and then affect other electronic products’ functions. The solution is to use well conductive material that operates the shielding process. The material includes metals and conductive polymers which are common sources of the protective materials in dealing with the main conductive surface. Although this masking method has been widely recognized, several problems are still observed in practice, including the vulnerability to scaling, abrasion, corrosion and process load.

           In this study, we adopt Ni-Fe alloy film as the shielding material and manufacture it by electroplating. We intend to explore the effects of plating solution composition, plating parameter and plating additives on structural strength and magnetic properties of the Ni-Fe alloy film. In electroplating, plating additives play important roles. The results suggest that various additives lead to different crystalline orientations, grain sizes, and surface roughness. A correlation between the plated structure and the magnetic properties is studied. Additionally, anti-corrosion is improved by doping a few boron in the film. The ultimate goal of the study is to meet the requirements of electronic industry in manufacturing Ni-Fe alloy with high permeability and good corrosion resistance.
Highly Adhesive Displacement Plated Cu Seed on Cowb Barrier for All-Wet TSV Fill Process
Authors: Ohta Kohei , Inoue Fumihiro , Shimizu Tomohiro , Shingubara Shoso
Published: February 2020

Fabrication  of  TSV is one of key technology for 3D-ICs.  For realizing  conformal barrier layers against Cu diffusion with a low temperature process is important to achieve highly reliable TSVs. Electroless plated metals such as Co-alloy and Ni-alloy are  considered to have a high potential as a barrier layer.

We  succeeded in conformal electroless plating of CoWB on SiO2,  using DMAB  as a reducing agent after forming self-assembled monolayer (SAM) of silane coupling   agent (APTES) on  SiO2  [1-2],    assisted with Pd nanoparticle catalyst.   The adhesion strength of CoWB decreased with an increase in film thickness [1], which might be due to an increase in film  intrinsic stress.  Electroless Cu plated film using reducing agent on the CoWB layer showed a very poor adhesion property. In this study, we studied to form electroless Cu seed layer with a high adhesion strength by displacement reaction without reducing agent, and furthermore examined the barrier and seed formation into a high aspect ratio TSVs.

The electroless CoWB plating bath composed of cobalt sulfate and tungstic acid as a metal salt, citric acid as a complex agent, DMAB as a reduction agent. The Cu displacement plating bath composed of sulfuric acid and copper sulfate, and its pH was 3.5.  The adhesion strength was  evaluated  by the  stud-pull  test. Table 1 shows the adhesion strengths of various films such as CoWB (70nm) only, displacement plated Cu on CoWB, electroless Cu plated with reducing agent (glyoxylic acid) on CoWB. The adhesion  strength  of the 70 nm CoWB film was 20MPa.  That of displacement plated Cu/CoWB was 50 MPa. The adhesion strength of electroless plated Cu with reducing agent was very poor. We succeeded in obtaining a high adhesion strength by Cu displacement plating.

Figure 1 shows the displacement plated Cu seed layer on 80 nm electroless CoWB layer in TSV. The diameter is 3 μm and aspect ratio is 10.  Displacement plated Cu film was formed almost uniformly from top to bottom of TSV. The sidewall and bottom coverages of  Cu/CoWB bilayer in TSV was 70 to 80 % against that of  the flat area. At the bottom of TSV, Cu(40nm)/CoWB(40nm) bilayer was formed succesfully without delamination.

We succeeded in the formation of highly adhesive electroless plated Cu seed layer on CoWB layer.  Further study of complete fill of TSV with ECP Cu is in progress. 

 References

[1] F. Inoue, T. Shimizu, H. Miyake, R. Arima, T. Ito, H.Seki, Y. Shinozaki, T. Yamamoto, and S.Shingubara, Microelectronic Engineering, 106 (2013) 164–167.

[2] F.Inoue, T.Shimizu, T. Yokoyama, H. Miyake, K. Kondo, T. Saito, T. Hayashi, S. Tanaka, T. Terui and S. Shingubara, Electrochimica Acta, 56-17 ,6245-6250, (2011).

Figure 1
(Invited) Probing Oxygen Activities and Their Effects on Cation Migration in Li Rich Mn Rich Layered Oxides
Authors: Meng Shirley
Published: February 2020

Combining first principles computation with STEM/EELS experimental observations, we demonstrated that in the Li-excess materials oxygen vacancies are present in surface regions and assist the TM ion migration through a novel mechanism: during first cycle charging, after most TM ions are fully oxidized, oxygen ions start to participate in the oxidation process (lose electron) and oxygen vacancies would form with a formation energy about 0.5–0.6 eV. Possibly due to the slow oxygen migration, oxygen vacancies mostly form near the material surfaces and sub-surfaces with 5–6 atomic layers. A significant fraction of the TM ions in these regions therefore are subjected to five (or even less) O-coordination due to the presence of either oxygen vacancies or the broken TM–O bonds on the particle surfaces. TM ions in those five (or less) coordinated defect polyhedral sites become much unstable and will spontaneously migrate to the fully-coordinated polyhedral sites nearby in the Li layer. On the other hand, although many of the Li ions are extracted upon charging, stable Li–Li dumbbells are formed leaving only certain sites in Li layers that are available for TM occupation. Combination of the above two reactions therefore causes the formation of a spinel-like phase from the material surface towards the bulk until reaching a region (2–3 nm beneath the surface after the first cycle) where oxygen vacancy concentrations are too low to assist the TM ion migration. It is reported that although it might be subjected to a further phase change, this TM-ion-migrated region is present for 50 cycles with its thickness mostly unchanged.  

Based on these in-depth understanding, we will report a novel approach in optimizing the lithium excess manganese rich layered oxides whose first cycle columbic efficiency and long term cycling stability and voltage stability could be significantly improved.

Acknowledgement: This work is supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. DOE under Contract No. DE-AC02-05CH11231, Subcontract No. 7056412, under the Batteries for Advanced Transportation Technologies (BATT) Program
Modeling of LiFePO4 Charging/Discharging Dynamics Based on the Many-Unit Concept: Validation Against Operando XRD Data
Authors: Delacourt Charles , Farkhondeh Mohammad , Pritzker Mark , Fowler Michael
Published: February 2020

LiFePO4 (LFP) was proposed as a battery material over 15 years ago and has been implemented in commercial cells for about 10 years now. In spite of its maturity, LFP is still the subject of intensive research, particularly related to the phase-separating nature of the material. A number of interesting and unusual experimental features of the LFP system have been reported in the literature, including the zero-current potential hysteresis,1 rate-dependent lithiation/delithiation mechanism,2 cycle-path dependence3 and the memory effect.4 All of these observations were successfully predicted using a simple mesoscopic model that we recently published and that relies on a many-unit approach.5 In this presentation, we demonstrate an extended mesoscopic model for phase-change materials and its validation by simulating operando X-ray diffraction results recently reported in the literature.6,7 This validation step helps refine the physical representation of the electrode because it simultaneously accounts for phase dynamics as revealed by the XRD data and the electrochemical features of LFP. This work paves the way towards a mathematical model that unifies all the experimental observations reported for this material over the years.

References:

1. W. Dreyer, J. Jamnik, C. Guhlke, R. Huth, J. Moskon and M. Gaberscek, Nature Mater., 2010, 9, 448–453.

2. R. Malik, A. Abdellahi and G. Ceder, J. Electrochem. Soc., 2013, 160, A3179–A3197.

3. V. Srinivasan and J. Newman, Electrochem. Solid State Lett., 2006, 9, A110–A114.

4. T. Sasaki, Y. Ukyo and P. Novak, Nature Mater., 2013, 12, 569–575.

5. M. Farkhondeh, M. Pritzker, M. Fowler, M. Safari, and C. Delacourt, Phys. Chem. Chem. Phys., 2014, 16, 22555.

6. H. Liu, F. C. Strobridge, O. J. Borkiewicz, K. M. Wiaderek, K. W. Chapman, P. J. Chupas, C. P. Grey, Science, 2014, 344, 1480.

7. X. Zhang, M. van Hulzen, D. P. Singh, A. Brownrigg, J. P. Wright, N. H. van Dijk, and M. Wagemaker, NanoLett., 2014, 14, 2279.
Implementation of Porous Media Flow Model in Sodium Sulfur Battery Simulations
Authors: Mason Jerry Hunter , Celik Ismail Bektas
Published: February 2020

Sodium sulfur batteries are comprises of liquid electrode materials suspended in porous media. The sodium anode and the sulfur/sodium-polysulfide cathode are separated by a solid electrolyte made of beta-alumina or NASICON material. Due to the presence of porous media, capillary pressure and the resulting capillary action become important. Because of the exponential dependence of capillary pressure on wetting phase saturation, sharp concentration gradients are possible between the inert gas and the sulfur/sodium polysulfide liquid within the cathode. These gradients may result in areas of high electrical potential variation leading to increased reaction rates which in turn can cause overconsumption of sodium in the cathode during discharge, thus preventing sodium from penetrating the entire depth of the cathode. During charge, high reaction rates cause sulfur to accumulate on the electrolyte surface at a rate faster than the sodium-polysulfide can displace it producing an insulating effect. Both of these occurrences can lead to even higher potential variations, which can lead to decreased efficiency and even cause failures due to effects of overheating.

A porous media flow model is implemented into a three-dimensional, time dependent, multiphysics model for sodium sulfur batteries in order to study the aforementioned phenomena. Transport equations for charge, mass and heat transport are discretized using the finite volume method and then solved simultaneously in a time marching fashion. Properties required for solving the transport equations, including fluid density, heat capacity and ionic conductivity, are calculated and updated at each grid location as a function of time based on the volumetric content and phase of each species within each control volume.  Electro-chemical boundary conditions range from prescribed voltage to external circuitry, including resistance, power consuming and power producing loads (for the purpose of charging). Mass transport is coupled with charge transport via Faraday’s law. Darcy’s law is used to model capillary action within the porous media between the wetting phase (liquid) and non-wetting phase (inert gas). The porous media model is coupled with the continuity equation and with a separate diffusion equation which is solved only within the liquid phase. The porous media model has been verified and validated by simplified analytical solutions and numerical results from similar models found in the literature. This validated model is being applied to sodium sulfur batteries currently. A comparison study will be performed to analyze the importance of porous media effects in multiphysics sodium sulfur battery modelling.
Mesoscale Modeling and Simulation of Composition, Manufacturing, and Microstructure Effects on Electrical Conduction in Thermal Battery Cathodes
Authors: Reinholz Emilee Lolita , Roberts Scott A. , Schunk P. Randall , Apblett Christopher A.
Published: February 2020

Li/FeS2 thermal batteries provide a stable, robust, and reliable power source capable of long-term electrical energy storage without performance degradation. These systems rely on a eutectic salt that melts at elevated temperature, activating the cell. When the electrolyte melts, the cathode becomes a suspension, with cathode particles suspended in a liquid molten salt. This suspension experiences mechanical deformation, or “slumping.” This slump changes the mechanical compression of the cell, as well as the tortuosity and electronic and ionic conductivity of the cell as the mesostructure of the cathode is reordered in response to the external compressive stress. The combined effect of deformation, component composition, and manufacturing conditions on electrical conduction has not been studied, yet the cathode electrical properties are critically important to battery performance.

We present simulation results from a computer model validated with experiments to elucidate the effects of conduction in FeS2 cathode pellets when composition and manufacturing parameters are varied. Experimental validation was achieved through impedance spectroscopy measurements of pressed-powder cathode pellets. Pellets were manufactured in-house with variations in pellet density, FeS2 particle size distribution, and ratio of FeS2 to electrolyte content. Impedance measurements of solid-state pellets were taken at 25, 100, and 200°C before and after slumping. We observed that electrical conductivity increased with relative FeS2 content and decreased with the FeS2 particle size distribution, but that the density of the pellets did not demonstrate a clear effect. Slumped pellets exhibited greater electrical conductivity at all temperatures and pellet thickness decreased by 1.8% on average due to slumping.

Sandia’s novel conformal decomposition finite element method (CDFEM) was applied to surface-meshed geometric representations of cathode microstructures generated from microcomputed tomography (MicroCT) reconstructions. MicroCT was performed on all pellet types before and after slumping, with approximately 0.5 μm pixel size achieved for >0.1 mm3 volumes. A particle surface mesh was generated for each volume using FEI Avizo software and combined with the CDFEM background mesh. Results from the SIERRA/Aria finite element code will be presented, including the effects of anisotropy, mesh size, system volume, and manufacturing conditions on electrical conduction through cathode models, and compared with the experimental trends that were observed in the laboratory. The understanding of manufacturing effects on battery performance is not well developed, and this effort represents a step forward in correlated and predicting performance of cells based upon observed manufacturing trends.

Figure 1
Real Time Multi-Cell Multiple Chemistry Simulation of Reformulated Electrochemical Battery Models for EV and Grid Applications
Authors: Lee Seong Beom , Pathak Manan , Lawder Matthew T , Subramanian Venkat
Published: February 2020

The porous electrode pseudo-two-dimensional (P2D) model  which includes several meaningful internal variables (including potentials and concentrations in solid and liquid phase) provides good predictive capability for battery simulation1. We have performed an orthogonal collocation reformulation of the P2D model for lithium-ion batteries2,3 . The accuracy and short computation time of the reformulated model4are well suited for electric vehicle (EV) and grid application. The use of a electrochemical based model allows for the inclusion of additional physics based phenomena in the model such as temperature, stress, and capacity fade mechanisms.

     EV and Grid application involve large battery modules. In order to perform the most accurate simulation and control of these systems the model must include multiple cells in series parallel combination. For large modules charge balancing becomes problematic. Not all the cells will be at the same state of charge and health. In addition, for grid applications, one might visualize a situation in which lithium-ion batteries with different chemistries being used simultaneously, sometimes even flow batteries in combination with lithium-ion batteries. Systems like these require a thorough multiple cell system model to understand all of these effects.

     This talk will present progress in real-time simulation of physics based models for batteries in hybrid environments. 

Acknowledgements

The authors acknowledge financial support from the U.S. Department of Energy’s Advanced Research Projects Agency- Energy (ARPA-E), and the Solar Energy Research Institute in India and the United States (SERIIUS).

References

1. M. Doyle, T. F. Fuller, and J. Newman, J. Electrochem. Soc., 140, 1526 (1993)

2. Venkat R. Subramanian, Vijayasekaran Boovaragavan, Venkatasailanathan Ramadesigan, and Mounika Arabandi, J. Electrochem. Soc.,
156
(4) A260-A271 
(2009)

3. Paul W. C. Northrop, Venkatasailanathan Ramadesigan, Sumitava De, and Venkat R. Subramanian, J. Electrochem. Soc., 158 (12) A1461-A1477 (2011)

4. Venkatasailanathan Ramadesigan, Kejia Chen, Nancy A. Burns, Vijayasekaran Boovaragavan, Richard D. Braatz, and Venkat R. Subramanian, J. Electrochem. Soc., 158 (9)  A1048-A1054 (2011)
Influence of Binder Property and Interaction on Electrode Microstructure Formation in Energy Storage
Authors: Liu Zhixiao , Mukherjee Partha P.
Published: February 2020

Energy storage, such as lithium-ion batteries (LIBs), is key enabler for grid energy storage and vehicle electrification. The electrode microstructure, which is affected by processing scheme, plays an important role in determining the electrode property and performance.1-5In the multiphase electrode slurry, physicochemical interactions affect the assembly of active material and conductive additive particles. Additionally, the pattern of nanoparticle assembly is also affected by the solvent evaporation rate.

Polymer-mediated nanoparticle assembly can be a promising method to control a composite microstructure.6 However, there are only a few studies focusing on the effect of binder interaction (such as binder molecular weight) on the electrode microstructure formation and the relative performance.7, 8

In the present study, we developed a mesoscale model accompanied by stochastic dynamics simulation to illustrate the influence of binder interaction and evaporation on microstructures during the electrode processing. Present simulations demonstrate that the lower drying temperature can produce electrode films with micropores as shown in Figs. 1 (a) ~ (c). The depth of micropores tends to increase as binder length (L) increases. Drying temperature affects binder distribution along thickness direction as shown in Fig. 1 (d). The lower drying temperature reduces the fraction of on-surface binder. Additionally, binder length also affects the binder distribution. It can be seen in Fig. 1 (d), that an increase of binder length is beneficial for keep high volume fraction of binder in the film which has implication in better mechanical stability of the electrode film.

Refernces

1. J. Li, B. L. Armstrong, J. Kiggans, C. Daniel, and D. L. Wood III, Langmuir,
28 (8), 3783-3790 (2012).

2. H. Zheng, R. Yang, G. Liu, X. Song, and V. S. Battaglia, The Journal of Physical Chemistry C,
116 (7), 4875-4882 (2012).

3. G. Liu, H. Zheng, S. Kim, Y. Deng, A. Minor, X. Song, and V. Battaglia, J Electrochem Soc,
155 (12), A887-A892 (2008).

4. Z. Liu and P. P. Mukherjee, J Electrochem Soc,
161 (8), E3248-E3258 (2014).

5. Z. Liu, V. Battaglia, and P. P. Mukherjee, Langmuir,
30 (50), 15102-15113 (2014).

6. P. Akcora, H. Liu, S. K. Kumar, J. Moll, Y. Li, B. C. Benicewicz, L. S. Schadler, D. Acehan, A. Z. Panagiotopoulos, V. Pryamitsyn, V. Ganesan, J. Ilavsky, P. Thiyagarajan, R. H. Colby, and J. F. Douglas, Nat Mater,
8 (4), 354-359 (2009).

7. B.-R. Lee and E.-S. Oh, The Journal of Physical Chemistry C,
117 (9), 4404-4409 (2013).

8. N. Tasić, Z. Branković, Z. Marinković-Stanojević, and G. Branković, Science of Sintering,
44 (3), 365-372 (2012).

Figure 1
Robust Fail-Safe Iteration Free Solvers for Battery Models
Authors: Pathak Manan , Sonawane Dayaram , Lawder Matthew T , Subramanian Venkat
Published: February 2020

Mathematical models of batteries1, 3, 4 are dynamic systems. which are typically solved by using a finite difference or other discretization technique in the spatial direction and solving the resulting system of nonlinear differential algebraic equations (DAEs) in time2.

The resulting DAEs are stiff, often times ill-conditioned and many standard solvers fail to solve them. The complications in solving the system of DAEs also include the inability of the solvers to find consistent initial conditions for the algebraic variables5,6.  Most stiff solvers include a Newton-Raphson type iterative methods to solve these stiff equations. (DASKR, RADAU, IDA7).

In this work, we propose a single-step iteration free approach to system initialization and simulation allowing for systems of DAEs to be solved using explicit ODE solvers without exact knowledge of the initial conditions for the algebraic variables. We will present this new solver which is guaranteed to not fail for any meaningful physical situations.

 Acknowledgements

The work presented herein was funded in part by the Advanced Research Projects Agency – Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000275.

References

Methekar, R. N., Ramadesigan, V., Pirkle, J. C. and Subramanian, V. R. A perturbation approach for consistent initialization of index-1 explicit differential-algebraic equations arising from battery model simulations. Computers & Chemical Engineering 2011; 35(11): 2227-2234.

Michelsen, M. L. Application of Semi-Implicit Runge-Kutta Methods for Integration of Ordinary and Partial-Differential Equations. Chem Eng J Bioch Eng 1977; 14(2): 107-112.

M. Doyle, T. F. Fuller and J. Newman, J. Electrochem. Soc., 140, 1526 (1993).

T. F. Fuller, M. Doyle and J. Newman, J. Electrochem. Soc., 141, 1 (1994).

Cash, J. R. Efficient numerical methods for the solution of stiff initial-value problems and differential algebraic equations. P Roy Soc a-Math Phy 2003; 459(2032): 797-815.

E. Hairer, G. Wanner, Solving Ordinary Differential Equations II: Stiff and Differential–algebraic Problems, second ed., Springer-Verlag, 1996.

IDA,[http://computation.llnl.gov/casc/sundials/main.html]
Modeling Degradation Mechanisms in Magnesium Batteries with Electronic Structure Calculations
Authors: Lowe Jeffrey S , Siegel Donald J
Published: February 2020

With ever-increasing global energy demands, emphasis on the development of renewable sources of energy continues to increase. Of particular interest are energy storage technologies that include multi-valent systems based on magnesium, rather than monovalent lithium. These systems promise energy densities which could surpass state-of-the art Li-ion batteries. One potential drawback of this technology, however, is the degradation of the electrolyte due to reactions with battery electrodes. To investigate this issue, electronic structure calculations are employed to map-out degradation mechanisms for a range of common electrolytic solutions with a magnesium anode. Classical Monte Carlo techniques coupled with density functional theory were used to identify and classify the most likely sites for adsorption of electrolyte components on low-energy magnesium surfaces. Further, energy landscapes for the various degradation mechanisms were determined. From these results, we postulate the most likely degradation pathways, identify the factors that control electrolyte stability, and ultimately pinpoint promising electrolyte compositions.
(Invited) Computational Insight and Design of Cathode Materials and Electrolytes for Li-O2 Batteries
Authors: Curtiss Larry , Lau Kah Chun , Assary Rajeev , Welland Michael , Liang Linyun , Redfern Paul , Wolf Dieter
Published: February 2020

Rechargeable aprotic lithium-oxygen (Li-O2) batteries are the subject of much current research because their potential high energy density; however, many challenges remain for Li-O2 batteries.  Computational studies of cathode and electrolyte materials for Li-O2 batteries can provide key insight into their materials properties as well as aid in the design of new improved materials.  In this paper we report on density functional calculations and mesoscale level simulations being carried out to try to understand the properties of cathode materials and how they control the growth and nucleation mechanism, which result in different morphologies and affects the charge overpotentials. Design of new cathode materials based on the structure-function relationships found in these studies is discussed. In addition, we also report on electrolyte decomposition mechanisms that can occur in Li-O2 batteries due to surface reactions and solution phase reactions. The use of high throughput computational screening techniques for discovery of new electrolytes for Li-O2 batteries will be discussed. In this approach we effectively down-select large pools of candidates based on successive property evaluation.
(Invited) Density Functional Theory Modeling of Coupled Mechanical/Electrochemical Interfacial Processes during Li-Insertion into Silicon Anode
Authors: Leung Kevin , Soto Fernando , Balbuena Perla B
Published: February 2020

Silicon anodes, unlike graphite widely used in commercial batteries, experience large (up to 400%) volumetric expansion after Li insertion during charging.  This likely leads to unique SEI structures and formation mechanisms, especially at atomic lengthscales  not readily probed using existing experimental techniques.  We apply DFT modeling to model the incremental expansion of amorphous LixSi as the Li-content (“x”) increases; examine how such expansion stretches or even cracks the model passivating layers; and how such SEI evolution/degradation leads to additional electrolyte decomposition.  First we create a series of amorphous LixSi slabs by incrementally increasing the Li content.  The stoichiometry can range from LiSi to Li13Si4.  The slabs are coated by a thin passivating layer (e.g., LiFz, which should form rapidly in the presence of FEC additives).  During expansion, the surface films evolve, become stretched, or even crack. AIMD simulations of liquid ethylene carbonate (EC) films are then conducted on expanded LixSiy with stretched passivating LiFx layers.  The instantaneous, electronic voltage, responsible for SEI formation, is periodically computed to ensure the modeling conditions conform to the experimental voltage window.  The effect of spatial inhomogeneity, e.g., holes in the passivating layer, on inducing voltage ”hot-spots” that can accelerate electrolyte decomposition, are highlighted.  To some extent, the modeling work represents very fast Li insertion, on the time scale of SEI formation.  Despite this, studying the stretching and potential breaking of model SEI layers can provide valuable insight concernin potentially unique SEI behavior on Si anode surfaces.

This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, Subcontract No. 7060634 under the Batteries for Advanced Transportation Technologies (BATT) Program. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corpo ration, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Figure 1
(Invited) What's New with Metal-Oxygen Batteries? a Multi-Scale Perspective
Authors: Siegel Donald J
Published: February 2020

Metal-oxygen batteries continue to attract interest due to their high theoretical specific energies. However, several challenges must to be overcome before these batteries can be viable. For example, in the case of Li-O2 systems a combination of sluggish charge transport within the Li2O2 discharge product and electrolyte decomposition at the electrolyte/Li2O2 interface have been proposed as limiting factors. This presentation will describe multi-scale computational studies aimed at revealing the mechanisms responsible for these limitations. Based on these findings, opportunities for improving cell performance will be discussed.
Thermodynamics and Kinetics of the Multi-Electron ε-VOPO4 cathode Across Two Lithium Insertion
Authors: Lin Yuh-Chieh , Wen Bohua , Quackenbush Nicholas F. , Piper Louis F.J. , Whittingham M. Stanley , Ong Shyue Ping
Published: February 2020

LiVOPO4 is one of the few polyanion cathode materials that can reversibly insert/extract more than one lithium ion per transition metal and has a very high theoretical capacity of 318 mAh/g. Here, we present a detailed first principles and experimental investigation on ε-LixVOPO4 (0 ≤ x ≤ 2) to understand its structural evolution, thermodynamics and kinetics during lithium intercalation. We show that while no intermediate phases are predicted to be stable in the range of 0 ≤ x ≤ 1, first principles calculations predict two intermediate phases in the low voltage regime (1 ≤ x ≤ 2), in agreement with recent experiments.1 These intermediate phases are confirmed by V L-edge soft XAS and XRD data. The calculated voltage profile over 0 ≤ x ≤ 2 is also in excellent agreement with experiments. We predict decreasing phase stability with the incorporation of two Li into ε-VOPO4, suggesting that there are inherent challenges to achieving stable two-electron cycling without structural modification. We will also present a comprehensive analysis of the kinetics (ionic and electronic) of ε-LixVOPO4over the entire lithiation range. This work was supported as part of NECCES, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001294.

1. Z. Chen, Q. Chen, L. Chen, R. Zhang, H. Zhou, N. A. Chernova and M. S. Whittingham, J. Electrochem. Soc., 2013, 160, A1777
Electrodeposition from Liquid Metal Salts
Authors: Fransaer Jan
Published: February 2020

Ionic liquids are ideal for performing electrochemical reactions which cannot be carried out in aqueous solutions, due to their wide electrochemical window, intrinsic electrical conductivity and large liquidus range. One drawback is the limited solubility of simple inorganic metal salts, such as chlorides and sulfates. The lack of solubility leads to a correspondingly low limiting current density. This disadvantage can be circumvented by making the metal ion a part of the ionic liquid in a so-called Liquid Metal Salt. A general formula is e.g. [M(L)x][A], with M a metal ion, L a neutral ligand and A a counter anion.

By making the metal ion a structural part of the ionic liquid, the concentration of metal ions can be as high as 3 mol dm-3 without the need to add a salt as metal source. Hence, even at 25 A dm-2 which is a large current in unstirred solutions, no sign of the decomposition of the ligand L or anion A could be detected in the metal deposits. These high current densities are explained by the fact that the electrochemical experiments are performed in a pure ionic liquid that acts as both the supporting electrolyte and the electrochemically active species, which is therefore present in a high concentration. Additionally, these Liquid Metal
Salts do not have a cathodic decomposition potential since their cathodic limit is the metal reduction. The use of solution additives, such as thiourea or benzotriazole, was investigated by Raman spectroscopy for their influence on the deposit morphology.

 So far we have synthesized and tested Liquid Metal Salts based on copper, silver, lithium, zinc, cobalt, nickel and palladium. Investigated ligands are (o.a.) acetonitrile, alkylimidazoles, py-N-O and amines. These cations were combined with anions such as bistriflimide, triflate or nitrate.

These liquid metal salts show great promise in a wide variety of electrochemical applications.
(Invited) Self-Terminated Electrodeposition Reactions
Authors: Ahn Sang Hyun , Liu Yihua , Wang Rongyue , Gokcen Dincer , Hangarter Carlos M , Bertocci Ugo , Moffat Thomas
Published: February 2020

In a recent publication Pt deposition at negative potentials revealed an unanticipated self-terminating characteristic that enables controlled deposition of Pt monolayer films from a K2PtCl4-NaCl electrolyte. In the case of Pt, the deposition reaction is quenched at potentials just negative of proton reduction by alteration of the double layer structure and adsorption properties induced by a saturated surface coverage of underpotential deposited hydrogen, (Hupd). The surface may be reactivated for Pt deposition by stepping the potential to more positive values where Hupd is oxidized and fresh sites for adsorption of PtCl4
2- become available. Periodic pulsing of the potential enables sequential deposition of additional Pt layers to fabricate films of desired thickness relevant to a range of advanced technologies in manner that is tantamount to wet atomic layer deposition (ALD).  In the presence of iron group metal the Hupd induced suppression is lifted by underpotential deposition of the iron group metal as revealed in voltammetric studies of singular surfaces and thin film deposition studies of the binary Pt100-xNix and Pt100-xCox alloy. Bulk alloy formation is facilitated by ongoing Pt deposition that incorporates the iron group metals in accord with the excess enthalpy of alloy formation. This talk will present an update on the exploration of the generality of self-terminating deposition reaction to other chemical system such as Ir and other transition metals.
(Invited) Electroless Deposition of Ruthenium Using Sodium Borohydride Reducing Agent: A Mechanistic Study Using Electrochemical Quartz Crystal Microbalance
Authors: Joi Aniruddha , Zieliene Albina , Norkus Eugenijus , Tamasauskaite-Tamasiunaite Loreta , Dordi Yezdi
Published: February 2020

Further miniaturization of interconnects and devices to keep up with Moore’s law in the 21st century requires materials innovation.  Copper, as the interconnect metal has been the workhorse of the semiconductor industry for the past two decades. As wire dimensions shrink below 20 nm in future technology nodes, the ability of copper to meet the conductivity and reliability benchmarks is strained1.  One metal that becomes attractive at smaller dimensions (<10 nm) is ruthenium, due to its high conductivity and electromigration resistance2.  Traditional routes for metallization of ruthenium includes physical vapor (PVD), chemical vapor (CVD) and atomic layer deposition (ALD).  PVD suffers from its line-of-sight, non-conformal deposition process that is not suitable for narrow, high aspect ratio geometries.  CVD and ALD processes are slower and more expensive than PVD.  Here we present an electroless deposition process (ELD) for ruthenium that overcomes some of the obstacles associated with the aforementioned processes.  ELD is inherently selective which yields conformal coating in challenging geometries.  Furthermore, ELD has lower cost of ownership due to relatively inexpensive precursors and significantly higher deposition rate than ALD and CVD.  Here, sodium borohydride is used as the reducing agent for electroless deposition of Ru, and the effects of temperature, precursor and ligand concentrations on ruthenium growth rate are characterized.  A linear increase in deposition rate is observed with increasing temperature and ruthenium concentration.  A critical borohydride concentration is observed at ~2 g/L, where the maximum deposition rate is obtained. The mechanism of the ruthenium deposition process (reduction half-reaction) is further investigated via electrochemical quartz crystal microbalance (EQCM) analysis to probe the role of pH and complexation.  Ru deposition on Cu initiates at a potential of -1.05 V vs. Ag/AgCl reference electrode, and further analysis indicates that a high pH of the electrolyte is needed to suppress any side reaction(s) and to form kinetically active ruthenium-hydroxy complexed species.  Finally, some challenges to integration and different applications for an electroless deposited Ru are highlighted.    

Figure 1: (a) Linear potential scan of the background electrolyte and the electrolyte containing Ru precursor. Increase in current density is observed at potential <-1.05 V vs. Ag/AgCl.  Coupled quartz crystal microbalance analysis (b) confirms Ru deposition at potentials more cathodic than -1.05 V vs. Ag/AgCl.

References:

1.         International Technology Roadmap for Semiconductors, www.itrs.net

2.         K. Sankaran, S. Clima, M. Mees, C. Adelmann, Z. Tokei and G. Pourtois. Proceedings of the IEEE International Interconnect Technology Conference, 193 (2014)

Figure 1
Modification of Electrodeposited Co-Pd Alloy Catalysts By Superimposed High Magnetic Field
Authors: Zabinski Piotr , Mech Krzysztof , Banbur-Pawlowska Sylwia , Kowalik Remigiusz
Published: February 2020

Palladium and its alloys have been a subject of interest in many research centers all over the world. Due to the price and accessibility of Pd, intensive tests are conducted aiming to invent alloys with catalytic properties similar to those of platinum, but much cheaper than palladium itself. Alloys of Co-Pd, Pd-Fe, Pd-Ni and Pd-Cr exhibit high catalytic activity for the four electron oxygen reduction reaction.

The properties of Co-Pd alloys for the hydrogen evolution reaction are close to the properties of pure platinum. This makes it possible to use them, for example, in fuel cells. Tests performed so far have demonstrated that the Pd-Co alloys are characterized by much better electrocatalytic properties for HER than pure palladium. Application of an external magnetic field during the deposition of an alloy causes an additional convection at the electrode surface through the magnetohydrodynamic effect (MHD), paramagnetic force and magnetic field gradient force. This additional convection results in changes of the alloy composition, structure and morphology, and these, in turn, affect the further properties as magnetic as catalytical of the produced alloys.

Magnetic field applied parallel to the surface of the electrode generates convection (magnetohydrodynamic effect MHD) of the electrolyte; it results in a laminar flow on the surface of the electrode which reduces the diffusion layer and increases the concentrations gradients. This results in change of the size of the grains and thus can also influence the texture and formation of various phases of the deposits. These various effects can be caused at the same time by the above mentioned convection but also by the magnetic properties, when the field is superimposed the growth in the direction of easier magnetization appears.

Optimal conditions of electrolytic deposition of cobalt matrix nanoalloys will be sought through selection of proper composition of electrolyte, changes of electrolysis parameters and by application of external electromagnetic field with intensity up to 12 Tesla.

Initial experiments, when the magnetic field was limited up to 1 T, show the improvement of catalytical properties together with increase of magnetic field orientated parallel to the surface of electrode. The influence of magnetic field with higher strength on electrodeposition of alloys with catalytical properties is needed to be clarified.

Acknowledgement

This work was supported by Polish National Science Center under grants 011/01/N/ST5/05509 and 2013/09/B/ST8/00211. This work was also supported by Polish Ministry of Science and Higher Education under grant IP2012/001072.
Intensity Modulated Photocurrent Spectroscopy (IMPS) Used to Detect Photoactive Intermediates during Ni-W Electrodeposition
Authors: Sun Shaopeng , Podlaha Elizabeth J
Published: February 2020

Intensity modulated photocurrent spectroscopy (IMPS) is a technique conventionally used to characterize the semiconductor/electrolyte interface.  It is used here in a new way, to track the presence of adsorbed, photoactive intermediates during the electrodeposition process, using Ni-W alloy electrodeposition as an example. Interest in Ni-W alloys are related to their high corrosion resistance, ability to catalyze the hydrogen evolution reaction from water, and superior wear resistance. The Ni-W deposition behavior from aqueous solutions is described as a coupled reaction mechanism and better understanding of the mechanism can help to control the deposit composition, which in turn is related to the resulting properties. To this end, IMPS was used to examine codeposition using an ammonia free citrate-boric acid electrolyte. The IMPS spectra was generated for different applied potentials. A significant current response to the incident modulated UV light was detected where steady state Ni-W codeposition takes place. The results confirm the presence of photoactive intermediates during codeposition, and demonstrates the first use of this technique in the electrodeposition process of a metallic alloy.  

The attached figure shows a typical response during cathodic deposition of a Ni-W alloy at -1 V vs AglAgCl  (42 wt % W) during IMPS compared to a potential where open circuit conditions are achieved and when clearly the alloy is treated anodically. A three electrode, single compartment cell with a flat quartz window was used with the following electrolyte: 0.375 M sodium citrate, 1.0 M boric acid, 0.075 M sodium tungstate, and 0.1 M nickel sulfate at a pH of 7. The response during deposition is significantly larger than that which occurs when a surface oxide is purposely generated; helping to valid that the deposition intermediate contributes to the observed impedance results. A simple model that includes the generated photocurrent contributing to an electrochemical reaction at the electrode/electrolyte interface or being lost to recombination was used to interpret the IMPS results. The dominate process occurring during IMPS is electron-hole pair recombination and thus, the modulated light does not significantly change the deposit composition, which was experimentally confirmed.  

Acknowledgments

This material is based upon work supported by the U.S. National Science Foundation under Grant No.0957448.

Figure 1
Nanostructured Zinc Electrodeposited from Protic Ionic Liquids: Comparison with Zinc Aqueous Electrodeposition Processes
Authors: Ortega R. , Brisard Gessie , Rivas Esquivel Flor
Published: February 2020

Zinc electrodepositon is one of the more important electrochemical process for surface treatment because of its application in anticorrosion protection and also as electrode material in zinc batteries. The main limitation of the electrodepositon of zinc from acidic or basic solutions in aqueous media, in addition to the very negative potential needed to carry out the electrodeposition,  is  associated to the simultaneous hydrogen evolucion reaction (HER) limiting the farad¡c efficiency of the electrochemical process. The HER has also a direct effect on the nucleation and on the electrocrystallization of zinc with some negative effects on the physical and structural proporties of zinc electrodeposits obtained from these solution (e.g. (poor adhesion, inhomogeneous deposits, etc).

In this work the electrodeposition processes of zinc from protic ionic liquids is studied and compared with results of electrodeposition from aqueous solution  in order to determine the avantages of electrodeposition from ionic liquids. 

Results show that in protic carboxylated ionic liquids, as ethanolammonium propionate, homogeneous electrodeposits of pure metallic zinc are obtained, with a narrow distribution of grain size in the range of 50-70nm, contrariously to electrodeposits obtained from aqueos solutions with grain sizes from 20 to 100nm. 

In addition, differences in the nucleation-electrocrystallization mechanism and on the electrodeposition rate are observed and they are dependent on the nature of the nature of the solvent.

Results allow to conclude that zinc electrodeposits continous, homogeneous and with a well controlled grain sizes can be obtained from  protic ionic liquids. These results allow to envisage that these deposits can be more effective for anticorrosion protection since this property is dependent on the homogeneity and contoinuity of an electrodeposit.

ACKNOWLEDGEMENTS. The financial support provided by CONACYT (México), project Fondo Sectorial SEP-CONACYT CB 2011 168032 and The Engineering Research Council of Canada (NSERC) are gratefully acknowledged.
Metal Oxide Conductivity and Nanomechanical Properties of ZnO/Mo/ZnO Multilayer Thin Films Deposited By RF Magnetron Sputtering
Authors: Wang Shi-Hao , Hsiao Yu-Jen , Fang Te-Hua
Published: February 2020

The structural, optical, electrical, and nanomechanical properties of zinc oxide (ZnO/Mo/ZnO) trilayer films was investigated using X-ray diffraction, atomic force microscopy, ultraviolet-visible spectroscopy, sheet resistance measurements, and nanoindentation techniques. It was found that the transparency, sheet resistance, and nanoindentation of the trilayer films depend on the Mo layer thickness and the annealing temperature. Sheet resistance of the ZnO/Mo/ZnO multilayer films decreased with the increase of Mo thickness and the increase of the annealing temperature.

Figure 1
Study of Aminosilane-Compound Modification Condition on Polished Silicon Wafer and Its Influence on the Adhesion of Electroless Nickel/Phosphorous Film
Authors: Wang Wei-Yan , Hsu Chin Wei , Wei Tzu Chien , Chen Chih-Ming , Lai Kuei-Chang
Published: February 2020

Electroless deposition (ELD) of nickel/phosphorous (Ni/P) layer has been a special interest in modern technique, especially in the production of diffusion barriers in the silicon industry [1]. The crucial part of ELD is a catalytic reaction that needs a trace amount of palladium [2] as the activator to lower the activation energy of metal formation. Due to the adhesion of ELD Ni/P film is associated with the interfacial property of catalyst and silicon surface. In order to increase the bridging between the silicon substrate and palladium catalyst, modifying silicon surface with organo-silane compound such as 3-[2-(2-aminoethylamino)ethylamino] propyl-trimethoxysilane (ETAS). The ETAS then form a self-assembled monolayer (SAM) to facilitate the adsorption of palladium catalyst [3]. However, it is known that the SAM formation is very sensitive to process condition such as soaking time, soaking temperature and solvent agents. In this study, the ETAS modification condition on silicon wafer is investigated. In particular, the ETAS-modified film was fabricated by a wet-soaking method and the effects of soaking time, soaking temperature and solvent agents onto silicon surface were discussed. As shown in Fig 1, the images of AFM with various soaking time of ETAS-modified silicon surface showed significant difference; this means that the long soaking time did influence SAM formation. Finally, the adhesion of ELD Ni/P on ETAS-modified silicon surface with different process parameters is discussed.

REFERENCES

[1] A. Brenner, G.E. Riddell, J. Res. Nat'l Bur. Std. 37 (1946) 31.

[2] L. Li, B. Liu, Mater. Chem. Phys. 128 (2011) 303.

[3] T. C. Wei, T. P. Pan, C. M. Chen, K. C. Lai, C. H. Wu, Electrochem. Commun. 54 (2015) 6

Figure 1