bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrode Stimulation
Authors: Scherson Daniel , Han Qi 
Published: May 2020

According to Newman[1], the rates of heterogeneous redox reactions can be written in terms of the surface overpotential, η
s
, i = io{exp(aanFηs/RT)- exp(-acnFηs/RT)}, where η
s
is defined as “the potential of the working electrode, relative to a reference electrode of the same kind placed in the solution adjacent to the surface of the working electrode.” On this basis, η
s
can significantly alter the current flowing across the electrode-electrolyte interface. Due to its intrinsic resistive character, the flow of electricity through the electrolyte will elicit changes in the electrostatic potential within that phase, which can be conveniently measured using reference electrodes, as has been implemented in this[2-4] and other laboratories[5]. To be described in this presentation is a novel means of inducing local changes in η
s
by passing current between a
stimulating
electrode, SE, and a distant counter electrode in the same solution. The overall tactic was demonstrated using a redox active self-assembled monolayer of N-ethyl-N’-octadecyl-4,4’-bipyridinium dibromide (EOB) adsorbed on a Au(poly) disk electrode as the WE and a Au(poly) disk of larger diameter placed parallel to the WE with its normal axis aligned along the corresponding axis of the WE, as the SE. The potential of the WE, EWE, was set at EWE= -0.35 V, i.e. the layer was polarized in its fully oxidized state (See the cyclic voltammogram in the Insert, Fig 1), while the SE placed at a distance d = 0.5 mm from the WE was scanned from 0.65 V up to 0.8 V, and back at ν = 1 V/s, yielding a iSE vs time curve shown in red dots in Fig. 1. The response of the WE is shown in blue in Fig. 1. As clearly indicated, iSE > 0 elicits a corresponding iWE < 0 due to the change in the electrostatic potential in the vicinity of the WE. Once iSE is reversed, the previously reduced fraction of EOB is oxidized returning the redox layer to its original fully oxidized state. This explanation is also consistent with the increase in iWE induced by a decrease in d (See black, green and magenta curves in Fig. 1). Implementation of this tactic will enable application of a local potential in a region next to a working electrode and thus promote electrochemical processes in that region without the need of a mask.

Acknowledgements

This work was supported by NSF, CHE-1808592.

References

[1] J. Newman, K.E. Thomas-Alyea. Electrochemical Systems, 3rd Edition, Wiley-Interscience, 2004.
[2] Y. Chen, A. Belianinov, D.A. Scherson. J. Phys. Chem. C, 112 (2008), 8754-8758.
[3] C. A. Cartier, D. Kumsa, Z. Feng, H. Zhu, D. A. Scherson, Anal. Chem., 84 (2012), 7080-7084.
[4] Z. Feng, N. S. Georgescu, D. A. Scherson, Russian Journal of Electrochemistry, 53 (2017),1003-1010.
[5] I. Plettenberg, G. Wittstock, Energy Technology, 4 (2016), 1-8.

Figure 1
Direct Conversion of Low-Grade Heat to Electricity Based on Transition Metal Coordination Complexes
Authors: Yin Yichun , Li Kangkang , Jones Timothy , Feron Paul 
Published: May 2020

Thermo-electrochemical cells (or thermocells), which could convert thermal energy to electrical power, are promising for waste heat utilization. Steady and continuous electricity can be generated through thermocells as long as there is a temperature gradient. The commercialization of thermocells is presently limited by low power output, energy conversion efficiency and high capital investment.
Liquid-based thermo-electrochemical cells have great potential for large-scale industrialization. Transition metal (Fe, Ni, Co, Ru, Cr etc.) redox pairs, as well as their coordination complexes, have shown excellent thermo-electrochemical properties. The corresponding electromotive force is linked to the entropy changes of the redox reactions. Further, the thermodynamic and kinetics of the redox reactions are significantly influenced by the type of coordinating ligands, solvents and electrodes materials. Therefore, the design of an efficient thermo-electrochemical cell with outstanding thermal-to-electrical power output requires careful design and consideration of all components within the cell.
In this study, transition metal coordination redox couples have been investigated for thermo-electrochemical energy conversion. Iron and cobalt are screened out for their spin states and low cost. By tuning the chelating ligands of transition metals in various solvents, increased Seebeck coefficient and fast ion diffusion were obtained, resulting in significant improvement of the performances in cell voltage and power density.

Figure 1
Alloy Plating for Improved Molten Salt Reactor Performance
Authors: Hall Timothy D. , Radhakrishnan Rajeswaran , Ahmadi Kamyar , Raiman Stephen S 
Published: May 2020

The use of molten fluoride salts as a primary coolant within next generation nuclear reactors has the potential to improve efficiency and nuclear reactor safety by operating at low pressures and high temperatures without boiling. However, these coolants will require the development of new corrosion resistant material systems that will have to meet or supersede existing standard codes for these systems. Therefore, state of the art reactors require validation and testing of new material systems that can produce robust component structures and enable them to withstand these corrosive environments. Furthermore, any next generation process to apply protective coatings must allow for a conformal, thick, dense, and bonded materials to be formed onto any low cost ASME material (like 316H SS) that comprises the structure of heat exchanger and containment vessel components.
Within this context, Faraday Technology Inc. is working on developing low cost and high value corrosion-resistant alloy coatings for next generation molten salt reactors with the goal of increasing their functional lifetime, while reducing the component cost. The manufacturing process involves electrodeposition of functionally graded NiMo alloys onto ASME certified substrates and subsequent high temperature corrosion evaluation in molten fluoride salt electrolytes. A wide array of electrolytes and processing parameters were evaluated in order to understand these effects on the deposit composition, structure, and corrosion resistance properties towards the goal of developing an ideal alloy coating. Specifically, we demonstrated the potential to apply graded NiMo coating to the 316H SS surface (Figure 1) and found that a coating composition of ~25% Mo has the potential to improve the components lifetime.

Figure 1: Top) show a cross-sectional image of a NiMo coated 316HSS component. Bottom) shows composition of Ni (Left/Dashed) and Mo (Right/Solid) as measured by EDX trace from the SEM along the red line (Top image).

Acknowledgements: The financial support of DOE Contract No. DE-SC0019602 is acknowledged.

Figure 1
Electrochemical Deposition of Sn-Cu Alloys for Applications in 3D Stacking in Microelectronics Industry
Authors: Inoue Fumihiro , El-Mekki Zaid , Struyf Herbert , Hou Lin , Derakhshandeh Jaber , Beyne Eric , Radisic Aleksandar , Hsia Chih-Hao , Chang Iris , Kuttner Elisabeth , Flügel Alexander , Arnold Marco 
Published: May 2020

The use of eutectic Sn-Cu alloys in packaging applications in microelectronics industry is not something entirely new. However, this alloy was mostly used in large features and fabricated using metal powders and metallurgical deposition techniques. The diameter of an individual grain of the eutectic Sn-Cu powder is typically similar in size to the diameter of pillars or bumps currently used in 3D stacking, and if we were to check its usefulness as a solder on this scale, an alternative manufacturing technique had to be used.
We have electrochemically deposited Sn-Cu alloys having up to 10 wt.% Cu and explored its possible benefits when used as a solder in combination with different Under bump metallization (UBM) materials. Sn-Cu alloys were deposited on blanket and patterned coupons, and promising experiments then transferred to a wafer-scale, i.e. Sn-Cu alloys were deposited on 300 mm wafers in an industrial-type plating tool. A typical sample/wafer had a Cu seed with a diffusion barrier (e.g. TiW) underneath and patterned features defined with a photoresist mask. Characteristic dimensions of the patterned features were on the order of mm and cm (lines), (diameter, d)50µm × (height, H)60µm (pillars), and (d)8µm × (H)15µm (bumps). Cu, Ni, or Co were used as UBM layers.
Chemical composition of deposited alloys has been examined by using X-ray fluorescence (XRF), Micro X-ray fluorescence (Micro-XRF), Inductively coupled plasma mass spectrometry (ICP-MS), and Electron probe microanalysis (EPMA). Surface morphology and the shape of deposited features have been examined using Scanning electron microscopy (SEM) and Laser scanning microscopy (LSM), while thermodynamic properties have been studied using Differential scanning calorimetry (DSC). Within-wafer (WIW) and within-die (WID) height uniformity of the pillars has been analyzed using Falcon 630 Plus tool (Camtek Ltd), capable of capturing heights of all the structures on the wafer simultaneously. The kinetics of Intermetallic compound (IMC) formation have been studied in the number of selected samples by combining ex-situ Focused ion beam (FIB) and in-situ measurements of resistance change of the features during anneal/thermal ageing [1].
We will discuss possible benefits and drawbacks for use of electrochemically deposited Sn-Cu alloy solders in combination with different UBM layers based on these results.
References:
[1] Lin Hou, Jaber Derakhshandeh, Eric Beyne, and Ingrid De Wolf, “A Novel Resistance Measurement Methodology for in-situ UBM/Solder Interfacial Reaction Monitoring”, DOI 10.1109/TCPMT.2019.2950448, IEEE Transactions on Components, Packaging and Manufacturing Technology.

Figure 1
Electrodeposited TiB2 Coating on Graphite As Wettable Cathode for Al Production
Authors: Yvenou Etienne , Guay Daniel , Roué Lionel 
Published: May 2020

Greenhouse gas (GHG) emission from the Canadian aluminum industry was about 6 Mt of CO2 eq in 2017, an amount equivalent to the GHG emitted by about 1.3 million cars [1-2]. The use of inert anodes, like Ni-Fe-Cu alloys [3], instead of carbon anodes to produce O2 rather than CO2 during aluminum electrolysis is paramount to curb GHG emissions from that industry. However, to maintain the energy efficiency of the process, the opposite cathode material must be wetted by molten aluminum to decrease the anode-to-cathode distance and thus reduce the overall cell voltage. TiB2 presents a good wettability by molten Al. Also, it has good electrical conductivity and good chemical stability under Al electrolysis. Accordingly, TiB2 is considered as an interesting cathode material to use in conjunction with inert anodes. However, its production as dense bulk cathode is challenging.
In this work, the electrodeposition of TiB2 on graphite substrate was performed by periodically interrupted current method in a molten LiF-NaF-KF salt at 600°C containing K2TiF6 and KBF4 as titanium and boron precursors, respectively [4]. The impact of the electrodeposition parameters on the crystalline structure, morphology, adhesion strength, Al wettability and Al penetration resistance of the TiB2 deposits will be presented.
[1] 2017 sustainable development report. Aluminium Association of Canada.
[2] Greenhouse Gas Emissions from a Typical Passenger Vehicle. United States Environnemental Protection Agency, 2018
[3] S. Helle, M. Pedron, B. Assouli, B. Davis, D. Guay, L. Roué, Structure and high-temperature oxidation behaviour of Cu–Ni–Fe alloys prepared by high-energy ball milling for application as inert anodes in aluminium electrolysis. Corros. Sci. 52 (2010) 3348.
[4] G. Ett, E.J. Pessine, Electrochim. Acta. 44 (1999) 2859.

Figure 1: (A) SEM cross-section image of electrodeposited TiB2 coating on graphite substrate. Optical images of Al droplet at 1000 °C on (B) TiB2-coated and (C) pure graphite substrates.Fig

Figure 1
TiB2-Coated Graphite As Wettable Cathode for Al Production
Authors: Yvenou Etienne , Bily Alexandre , Dolatabadi Ali , Moreau Christian , Davis Boyd , Guay Daniel , Roué Lionel 
Published: May 2020

A significant reduction in greenhouse gas emissions from aluminum smelters will only be achieved with the emergence of new technologies. The most effective way to decrease significantly CO2 emissions from this industry is to replace the consumable carbon anodes that are used nowadays with so-called inert anodes that emit O2 instead of CO2 during Al electrolysis [1]. However, the implementation of inert anodes in Al smelters will induce an increase of the cell voltage, which could be compensated by reducing the cell ohmic drop by decreasing the anode-to-cathode distance. For that purpose, the thickness of the molten Al layer presents on the surface of the cathode must be minimized, which requires a high wettability of molten Al on the cathode. To date, the most promising cathode material is TiB2, which has an excellent Al wettability, good electrical conductivity and good chemical stability under Al electrolysis conditions. However, the manufacturing of bulk TiB2 electrodes at the industrial scale poses challenges. Sintering of TiB2 must be performed at high temperature (~2000°C), which induces significant crystal growth that has dramatic consequences on the mechanical properties of the electrode. Faced with these constraints, various consolidation methods operating at lower temperatures have been evaluated (sintering under pressure, spark plasma sintering...), but they are expensive and/or poorly adapted to the production of large electrodes of complex shape as required for Al electrolysis application.
In the present study, new avenues based on the elaboration of TiB2 coated graphite cathodes by electrochemical and thermal spray methods are evaluated. The influence of the deposition conditions on the crystalline structure, morphology, mechanical resistance and Al wettability of TiB2 coatings will be presented in this communication.
Investigation of the Effect of Bath Ageing on Electropolishing Efficiency
Authors: Krishna Bivi , Manoharan Gobinath Vellapalayam , Wüthrich Rolf 
Published: May 2020

The bath age poses a serious challenge during prolonged electropolishing processes. It is a general practice in electropolishing industry to reuse the bath to cut down the cost and to minimize the harmful effects on the environment. It is well known in the electropolishing industry that the final polishing quality declines over time due to the increased dissolved metal ions. The present study aims to quantify this effect.
Various sets of experiments were conducted to investigate the effect of bath aging during prolonged electropolishing on polishing quality. The experiments were performed in a bath with an initial composition of 50% phosphoric acid (H3PO4), 35% sulfuric acid (H2SO4) and remaining water. The variations in the properties of the bath (conductivity, viscosity and specific gravity) were measured over prolonged polishing (Electropolishing tests were conducted up to passing 72000 C/ L of the bath). Variation of quality (in term of surface roughness and gloss) of standard workpieces polished under identical conditions (constant voltage, inter-electrode distance and time) were determined at various bath ages. Further bath composition (in term of the relative amount of acids) was determined periodically by titration.
It was observed that as the bath properties change throughout the electropolishing experiments with bath aging, significant variation was seen in roughness and gloss of the polished workpiece. The roughness result for the workpiece polished in the most-aged bath was ~12 times higher than the workpiece polished in the fresh bath. Also, the first few polished workpieces had a shiny, mirror finish whereas the workpieces polished for the prolonged bath usage had a dull, matte finish.
Bath composition varied from the initial composition of 50:35:15 (phosphoric acid: sulfuric acid: water) to 31:22:47 as the bath aged. Recovering initial bath composition (by adding an adequate amount of acids to the aged bath) allowed to recover the similar quality of polished samples (very similar surface roughness but less bright surface finish). Correlation between measured bath properties and composition with polishing achieved under standard conditions can be considered for further studies to develop strategies to make polishing parameters adaptable to given bath states.
New Method for Characterization of the Open Circuit Potential Curve for Battery Cathode Materials
Authors: Usubelli Camille , Kimura Kevin Wayne , Klein Reinhardt , Christensen Jake , Gorlin Yelena 
Published: May 2020

Battery management system (BMS) is a key component of the battery for electric vehicles and portable electronics, as it guaranties reliable and safe operation of the battery, while ensuring its longevity and optimal performance. State-of-the-art BMS relies on an equivalent circuit model, while an important research topic is the development of BMS, which is based on an electrochemical model.[1] The main task of BMS is to accurately estimate the available energy and power of the battery by tracking its current state of charge (SOC). The open circuit voltage (OCV) of a cell is often used for estimation of the SOC of a battery. It depends on the open circuit potential (OCP) of the anode and the cathode materials, which give the potential associated with a certain amount of lithium stored in each structure. The accuracy of the OCP curves of each electrode material is critical for use with BMS based on electrochemical models, as in addition to tracking the bulk SOC of a battery, it also tracks the surface SOC.[1] As a result, BMS based on electrochemical models can offer improved prediction for both instantaneous and pulse power relative to systems based on an equivalent circuit model.
In this contribution, we propose a novel method for characterization of the open circuit potential vs. state of lithiation (OCP) curves for active materials commonly used in lithium-ion batteries. Our method offers increased accuracy over existing electrochemical procedures [1-3]by providing a standardized mapping process from the measured gravimetric capacity to state of lithiation and improving characterization in the region of the curve that is close to the lithium content of 1. We demonstrate the strengths of the method on two different cathode materials: LiCoO2 and LiNi1/3Mn1/3Co1/3O2, which are widely used in commercial cells for portable electronics and electric vehicles. [2-3]
1. Chaturvedi, N. A., Klein, R., Christensen, J., Ahmed, J. & Kojic, A. Algorithms for Advanced battery-Management Systems. IEEE Control Syst. Mag. 49–68 (2010).
2. Daniel, C., Mohanty, D., Li, J. & Wood, D. L. Cathode materials review. AIP Conf. Proc.
1597, 26–43 (2014).
3. Cairns, E. J. & Albertus, P. Batteries for Electric and Hybrid-Electric Vehicles. Annu. Rev. Chem. Biomol. Eng.
1, 299–320 (2010).
Diffusion Control of Organic Cathode Materials in Lithium Metal Battery Using a Graphite Modified Separator
Authors: L. Belanger Rachel , Commarieu Basile , Paolella Andrea , Daigle Jean-Christophe , Claverie Jerome P. , Zaghib Karim 
Published: May 2020

Energy storage technology is a critical research area for the success of portable electronic devices and electrical transportation. Such applications need affordable, durable, safe and environmentally friendly battery materials with high energy density. Organic cathode materials are currently promising candidates because they fulfill most of these requirements for an active battery material1. However, they usually suffer from a major limitation, namely their solubility in organic electrolytes2. Even a very low solubility translates into a decreased capacity upon cycling due to the loss of active material. Among organic cathode materials, conjugated carbonyl compounds have been intensively scrutinized because of a combination of desirable properties, such as low cost, good theoretical capacity, reversible oxidative behavior, high discharge potential and commercial availability. For example, 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) is an inexpensive red pigment that is widely investigated as an active material for energy devices. However, Li-PTCDA batteries suffer from poor and irreversible cycling stability due to the dissolution in the electrolyte. Even more problematic, the dissolved PTCDA migrates through the porous separator and deposits on the anode surface causing irreversible damage3. In order to solve this problem, chemical modifications such as polymerisation, functionalization and immobilization on carbon materials have improved cycling stability. However, these modified cathode materials, which are often prepared by complex processes, contain considerable amounts of inactive mass that cause a decreases of the energy density. We developed a Janus membrane, which consists of two layers – a commercial polypropylene separator (CelgardTM) and a 300-600 nm layer of exfoliated graphite that was applied by a simple and environmentally friendly process. The submicron graphite layer is only permeable to Li+ and it drastically improves the battery performance, as measured by capacity retention and high coulombic efficiency, even at 2C rates. Post-mortem analysis of the battery indicates that the new membrane protects the anode against corrosion, and cathode dissolution is reduced. This graphite-based membrane is expected to greatly expedite the deployment of lithium batteries using organic moities as active materials.

References

[1] Armand, M. & Tarascon, J. M. Building better batteries. Nature
451, 652–657 (2008).
[2] Zhao, Q., Zhu, Z. & Chen, J. Molecular Engineering with Organic Carbonyl Electrode Materials for Advanced Stationary and Redox Flow Rechargeable Batteries. Adv. Mater.
29, 1–25 (2017).
[3] Wang, J., Wang, X., Li, H., Yang, X. & Zhang, Y. Intrinsic factors attenuate the performance of anhydride organic cathode materials of lithium battery. J. Electroanal. Chem.
773, 22–26 (2016).