bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding Electrolyte Remixing As a Capacity Fade Mitigation Technique for Vanadium Redox Flow Batteries
Authors: Casco Nicholas Houghton , Kourmanopoulos Nicholas , Dennison Christopher R , Kumbur E. Caglan , Agar Ertan
Published: February 2020

Capacity fade during long-term charge/discharge cycling is considered as one of the key issues that limits the long-term performance and lifetime of vanadium redox flow batteries (VRFBs) [1]. This issue is primarily caused by oxygen and hydrogen gas evolution as well as vanadium crossover and leads to a decrease in battery performance through its lifetime [2]. One potential solution to address the problem of vanadium crossover is remixing the electrolyte, i.e. transferring a portion of electrolyte from one tank to the other (Figure 1a), to balance the total vanadium concentration in both tanks [3]. Although this approach has been widely implemented in recent studies, the literature still lacks a descriptive theoretical framework to accurately assess the connection between electrolyte remixing and VRFB performance both in a specific cycle and during exhaustive cycling. If this relationship could be understood, then more effective strategies to reduce the negative impacts of crossover and related capacity fade could be developed.

In this talk, we will present a modeling study to establish a fundamental understanding of electrolyte remixing as a capacity fade mitigation strategy. The effects of remixing frequency (Figure 1b) and the amount of electrolyte remixed on the long-term performance of these systems will be reported. Additionally, the trade-off between improved capacity fade during long-term cycling and reduced single-cycle performance at which remixing applied will be discussed.

References

[1] Boettcher, P. A., Agar, E., Dennison, C. R., Kumbur, E. C. J. Electrochem. Soc.
2016, 163 (1), A5244-A5252.

[2] Knehr, K. W., Agar, E. Dennison, C. R., Kalidindi, A. R., Kumbur, E. C. J. Electrochem. Soc.
2012, 159 (9), A1446-A1459.

[3] Wang, K., Liu, L., Xi, J., Wu, Z., Qui, X. J. Power Sources, 2017, 338, 17-25.

Figure 1
Effects of Cell Geometry on Rate Performance of Secondary Batteries
Authors: Thorne John S , Greer Julia R
Published: February 2020

3D geometries for microbattery applications have been explored to increase capacity per footprint area, relevant for small footprint area micro devices [1] [2]. Simulations of interdigitated Li-ion batteries suggest 4 orders of magnitude increase in areal capacity at 330 C-rate from 0.58 Ah/m2in the conventional geometry to 318 Ah/m2 for the 3D geometry [3]. Realization of practical 3D battery designs can potentially decouple their power and energy [4], properties that are historically coupled in conventional battery design, which might have significant implications for high power devices.

Using commonly found commercially available materials and tools, we designed and conducted a simple experiment to elucidate how battery performance can be improved by varying the relative arrangements of the active and inactive components. Examples include using Li/LiCoO2 2032-type coin cells with 1M LiPF6 and carbonate containing electrolytes. The maximum active ion diffusion length required to fully delithiate the LiCoO2 electrodes during cycling was increased by 400-6500 μm compared with standard reference cells, and the effect on rate performance was measured between C/24 and C/3. Results suggest that extending the maximum active ion diffusion path length by >1600 μm still allows for attaining specific capacity that matches that of the reference cell at C/24. We discuss possible new geometries and optimized designs in the framework of battery performance.

[1] C. Liu, E.I. Gillette, X. Chen, A.J. Pearse, A.C. Kozen, M.A. Schroeder, K.E. Gregorczyk, S.B. Lee, G.W. Rubloff. Nature Nanotechnology 9 (2014) 1031-1039. [2] T.S. Arthur, D.J. Bates, N. Cirigliano, D.C. Johnson, P. Malati, J.M. Mosby, E. Perre, M.T. Rawls, A.L. Prieto, B.Dunn. MRS Bulletin 36 (2011) 523-531. [3] D. Miranda, C.M. Costa, A.M. Almeida, S. Lanceros-Méndez. Applied Energy 165 (2016) 318-328. [4] N. Cirigliano, G. Sun, D. Membreno, P. Malati, C.J. Kim, B. Dunn. Energy Technology 2 (2014) 362-369.
Investigation of Thermal Compatibility of Various Cathode Materials with Li6.25Al0.25La3Zr2O12 Solid Electrolyte for All-Solid-State Rechargeable Lithium Batteries
Authors: Munakata Hirokazu , Wakasugi Jungo , Kanamura Kiyoshi
Published: February 2020

Aluminum-doped lithium lanthanum zirconate (Li6.25Al0.25La3Zr2O12, Al-LLZ) has a relatively high Li+-ion conductivity of ~10-4 S cm-1 at room temperature and a wide electrochemical window enabling to use both lithium-metal anode and high potential cathodes, so that it has been focused as a promising solid electrolyte for all-solid-state rechargeable lithium batteries with high energy density. Several kinds of fabrication methods, which usually include heat treatment processes, have been utilized to fabricate cathode on Al-LLZ. However, the effect of heat treatments on the formation of impurities at the interface between Al-LLZ and cathode has not been fully understood yet. In this study, we investigated the thermal compatibility of conventional cathode materials (LiCoO2, LiMn2O4 and LiFePO4) with Al-LLZ by X-ray diffraction (XRD) and charge-discharge tests. The XRD analysis showed that LiCoO2/Al-LLZ mixture is stable up to 800°C, but impurities are formed in LiMn2O4/Al-LLZ mixture and LiFePO4/Al-LLZ mixture at 600 °C and 400 °C, respectively. This result indicates that the limit of heat treatment temperature for the formation of electrode/Al-LLZ interface strongly depends on the kind of electrode materials.
Impact of Electrolyte Transference Number on Lithium Dendrite Growth Process
Authors: Barai Pallab , Higa Kenneth , Srinivasan Venkat
Published: February 2020

Growth of dendritic protrusions leading to short circuits of cells is presently the largest barrier to widespread usage of lithium metal anodes in commercial lithium ion batteries. Dendrite growth becomes more severe at high current density and low temperature operations because of the onset of diffusion limitations. Improving the elastic-plastic mechanical properties of the electrolyte material can significantly suppress the propagation of dendritic protrusions[1]. However, it has also been argued that enhanced electrolyte transport properties can decrease the propensity for dendrite growth. For example, increased diffusivity of the electrolyte at higher temperature leads to stable deposition of lithium[2], as does increasing the cation transference number of the electrolyte[3].

The propensity for growth of dendritic protrusions can be estimated by solving the mechanical equilibrium, mass transport and charge transport equations, coupled with the nonlinear Butler-Volmer relation. Based on this computational approach, a map correlating growth during operation at 75% of the limiting current density to the electrolyte shear modulus and transference number (see Figure 1) has been developed, showing regimes in which prevention of dendritic protrusion is possible. The results are consistent with experimental observations[4] of dendrite growth in liquid and polymer (PEO) based electrolytes (demarcated by the red regions). This phase-map is expected to help in designing new electrolyte materials that promote dendrite-free lithium deposition.

References

1. Monroe, C. and J. Newman, The impact of elastic deformation on deposition kinetics at lithium/polymer interfaces. Journal of the Electrochemical Society, 2005. 152(2): p. A396-A404.

2. Love, C.T., O.A. Baturina, and K.E. Swider-Lyons, Observation of Lithium Dendrites at Ambient Temperature and Below. Ecs Electrochemistry Letters, 2015. 4(2): p. A24-A27.

3. Tikekar, M.D., L.A. Archer, and D.L. Koch, Stability Analysis of Electrodeposition across a Structured Electrolyte with Immobilized Anions. Journal of the Electrochemical Society, 2014. 161(6): p. A847-A855.

4. Brissot, C., et al., Dendritic growth mechanisms in lithium/polymer cells. Journal of Power Sources, 1999. 81: p. 925-929.

Figure 1
(Invited) High Strength and Corrosion Resistant Light Alloys Via High-Energy Ball Milling
Authors: Gupta Rajeev Kumar , Esquivel Javier
Published: February 2020

The corrosion of metallic materials in a given environment depends on the microstructure stemmed from the concurrent influence of the composition, production route, thermomechanical processing, and service conditions. Microstructures and therefore the properties of the alloys produced via high-energy ball milling are known to be significantly different than that produced via conventional techniques even for the same alloy composition. Grain refinement, extended solid solubilities, formation of metastable phases, unique grain boundaries, super saturation of vacancies, high stored energy, increased diffusivities are some of the principle characteristics of the microstructure produced by the high-energy ball milling process.

It has been shown recently that development of corrosion resistant light alloys (Al alloys and Mg alloys) is possible by high-energy ball milling in combination with the suitable alloying elements. Al- transition metal alloys have been produced by the high-energy ball milling and subsequent consolidation. X-ray diffraction analysis and scanning electron microscopy indicated significantly higher solid solubility of the transition metals in Al and nanoscale grain refinement. The cyclic potentiodynamic polarization tests revealed significant ennoblement of pitting and repassivation potentials of the high-energy ball milled Al -transition metal alloys. The Grain refinement < 100 nm and high solid solubility also increased mechanical strength- compressive yield strength exceeding 1 GPa. High-energy ball milling has been found capable of improving corrosion resistance and strength simultaneously. Mechanisms of the improved corrosion and mechanical properties of the high-energy ball milled alloys will be discussed.
Reaction Mechanism and Kinetics of Boron Removal from Metallurgical-Grade Silicon Based on Li2o-SiO2 slags
Authors: Luo Xuetao , Lai Huixian
Published: February 2020

Slag refining is generally considered as one of the most optimal options for boron removal from metallurgical-grade silicon. Therefore, finding an effective refining agent to eliminate boron from metallurgical-grade silicon is of great importance. In this work, a new Li2O-SiO2 slag system was chosen as a promising agent to remove boron impurity from metallurgical-grade silicon at the conditions of holding time, slag composition and mass ratio of slag to silicon. To lower the production cost and achieve industrial application, slag treatments were carried out under an air atmosphere rather than under protective gas atmosphere. The boron concentration in metallurgical-grade silicon was successfully reduced from 8.6 ppmw to 0.4 ppmw after slag refining for 0.5 h at 1973 K when the mass ratio of the 60wt.% Li2O-40wt.% SiO2 slag to metallurgical-grade silicon was 3. This figure is significantly close to the required boron purity of SOG-Si (below 0.3 ppmw). It was proposed that the addition of CaF2 decreased the activity of silica, which brings about a negative effect on the boron removal capacity of Li2O-SiO2 slags. Moreover, the reaction mechanism and kinetics of boron removal were further investigated. Analysis of the boron concentration in the resulting slag after refining revealed that the primary boron removal approach was that a large amount of boron was oxidized and then volatilized to the atmosphere in the form of gaseous borates. Based on the two-film theory, the total mass transfer coefficient of boron was determined to be 2.3×10-2 μm s-1.
(Invited) In-Situ X-Ray Spectro-Microscopy of Nanoscale Materials Systems
Authors: Goode Angela E , Koronfel Mohamed , Gomez Gonzalez Miguel A , Quinn Paul , Weker Johanna Nelson , Porter Alexandra E , Toney Michael F , Ryan Mary P
Published: February 2020

The degradation behaviour of nanoscale materials is a key determinant of their potential human and environmental toxicity, and can be chemical or electrochemical in nature. In addition, the environmental transformation of materials released from consumer products determines their end-point eco-toxicity. These processes are a challenge to study as they require high resolution– but statistically meaningful analysis. More generally the stability of nanomaterials is of importance for device lifetime. We are developing tools to study such reactions for a range of relevant materials (e.g. ZnO, Ag, CoCr, CeO2, CNTs).

The development of nanoprobe X-ray systems at synchrotron sources is providing new insights into the behaviour of materials-environment interactions at nanoscale resolution. In this paper we will discuss our recent work on in-situ observation of deposition, localized dissolution and environmental transformation of nanoscale systems: providing both spatial and spectral information. In situ observation of local super-saturation, dealloying and nanoparticle chemical transformation all demonstrate the capabilities and opportunities for this technique. In addition, we will discuss the correlative use of ex-situ electron microscopy and assembly-averaged in-situ studies to develop holistic understanding of these systems.
(Invited) In Situ Analytical Methods for Atmospheric Corrosion: Recent Advances and Challenges
Authors: Schindelholz Eric John
Published: February 2020

A foundational challenge inhibiting fundamental study of atmospheric corrosion is the limited ability to directly probe physicochemical processes occurring within electrolytes on surfaces at the micro- and sub-microscale. This talk will overview current and emerging in situ methods for electrochemical and chemical characterization of atmospherically corroding surfaces. Multi-electrode array sensing, microelectrode techniques, optical spectroscopy and other methods will be addressed along with current limitations and future prospects. Some recent advances in these areas will be exemplified through discussion of current research aimed at understanding the thermodynamic and kinetic linkages between evolving electrolytes and electrochemical processes for sodium chloride deposits on copper and aluminum. The role of integrated computational approaches as a means of advancing in-situ methods and providing complimentary physicochemical information will be addressed.
1st Cut Spent Pot Liner-Modified Epoxy Coatings for C-Steel
Authors: Thekkethottiyil Elizabeth Jacob , Abdullah Aboubakr Moustafa
Published: February 2020

Aluminum extraction from alumina is conducted in huge electrolytic cells, arranged in ‘pot lines’. These pots have a carbonaceous lining to act as the cathode. After a few years of service, this lining is ‘spent’ and must be replaced. This waste material, called 1stcut Spent Pot Lining (SPL1), is collected in thousands of tons. SPL1 is considered a ‘hazardous’ material by the US Environmental Protection Agency and its European counterpart. Storage, transportation and treatment of SPL1 is a major problem for the aluminum industry. In the most common recycling procedure, SPL1 is treated either thermally or chemically by expensive processes to retrieve the carbon, which is then used as fuel. Alternative uses for this carbon-rich material in other applications are being explored.

Epoxy resin is a thermoset polymer coating material which has wide industry acceptance due to its toughness, adhesion, durability, thermal stability, high chemical resistance, low shrinkage and ease of fabrication. However, epoxy coatings suffer from brittleness, a poor resistance to crack propagation especially in presence of UV radiations. It is expected that addition of carbon-based conductive fillers can decrease the susceptibility of epoxy to aggressive UV radiation and thus increase its corrosion protection properties.

The objective of this work is to explore the use of SPL1 as an additive in fast-cure epoxy coatings on mild steel substrates and study the thermal and electrical properties of the resulting composite at various concentrations of functionalized and unfunctionalized SPL1. The weathering behavior of these coatings under UV radiation were also investigated. The results showed that the electrochemical corrosion behavior of the coating was significantly improved although some microcracks developed on the surface of the coatings after prolonged exposure to UV radiation.

Figure 1
Viability of Post-Transition Metal As Anode for Nano-Ionic Resistive Switching Based Devices
Authors: Sonde Sushant Sudam , Chakrabarti Bhaswar , Sasikumar Kiran , Stan Liliana , Sankaranarayanan Subramanian , Guha Supratik
Published: February 2020

The phenomenon of electric field mediated resistance switching in metal oxides is critical to nanoscale electronic devices ranging from conventional energy efficient MOSFETs to emerging memory devices as well as artificial neuron and synaptic devices. Such resistance transition can be facilitated by two main mechanisms: i) conduction of oxygen ions in non-stoichiometric compounds e .g. HfOx, AlOx. In this case the redox reaction of the oxide itself is manifested by oxygen anion transport, ii) the oxides serve as electrolyte dielectrics to conduct electrochemically active metal cations, such as Ag or Cu, forming the so-called electrochemical metallization memory (ECM) devices.

So far inert and electrochemically active transition metals such as Pt and Cu/Ag respectively have been implemented to demonstrate resistive switching in Metal-Insulator-Metal (MIM) devices for application in steep slope transistors and as non-volatile memory and selector device. However, post transition metal e. g. Sn with lower cohesive energy as well as lower negative heat of formation of metal oxide offers viable alternative to Cu and Ag in ECM type devices.

In this study, we fabricated asymmetric two terminal MIM structures in a cross-bar array with atomic layer deposited HfO2 thin film sandwiched between Pt and post-transition metal (Sn). We demonstrate reversible resistance switching in HfO2. Filamentary conduction by cations beyond a threshold voltage was verified by varying device areas. A recent report demonstrated coexistence of both oxygen anion and metal cation transport being responsible for resistance switching in a single oxide depending on the anode metal. We present a comparative investigation based on current-time (I-t) measurements to distinguish contributions from oxygen anions and metal cations in the resistance switching process.

Using Sn anode we demonstrate bidirectional threshold switching as well as bipolar memory switching. We further evaluate viability of Sn anode in terms of switching speed in comparison with Cu and Ag. Furthermore, we discuss considerations for bidirectional threshold switching and bipolar memory switching with Sn anode substantiated with our ongoing molecular dynamic simulations.
(Invited) Characterization of Advanced Devices: Identifying Performance & Degradation Drivers
Authors: Bersuker Gennadi , Pierce Donald G. , Mason Maribeth S.
Published: February 2020

The proliferation of complex multi-component gate stack/electrode structures and introduction of new dielectric and semiconductor materials may lead to new degradation mechanisms that complicate characterization and reliability evaluations of advanced CMOS devices. Aggressive scaling of device dimensions, which tends to increase device-to-device variability, further diminishes effectiveness of well-established test methods requiring ever increasing numbers of samples. Charge transfer across nanometer scale layers of different materials is strongly affected by the interface regions, where structure and composition are determined by inter-material interactions, which are influenced by fabrication conditions.

This trend points to a growing need for physics-based degradation models explicitly taking into consideration atomic-level material properties while being relevant to the application conditions and complementary to the widely used phenomenological approaches. The critical task is to link structural and electrical characteristics of multicomponent material stacks in order to identify and eventually control defects affecting charge transfer. Understanding of the degradation mechanism and its structural drivers enables the selection of adequate test conditions, which ensure degradation and lifetime assessments consistent with the use-conditions are obtained. We discuss limitations of the traditional methodology and provide examples of implementations of the microscopic evaluation approach.
Low Cost and Metal Free Counter Electrode for Dye Sensitzed Solar Cell
Authors: Kouhanavard Mojgan , V-Ghaffari Babak , Miyake Mikio
Published: February 2020

Dye-Sensitized Solar Cells (DSSCs) are currently the leading photovoltaic device among third generation solar cells due to their low production cost, ease of manufacturing and relatively high conversion efficiency. One of the most expensive component of the DSSC is the highly efficient Platinum Counter Electrode (Pt CE) but considerable cost reductions can be achieved by changing it to carbon-based CEs. Therefore, the objective of this research is to study a type of hydrophilic carbon (HC) particle for the first time as a novel CE in DSSCs. The easy synthesis, low cost and reasonable electrocatalytic property of the HC particle may help the DSSC in commercialization by making it more environmental friendly and a less expensive device. In this research, the HC past was prepared and deposited on FTO glass as a CE with different thickness ranging from 1 to 3μm. The effects of the thickness and morphology of a HC CE on the performance of a DSSC were then investigated. The increase in the HC film gradually increase the surface roughness of the electrodes. The HC CE with 2μm thickness showed the highest catalytic activity and the lowest charge transfer resistance among other electrodes. As a result, the highest energy conversion efficiency of approximately 3% was achieved by HC CE with 2 μm thickness compare to the Pt electrode prepared at the same experimental condition, which achieved 3.5%. Thus, HC CE has the potential to replace the rare and expensive Pt CE in DSSC.
Characterization of Transferred Graphene Based Solar Cell
Authors: Shin Junsung , Kwon Younghwi , Seo Yongho
Published: February 2020

Graphene is a two-dimensional material which is flexible and has a high conductivity. We grow a single layer graphene through chemical vapor deposition (CVD). Graphene which is grown by CVD has single layer and large specific surface area about 2620 m2/g, theoretically. Among the properties of graphene, high electrical conductivity and transparency are important advantages as an emerging material of solar cell. Using Schottky barrier at the interface between graphene and Si, solar cells have been developed. In order to enhance the solar cell efficiency, IV characteristics of the Schottky junction have been studied.

 We use CVD graphene grown on copper foil and silicon wafer (n-doped <100>, 1-10 Ohm·cm, 300 nm oxide, LG Siltron). First, (5x5 mm2) window pattern is exposed on silicon through photolithography. The oxygen layer of the patterned area is removed using BOE (7:1 water:HF) for 4 minutes. The photoresist is removed in acetone at least 10h. A square shape electrode with Ti (10 nm)/Au (90 nm) is deposited on silicon oxide. Ag (300 nm) is deposited on backside of silicon and annealed to have an Ohmic contact. After all these processes are finished, graphene was transferred. Doping on graphene is one way to increase the efficiency of Schottky junction solar cell. We compare none-doped graphene with chemically doped graphene by HNO3 and bis (trifluoromethanesulfonyl) amide. This could be an alternative for the cheap and environmentally friendly solar cell in the future.
Electrodeposition and Characterization of Thin Film of Black-Gold
Authors: Piciollo Emanuele , Picchi Claudio , Ceccarini Alessio , Salvietti Emanuele , De Luca Antonio , Di Benedetto Francesco , Caporali Stefano , Innocenti Massimo
Published: February 2020

White gold and yellow gold are the most common types of gold colours used in jewellery making. Anyway lots of other colours of gold are also possible to achieve by electroplating and some of these colours may surprise. At the moment the market is gaining more and more interesting in purple gold, or black gold and even blue gold.

There are two electrochemical deposition processes used to obtain such colours: the first one is by formation of special gold metal compounds also referred to as Intermetallic Compounds. The second process is by forming a surface coating on gold, also referred to as Patination of Gold.

Here we present some methods to prepare Black gold thin films.

Amorphous carbon is used at times during Plasma Assisted Chemical Vapour Deposition process. Controlled oxidation of carat gold containing chromium or cobalt can also be used to yield black gold.

We investigate mainly thin films obtained by Electrodeposition processes.

Electrodeposition using black Rhodium or Ruthenium added to gold electroplating solution is one way. Electroplating solutions containing Ruthenium give a slightly harder black coating as compared to electroplating solutions containing Rhodium. We present some electrochemical results about the formation of thin films of black gold and their morphological characterizations by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM).

We’re going also to evaluate a correlation between films electrodeposited from different plating baths and corrosion resistance of the films themselves.
Electrochemical Behavior of Silver Electrodeposition Using Gel Electrolyte
Authors: Sato Haruto , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki , Tagaya Michiko
Published: February 2020

Partial plating method is often applied to the fabrication of the printed wiring board by using silk-screen printing. However, the complex preprocessing and post-processing for mask pattern formation and removal are necessary in this method. In addition, a large amount of plating solution is required in the plating tank in which the substrate for electrodeposition is immersed. In order to solve these problems, Itagaki et al. 1, 2) applied the gel electrolyte as the electrolyte solution for the partial plating of copper and nickel. In this case, a little plating solution was only used for the partial plating without masking process.

On the basis of the partial plating method using the gel electrolyte reported by Itagaki et al. 1), the partial plating of silver was performed in the present study. A three-electrode cell was used for the electrochemical measurement. The working electrode was the copper plate whose surface was covered with the gel electrolyte containing the silver ions. In this case, the preprocessing of copper plate was performed to remove the oxide film formed on the copper surface in the air. The counter electrode was a platinum wire. The reference electrode was a KCl-saturated silver/silver chloride electrode (SSE). The electrolyte solution was gellan gum solution containing KOH (pH=7), which was prepared from reagent grade chemicals and distilled water. All measurements were carried out by a potentiostat (Hokuto Denko, HZ-7000).

The partial plating of silver was performed by a galvanostatic polarization to determine the suitable condition of electrodeposition. In addition, the potentistatic polarization measurement was carried out for investigation of electrodeposition behavior.

Reference

[1] M. Itagaki, K. Shimoda, K. Watanabe, K. Yasuda, J. Surf. Finish. Soc. Jpn., 54, 41 (2003).

[2] M. Itagaki, I. Shitanda, W. Nakamura, K. Watanabe, Electrochim. Acta, 52, 6421 (2007).
The Critical Role of Supporting Electrolyte Selection on Flow Battery Cost
Authors: Perry Mike L. , Milshtein Jarrod David , Darling Robert M. , Drake Javit A , Brushett Fikile R.
Published: February 2020

Redox flow batteries (RFBs) are promising electrochemical devices for grid-scale energy storage due to their many favorable inherent attributes, such as decoupled power and energy ratings, as well as excellent performance and capacity retention. Recently, significant improvements in cell performance have made RFB systems more viable than ever. However, to meet the U.S. Department of Energy long range capital-cost target of $150 kWh-1, additional cost reductions are needed. One promising route is new active species for RFBs designed for lower cost or improved performance. These next-generation RFB chemistries are likely to be engineered molecules or complexes, such as redox-active organic or organometallic compounds, which offer a multitude of possibilities. A key consideration in the selection of any new RFB chemistry is the supporting electrolyte, which has a significant influence on the membrane resistance, electrolyte conductivity, and electrolyte viscosity. All of these physical parameters have a major impact on RFB performance and cost. Therefore, it is useful to quantify changes in economic viability for various RFB chemistry options with different aqueous supporting electrolytes paired with different types of membranes, which is the focus of this work. A techno-economic model is used to estimate RFB-system costs for the different membrane and supporting electrolyte options considered herein. Variations in cell performance due to the working ion selection and electrolyte viscosity can yield battery cost differences in the $100’s kWh-1, and this analysis allows for quantification of cost performance changes by selecting certain electrolyte characteristics. Beyond the conventional RFB design incorporating small active species and an ion-exchange membrane (IEM), this work also considers size-selective separators (SSS) as a cost-effective alternative to IEMs. The SSS concept utilizes nano-porous materials with no functionalization for ion selectivity, and active species that are too large to pass through the pores. Across the entire design space, SSS separators with low viscosity electrolytes offer the lowest RFB costs. Acknowledgements

This work was supported by the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the United States Department of Energy. J.D.M. acknowledges additional financial support from the National Science Foundation Graduate Research Fellowship Program.
Electrodeposition of NiPd Alloy in Alkaline Ni2+ – Pd2+ – Cl– – NH3 – H2O System
Authors: Mech Krzysztof , Chopart Jean Paul , Wrobel Miroslaw , Zabinski Piotr , Szacilowski Konrad
Published: February 2020

Synthesis of NiPd alloy is investigated in many research centers in the world mainly due to its interesting properties making possible its application as magnetic and catalytic materials. NiPd alloys were investigated also as catalysts in autothermal reforming of methane (1), counter electrode electrocatalyst in liquid-junction solar cells (2), utilization of CO2 and methane in dry reforming process (3), anodes in methanol oxidation (4) and toluene hydrogenation (5). Exchange current density versus the enthalpy of hydrogen adsorption (Log(i0)-dGMe-H) dependence allows on assumption that material composed of Ni and Pd will exhibit high catalytic properties towards hydrogen evolution reaction (HER). Previously we reported studies on electrochemical co-deposition of nickel with palladium from acidic solutions containing aquachloro- complexes of both elements (6) as well as palladium with cobalt (7, 8) and nickel with molybdenum (9). In literature, in spite of its wide application range, few reports exist concerning electrodeposition of NiPd alloys. Existing reports are focused on synthesis of NiPd alloys from suplphate-chloride (5), ethylenediamine (4) and chloride (6) based baths. In present work authors reported studies focused on electrochemical deposition in alkaline ammonia based system for first time.

Described studies were started from thermodynamic and UV-Vis analysis enabling qualitative description of analysed system. Electrochemistry of Ni2+ – Pd2+ – Cl– – NH3 – H2O system was analyzed based on results of cyclic voltammetry combined with electrochemical quartz crystal microbalance (EQCM). In further step synthesized alloys were characterized towards their compositions (WD-XRF), morphology (SEM, AFM), structure (XRD) and catalytic properties towards HER.

 References

 1. I. Z. Ismagilov, et al., International Journal of Hydrogen Energy(2014).

2. P. Yang, C. Ma and Q. Tang, Electrochimica Acta, 184, 226 (2015).

3. B. Steinhauer, et al., Applied Catalysis A: General, 366, 333 (2009).

4. K. S. Kumar, et al., Surface and Coatings Technology, 202, 1764 (2008).

5. K. Chen, et al., Chinese Journal of Catalysis, 17, 352 (1996).

6. K. Mech, et al., Applied Surface Science(2016).

7. K. Mech, et al., J Appl Electrochem, 44, 97 (2014).

8. K. Mech, et al., Electrochimica Acta, 104, 468 (2013).

9. K. Mech, et al., Archives of Metallurgy and Materials, 58, 227 (2013).
Impedance-Based Characterization of Raw Materials Used in Electrochemical Manufacturing
Authors: Orazem Mark E , Riemer Douglas P.
Published: February 2020

The impedance-based screening of raw materials has a tremendous positive impact in an industry where the state of the oxide film on stainless steel strongly influences process and product performance. This application was made possible by the significant progress made in the understanding of impedance data obtained on stainless steels. Huang et al. [1,2] have demonstrated that, for a disk electrode, frequency dispersion can be avoided by reducing the size of the electrode. Alexander et al. [3] have shown that frequency dispersion associated with specific geometries or distributions can be correlated by use of a characteristic dimension. The frequency at which the impedance response is corrupted by time-constant dispersion is inversely related to the characteristic dimension. This work facilitates selection of proper electrode design.

Even at frequencies below that at which specific geometries or distributions cause distortions to the impedance response, constant-phase-element (CPE) behavior can be seen which is attributed to properties of oxides on steel. Hirshorn et al. [4,5] have identified an approach through which CPE parameters may be interpreted in terms of oxide film thickness and dielectric constant. Orazem et al. [6] described application to different types of steel and to human skin. Riemer and Orazem [7] have described how this improved understanding of the origin of frequency dispersion has given rise to industrial application of impedance spectroscopy to provide rapid, inexpensive, and accurate measurement of the oxide film thickness.

Understanding what parts of the impedance spectra are truly useful requires an inherent understanding of the fundamental mathematics, and leads to the ability to make accurate and rapid measurements of oxide film thickness by EIS. Riemer and Orazem [7] stated that “This ability is invaluable from a manufacturing perspective as it serves as a method to screen the incoming raw material, as well as the product in-between different steps in the manufacturing process, allowing for greatly enhanced quality control.”

References

V. Huang, V. Vivier, M. E. Orazem, N. Pébère, and B. Tribollet, Journal of The Electrochemical Society, 154 (2007), C81-C88.

V. Huang, V. Vivier, M. E. Orazem, I. Frateur, and B. Tribollet, Journal of The Electrochemical Society, 154 (2007), C89-C98.

C. L. Alexander, B. Tribollet, and M. E. Orazem, Electrochimica Acta, 201 (2016), 374-379.

B. Hirschorn, M. E. Orazem, B. Tribollet, V. Vivier, I. Frateur, and M. Musiani, Journal of The Electrochemical Society, 157 (2010) C452-C457.

B. Hirschorn, M. E. Orazem, B. Tribollet, V. Vivier, I. Frateur, and M. Musiani, Journal of The Electrochemical Society, 157 (2010) C458-C463.

M. E. Orazem, B. Tribollet, V. Vivier, S. Marcelin, N. Pébère, A. L. Bunge, E. A. White, D. P. Riemer, I. Frateur, and M. Musiani, Journal of The Electrochemical Society, 160 (2013), C215-C225.

D. P. Riemer and M. E. Orazem, The Electrochemical Society Interface, Fall 2014, 23:3 (2014), 63-67.
Electrodeposition of Al from Dimethyl Sulfone-Aluminum Chloride Baths Under Dry Air
Authors: Miyake Masao , Okamoto Hiroaki , Hirata Mizuki , Hirato Tetsuji
Published: February 2020

Electrodeposition of Al requires the use of a non-aqueous bath, and it is usually carried out under an inert gas atmosphere such as nitrogen and argon using a glove box to protect the bath from absorbing moisture. However, the operation of the electrodeposition process under such conditions reduces the producibility and increases the cost, hindering its industrialization. If Al electrodeposition can be carried out in dry air, it would facilitate the operation and drastically lower the process cost. In this study, we examine the feasibility of the electrodeposition of Al under dry air using an organic bath, dimethylsulfone (DMSO2)-AlCl3 system (1-6).

The electrodeposition of Al was carried out at 110°C under dry air with a dew point of ~−60°C in a dry chamber. The electrodeposition was also carried out under Ar atmosphere using a glove box, and the deposits obtained under the two atmospheres were compared.

Cyclic voltammetry and XRD analysis of the deposits confirmed that the Al metal can be electrodeposited from the DMSO2-AlCl3 bath even in dry air. However, the Al film obtained in dry air tended to have black spots and a rough surface with scratch-like non-deposited portions. In contrast, a uniform, flat, silver-white Al film covering entirely the surface of the substrate is electrodeposited in Ar atmosphere under the same conditions, except for the atmosphere. This poor appearance of the Al film electrodeposited in dry air could be resolved by adding an additive to the bath. The current efficiency for the Al electrodeposition was slightly lower in dry air than that in Ar atmosphere, but it was still higher than 90%.

References

1. T. Hirato, J. Fransaer and J. P. Celis, J Electrochem Soc, 148, C280 (2001).

2. S. Shiomi, M. Miyake and T. Hirato, J Electrochem Soc, 159, D225 (2012).

3. M. Miyake, S. Tajikara and T. Hirato, Surf Coat Tech, 205, 5141 (2011).

4. M. Miyake, H. Motonami, S. Shiomi and T. Hirato, Surf Coat Tech, 206, 4225 (2012).

5. M. Miyake, Y. Kubo and T. Hirato, Electrochim Acta, 120, 423 (2014).

6. M. Miyake, H. Fujii and T. Hirato, Surf Coat Tech, 277, 160 (2015).
The Mechanism of Impedance Increase in Nickel-Rich NMC Cathodes
Authors: Lee Rung-Chuan , Tian Chixia , Doeff Marca , Kostecki Robert
Published: February 2020

The electrochemical performance of nickel-rich NMC cathode materials in Li-ion batteries depends on the kinetic control of side reactions at NMC-electrolyte/interface such as electrolyte oxidation, surface film formation, surface structure transformation and transition metal dissolution. However, the exact mechanism i.e. interdependence, sequence and impact of these interfacial phenomena is still poorly understood. The effect of surface reconstruction from layered- to spinel- or rock salt-phase(1, 2) in NMC materials during cycling on the kinetics of charge/discharge process remains unclear. As much as the exact chemical and physical properties of such surface reconstruction layer are still largely unknown, it is likely that it occurs simultaneously with other surface reactions and phenomena, which all together are difficult to deconvolute and evaluate.

To understand the mechanism of the surface reconstruction layer formation in Ni-rich NMC material during battery storage and its possible effect on the electrode and cell impedance a surface modification was deliberately induced in NMC particles artificially a priori via exposure to the electrolyte at elevated temperatures. The reaction of the electrolyte with NMC powders and the phase reconstruction of NMC surface were probed by surface sensitive techniques, including Raman, IR, SEM and X-ray absorption spectroscopy in total electron yield mode (XAS-TEY). Accompanying electrochemical testing including electrochemical impedance spectroscopy (EIS) was performed with half-cell configuration coin cells. Through comparison of the surface chemical properties and electrochemical performance between pristine NMC and treated samples, we were able to demonstrate that this artificial reconstruction layer on NMC does not cause a critical resistance in the battery. The treatment was shown to demonstrate some positive effects on the performance: i) higher capacity retention and ii)less resistance growth during electrochemical cycling. Surface chemical analysis shows that treated electrodes had reduced amount of organic film formation and less subsequent growth of reconstruction layers during electrochemical cycling compared with pristine NMC, indicating that an artificial reconstruction layer might suppress other degradation process of the battery, such as film formation and metal dissolution.

Acknowledgement

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.

Reference

1. F. Lin, I. M. Markus, D. Nordlund, T. C. Weng, M. D. Asta, H. L. L. Xin and M. M. Doeff, Nat Commun, 5(2014).

2. S. K. Jung, H. Gwon, J. Hong, K. Y. Park, D. H. Seo, H. Kim, J. Hyun, W. Yang and K. Kang, Adv Energy Mater, 4 (2014).
(Invited) Unveiling Irreversible Side-Reactions in Li-Ion Batteries with Online Electrochemical Mass Spectrometry
Authors: Bolli Christoph , Guéguen Aurélie , Berg Erik J.
Published: February 2020

Li-ion batteries will dominate the high-end rechargeable energy storage market for a foreseeable future. Current research and development of commercially relevant electrode/electrolyte systems focus strongly on extending the lifetime of the cells. Progress is however impeded by the lack of fundamental understanding of the underlying lifetime-limiting processes. Online Electrochemical Mass Spectrometry (OEMS) provides unique means for mechanistic studies of such adverse processes by enabling an operando monitoring of the onset, rate and extent of side-reactions with unparalleled sensitivity and selectivity.

Decomposition reactions involving (1) the electrode active material, (2) conductive carbon and (3) binder, as well as (4) the electrolyte solvent, (5) salt, along with (6) eventual additives, will be discussed. The Ni-rich layered mixed transition metal oxides (LiNixCoyMnzO2) are currently the best performing Li-ion cathode materials on the market. Surface phase transformations during the initial cycles however lead to composition- and potential-dependent evolution of O2, which is shown to be strongly related to the Ni-content of the oxides.1 Decomposition of electrode-processing-related residues and of electrolyte solvents leads to evolution of CO2, particularly in the first cycles, and initiates further chemical reactions with electrolyte salt (e.g. observed as HF and POF3).2 Electrolyte additives (e.g. vinylene carbonate, silyl-phosphates, etc.) can however suppress these side-reactions, e.g. by scavenging intermediate side-products and OEMS provides further verification of their reaction mechanism. In addition, electrolyte additives may also be exploited as chemical probes enabling operando monitoring of the degradation of other cell components, such as for example the electrode binder.3

References

D. Streich, C. Erk, A. Guéguen, P. Müller, F. Chesneau, E. J. Berg, Submitted.

A. Guéguen, D. Streich, M. He, M. Mendez, F. F. Chesneau, P. Novák, E. J. Berg, J. Electrochem. Soc. 163 A1095-A1100 (2016).

A. Guéguen, C. Bolli, M. Mendez, F. F. Chesneau, E. J. Berg, Submitted.
(Invited) Electrode Crosstalk during Lithium-Ion Battery Aging
Authors: Abraham Daniel P , Gilbert James A , Shkrob Ilya A , Kalaga Kaushik
Published: February 2020

Lithium-ion cells containing layered-oxide based positive electrodes and graphite-based negative electrodes are being cycled at high voltages (> 4.30 V) to increase energy density. In this presentation we will detail performance changes in these cells during cycling, with a particular focus on the crosstalk between electrodes. We show that the dissolution of transition metal (TM) ions from the positive electrode, and their migration and incorporation into the solid electrolyte interphase (SEI) of the negative electrode, accelerates markedly as the upper cutoff voltage (UCV) exceeds 4.30 V. At voltages ≥ 4.40 V there is enhanced fracture of the oxide during cycling that creates new surfaces and causes increased solvent oxidation and TM dissolution. Despite this deterioration, cell capacity fade still mainly results from lithium loss in the negative electrode SEI. Among TMs, Mn content in the SEI shows a better correlation with cell capacity loss than Co and Ni contents. We estimate that each Mn ion deposited in the SEI causes trapping of ~100 additional Li+ ions thereby hastening the depletion of cyclable lithium ions. During the presentation we will highlight an electrocatalysis mechanism through which the deposited Mn ions accelerate electrolyte reduction and increase Li trapping in the negative electrode SEI. Methods to mitigate this cross-talk, through the use of coatings and additives, will also be discussed.
Dynamic Chemical X-Ray Microscopy on Energy Storage Materials
Authors: Weker Johanna Nelson , Wise Anna M , Li Yiyang , Ruther Rose Emily , Chueh William C , Nanda Jagjit , Toney Michael F
Published: February 2020

The shift from fossil fuels toward clean, renewable energy will require significant improvements in rechargeable battery technology for electric vehicles. Current battery technology limits electric vehicles to a short travel range, slow recharge, and costly price tag. Li-ion batteries promise the high specific capacity required to replace the internal combustion engine with a number of possible earth abundant electrode materials; however, setbacks such as capacity fading hinder the full capability of these rechargeable batteries. In the search for better electrode materials, high resolution chemical imaging during typical battery operation is vital in understand and overcoming the failure mechanisms of these materials.

By combining X-ray absorption spectroscopy with high resolution, hard X-ray transmission microscopy (TXM), we have tracked the chemical changes of electrode material in real time during typical battery operation (Figure). [1, 2] We will discuss recent results tracking electrochemical and morphological changes in cathode materials during cycling, including LiFePO4,[3] LiCoO2, and Li2Cu0.5Ni0.5O2. Finally, we will discuss how ptychography, an emerging X-ray microscopy technique that promises sub-5 nm resolution, has the potential to image batteries during cycling at resolutions that rival in situ TEM with liquid cells.

[1] J.N. Weker, X. Huang, M.F. Toney, 2 (2016) 14-21.

[2] J. Nelson Weker, M.F. Toney, Advanced Functional Materials, 25 (2015) 1622-1637.

[3] J. Nelson Weker, Y. Li, R. Shanmugam, W. Lai, W.C. Chueh, ChemElectroChem, 2 (2015) 1576-1581.

Figure 1