bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards Bottom-up Engineered Electrode Microstructures for Redox Flow Batteries
Authors: Forner-Cuenca Antoni , Wan Charles Tai-Chieh , Jacquemond Remy , Weijers Cees , Tenny Kevin , Greco Katharine Virginia , Brushett Fikile R. 
Published: February 2020

Redox flow batteries (RFBs) are promising rechargeable electrochemical devices for grid-scale energy storage, but further cost reductions are needed for widespread implementation. While research efforts have primarily focused on molecular discovery, there has been significantly less attention paid to the engineering aspects (i.e. transport, reactor design) of the battery. Of particular importance are the porous electrodes used in the electrochemical stack. Today’s electrodes largely draw from the fuel cell material set, but, within a RFB, the porous electrode must perform a number of different roles including providing active surfaces for electrochemical reactions, facilitating uniform liquid electrolyte distribution, and supporting low pressure drops. Accordingly, before purpose-built electrodes can be developed for RFB applications, performance-limiting factors for the present materials set must be quantified. Unambiguous analysis is challenging in an operating RFB due to the complex coupling of transport and reactions, which vary as a function of state of charge during cell cycling. Deconvoluting the role of electrode properties on flow battery performance requires the development of diagnostic techniques that enable electrode characterization under well-controlled but application-relevant conditions.
To this end, we systematically evaluate the performance of several different carbon paper, felt, and cloth electrodes using the single-electrolyte cell configuration [1] and a model organic redox couple (TEMPO/TEMPO+) [2]. Using polarization and electrochemical impedance spectroscopy, we quantify the impact of electrode microstructure on battery performance. To further understand the role of electrode microstructure on the performance, we use tomography, and numerical simulation in tandem with the aforementioned electrochemical diagnostics. We find that woven electrodes, which feature a bimodal pore size distribution, provide an outstanding electrochemical performance and low pressure drop [3]. Inspired on these learnings, our most recent work focuses on developing bottom-up synthetic methods to fabricate porous electrodes with engineered microstructures, with a particular interest in bimodal pore size distributions and porosity gradients across the electrode thickness. In this talk, I will discuss our most recent experimental strategies to engineer electrodes with highly-controlled microstructures tailored for specific RFB chemistries.

Darling et al., J. Electrochem. Soc., 161, A1381 (2014).

D. Milshtein et al., J. Power Sources, 327, 151 (2016).

Forner-Cuenca et al., Under Review at Electrochem. Soc.

Acknowledgments
We gratefully acknowledge the financial support of the Swiss National Science Foundation (P2EZP2_172183) and the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the United States Department of Energy.
Petroleum Coke As Active Material of Negative Electrode for Lithium-Sulfur Batteries
Authors: Kuzmina Elena , Chudova Nadezhda , Dmitrieva Liana , Ivanov Alexey , Karaseva Elena , Kolosnitsyn Vladimir 
Published: February 2020

We studied the possibility of using graphite and petroleum coke as active materials of negative electrodes for lithium-sulfur batteries.
Petroleum coke was previously subjected to thermochemical activation in its own vapor in an air atmosphere for 10 hours at 800 °C.
Positive sulfur electrodes were made by casting a slurry on aluminum foil. The composition of the electrode layer was 70% wt. sulfur, 10% wt. carbon (Ketjenblack EC-600JD), and 20% wt. binder (poly(ethylene) oxide, MW 4x106).
The separator was 1 layer of microporous polypropylene Celgard®3501. The electrolyte was 1M LiClO4 in sulfolane.
Negative electrodes based on graphite and activated petroleum coke were prepared by slurry casting onto copper foil. The composition of the electrode layer was 94% wt. of the active material (petroleum coke or graphite), 1% wt. of the carbon black (Super P), and 5% wt. of the binder (LA-132).
Negative electrodes based on carbon materials were pre-lithiated. For this purpose, cells with a lithium electrode and carbon electrode were assembled and subjected to 5 molding cycles. Figure (a) shows the typical charge-discharge voltage profiles of the semi-cells of Li - Carbon electrode. After 5 molding cycles, the cells were transferred to the glove box and lithiated carbon electrodes were removed from them. Lithium sulfur cells were assembled with these lithiated carbon electrodes.
It was shown that regardless of the negative electrodes used, there are two plateau on the discharge voltage profiles of lithium-sulfur cells, corresponding to electrochemical reduction (Figure b):
(1) sulfur and high ordered lithium polysulfides through a series of intermediate stages to lithium tetrasulfide:
S8 + 4Li+ + 4e- → 2Li2S4

(2) Lithium tetrasulfide to lithium disulfide and lithium sulfide:
Li2S4 + 4Li+ + 4e- → 2Li2S + Li2S2.
It should be noted that the discharge voltage of lithium-sulfur cells with carbon electrodes is decreased by the magnitude of the voltage of lithium-carbon semi-cells (Figure (a) and (b)).
At the initial stages, the rate of decrease in the discharge capacity of lithium-sulfur cells weakly depends on the composition of the negative electrode. Cycling efficiency is 91-92%.
Based on the obtained results, it can be concluded that activated petroleum coke can be used as the active material of the negative electrode for lithium-sulfur batteries.

This work was performed as part of a Government Order to Ufa Institute of Chemistry of the Russian Academy of Sciences by the Ministry of Science and Higher Education of the Russian Federation (Theme No. AAAA-A17-117011910031-7) Russia and was also financially supported by the Russian Science Foundation (project No 17-73-20115).

Figure 1
Conductivity, Thermal and Electrochemical Stability of Solutions of Lithium Bis(Oxalato) Borate in Sulfolane
Authors: Sheina Ludmila , Kuzmina Elena , Karaseva Elena , Ivanov Alexey , Kolosnitsyn Vladimir 
Published: February 2020

Lithium bis(oxalato) borate (LiBoB) is promising lithium salt for electrolyte solutions of lithium-ion and lithium batteries because of high thermal and hydrolytic stability as well as high electrochemical stability of BoB- anion in wide potential range [1,2].
Sulfones are promising solvents and co-solvents for high-voltage batteries [3-7]. Sulfolane (tetramethylene sulfone) is the most known representative of sulfones. It has high dielectric permittivity (43.3 at 30 °C), high oxidizing stability (≥5 V vs. Li/Li+), high flash point (> 166 °C [8]) and low toxicity [3-5].
This work summarizes the results of studies on the conductivity, viscosity, electrochemical and thermal stability of LiBoB solutions in sulfolane with concentration range of 6·10-4 – 1.1 mol L-1.
The maximum of specific conductivity is 1,7·10-3 S·cm-1 at 30 ºС and corresponds to ~0.8 mol L-1 (Fig. a). Activation energy of conductivity of 1M LiBoB in sulfolane is 23.3±0.5 kJ mol-1.
Solutions of LiBoB in sulfolane are viscous (Fig. b). Activation energy of viscous flow for 1M LiBoB in sulfolane is 29.4±0.5 kJ mol-1.
Association constant and limiting molar conductivity (λ0) of LiBoB in sulfolane are 6 mol-1·L and 8·10-4 S·m2·mol-1, correspondingly.

The decomposition temperature (temperature at the initial decomposition) of 1M LiBoB in sulfolane is 286 °C, estimated by DSC method (Fig. c), and 260 °C, estimated by DTA method (Fig. d).
Anodic stability of 1M LiBoB in sulfolane is ~5.8 V vs. Li/Li+, estimated at Pt working electrode.
Therefore, lithium bis(oxalato) borate dissociates well in sulfolane, its solution has moderate conductivity, high thermal and electrochemical stability.
Figure. Isotherms of specific conductivity (a) and dynamic viscosity (b) of LiBoB solutions in sulfolane; DSC (c) and DTA (d) of 1M LiBoB in sulfolane.
This work was performed as part of a Government Order to Ufa Institute of Chemistry of the Russian Academy of Sciences by the Ministry of Science and Higher Education of the Russian Federation (Theme No. AAAA-A17-117011910031-7).

References

R. Younesi, G. M. Veith, P. Johansson, K. Edstrӧm, T. Vegge // Energy Environ.
Sci., 2015, 8, pp. 1905-1922.

Z. Liu, J. Chai, G. Xu, Q. Wang, G. Cui //Coordination Chemistry Reviews, 2015, 292, pp. 56-73.

K. Xu //
Chemical Reviews, 2004, 104 (10), pp. 4303-4417.

A. Abouimrane, I. Belharouak, K. Amine // Electrochemistry Communications, 2009, 11, pp. 1073-1076.

N. Shao, X.-G. Sun, S. Dai, D. Jiang // J. Phys. Chem. B., 2011, 115, pp. 12120-12125.

S. Li, W. Zhao, C. Xiaoling, Y. Zhao, B. Li, H. Zhang, Y. Li, G. Li, X. Ye, Y. Luo // Electrochimica Acta, 2013, 91, pp. 282-292.

F. Wu, H. Zhou, Y. Bai, H. Wang, C. Wu // ACS Appl. Mater. Interfaces, 2015, 7 (27), pp. 15098-15107.

Electrolytes for Lithium and Lithium-Ion Batteries / Editors T. R. Jow, K. Xu, O. Borodin, M. Ue. // Modern Aspects of Electrochemistry, Springer, 2014, V. 58, 476 p. DOI: 10.1007/978-1-4939-0302-3.

Figure 1
A Reversible Electrochemical Side Reaction of Li Electrodeposition / Dissolution Using N(SO2)X(SO2)Y Anion-Containing Molten Salt (X, Y = F, CF3)
Authors: Sano Hikaru , Kubota Keigo , Siroma Zyun , Kuwabata Susumu , Matsumoto Hajime 
Published: February 2020

LiTFSA (Lithium Bis(trifluoromethanesulfonyl)imide) and LiFSA (Lithium bis(fluorosulfonyl)imide) are well-known as a salt of an electrolyte of a Li-based secondary battery, and also used as a salt of an electrolyte of a secondary battery using metal Li as a negative electrode. In many cases, when using these electrolytes to electrodeposit metal Li, side reactions occur at about 1.8 V vs Li+/Li.1,2 Recently, we have discovered that this side reaction is reversible and appears prominently at temperatures as high as 150 ° C.
The electrolyte was prepared by dissolving 1 M of Li [TFSA] in Pyr13 [TFSA] (N-Propyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide). A Ni (Nickel) substrate was immersed in this electrolytic solution to form a working electrode. A metal Li was used as a counter electrode to form a two-electrode cell. A current was flowed to the reduction side at a current density of 0.2 and 1 mA cm-2, and a current was flowed to the oxidation side when it reached 0.1 V. The voltage-time profiles are shown in Figure (a)(b). At the time of reduction, it has a plateau at a voltage of 1.5 V, indicating that some electrochemical reaction has occurred. The oxidation has a plateau near 1.9 V, suggesting that this reaction is electrochemically reversible.
The result of performing cyclic voltammetry measurement for the cells of the same configuration is shown in Figure (c). Reversible reduction and oxidation waves can be confirmed at the potential (ca. 1.5 V and 1.9 V) corresponding to the plateau potential in constant current measurement. Also, it was seen that the peak increases with each cycle.
At the meeting site, we will also describe the results of using LiFTA (lithium (fluorosulfonyl)(trifluoromethylsulfonyl)amide), which is a molten Li single salt, and discuss the origin of side reactions.

Acknowledgments

This work was performed as a cross-appointment project between Osaka University and the National Institute of Advanced Industrial Science and Technology (AIST).

References

1. D.Aurbach, M. Daroux, P. Faguy, E. Yeager, J. Electroanal. Chem. Interfacial Electrochem., 297, 225 (1991).
2. T. Shiga, Y. Kato, M. Inoue, N. Takahashi, Y. Hase, J. Phys. Chem. C, 119, 3488 (2015).

Figure 1
Corrosion of Candidate Alloys in Molten LiCl-Li2O-Li for Pyroprocessing of Used Nuclear Fuel
Authors: Moon Jeremy , Phillips William , Chidambaram Dev 
Published: February 2020

Pyrochemical reprocessing of used nuclear fuel (UNF) requires large structural process vessels and functional components fabricated from stainless steel 316L (SS316L) or another high-temperature molten salt-compatible material like Inconel 625 (I625). The unique chemistry of the molten salt electrolyte during processing of UNF leads to complex interactions between container materials and the electrolyte that have been well documented by our group.
In the head-end process to incorporate oxide UNF into the pyrochemical reprocessing scheme, LiCl with 1-2 wt. % Li2O is utilized as an electrolyte to facilitate the electrolytic reduction of UO2 via the Fray-Farthing-Chem (FFC) process. The Li+ reduction potential is quite close to the UO2 reduction potential and it is generally recognized that lithium metal will be produced at the cathode during the reduction process. While much of the metallic lithium further facilitates the reduction of UO2 via a metallothermic pathway, forming Li2O, a fraction of the metallic lithium dissolves or otherwise disperses into the molten salt. The metallic lithium then diffuses throughout the salt and reacts with process vessels and other components.
To further understand corrosion in these conditions, SS316L and I625 coupons were exposed to LiCl-1 wt. % Li2O-Li and LiCl-2 wt. % Li­2O-Li with lithium metal concentrations of 0, 0.3, 0.6 or 1.0 wt. %. These samples were then studied using focused ion beam (FIB) milling, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and energy dispersive spectroscopy (EDS). Results from these studies will be discussed.
Acknowledgements: The authors thank Zachary Karmiol, research scientist at Materials Characterization Nevada, for technical input. One of the authors, JM, acknowledges the Graduate Research Fellowship from the US National Science Foundation. This work was supported by the United States Department of Energy (DOE) under contracts, DE-NE0008262, DE-NE0008236, and DE-NE0008572, and the United States Nuclear Regulatory Commission (NRC) under Contract NRC-HQ-13-G-38-0027. Dr. Kenny Osborne and Ms. Nancy Hebron-Israel serve as the DOE and NRC award program managers, respectively. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1447692.
Application of a Reaction-Transport Model with Cation Complexation and Variable Diffusivity to Galvele’s Criteria for Pitting Corrosion
Authors: Nguyen Van Anh T. , Newman Roger C. 
Published: February 2020

A reaction-transport model in a one-dimensional pit geometry is constructed to study the effects of cation complexation, hydrolysis and multiple aggressive anions on the mass transport of ions, and the IR drop, within a pit at the anodic limiting current density. In particular, the study focuses on the B value in Galvele’s pit model, which states the dependence of pitting potential (Epit
) on chloride concentration ([Cl-])

Epit = A- B log[Cl-]

where the B value is predicted to be 60 mV from Galvele’s model [1]. However, this value is found to vary up to around 100 mV in practice for stainless steels, indicating that the IR drop inside the developing pit is not explainable by a simple model [1-4]. The present model is constructed at steady state and with a limiting anodic current density (fixed dissolved metal concentration at the bottom of the pit), which is carried by metal-containing species. When there is no cation complexation or hydrolysis, the B value remains at 60 mV in NaCl and 30 mV in Na2SO4, even when the ionic diffusivities are functions of chloride concentration. However, the B value is found to vary between 30 mV and 60 mV at different ratios of anionic bulk concentration in the mixed solution of singly and doubly charged anions (such as chloride-thiosulfate systems). Due to the charge difference between these anions, the bulk ratio between the anionic concentrations is not preserved inside the pit, which results in an enrichment of the doubly charged anions at the bottom of the pit. For a one metal system, the effect of hydrolysis on the B value is negligible compared with that of cation complexation, which is very significant and could potentially explain a lot of practical observations. For an Fe-17Cr alloy, the B value increases up to 100 mV, in agreement with experiments, assuming dissolved chromium can make cationic chloro-complexes. The obtained results can be rationalized via the change of potential gradient and ionic fluxes near the top of the pit at different bulk NaCl concentration, to maintain the critical chemistry for pit stability and the complexation reaction inside the pit.
References:

J. R. Galvele, Transport Processes and the Mechanism of Pitting of Metals, J. Electrochem. Soc., 123, 464 (1976).

N. J. Laycock, R.C. Newman, Localised Dissolution Kinetics, Salt Films and Pitting Potentials. Corros. Sci., 39, 1771 (1997).

R. C. Newman, Pitting Corrosion of Metals, The Electrochemical Society Interface, 19, 33 (2010).

W. Zhang, A. G. Carcea, R. C. Newman, Pitting of Steam-generator Tubing Alloys in Solutions Containing Thiosulfate and Sulfate or Chloride, Faraday Discussions, 180, 233 (2015).
Visualization of pH and Cl− Distributions inside Crevice of Type 430 Stainless Steel
Authors: Matsumura Kengo , Muto Izumi , Sugawara Yu 
Published: February 2020

The decrease in pH caused by the hydrolysis of metal ions inside crevice is widely accepted to be the predominant factor affecting the initiation of crevice corrosion for stainless steels. The accumulation of chloride ions inside crevice is also thought to be of great importance for the initiation of crevice corrosion. 1, 2 In this study, a simultaneous measurement technique for pH and Cl− concentration was applied to the visualization of pH and Cl− distributions inside crevice in the initial stage of crevice corrosion of Type 430 stainless steel.
A sensing layer with fluorescent dyes was made on one side of a SiO2 plate using the sol-gel SiO2 coating technique. Quinine sulfate (fluorescent dye) was used to measure Cl− concentration. The excitation wavelength was 350 nm. The emitted light was filtered through a 420-nm long-pass filter, since quinine sulfate has a peak wavelength of 451 nm (blue fluorescence). 1 Tb3+-DPA (dipicolinic acid) complex was used as the fluorescent dye for pH measurements. 2 The excitation wavelength of this dye was 270 nm, and the emitted light was filtered through a 510–550-nm band-pass filter. In this case, green fluorescence was observed.
The crevice specimens were prepared from Type 430 stainless steel (Fe-16.5Cr). A crevice (3 mm × 3 mm) was made between the stainless steel and the sensing plate. 1,2 Crevice corrosion tests were carried out in a naturally aerated 0.01 M NaCl at pH 3.0, and the specimen was polarized at 0.0 V (vs. Ag/AgCl, 3.33 M KCl). Before the initiation of crevice corrosion, pH inside the crevice gradually decreased with time. And also, Cl− concentration increased with time. At pH 1.8 and ca. 0.1 M Cl−, crevice corrosion initiated, and a large pH drop and a large Cl− increase were observed.
References:

T. Kaji, T. Sekiai, I. Muto, Y. Sugawara, N. Hara, J. Electrochem. Soc., 159, C289-C297 (2012).

M. Nishimoto, J. Ogawa, I. Muto, Y. Sugawara, N. Hara, Corros. Sci., 106, 298-302 (2016).
Pit Initiation Behavior at Sulfide Particles in Sintered Stainless Steels
Authors: Nishimoto Masashi , Muto Izumi , Sugawara Yu , Hara Nobuyoshi 
Published: February 2020

The pit initiation sites for commercial stainless steels have been attributed to sulfide inclusions such as MnS. The chemical composition of the inclusions affects the pitting corrosion resistance of stainless steels. Systematic investigation on the relationship between the chemical composition of the inclusions and the pitting corrosion resistance is required. However, it is difficult to prepare a series of the steel specimens of which the chemical composition of the inclusions is precisely controlled. In this study, spark plasma sintering was used to fabricate stainless steel specimens containing sulfide particles, and a microelectrochemical technique was applied to analyze the effect of the chemical composition of the sulfides on the pitting corrosion resistance of stainless steels.
A type 304 stainless steel powder was mixed with a MnS powder to prepare the sintered specimen containing 0.03 mass% S. The particle sizes of the stainless steel and the MnS powder were –100 mesh and –325 mesh, respectively. The mixed powders were loaded into a cylindrical graphite die and were compressed using a hydraulic press. The pressed compact was spark plasma sintered in vacuum, under uniaxial pressure at 30 MPa. The sintered specimen was ground with SiC papers and then was polished with an 1 µm diamond paste. Potentiodynamic polarization was conducted in naturally aerated 0.1 M NaCl (pH 5.5) at 298 K. The specimen surface was masked to make an electrode area of ca. 100 µm × 100 µm containing a sulfide particle. All the potentials reported in this study refer to the Ag/AgCl (3.33 M KCl) electrode (0.206 V vs. standard hydrogen electrode at 298 K). The potential scan rate was 3.8 × 10-4 V/s.
The anodic polarization curve was measured in 0.1 M NaCl to characterize the pit initiation behavior at the MnS particle in the sintered stainless steel. Polarization was started at –0.2 V and was stopped after the large increase in the current density was measured. The electrode area was observed using an optical microscope after polarization. The MnS particle partly dissolved, and the pit was found at the boundary between the particle and the steel matrix. This suggests that the large current increase was attributed to the pit initiation at the particle. It is expected that the sintered specimen can be used to investigate the pit initiation behavior at the sulfides in stainless steels.
Corrosion Behavior of High Entropy Alloys Made By Directed Energy Deposition Additive Manufacturing
Authors: Melia Michael Anthony , Carroll Jay , Argibay Nicolas , Kustas Andrew , Schindelholz Eric John 
Published: February 2020

Additive manufacturing (AM) is an attractive process for fabricating high entropy alloys (HEAs) with the ability to leverage high cooling rates for the single phase formation of complex alloys. This study investigates the corrosion behavior of the equi-atomic CoCrFeMnNi HEA made by directed energy deposition in the as-built and homogenized condition (1100oC for 1 hr). The as-built microstructure exhibited dendritic chemical segregation with interdendrite areas enriched with Mn and Ni compared to the chemically uniform microstructure after annealing. Corrosion behavior of the CoCrFeMnNi HEAs was investigated using potentiodynamic polarization measurements in 0.6 M NaCl solutions to determine each materials open circuit and breakdown potential, on average -0.25 VSCE and ~0.40VSCE, respectively for both conditions. Comparison in pit propagation was also explored with the as-built microstructure showing preferential corrosion of the Mn/Ni enriched interdendrite areas while the annealed materials pits were similar to those observed on 304L stainless steel.
Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.