bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemistry of Neodymium in an Equimolar NaCl-KCl Melt without and with Addition of Fluoride Ions
Authors: Markovich Sergey I , Popova Anna V , Kuznetsov Sergey A 
Published: November 2022

An investigation of compounds of those few elements in the oxidation state (II), by opposition to the general trivalent lanthanides is of special interest. The present work follows our previous investigations on samarium, europium ytterbium chloride systems and, in particular, the electrochemical behavior of the Sm(III)/Sm(II), Eu(III)/Eu(II) Yb(III)/Yb(II) redox couples. It deals with neodimium compounds.
The electrochemical behavior of NdCl3 in molten salts was studied in few works, but only melts with a low melting point LiCl-KCl and LiCl-KCl-CsCl were investigated.
The electroreduction of NdCl3 in an equimolar NaCl-KCl mixture was studied in the temperature range 973-1123 K by different electrochemical methods. It was shown that the discharge of Nd(III) to Nd(II) is complicated by the disproportionation reaction (DPP):
3Nd(II) ↔ 2Nd(III) + Nd (1)
Ignoring of reaction DPP can lead to incorrect determination of values diffusion coefficients and formal standard redox potentials of the Nd(III)/Nd(II) redox couple. The relatively narrow interval of polarization rate was found when the recharge process was reversible and not accompanied by the DPP reaction. At these scan rates the diffusion coefficients and formal standard redox potentials of the Nd(III)/Nd(II) redox couple were determined by cyclic voltammetry.
The standard rate constants for the redox reaction Nd(III) + e- ↔ Nd(II) were calculated on the basis of cyclic voltammetry at sweep rates corresponding to the quasy-reversible process. The nature of working electrode on the rate of charge transfer for the Nd(III)/Nd(II) redox couple was studied. It was found that the values of k
s determined at a molybdenum electrode were higher than those at a glassy carbon electrode.
The introduction of fluorine anions into a chloride melt at a molar ratio of F-/Nd(III) = 5 leads to the disappearance of the recharge wave and only an ascending section associated with joint discharge of neodymium complexes and sodium and potassium cations was observed. Thus, the introduction of fluorine anions leads to stabilization of the highest oxidation state of neodymium in chloride-fluoride melt and neodymium in the oxidation state +2 does not exist in the melt.
Introducing of fluoride ions to the melt NaCl-KCl containing Nd(II) accompanied by reaction of disproportionation:
3NdCl4
2- + 12F- ↔ 2NdF6
3- + Nd + 12Cl- (2)
The standard rate constants of charge transfer for the Nd(III)/Nd(II) redox couple were compared with the values obtained for other redox couples of lanthanides and these results were discussed in connection with the strength and stability of complexes.
Electrodeposition of Aluminium and Co-Deposition of Alloying Elements Titanium, Manganese and Silicon in Molten Fluoride Electrolyte
Authors: Haarberg Geir Martin , Awayssa Omar , Meirbekova Rauan , Xu Wenting , Saevarsdottir Gudrun 
Published: November 2022

Primary aluminium is produced by the Hall-Heroult process which is based on electrolysis in molten fluoride electrolyte, Na3AlF6-AlF3, at ~960 oC in which the raw material alumina is dissolved and decomposed into pure aluminium and CO2 gas due to the use of carbon anodes. Alloys are made by adding pure metals prior to the casting process. An alternative approach to produce alloys by co-deposition of alloying elements during electrolysis, where metal oxides of alloying elements are added to the electrolyte, is under study. Laboratory experiments were carried out to quantify the impact of co-deposition of alloying elements of titanium, manganese and silicon. The experimental set-up was dedicated to determine the current efficiency of aluminium and aluminium based alloys during galvanostatic electrolysis.
Current efficiencies above 90 % were obtained for electrodeposition of aluminium alloys with titanium, manganese and silicon. It was found that the current efficency decreasde a few percentage points compared to the current efficiency for deposition of pure aluminium. The content of deposited allloying element was determined by ICP analysis of deposits. By adding from 1 - 3 wt% of metal oxide to the electrolyte the content of alloying element was found to be typically ~ 5 - 10 wt% after electrolysis. Experiments were carried out by changing temperature and amount of added metal oxide.
The proposed method for producing aluminium based alloys directly in the Hall-Heroult process may give substantial benefits in terms of cost and efficiency. Challenges are related to metal oxide solubilities and control of the alloy composition.
(Invited) Concentrated Hydrogen Bonded Electrolytes: Definition and Bulk & Interfacial Properties
Authors: Gurkan Burcu , Dean William , Penley Drace 
Published: November 2022

We broadly refer to deep eutectic solvents (DESs) as concentrated H-bonded electrolytes (CoHBEs) where a composition specific to the “deep eutectic temperature” does not have to be met as long as the electrolyte possesses high salt concentration of the salt or the redox active specie and suppressed volatility are desired in energy storage, electrocatalysis, and electrodeposition processes. Liquid heterogeneity owing to H-bonding, similar to ionic liquids and DESs, CoHBEs present distinct electrode-electrolyte interfacial behavior.
As a way to probe the electrode-electrolyte behavior of CoHBEs as a function of composition, we have performed electrochemical impedance spectroscopy and surface enhanced Raman spectroscopy (SERS). The potential dependent differential capacitance of choline chloride and ethylene glycol (1:2, 1:4, 1:6 molar ratio) mixtures do not present camel shaped curves as in the case of more extreme examples of concentrated electrolytes such as ionic liquids. The interfacial behavior is more similar to dilute systems, however, the H-bonding network presents a less mobile diffuse layer. While on glassy carbon, there is no specific ion adsorption, on metal electrodes chloride adsorption is observed. In chloride-free systems that are based choline oxalate mixed with ethylene glycol, capacitance is measured to be almost independent of the applied voltage on glassy carbon and gold. This is attributed to the strong binding energy of the solvation structure, as determined from theory, that hinders voltage-induced reorientations. Consistent to this behavior, the oxalate system also presents a very high viscosity. In addition, the voltage sweep range is limited in the case of oxalate system as it has narrower electrochemical window. On the other hand, choline acetate, which has a very similar chemical structure to the oxalate, undergoes specific ion adsorption particularly on gold electrode at a positive applied potential as confirmed by SERS. This is believed to be due to the reduced binding energy as calculated by density functional theory with -1 charge of the acetate in comparison to -2 charge in oxalate that leads to the desolvation and then the surface adsorption of the acetate. In the case of the choline bis(trifluorosulfonyl)imide and ethylene glycol mixture, a wider electrochemical window accompanied by a dampened u-shaped capacitance was observed with no specific ion adsorption.
This study presents tuning of DESs and more broadly CoHBEs in terms of the bulk physical properties, the interfacial behavior near an electrode, and the coupled structuring effects through the variation in anion charge density and the extent of H-bonding.
Redox Couple Stability Studies for Thermodynamic Reference Electrodes and Fluoroacidity Investigation
Authors: Williams Haley , Scarlat Raluca O. 
Published: November 2022

A stable reference electrode is essential for electrochemical studies in molten fluoride salts, yet reference electrode design is hindered by challenges such as materials compatibility and high temperature operation. Electroanalytical studies are relevant to sensor development for molten fluoride salt systems as well as fundamental chemistry studies of salt structure and speciation. Dynamic reference electrode techniques have been used to find benchmark reference potentials, but the application of a constant current for the technique may not be feasible for sensing or high throughput studies. A thermodynamic reference electrode which is durable, stable, and reproduceable is urgently needed for both scientific studies and engineering applications of molten fluoride salts.
Fluoroacidity studies are of particular interest for a fundamental understanding of molten salt speciation. The more dissociated fluoride anions present in a melt, the more of a fluorodonor it is. Thus, it is considered to have a higher fluorobasicity due to its Lewis base behavior. Fluoroacidity is related to the coordination of solvent and solute ions and, therefore, solute diffusion coefficients and viscosity. Ion solvation differs in fluoride salts of various fluoroacidities, so solvated ions have different activity coefficients in different fluoride solvents. The relationship between activity coefficients of solvated ions and a melt’s fluoroacidity is not fully understood. The electrochemical determination of these activity coefficients benefits from a stable reference electrode. In addition, quantification of fluoroacidity requires the measurement of the activity of dissociated fluoride, which can be done electrochemically. The measurement of redox potential of a given couple in various fluoride melts can lead to a classification of the solvent melts based on the Nernst equation. Therefore, the study of redox couple behavior in various fluoride melts is relevant to both the development of a robust thermodynamic reference electrode & the quantification and theory of fluoroacidity.
The Ni/NiF2 and Ag/AgF redox couples have been previously investigated for use in thermodynamic reference electrodes for molten fluoride salt. Ni/NiF2 has been characterized for its stability in molten fluorides. The Ag/AgCl redox couple has commonly been used for chloride mixtures but literature on the fluoride couple is marginal. Our preliminary studies have shown the stability of the Ag/AgF redox couple in a FLiNaK melt by OCP measurement. Polarization studies will be carried out to test for reversibility, and other redox couples may be investigated. In this presentation, we present results from the Ag/AgF redox couple studies in FLiNaK, as well as their impact on current understandings of fluoroacidity.
Up-Scaling and Stabilization of Processes for the Electrodeposition of Aluminum Alloys for Corrosion Protection
Authors: Böttcher Rene , Ispas Adriana , Bund Andreas 
Published: November 2022

Aluminum and its alloys have excellent properties (e.g. specific weight, corrosion resistance) that are beneficial for a wide range of industrial applications. By forming a natural oxide layer of a few nm thickness, these materials are able to protect themselves from the progression of corrosive attack. Unfortunately, this oxide layer limits the use of pure aluminum for cathodic corrosion protection. Adding the right alloying elements can help to prevent the formation of the oxide layer and thus self-passivation.
Electrodeposition is an elegant and cost-efficient method to deposit thin films on substrates with complex shapes. The choice of the electrolyte, its composition and the deposition parameters allow the tuning of the layer properties. Electroplated aluminum materials open up the possibility of replacing environmentally hazardous materials such as cadmium. Aluminum cannot be electrodeposited from aqueous electrolytes due to its negative Nernst potential (-1.66 V vs. NHE). Non-aqueous media make this possible due to large electrochemical windows. However, they are often limited by expensive and highly flammable chemicals (e.g. SIGAL and REAL process). High investment costs for process and plant technology are the consequence. Ionic liquids (ILs) allow the deposition of reactive metals such as aluminum at room temperature. They have a very low vapor pressure and are non-flammable. In addition, they exhibit good solubility for numerous metal salts and lower differences in the deposition potentials of the metals.
This paper discusses the use of imidazolium-based chloroaluminate ILs for the electrochemical deposition of aluminum alloys for cathodic corrosion protection of high-strength steel. As an essential part of upscaling IL-based processes, the use of multianodes, their limitations, and the use of additives to optimize the deposition process and the coating properties will be discussed.
(Invited) Promises and Challenges of Multivalent Ion Battery Chemistries
Authors: Ma Lin , Schroeder Marshall , Pastel Glenn , Borodin Oleg , Pollard Travis , Ding Michael , Ho Janet , Cresce Arthur v. , Xu Kang 
Published: November 2022

Extensive efforts have been made to seek new battery chemistries based on multivalent working ions, with the aim to replace the mature lithium-ion batteries. These efforts were initially driven by the pursuit of higher capacity/energy, better safety and lower cost, and more recently have significantly intensified with the increasing concerns over the climate change, the limited resources of Co and Ni, and the anxieties over geopolitical as well as ethical risks of the corresponding supply chain. But how far are we from a practical multivalent battery?
This talk rigorously examines the achievements made in MV batteries as reported in the current literature, while attempting to explore a pathway through the fog-of-war ahead of us.
Electrolyte-Centric Thermal Model of Li-Ion Battery Under Abuse Conditions
Authors: Guillamon Joaquin I. , Verma Amit 
Published: November 2022

Safety is an important concern in Li-ion battery operation and storage. As both energy stored per unit volume and current densities have increased in these batteries, energy dissipation in the form of heat has become one of the main issues for proper battery operation. As temperature increases, secondary chemical reactions may be initiated. These reactions release more heat and undesired products, triggering an auto-catalytic feedback process, commonly classified as thermal-runaway mechanisms. This can potentially lead to a complete degradation of the battery and possible explosion or combustion of the battery components.
Several researchers have worked on developing models to predict thermal behavior under conditions with potential thermal runaway outcomes on Li-ion batteries. The first studies proposed a model that emulates the solid electrolyte interface (SEI) decomposition and regeneration reactions on a standard 18650 cylindrical cell. Later works extended these models and included the reactions of cathode decomposition and electrolyte decomposition with potential combustion. Although macroscopic level energy balance helps predict potential thermal behavior in a battery of multiple layers, the study of all the different transport mechanisms that happen inside a single layer battery is essential for a better understanding of the process taking place when temperature begins to rise. With the aim of improving heat dissipation inside a battery, the electrolyte is a key component to consider as it can potentially handle heat flux easier through convection within the solution.
Our work investigates spatially dependent electrolyte conditions in the presence of a thermal gradient to produce an electrolyte-centric thermal runaway model. Non-current conditions are considered for emulating oven-test experiments or storage conditions. Furthermore, this specific case study aims to extend our previous model by accounting for the influence of the Joule effect on simulating a battery's operational conditions. The purpose of the study is to model transport mechanisms that can potentially lead to thermal degradation of the battery. Li-ions, momentum, and thermal flux are the main components of the analysis. This objective is achieved by using numerical simulation techniques. A detailed understanding of the transport processes taking place inside the battery will contribute towards mitigating damage induced due to thermal abuse conditions.

Figure 1
(Invited) 4C 15-Minute Fast-Charging Li-Ion Battery Enabled By Novel Electrolytes
Authors: Gao Tao 
Published: November 2022

Electrifying our transportation is one key step to decrease human society’s fossil fuel consumption, therefore, reducing CO2 emissions. In the past decade, electric vehicles (EVs), especially electric passenger cars, are successfully commercialized and are gaining increasing market shares. Most of these EVs are powered by Li-ion batteries (LiBs) due to their high performance over other alternative vehicle power sources. After three decades of development, the energy density of LiBs has steadily increased to >250 Wh/kg at the cell level, which enables EVs with a comparable drive range to their gasoline counterparts. However, the charging time of LiBs is much longer than the refueling of a gasoline tank. The current battery technology can only achieve 80% charge for >30-40 minutes at a high temperature (40-50°C), which falls short of the U.S. Department of Energy (DOE)’s target of 80% charge within 10 minutes. Achieving such a super-fast charging performance without degrading battery life is a challenge that still has not been solved.
In this talk, I will discuss our latest findings that by engineering the composition of the electrolyte, the charging performance of LiB can be significantly enhanced. When compared with the commercial carbonate electrolytes (1M LiPF6 in EC-DMC, LP30; or 1M LiPF6 in EC-EMC, LP50), our electrolytes show remarkably better charging performance at all charging rate > 1C. Some formulation of our electrolyte is able to deliver >80% charge at 4C rate within 15 minutes at room temperature. I will discuss our fundamental study to understand the mechanisms underlying the remarkable charging performance of our electrolytes compared to the commercial carbonate electrolytes.
Carbon-Binder Optimization for Lithium-Ion Battery Extreme Fast Charge
Authors: Usseglio-Viretta Francois L. E. , Colclasure Andrew M. , Dunlop Alison , Trask Stephen E. , Jansen Andrew N. , Abraham Daniel P. , Rodrigues Marco-Tulio F , Dufek Eric J. , Tanim Tanvir R. , Chinnam Parameswara R. , Ha Yeyoung , Smith Kandler 
Published: November 2022

Battery performance is strongly correlated with electrode microstructure and weight loading of the electrode components. Among them are the carbon-black and binder additives that enhance effective conductivity and provide mechanical integrity. However, these both reduce effective ionic transport in the electrolyte phase and reduce energy density. Therefore, an optimal additive loading is required to maximize performance, especially for fast charging where ionic transport is essential. Such optimization analysis is however challenging due to the nanoscale imaging limitations that prevent characterizing this additive phase and thus quantifying its impact on performance.
In this work [1], an additive-phase generation algorithm [2] has been developed to remedy this limitation and identify percolation threshold used to define a minimal additive loading (cf. figure, left). Impact of carbon-black binder (CBD) loading on electrochemical performance has been investigated through a wide array of numerical methods and experiments on NMC/graphite cells. These range from the representation, characterization, and homogenization of electrode microstructures, battery macroscale modeling, and impedance and rate capabilities measurements on various cell formats. The combined work provides information on connectivity/percolation of the solid network, effective solid conductivity and ionic diffusivity, interfacial area, cell capacity, lithium plating, impedance, and transport polarization at the beginning of life (BOL) [1]. Rate capability test demonstrates capacity improvement at fast charge at BOL (cf. figure, right), from 37% to 55%, respectively for high (10%wt) and low (4%wt) additive loading during 6C CC charging (and from 80% to 86% at the end of 10 min 6 CC-CV), in agreement with macroscale model. Improvements are attributed to a combination of lower cathode impedance, reduced electrode tortuosity and cathode thickness [1].
[1] F. Usseglio-Viretta et. al., Carbon-binder Weight Loading Optimization for Improved Lithium-ion Battery Rate Capability, submitted to Journal of the Electrochemical Society

[2] F. Usseglio-Viretta et. al., SoftwareX, 17, 100915 (2022), https://doi.org/10.1016/j.softx.2021.100915

Figure 1
Understanding the Unreliability Issues of Performance and Safety Diagnostics of Lithium-Ion Batteries Under Extreme Conditions
Authors: Tanim Tanvir R. , Walker Lee K , Todd Jordan 
Published: November 2022

The research and development (R&D) community is continually pushing for high energy density Lithium-ion batteries (LiBs) by innovating materials, designs, and operating conditions.1 We expect these batteries to operate under a range of conditions (e.g., fast charging, fast discharging, low temperatures, etc.).1,2 Advanced diagnostics could play a key role in ensuring an extended life of these energy-dense LiBs while ensuring their safety. Therefore, a parallel effort is enabling advanced diagnostics and prognostics to ensure the safe operation of these batteries under the stated conditions throughout their service lives.
Many researchers have proposed different performance and safety diagnostics of LiB in their early stages, often using small or specially designed cells through controlled tests.1 Extending these diagnostics to automotive grade cells in real life environments has not been performed extensively to understand their uncertainties. This gap in development between the early R&D stage to near the deployment stage is impeding their maturity; hence, delaying their adoption in their expected applications.
In this presentation, we will discuss the unreliability issues of different electrochemical and electromechanical diagnostics related to LiBs under different safety critical conditions when cell size, age, and operating conditions changes. We will discuss the underlying issues of unreliability in different diagnostics with experimental data, followed by a discussion of several emerging safety diagnostics. Finally, the need for independent evaluation of LiB safety diagnostics along with some logistical pathways to do so will be discussed.

References

T.R. Tanim, E. J. Dufek, and S. V. Sazhin, MRS Bulletin, 46, 420-428 (2021)

S. Ahmed et al., J. Power Sources, 367, 250–262 (2017).