bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Temperature Dependence of Nonradiative Transitions of an Excited Optical Ion in Solids Using the Proper Adiabatic Approximation
Authors: Collins John , Mishra Kailash C , Osborn Benjamin
Published: November 2022

We have investigated the theory of the temperature dependence of nonradiative transitions of an optical ion in a solid from one electronic state to another using the proper adiabatic theory. The Hamiltonian, based on the nonadiabaticity operator, has been used to calculate the temperature dependence of nonradiative transition rates. The Hamiltonian, Hna

, consists of two terms, as shown in Equation 1 below.

The first term is usually used to explain nonradiative transitions of an optical ion in solids. We have shown that the first term alone leads to a zero of the transition rates at s = z for low temperature where s represents the Huang-Rhys parameter, and z relates to the energy gap between the excited state and ground state in terms of vibrational quantum of energy, hν. This zero of the transition rate cannot be removed unless the second term is included in the calculation of the transition rates on the basis of the Fermi Golden rule and the Boltzmann distribution of occupation of the vibrational states in thermal equilibrium at temperature, T, in the excited state.

Additionally, we define three functions, U1
, U2
, and U3
to describe the thermal dependence of the transition rate, corresponding to the two terms of Hna
and a cross term that appears when applying the Fermi Golden rule to calculate the transition rates. A linear combination of these three terms leads to a physically meaningful description of the temperature-dependent, nonradiative transition rate between two electronic states. These functions are used to express the temperature dependence of the quantum efficiency of a phosphor. A comparison of results from simulations and experiments will be presented.

Figure 1
30-Seconds Sars-Cov-2 Human Sample Diagnosis and Analytical Specificity Analysis Using Disposable Strips on a Metal-Oxide-Semiconductor Field-Effect Transistor Platform
Authors: Chiang Chao-Ching , Chiu Chan-Wen , Xian Minghan , Ren Fan , Tsai Cheng-Tse , Liao Yu-Te , Esquivel-Upshaw Josephine F , Pearton Stephen J
Published: November 2022

A SARS-CoV-2 rapid detection technology employed commercially available test strips similar to the blood glucose test strips were developed with a detection time of 30 sec and the sensitivity as good as polymerase chain reaction (PCR). The analytical specificity of this technology was also investigated by testing the cross-reactivity and microbial interference on this biosensor platform using FDA suggested 31 different contaminants. Variants of SARS-CoV-2 have mutated along with the worldwide spread of the pandemic. Currently, the most common detection methods are PCR and lateral flow tests. The former takes more than an hour to obtain results and the latter has difficulty detecting the virus at low concentrations (for cycling threshold values, CT values, >25 to 27). Therefore, the demand for a fast, cost-effective, and low detection limit testing method has been significantly increased. In this work, 60 human saliva samples with 30 positive and 30 negative were collected and tested with PCR for SARS-CoV-2 prior to using our disposable strips. For this technology, the test strip was connected to the gate electrode of the MOSFET on the printed circuit board that serves to amplify signals. A synchronous double-pulsed bias voltages (around 1 ms) were sent to both the drain and gate of the MOSFET. The resulting change in drain waveforms was converted to digital readings and compared with cycling threshold (Ct) values of human samples to assess this sensor technology. The result signifies that positive human samples with a range of Ct values from 17.8 to 40 can be differentiated, along with proving none of those high-risk organisms would hinder the sensitivity of our system. Which demonstrated the potential of this system to be developed into a cost-effective and point-of-care rapid detection for SARS-CoV-2.

Figure 1
(Digital Presentation) Electrochemical and Spectroscopic Studies of Bismuth(III) Compounds with L-Cysteine and L-Glutathione
Authors: Cheek Graham , Schlessman Jamie , Pena Dominik , Huang Jonathan
Published: November 2022

Introduction

Previous research from this laboratory has involved the investigation of bismuth(III) compounds with L-cysteine1. It was found that bismuth(III) nitrate interacts extensively with L-cysteine in aqueous solutions, primarily through the strong bond between the bismuth(III) and the L-cysteine thiol group. The extent of this interaction was assessed by monitoring changes in cyclic voltammetric peak potentials, as well as UV-VIS absorption characteristics, as L-cysteine was added to the solutions. Considerable work has now been carried out on pharmaceutical medications2 such as bismuth subsalicylate (BSS) and bismuth citrate (BC) at pH 1.00 and 3.00 to simulate conditions in the human stomach, as well at pH 7.40 MOPS [(3-N-morpholino)propanesulfonic acid] to simulate general physiological conditions. In addition, studies of the cysteine-containing tripeptide glutathione have also been conducted.

Results and Discussion

By comparing results at pH 1.00 and 3.00 to those at pH 7.40 for all bismuth compounds investigated, it has been found that the extent of interaction of these compounds with added L-cysteine is much less at the lower pH levels. This conclusion was reached by noting that the absorbance of the characteristic band at 340 nm, due to the bismuth-sulfur interaction, was much lower at pH 1.00 and pH 3.00 than at pH 7.40 at corresponding levels of L-cysteine addition. Such results can be explained by the higher L-cysteine protonation state at the lower pH values compared to that at pH 7.40. This higher protonation state lessens the bismuth-sulfur interaction at the lower pH values. Interesting changes were also found in the cyclic voltammograms as L-cysteine was added in these situations. For bismuth(III) citrate (BC) at pH 7.40, a well-formed absorbance band at 320 nm was formed upon L-cysteine addition, reaching a limiting absorbance value at a 2:1 L-cysteine:BC ratio. For bismuth(III) salicylate, however, the absorbance at 300 nm to 340 nm was much lower than for BC, showing that the salicylate ligand strength is somewhat less than that for the citrate ligand under these conditions. It is also planned to present the results of similar work involving glutathione as a ligand.

References

T. Cheek and D. Peña, J. Electrochem. Soc.,
167, 155522 (2020)

Li, R. Wang, and H. Sun, Acc. Chem. Res.,
52, 216 (2019).
Carbon Nanomaterials Interfaced to Photosystem I for Bioelectrochemical Energy
Authors: Cliffel David E , Stachurski Christopher , Williams John
Published: November 2022

Photosystem I (PSI) is one of the primary macromolecular machines that drive photosynthesis in green plants and cyanobacteria. Extracted PSI has been employed successfully as a macromolecular photosensitizer within a host of low-cost electrochemical and solid-state photovoltaic architectures. This presentation will also explore our group’s recent efforts to integrate PSI with advanced nanomaterials, including carbon nanotubes, carbon quantum dots, and conducting polymers polyaniline (PANI), polypyrrole, polyviologens, and poly(3,4-ethylenedioxythiophene). These composite assemblies enhance charge shuttling processes from individual proteins within multilayer assemblies—greatly reducing charge transfer resistances and improving overall efficiency of photocells. The group has reported two new prototype solid-state devices in which PSI or PSI/PANI is sandwiched between energetically appropriate electrodes. The group has also succeeded in stabilizing PSI films via crosslinking to create “wet” photoelectrochemical cells with greater performance and longevity. Finally, our current work is aimed at building new prototypes using PSI in solid state interfaces for scalable solar energy conversion. Finally, the incorporation of PSI into conducting polymer frameworks holds promise for improved conductivity and orientational control in the photoactive layers in these devices.
(Digital Presentation) Cathodic Exfoliation of Few-Layer Tellurium As Electrocatalyst Support for Hydrogen Evolution
Authors: Zheng Weiran , Lee Lawrence Yoon Suk
Published: November 2022

Few-layer tellurium represents the two-dimensional (2D) form of tellurium crystal with the majority of the Te atoms exposed on its surface. Recent studies demonstrated that 2D Te has good environmental stability and high charge carrier mobility, making it suitable electrocatalyst support to host active sites and assist electron transfer between the electrode and the sites [1]. Yet, its mass production for electrocatalysis application remains challenging.

In this study, we present a simple cathodic exfoliation method to exfoliate commercially available Te crystal directly into few-layer tellurium with exceptionally high yield [2] (see Figure 1A). Using alkaline aqueous electrolyte (1.0 M KOH), Te nanosheets with the thickness of 7~10 nm and lateral size of 1~4 µm were produced at an applied potential of −0.42 V (vs. RHE). Combining in situ Raman spectroscopy and ex situcharacterization results, we were able to reveal the exfoliation mechanism, where the in situ generated ditelluride (Te2
2−) anions on the nanosheets played the critical role of separating nanosheets from the bulk crystal (see Figure 1B).

At the presence of transition metal ions in the electrolyte, such as Pt2+ and Ni2+, simultaneous surface doping of Te nanosheets was enabled by the interaction between Te2
2− anions and metal ions, producing Pt/Ni-doped Te with tunable doping level. Such doped nanosheets exhibited high stability and hydrogen evolution reaction (HER) activity. Particularly at high potential, Pt-doped Te nanosheets outperformed both polycrystalline Pt and commercial Pt/C catalysts (see Figure 1C). We suggested a collaborative hydrogen production mechanism via Volmer–Heyrovsky pathway to justify such unusual activity. In short, at HER conditions, the surface Te atoms of Pt-doped Te nanosheets are reduced to Te2
2− anions. Such species can help attract protons and assist their transfer to adjacent Pt atoms, where the protons are reduced to form hydrogen (see Figure 1D).

Figure 1 (A) Experimental setup and photos of the electrochemical exfoliation of Te crystal; (B) Exfoliation mechanism; (C) HER performance and relative energy of Pt-doped Te with various doping levels; (D) Collaborative HER mechanism.

Reference:

Shi, Z.; Cao, R.; Khan, K.; Tareen, A. K.; Liu, X.; Liang, W.; Zhang, Y.; Ma, C.; Guo, Z.; Luo, X.; Zhang, H., Nano-Micro Lett.
2020, 12 (1), 99.

Zheng, W.; Li, Y.; Liu, M.; Lee, L. Y. S., Small
2021, 17 (18), e2007768.

Figure 1
(Digital Presentation) Charge Trapping in TiO2 Nanoparticles
Authors: Juhasz Gergely
Published: November 2022

TiO2 is a common component of electrode surfaces and photocatalytic systems. Depending on the preparation, the oxide can be formed in different shapes and morphology which can effect the selectivity and efficiency of the electrode [1]. Since the morphology and shape of the nanoparticles can be easily tuned with experimental conditions, this may offer a new, unexplored strategy to improve electrode properties in these systems. The goal of our computational studies is to understand better how charge carriers behave in these oxide nanoparticles.

We studied the electronic states around the bandgap in anatase-type TiO2 nanoparticles of different shapes with (101) and (001) facets using Density Functional based Tight Binding (DFTB) and DFT methods. The previous calculation has already shown that most orbitals of the valence and conduction bands form delocalized band-like orbitals; however, there are a significant number of localized states at the lower edge of the conduction band, too. The calculations clearly show the position of these trapping sites when we compare the electron density of neutral and charged nanoparticles.

Reference:

[1] Selectivity enhancement in the electrochemical reduction of oxalic acid over titanium dioxide nanoparticles achieved by shape and energy-state control. H Eguchi, K Kato, G Juhasz, M Yamauchi - Catalysis Science & Technology, 2021

Figure 1. The electron density difference between negatively charged and neutral nanoparticle (left); electron density difference reflected in Mulliken charges of the atoms (right).

Figure 1
Production of Hydrogen in High-Temperature Molten Salts, and Its Utilization for the Clean Preparation of Metals and Alloys
Authors: Kamali Ali Reza , Xie Kaiyu
Published: November 2022

The economical production of hydrogen is an essential step towards the decarbonization of industrial sectors, including metals and alloys production processes. The available water electrolysis technologies used for hydrogen generation suffer from limitations, including the high voltage required in the electrolysis unit (typically > 1.8 V), reducing the energy efficiency of such processes and their compatibility with solar power systems. Here, the electrochemical generation of hydrogen in high-temperature molten salts at voltages as low as 1 V is discussed. Moreover, the utilization of the electrogenerated hydrogen for the in situ reduction of metal oxides into corresponding metals are evaluated using techniques such as voltammetry and constant voltage electrolysis operations combined with X-ray diffraction and electron microscopy examinations. To this end, the hydrogen generation in molten LiCl under humid atmosphere, and the hydrogen reduction of oxides of iron, nickel and cobalt in molten salt at the low-cell voltage of around 1.5 V are studied, and compared with each other. Moreover, the intermediates compounds formed during the reduction processes are identified, shedding light onto mechanisms involved in low-voltage green production of metals in molten salts.
Electrochemical Behavior of MgOH+ in Molten MgCl2-KCl-NaCl Salt
Authors: Witteman Liam , Rippy Kerry , Vidal Judith , Taylor Patrick R.
Published: November 2022

Research on molten chloride salts as a high-temperature (500-800 ℃) heat transfer fluid has been reinvigorated in recent years. Its abundance, low cost, and good thermohydraulic properties have drawn attention from the nuclear and concentrated solar power industry. Specifically, a ternary MgKNa chloride salt (45.98/38.91/15.11 wt.%) has been considered a prime candidate for commercial application. However, economic risk remains due to high corrosion of containment alloys.

The rate of corrosion in ternary MgKNa chloride salt has been primarily attributed to the impurity MgOH+, stemming from the reaction of MgCl2 with moisture. Extensive research has been conducted to purify chloride salts, but little attention has been given to on-line purification strategies once the salt is molten and circulating in the plant. One proposed strategy is continuous electrochemical purification via electrolysis using a Mg anode and W cathode. This strategy has been successfully demonstrated at the laboratory scale. Work done in our group indicate significant opportunity for the electrochemical process to be scaled up commercially as an electrochemical purification unit.

Here, we present a study on the electrochemical behavior of MgOH+ reduction on a W cathode in molten MgCl2-KCl-NaCl across the temperature range of 475-525 ℃. The kinetic parameters from this study aid in modeling and scaling up an electrochemical purification cell at industrially relevant scales.
The Transition (vs ΔpKa) from Triple Ions to Free Cations in Poor Protic Ionic Liquids Made from Weak Acids
Authors: Rana Smit S. , East Allan L. L.
Published: November 2022

In mixtures of amines with carboxylic acids, the limited ionicity at 1:1 stoichiometric mixtures is due to insufficient ionization and/or ion pairing in low-dielectric environments. Higher conductivities have historically been seen at 5:1 acid:base mixing ratios, where simulations have revealed large (and thus more stable) ions: homoassociated anions (AH)2A−(HA)3 and cationic triple ions B+(AH)A− (HA)2B+. Recent work in understanding the Gibbs energies for degree-of-ionization equilibria hints that there may be an onset, for systems with an acid-base pKa difference increasing towards 10, for the formation of free (unpaired) protonate-amine ions BH+. The speed (gradual? sudden?) of such an onset with increasing ΔpKa is explored in this work, with the aim of better understanding the limited ionicity phenomenon in protic ionic liquids.
Correlation between Ion Transport and Structural Heterogeneity in Triazole-Based Polymerized Ionic Liquids
Authors: Jeddi Javad , Sangoro Joshua , Niskanen Jukka , H. Lessard Benoît
Published: November 2022

In this study, the relationship between chemical structure, nanoscale organization, and ion transport in 1,2,3-triazolium polymerized ionic liquids (PILs) was investigated by wide-angle X-ray scattering (WAXS) and broadband dielectric spectroscopy (BDS). Analyzing the WAXS and BDS results indicated that mobile ion types and chemical structure of the pendant groups controlled structural heterogeneity and ion conduction of the PILs below Tg. The normalized heterogeneity length extracted from WAXS data was used to correlate the structural heterogeneity and ion conduction activation energy. For the polycation samples, larger TFSI– mobile anion results in a higher packed structure than small Cl– while in the polyanion samples inverse trend was observed. The calculated activation energy of the dc conductivity below Tg is quantitatively correlated to the structural heterogeneity obtained from nano structure analysis using WAXS. This suggested increasing the spatial heterogeneity of the PILs results in the reduction of the activation energy of long-range ion motions. These results highlight the role of spatial heterogeneity in designing efficient polymerized ionic liquids
Anodic Behaviour of Ni-Fe-Cu electrode In Molten Fluoride Salts
Authors: Saevarsdottir Gudrun , Singh Kamaljeet , Haarberg Geir Martin , Bourmaud Milane , Padamata Sai Krishna Krishna
Published: November 2022

The industrial process for Aluminium production is the Hall-Héroult process, an electrolysis process where the alumina raw material is dissolved in a cryolite based electrolyte, the aluminium is deposited at the cathode while the oxygen from the alumina reacts anodically with the carbon anodes, which are consumed in the process. The chemical energy in the carbon anodes provides part of the process energy, resulting in CO2 emission of about 1.6 kg/kg aluminium produced. In industrial cells, the electrolyte is modified from the cryolite, Na3AlF6, composition by adding AlF3 to lower the process temperature and improve current efficiency. This modification can be characterized by the Cryolite Ratio, CR, which is the molar ratio of NaF/AlF3. In modern cells, this ratio is often as low as 2.2, as compared to 3 in pure cryolite, which enables an operating temperature of around 960°C, as compared to more than 1009°C for Cryolite.

One way to eliminate CO2 process emissions from aluminium electrolysis is to switch from consumable carbon anodes to inert anodes, resulting in O2 emissions instead of CO2. Significant effort has been put into achieving this, but the challenge is to find anode materials that can withstand the harsh conditions in the high temperature cryolite based electrolyte. It would help anode life to reduce the electrolysis temperature from 960 °C to 800 °C or lower. Lowering the CR to 1.3 or lower would achieve this, but for traditional electrolyte components this would lower the alumina solubility to unacceptably low levels. By replacing some of the NaF in the electrolyte with KF, it is possible to operate at this very low CR with acceptable alumina solubility.

In this paper, we present a study on anode performance in potassium-rich low CR electrolyte. Both electrodes are vertical, the anodes made of homogenised CuFeNi alloy and cathodes of hot-pressed TiB2. The paper describes the effect of varying the anode composition, anode surface treatment as well as current density on anode stability. Also, the effect of varying the ratio of KR = KF/(NaF+KF), process temperature as well as alumina saturation is addressed.

In general, pre-oxidation of the metallic anodes as well as the Cu content greatly affects anode stability. It is possible to operate at low temperature at lower KR, improving the industrial viability of the process, as NaO is added to the cells with the alumina, this reduces the alumina solubility which puts constraints on the process control. The aluminium obtained by electrolysis in this system had less than 0.2% impurities from the electrodes.
Ionic Liquids Containing the Sulfonyl Fluoride Moiety: Integrating Chemical Biology with Materials Design
Authors: Anderson Grace I , Hillesheim Patrick C , Mirjafari Arsalan
Published: November 2022

Research involving functionalized ionic liquids has become quite wide speared. They can serve as powerful tools to improve society, with a wide range of applications in medicine, science, and technology. As a SuFExable functionality, the sulfonyl fluoride has become widely adopted throughout the field of chemical biology due to its unique stability─reactivity pattern, highlighting the underappreciated potential of the S(VI)--F motif in ionic liquid design. For the first time, we have developed a new series of task-specific ionic liquids containing the sulfonyl fluoride motif -- a thermally stable and chemically robust functionality -- in gram-quantity scale. Significantly, inclusion of active pharmaceutical precursors and judicious variation of heterocyclic headgroups throughout the synthetic design process, resulted in structural diversity with a priori reduced ecological footprint. We employed a combination of molecular design, synthesis, computational modeling, and X-ray crystallographic studies for understanding of their structure-property relationships.
Anion Equilibria and Stability of Quaternary Phosphonium Chloroaluminate Ionic Liquids
Authors: Durkin David P. , Stachurski Christopher D. , Cosby James , Trulove Paul C. , Mantz Robert A
Published: November 2022

While imidazolium based chloroaluminate ionic liquids have been studied for decades, with interest increasing over the last several years, phosphonium analogues have received less attention. Recent work has shown phosphonium-based chloroaluminate ionic liquids have significant potential as battery electrolytes due to their high thermal stability and wide electrochemical windows. In order to realize their full potential, fundamental studies on the ion dynamics and transport properties of these systems are required. This work focuses on studying the anion speciation and ion dynamics of a series of acidic chloroaluminates containing phosphonium cations with incrementally varied structures. Their properties are probed through broadband dielectric spectroscopy and oscillatory shear rheology to reveal the frequency and temperature dependence of properties such as conductivity, permittivity, and modulus. We will present preliminary work on the impact of changes in cation structure and ionic liquid composition on anion speciation, transport properties, and dynamics. The results expand our understanding of these important electrolyte systems that hold significant promise for applications such as energy storage, electrodeposition, and chemical synthesis.
(Invited) Using Machine Learning to Guide Ionic Liquid Design
Authors: Shah Jindal
Published: November 2022

Ionic liquids can be considered as nonaqueous, highly concentrated electrolytes composed entirely of ions with melting points typically less than 1000C. Many ionic liquids are derived from an organic cation and an organic/inorganic anion, at least one of them possessing low charge density, rendering them liquids near ambient conditions. Properties such as negligible vapor pressure, nonflammability, and high thermal stability are primary drivers for using ionic liquids as potential electrolytes in the next-generation batteries and energy storage devices. Despite the favorable attributes, challenges surrounding low ionic conductivity and sometimes low electrochemical stability need to be surmounted. Although ionic liquid properties can be tuned by changing the cation, anion, and/or substituents on the ions, the chemical space is too vast to be navigated efficiently either experimentally or using atomistic simulation techniques. In this presentation, our efforts at addressing these challenges with machine learning techniques will be described.
Determination of the Formation Potential of Solid-Electrolyte Interphase in Some Amide-Type Ionic Liquids Containing Metal Salts
Authors: Kato Shodai , Serizawa Nobuyuki , Katayama Yasushi
Published: November 2022

Amide-type ionic liquids (ILs) have been investigated as the electrolyte for secondary batteries because they have such favorable properties as non-flammability, low-volatility, and the electrochemical stability.1,2 However, the ILs have been reported to decompose cathodically at the potentials more positive than the deposition potential of Li and form solid-electrolyte interphase (SEI) on the electrode.3 Although the formation of the SEI is favorable for lithium secondary batteries, the SEI may hinder the electrode reactions of the active materials when the ILs are used as the electrolytes for redox flow batteries. In the present study, the formation potentials of the SEI in two amide-type ILs, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)amide (BMPFSA) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing metal salts were investigated in the presence of a redox species.

BMPBr was prepared by the reaction of 1-methylpyrrolidine and 1-bromobutane in acetonitrile. BMPFSA was obtained by the interaction of BMPBr with LiFSA in distilled water. BMPFSA was dried under vacuum at 80 °C for 48 hours before use. BMPTFSA and the metal salts were used as supplied. The water content in BMPFSA and BMPTFSA was less than 10 ppm. The electrochemical measurement was carried out with a three-electrode cell in an argon-filled globe box. A Pt disk and wire were used as a working and counter electrode, respectively. Ag wire immersed in BMPFSA or BMPTFSA containing 0.10 M AgCF3SO3 was used as a reference electrode, which is denoted by Ag|Ag(I).

The anodic peak potentials in the cyclic voltammograms in the ILs containing the redox species were almost constant after holding the potentials more positive than the cathodic decomposition potentials. On the other hand, the anodic peak potentials changed by holding the potential at the negative potential region in the presence of the metal species, suggesting that the potential of the SEI formation can be determined more sensitively by monitoring the redox reaction.

References

[1] M. Yamagata, Y. Katayama, and T. Miura, J. Electrochem. Soc., 153, E5 (2006).

[2] K. Matsumoto, T. Hosokawa, T. Nohira, R. Hagiwara, A. Fukunaga, K. Numata, E. Itani, S. Sakai, K. Nitta, and S. Inazawa, J. Power Sources, 265, 36 (2014).

[3] R. Furuya, N. Tachikawa, K. Yoshii, Y. Katayama, and T. Miura, J. Electrochem. Soc., 162, H634 (2015).
Optimizing the Current Collector for Sodium Iodide-Metal Halide Catholytes in Low-Temperature Molten Sodium Batteries
Authors: Maraschky Adam M. , Meyerson Melissa L , Percival Stephen J. , Gross Martha M. , Peretti Amanda S. , Spoerke Erik D. , Small Leo J.
Published: November 2022

Low-cost, long-duration energy storage is critically needed for a robust electric grid powered by renewable sources. In the pursuit of meeting this need, low-temperature (<130 °C) molten sodium batteries (MNaBs) with NaI-metal halide molten salt catholytes have been developed. This battery design circumvents many of the safety concerns caused by metal dendrites and flammable organic solvents found in Li-metal or Li-ion batteries. It also drastically reduces the high-temperature material requirements and operating costs compared to traditional MNaBs, such as ZEBRA, which operate near 300 °C. The presented battery operates at 110 °C—just above the melting point of Na (98 °C). It features a molten Na anode, a NaSICON ceramic separator, and a NaI/AlCl3 catholyte.

Among the key challenges to widespread utilization of these emerging MNaBs is reducing the overpotential on the cathode while operating at practical current densities over numerous cycles. To improve the performance of the cathode, we examined the electrochemical behavior of a variety of disk electrode materials, including W, Mo, Ta, and glassy carbon (GC) in a 3-electrode configuration. A custom cell was designed to mimic a full battery with separators for both the reference and counter electrodes. Excess molten salt was used to keep bulk concentrations practically constant over the course of the experiments. This enabled experiments that isolated the working electrode from other battery elements, such as a changing catholyte or the NaSICON interfaces. Voltammetry, electrochemical impedance spectroscopy, chronopotentiometry, and chronoamperometry were used to evaluate each material’s charge/discharge kinetics and stability. Instability on charging is hypothesized to be due to iodine (I2) adsorption on rapid iodide (I-) oxidation. Discharge, on the other hand, is limited by the transport of triiodide (I3
-), which depends on the battery’s state of charge. Insights from these studies serve as the foundation for the rational design of high-surface area electrodes for iodide-based molten salt catholytes. After initial testing in the 3-electrode cell, the performance of several high surface area current collectors was evaluated in rate tests and continuous cycling of lab-scale battery cells.

Sandia National Laboratories is a multi-mission 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.
Electrodeposition of Nickel From an Amide-Type Ionic Liquid Under a Magnetic Field
Authors: Katayama Yasushi , Manabe Yuina , Serizawa Nobuyuki
Published: November 2022

Aprotic ionic liquids are considered to be used as the promising electrolytes for electrodeposition of wide variety of metals and alloys. Nickel is one of the ferromagnetic metals and can be deposited in an amide-type ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing Ni(TFSA)2.[1] Furthermore, Ni nanoparticles were prepared in the ionic liquid by potentiostatic cathodic reduction at a negative potential region.[2] Recently, we reported that the nanowires of a ferromagnetic metal and alloy could be deposited electrochemically by applying a static magnetic field without any template.[3-5] The formation of metal nanowires is considered to be due to the magnetization and self-organization of the nanoparticles at the electrode-electrolyte interface. Thus, the similar nanowires are expected to be obtained for ferromagnetic metals like Ni. In the present study, electrodeposition of Ni was conducted in BMPTFSA containing Ni(TFSA)2 under a static magnetic field.

The cathodic reduction of Ni(II) was observed in the cyclic voltammogram of a glassy carbon (GC) electrode in BMPTFSA containing Ni(TFSA)2, as reported previously.[1] An increase in the cathodic peak current and the positive shift of the onset potential of the cathodic current were observed when a magnet was attached on the backside of the GC electrode. Granular deposits were observed after potentiostatic cathodic reduction without the magnet. However, nanowires were deposited on the GC electrode with the magnet, verifying the electrodeposition of ferromagnetic metals in the ionic liquid under a magnetic field leads to the formation of the nanowires.

References

[1] Y.-L. Zhu, Y. Katayama, and T. Miura, Electrochim. Acta, 54, 7502 (2009).

[2] Y.-L. Zhu, Y. Katayama, and T. Miura, Electrochem. Solid-State Lett., 14, D110 (2011).

[3] M. Manjum, N. Serizawa, A. Ispas, A. Bund, and Y. Katayama, J. Electrochem. Soc., 167, 042505 (2020).

[4] M. Manjum, N. Serizawa, and Y. Katayama, J. Electrochem. Soc., 168, 042504 (2021).

[5] H.-W. Yeh, N. Serizawa, and Y. Katayama, J. Electrochem. Soc., 168, 082502 (2021).
Primary Production of Aluminium and Its Alloys in Molten Salts with Oxygen Evolving Anodes: Overview
Authors: Padamata Sai Krishna Krishna , Singh Kamaljeet , Haarberg Geir Martin , Saevarsdottir Gudrun
Published: November 2022

Carbon dioxide and other greenhouse gases are emitted during the production of primary aluminium through the Hall-Heroult process. Moreover, the process requires specific energy consumption of as high as 14.685 kWh/tonne of Al. There is an urgency to replace the existing process with a more environmentally and economically friendly process. One such process involves the use of inert anodes instead of traditional carbon anodes, where Al2O3
→ 2Al + 1.5O2 occurs instead of 1.5C + Al2O3 → 2Al + 1.5CO2. The life span of inert anodes can be improved by using them at low operating temperatures, however, alumina solubility and dissolution rate decrease at low operating temperatures. Instead of using a traditional NaF-AlF3 molten solution, NaF-KF-AlF3 or KF-AlF3 could be used as low-temperature electrolytes. Introducing KF salt into the NaF-AlF3 mixture increases the alumina solubility and reduces the liquidus temperature of the molten salt. Another factor that affects the liquidus temperature of the mixture and alumina solubility in the electrolyte is the cryolite ratio , where M = Na or K (or both). It should be noted that the cells with AlF3-rich NaF electrolytes suffer with problems such as high cell voltage, low aluminium purity and unstable frozen side ledges. The addition of CaF2, MgF or LiF to the electrolyte mixture could improve the physical-chemical properties of the electrolyte. For instance, the addition of CaF2 to KF-AlF3 molten salts improves the electrical conductivity of the electrolyte. Specific energy consumption of the cell can be significantly reduced by using a vertical electrode cell with reduced anode-cathode distance (ACD). However, the major problem with low ACD is the contamination of reduced aluminium at cathode by anode products. This problem can be solved by using suspension electrolytes where the electrolyte contains excess about of Al2O3 in the electrolyte which obstructs the transportation of anode products into the aluminium diffusion layer on the cathode, thus maintaining high aluminium purity. In this paper, we summarise the developments obtained in designing the inert anode cells. We mainly focus on three main components: Inert anodes, wettable cathodes, and low-temperature electrolytes. The influence of additives on the properties of electrolytes will be discussed in detail. We also discuss the energy consumption, environmental impact and economic aspects of producing aluminium using vertical electrode cells.
(Invited) High-Performing Fibre Batteries at a Scalable Production
Authors: Peng Huisheng
Published: November 2022

Fibre batteries are pioneering as flexible power solutions because they can be woven into textiles. Textile batteries offer a convenient and seamless way to power future wearable electronics. However, current fibre batteries are only centimetres long because longer fibre batteries are difficult to produce and they are thought to have significantly higher internal resistances that compromise electrochemical performance. Here, we show our discovery that internal resistance of fibre battery has a hyperbolic cotangent function relationship with fibre length, where it firstly decreases before leveling off as length increases. Systematic studies confirm this is true for different fibre batteries. We thus produce metres of high-performing fibre lithium-ion batteries via an optimised industrial process. Our mass-produced fibre batteries had high certified energy density based on the total weight of a lithium-cobalt-oxide/graphite full battery including packaging. Over 80% capacity can be maintained after bending for 100,000 cycles, indicating high flexibility. We show fibre batteries woven into safe and washable textile by industrial rapier loom can wirelessly charge a cellphone or power a health management jacket integrated with fibre sensors and textile display.
(Invited) Synergy of Carbonyl and Azo Chemistries for Wide-Temperature-Range Rechargeable Aluminum Organic Batteries
Authors: Luo Chao , Qin Kaiqiang , Tan Sha , Mohammadiroudbari Motahareh , Yang Zhenzhen , Yang Xiao-Qing , Hu Enyuan
Published: November 2022

Developing low-cost, sustainable, and all-climate energy storage devices as alternatives to Li-ion batteries (LIBs) is critical for the global application of electric vehicles, grid-scale electrical energy storages. Among various emerging battery systems beyond LIBs, rechargeable aluminum organic batteries (RAOBs) stand out because of the high theoretical capacity, low cost, abundance, high sustainability, and high safety of Al and organic resources. However, the large ion size of Al complex ions, such as AlCl4
-, AlCl2
+ and AlCl2+, or the strong Coulombic interaction between Al3+ ions and active materials, as well as the high diffusion energy barrier of Al3+ ion, lead to poor cyclic stability and sluggish reaction kinetics. Moreover, the reaction mechanism, interphase structure, and the impact of multi-functional groups in redox-active organic materials to the electrochemical performance of RAOBs remains elusive. To address these challenges, we designed and synthesized a redox-active polymer bearing carbonyl and azo groups as the cathode to achieve high-performance and wide-temperature-range RAOBs. The polymeric cathode exhibits a high reversible specific capacity, superior cyclic stability, fast charging capability, and a wide operation temperature range (-40oC to 100oC). X-ray photoelectron spectroscopy (XPS), pair distribution function (PDF) analysis, and soft X-ray absorption near edge structure (XANES) were employed to gain fundamental insight into the carbonyl and azo chemistries in RAOBs, as well as the cathode electrolyte interphase (CEI) structure. We demonstrated a step-by-step alumination/de-alumination reaction for carbonyl and azo groups in the polymer cathode and unravel a Al2O3- and AlN-rich CEI, which is critical for the impressive performance of RAOBs.
(Invited) Electrolyte Design for Wide-Temperature Li-Ion and Li-Metal Batteries
Authors: Chen Zheng
Published: November 2022

Improving the wide temperature operation of rechargeable batteries is vital to the operation of electronics in extreme environments, where systems capable of higher energy, high-rate discharge and long cycling are in short supply. In this talk, we will show electrolyte designs to achieve high-energy density and stable cycling performance in wide temperature range for both lithium-ion and lithium metal batteries. We will show how to circumvent the sluggish ion desolvation process found in typical lithium-ion batteries during discharge. These batteries are enabled by a novel ester electrolyte, which simultaneously provided high electrochemical stability and ionic conductivity at low temperature. Then we will extend the fundamental understanding developed from these system to other high-capacity, high-rate electrodes, leading to further improved energy density and stability for both high and extremely low temperatures, demonstrated by rechargeable Li metal batteries using both high-Ni oxide and sulfur cathodes.
Probing Local Ion Insertion through Strain-Current Correlation
Authors: Tsai Wan-Yu , Balke Nina
Published: November 2022

Among different electrochemical energy storage devices, the ones that store a higher amount of energy (e.g., batteries) often undergo larger ion insertion-induced structural transformation and volume change, which results in lower rate performance. The ones that store a lower amount of energy (e.g., supercapacitors) usually show gradual structural change and smaller volume change. There is a strong correlation between electrochemistry and mechanical properties. Understanding the electro-chemo-mechanical coupling and controlling the ion insertion-induced strain is crucial for achieving high power and high energy storage devices. In-situ atomic force microscopy (AFM) is well suited to tackle this task as it allows tracking local volume changes and other mechanical responses sub-nanometer spatial resolution under the conditions close to the device operation

In this work, we monitored electrode volume change via in-situ AFM and demonstrated the electro-chemo-mechanical coupling behaviors during proton insertion into WO3 materials. The concept of mechanical cyclic voltammetry (mCV) curves was developed, and the relationship between electrochemical current and strain was investigated with simplified models. The results revealed multiple ion-intercalation processes with different mechanical responses are involved during electrode cycling. Local heterogeneity was investigated via mCV mapping, confirming that the charging mechanisms varied across the electrode. These local variations could be further correlated to local morphology, crystal orientations, or chemical compositions. We further demonstrate that the mCV approach is applicable to a variety of energy storage materials (e.g., birnessite and MXene) with the increasing complexity of current-deformation relationships.

The work was supported by the Fluid Interface Reactions, Structures, and Transport (FIRST), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Measurements were performed at the Center for Nanophase Materials Sciences (CNMS), which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences.
Developing in Situ Electrochemical Techniques to Understand Mechanisms of Bubble Formation at Aqueous Electrochemical Interfaces
Authors: Zhu Qianhong , Tarpeh William Abraham
Published: November 2022

Many electrochemical water treatment techniques (e.g. nitrate reduction, reactive oxygen species production, direct contaminant oxidation/reduction) rely on the electrochemical reactions that occur at the solid-liquid-gas triple-phase boundary layer, where gas species could be reactants, products, or undesired by-products. Developing foundational knowledge of the mechanisms by which surface bubbles form and how they impact chemical reactivity at surfaces would enhance the optimization and sustainability of electrified water treatment processes.

The overall research goal is to develop in situ scanning electrochemical microscopy (SECM) to improve the microscopic understanding of how gas bubbles nucleate, form, grow, and migrate at solid–liquid interfaces. An important subset of gas-involving or gas-evolving, interfacial electrochemical reactions produces gas molecules dissolved in solution that can nucleate as small nanobubbles on electrode surfaces. These bubbles can grow to macroscopic sizes and interfere with chemical processes by blocking reactants from reaching the electrode-electrolyte interface, or by increasing turbulent mixing via leaving the surface. SECM is used to map the bubble formation mechanisms on the interface and to quantify the chemical species (reactant and product) concentration profile within the diffusion layer of the electrode surface. Here we will use oxygen reduction reaction (ORR) to hydrogen peroxide and nitrate reduction reaction (NO3RR) to ammonium as two model systems to investigate how SECM could help us understand chemical reaction mechanisms at aqueous electrochemical interfaces.
A Comparative Study on Gold Dissolution in Broad pH Range from Acidic to Alkaline Media
Authors: Stojanovski Kevin , Briega Martos Valentin , Zlatar Matej , Cherevko Serhiy
Published: November 2022

Gold is often employed in nanotechnology to develop biosensors and new drug delivery and cancer therapy strategies. Since these applications are used in physiological pH, understanding the stability of gold in a broader pH range including neutral values will provide an useful insight into how to expand the use of gold safely.

By using buffer solutions with a constant concentration of phosphate species, electrochemical dissolution of gold in pH 1, 3, 5, 7, 9, 11 and 12.7 was investigated. The concentration of phosphate species was kept constant in order to minimize the possible effect of anion concentration on gold dissolution. Oxidation/reduction of the metal surface leads to transient dissolution peaks, which are labelled as A1 and C1 on the dissolution profiles on Figure 1. An additional dissolution peak A2 appears when the oxygen evolution reaction (OER) takes place. Quantitatively, there are significant differences. The amount of gold that is transiently dissolved in an alkaline medium is more than an order of magnitude higher than that in an acidic medium at lower potentials. Oppositely, steady-state gold dissolution in alkaline pH in the potential region of OER is hindered. There is an apparent shift in the mechanisms at pH 5. At higher potentials, i.e 1.9 V RHE, there is an apparent loss of peak A2 and a growth of C1. The loss of dissolution of gold due to a change in the mechanism of OER in more alkaline electrolytes is clear at pH 7. To explain the observed difference in gold dissolution, a difference in the thickness of compact oxide formed in acid and base is suggested. The formation of thicker oxide as a result of an increase in pH becomes noticeable with the observed increase in both peaks A1 and C1 that can be seen when the pH is increased from 7 to 12.7. These new data on Au dissolution in a broad potential and pH range should be used to minimize Au dissolution in various applications.

Figure 1
Surface Characterization of Catalyst-Ionomer Interactions for Pt Fuel Cell Electrodes Using Varied Carbon Supports
Authors: Foster Jayson , Zaccarine Sarah , Baez-Cotto Carlos , Dzara Michael , Kim Sara , Batool Mariah , Jankovic Jasna , Ulsh Michael , Mauger Scott A , Pylypenko Svitlana
Published: November 2022

Proton exchange membrane fuel cells (PEMFCs) are a progressive technology capable of providing on-demand energy without contributing to greenhouse gases. To meet the needs of transitioning from lab-scale fabrication to large-scale manufacturing, further analysis of catalyst layers is necessary. A common issue within the cathode catalyst layer (CL) is non-uniform distribution of the ionomer within the catalyst layer. Additionally, the interface between catalyst and ionomer is not well understood.

X-ray photoelectron spectroscopy (XPS) is a highly surface-sensitive technique primed to provide new insights into the challenging interfacial interactions and chemistries among the catalyst, support, and ionomer. Although Nafion is inherently susceptible to X-ray degradation, XPS can be used effectively through a modified acquisition strategy developed previously in our group. In this work, XPS has been used to probe CLs with focus on the catalyst-ionomer interface and interactions using a series of electrodes prepared by a Mayer rod coating method. The catalyst-ionomer interface was investigated as a function of support material, Pt loading on the support, and ionomer loading. Surface information was acquired using ex situ and in situ XPS to emphasize the evolution of this technique’s capabilities at probing ionomer interactions. Complementary characterization with scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) in combination with energy-dispersive X-ray spectroscopy (EDS) mapping of catalysts and electrode cross-sections were utilized to visualize distribution of catalyst, carbon, and ionomer in the CL to assist with interpretation of XPS data. Results from this dataset emphasize the potential of this technique to study complex interfaces in PEM catalysts layers motivating further work expanding to other catalysts and ionomers.