bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Asymmetry of Perfluoro anion in Ionic Liquids: From Basic Physical Properties to the Application in Lithium Batteries
Authors: Matsumoto Hajime , Kubota Keigo , Sano Hikaru 
Published: December 2024

From the late 1990s, room temperature molten salts composed of stable perfluoro anion became known as ionic liquids and have been widely recognized and applied in various fields of chemistry for almost three decades. Our research focuses on the use of aliphatic quaternary ammonium cations (AQA) as electrolytes for lithium secondary batteries, which possess unique properties of non-volatility, non-flammability and relatively wide electrochemical window that cannot be achieved with conventional electrolytes. To improve battery performance by reducing the internal resistance of the battery system, we investigated various perfluoro anion as shown in Figure 1. From these studies we concluded that the rate characteristics of lithium secondary batteries with ionic liquids depend not only on viscosity, which governs the diffusion of Li+, but also on the chemical structure of the perfluoro anion, which govern the interaction between Li+ and the anions.1)-3)

On the other hand, through these studies, we found that the asymmetry of the anion structure 4)-6) and the ether oxygen in the anion side chain7) have significant effects on thermal and transport properties of the ionic liquid, similar to the asymmetry of the cation represented by 1-ethyl-3-methylimidazolium and the ether oxygen in the side chain represented by N,N-dimethyl-N-ethyl-N-(2-methoxyethyl)ammonium. The most striking results are obtained by lithium (fluorosulfonyl) (trifluorosulfonyl) amide (LiFTA)8), which exhibits a relatively low melting point (T
m
= 100 °C) among the Li salts and has applications in battery electrolytes 8) and unique electrochemical properties9).
Here, we would like to show the importance of developing new anion species that give rise to novel ionic liquids and alkali metal salts based on our results.
1) H. Matsumoto, Y. Miyazaki, and H. Ishikawa, Japanese Patent Application (1998).
2) H. Matsumoto, “Electrochemical window of Room Temperature Ionic Liquids”,Electrochemical Aspects of Ionic Liquids (Ed. H. Ohno), Wiley (2005).
3) H. Matsumoto, Recent advances in Ionic Liquids for Lithium Secondary Batteries: Modern Aspects of Electrochemsitry No.58,: Electrolytes for Lithium and Lithium-Ion Batteries, Eds. T. R. Jow, K. Xu, O. Borodin, and M. Ue, chapter 4, Springer, 2014.
4) H. Matsumoto, H. Kageyama, and Y. Miyazaki, Chem. Commun., 1726 (2002).
5) H. Matsumoto, H. Sakaebe, and K. Tatsumi, J. Power Sources, 146(1–2), 45 (2005).
6) H. Matsumoto, N. Terasawa, T. Umecky, S. Tsuzuki, H. Sakaebe, K. Asaka, and K. Tatsumi, Chem. Lett., 37(10), 1020 (2008).
7) Terasawa, S. Tsuzuki, T. Umecky, Y. Saito, and H. Matsumoto, Chem. Commun., 46(10), 1730 (2010).
8) Kubota, and H. Matsumoto, J. Phys. Chem. C, 117(37), 18829 (2013).
9) H. Sano, K. Kubota, Z. Shiroma, S. Kuwabata, and H. Matsumoto, J. Electrochem. Soc., 167(7) 070502 (2019).

Figure 1
Melting Behavior and Ionic Conduction of Multicomponent Carbonates Coexisting with Porous Oxides
Authors: Mizuhata Minoru , Wang Jiayue , Sato Shizuku , Chen Xueling , Maki Hideshi , Minamimoto Hiro 
Published: December 2024

Multicomponent systems of alkali carbonates indicate high electrical conductivity, high chemical and thermal conductivity, and low viscosity in the medium temperature range around 500°C, and are used as high temperature reaction media, thermocouples, and sensing materials for CO However, in electrochemical reactions, the high reactivity of carbonates is accompanied by the problem of corrosion of electrodes and reaction systems. We have studied ceria-based oxides and zirconia, which have high reactivity through surface treatment of CO2 absorbing media, and have examined the electrical and thermal properties of the composite materials with molten carbonate. Ceria-based oxides have been considered for application in solid oxide fuel cells as solid electrolytes, whereas γ-LiAlO2 has insulating properties and is used as an electrolyte in molten carbonate fuel cells. In this study, lithium carbonate, sodium carbonate, and potassium carbonate are used as the liquid phase, and mono-, binary-, and ternary complex carbonates or carbonates with eutectic compositions are used. The results are summarized on the effect of salt complexation on the improvement of electrical conductivity at low temperature ranges and the lowering of melting points.
The solid phase was obtained by drying three types of γ-LiAlO2 (24.0 m2/g, 10.3 m2/g, 5.4 m2/g) and other various oxides such as α-Al2O3, MgO, ZrO2 etc. at 500°C for 2 hours under nitrogen. Li2CO3, Na2CO3, and K2CO3 were used for the carbonate phase and dried at 200°C for 48 hours under a carbon dioxide atmosphere. Eutectic carbonates were prepared by mixing them to form a eutectic composition. Each oxide powder was mixed thoroughly in a mortar to form carbonate at a given volume ratio. The sample was formed by pressurization and sintered at 500°C for 1 hour to obtain a tablet for the measurements of ionic conduction and thermal analysis.
As shown in Figure 1, the activation energy of electrical conductivity increased near the solid phase in all cases. The range of influence from the solid phase decreased significantly with increasing carbonate polymorphism: 40 nm for the mono-salt system, 10 nm for the binary system, and about 2 nm for the ternary system. These melting point drops are also affected by the solid phase, but the effect of the distance from the solid phase is not so great. In the vicinity of the solid phase, the effect of the solid phase on ionic conduction is not as strong as that on the phase change, and the more numerous ions move, the less affected by the solid phase the system is. In this presentation, we will discuss the influence of the solid phase from a viewpoint of thermodynamics.
Fig.1 Variation of ΔE
a with apparent average thickness for various carbonates /inorganic powders coexisting systems. Carbonates: (a)Li2CO3, (b) (Li0.52Na0.48)2CO3, and (c) (Li0.435Na0.315K0.25)2CO3.

Figure 1
Insight into Modulation of Ionic Liquids for Li-Ion Batteries: Unprotected Cation
Authors: Hwang Jinkwang , Zhang Shaoning , Wu Shengan , Matsumoto Kazuhiko 
Published: December 2024

Sulfonylamide-based ionic liquid electrolytes have shown promising physiochemical and electrochemical properties for secondary battery systems.[1-3] Recently, highly Li-concentrated IL electrolytes have exhibited wide electrochemical stability windows, stable solid electrolyte interphases, and enhanced Li+ transport properties.[4,5] However, a significant challenge lies in the uncontrollably large irreversible capacity of negative electrodes attributed to the emergence of "unprotected organic cations" in ionic liquid electrolytes, leading to unfavorable decomposition. This results in a high irreversible capacity and a gradual decrease in the initial Coulombic efficiency of graphite electrodes.[6]
In this presentation, we will delve into detailed physicochemical analyses and computational studies aimed at elucidating the causes behind the weakened ionic interactions between the organic cation and the [FSA]− anions based on Li
x
[C2C1im]1-x
[FSA] ([FSA]– = bis(fluorosulfonyl)amide and [C2C1im]+ = 1-ethyl-3-methylimidazolium) ionic liquid. Additionally, we will discuss the interaction facilitated by high donor number anions like [OTf]− (trifluoromethanesulfonate), which are suggested to strengthen interactions between the [C2C1im]+ cation and the [FSA]− anion.
Our series presentation, titled "Insight into Modulation of Ionic Liquids for Na-Ion Batteries: Cation Modification”, explores the effects of cation structure modification on the coordination environment of ions in sodium systems.
Synthesis and Characterization of Dicationic Ionic Liquids with the Difluorophosphate Anion
Authors: Kamada Kentaro , Nokami Toshiki , Inui Naoki , Nakajima Hideto , Nishimoto Kohei , Hwang Jinkwang , Matsumoto Kazuhiko 
Published: December 2024

Dicationic ionic liquids (DILs) can be diversely designed by tuning spacer and cationic-center structure. Their features possibly superior to conventional ionic liquids include thermal stability, wide potential window, and high Li ion transference number, which make them good electrolyte candidates for secondary batteries. However, there are few reports of DILs and many unknown factors about the relationship between their structure and physical properties.
Although Li[PO2F2] is known as an additive in lithium secondary batteries that improves the negative electrode performance, [1] PO2F2
- itself forms ionic liquids with a variety of onium cations. [2] In this study, we attempted syntheses of DILs with PO2F2
-, especially the ones with ether oxygen in the spacer and evaluated the physical properties of the resulting DILs.
The synthesis of DILs was carried out in three steps. Initially, ethylene glycol was reacted with paraformaldehyde and trimethylsilyl chloride in dichloromethane at room temperature to prepare 1,2-bis(chloromethoxy)ethane. In the second step, dihalide reacted with two equivalents of amines at room temperature and converted to the corresponding chloride salts. Finally, the chloride salts and K[PO2F2] were reacted in dichloromethane at room temperature to exchange anions.
According to the results of differential scanning calorimetry, the dication salts with ether spacer exhibit lower melting points than the corresponding dication salts without ether spacer owing to the flexibility around the ether group. Comparison of densities between pyrrolidinium- and linear alkylammonium-based DILs revealed the higher density of the former salt, which arises from the rotational freedom of the alkyl chain in the latter. The higher viscosity of the DIL with BF4
- than that of the DIL with PO2F2
- is due to the high dipole moment and thus polarity of PO2F2
- consisting of two oxygen and two fluorine atoms. High ionic conductivity is an important factor as electrolyte. The ion conductivity of the DIL with PO2F2
- is higher than that of the DIL with BF4
-, which implies the potential of PO2F2
- DILs in battery applications.
References:
1) G. Yang, J. Shi, C. Shen, S. Wang, L. Xia, H. Hu, H. Luo, Y. Xia, Z. Liu, RSC Adv. 7, 26052 (2017).
2) K. Matsumoto, R. Hagiwara, Inorg. Chem. 48, 7350 (2009).
Two-Dimensional, Multi-Reaction, and Multi-Species Porous Electrode Modeling of Metal Oxide Electroreduction with Applications in Nuclear Fuel Reprocessing and Iron Oxide Reduction
Authors: Kellamis Christian John , Sinclair Nicholas Scott , Kersten Bethany , Hawthorne Krista , Ruehl Matthew , Akolkar Rohan 
Published: December 2024

Many electrochemical processes involve the reduction of a porous solid metal oxide into pure metal such as the Fray-Farthing-Chen (FFC) Cambridge process 1 for titanium and ULCOWIN 2 process for iron. With optimal electrolysis cell designs, these processes would produce metal efficiently without energy losses to parasitic side reactions. Predictive modeling of the reaction rate (current) distribution underlying these processes can allow for increased energy efficiency and higher metal electrowinning yields. This would be beneficial to the fields of nuclear fuel reprocessing and sustainable metals production, which utilize electro-reduction of uranium oxides and iron oxides, respectively. This presentation will cover the development of a two-dimensional, multi-reaction model that simulates the current distribution during oxide reduction and models the potential profiles of both the metal oxide phase and the liquid electrolyte phase within the oxide pores. The model applies the concepts of porous electrode theory developed by Newman and Tobias 3 but modifies it to incorporate multiple reactions.4, 5 The model is then applied to uranium oxide reduction in a molten salt electrolyte, and aqueous processing of iron oxide ores for iron electrowinning. This modeling study helps establish the main controlling parameters for the current distribution uniformity, i.e., the solid electronic conductivity of the oxide phase, the liquid electrolyte conductivity of the molten (or aqueous) electrolyte, the tortuosity and porosity of the porous oxide matrix, and the exchange current densities of the metal oxide and the liquid electrolyte reactions. Experimentally measured current distribution profiles on a porous electrode comprising iron oxide particles will be shown as validation of model findings.
References

G. Z. Chen, D. J. Fray, and T. W. Farthing, Nature,
407 (6802), 361-364 (2000).

M. Abdul Quader, S. Ahmed, S. Z. Dawal, and Y. Nukman, Renewable and Sustainable Energy Reviews,
55 537-549 (2016).

J. S. Newman and C. W. Tobias, Journal of The Electrochemical Society,
109 (12), 1183 (1962).

D. R. Baker and M. W. Verbrugge, Journal of The Electrochemical Society,
165 (16), A3952-A3964 (2018).

D. R. Baker, M. W. Verbrugge, and W. Gu, Journal of The Electrochemical Society,
166 (4), A521-A531 (2019).
Electric Double Layer Modification Induces Progressive Nucleation and Nanoscale Zinc Deposition for Aqueous Zinc Metal Batteries
Authors: Wang Ziqing , Mullins Charles Buddie 
Published: December 2024

Aqueous zinc metal batteries have been regarded as a promising alternative to conventional lithium-ion batteries for grid-scale energy storage due to their high safety and low cost.1 However, the formation of zinc dendrites on the zinc metal surface during electrodeposition significantly deteriorates the sustainability and stability of aqueous zinc metal batteries.2 Hence, it is crucial to reduce the zinc dendrites and other side reactions and control the uniform zinc deposition on the electrode surface by regulating the electrolyte-electrode interface. In this work, we introduce a tiny amount of sodium-difluoro(oxalato)borate (NaDFOB) into the ZnSO4 electrolyte to modify the zinc deposition. The electrochemical tests and density functional theory simulations demonstrate that the DFOB− ions adsorb on the zinc electrode surface to construct a water-poor electric double layer. The molecular dynamics results confirm the occupation of DFOB− ions in the electric double layer. Because of the specific adsorption on the zinc metal surface, DFOB− ions not only suppress the aggregation of deposited zinc to form dendrites but also promote the unique progressive nucleation process. Through scanning electron microscope, the formation and growth of nanoscale zinc nuclei can be observed in the electrolyte with the addition of NaDFOB. Eventually, the early-stage nanoscale nuclei result in ultra-uniform zinc growth. Furthermore, the decomposition of adsorbed DFOB− ions yields the formation of an inorganic compound-rich solid electrolyte interphase, which effectively enhances the reaction kinetics on the electrode surface and reduces the parasitic reactions. As a consequence, the introduction of NaDFOB realizes high reversibility of zinc plating/stripping behavior in Zn/Cu asymmetric cells with a Coulombic efficiency of 99.3% and in Zn/Zn symmetric cells with a cycling life for over 500 hours under a high current density of 5 mA cm−2. Additionally, the full cells employing Na0.33V2O5 cathode materials exhibit a promising capacity of 200 mAh g−1 and long-term stability for over 400 cycles. The introduction of DFOB− anions provides a facile strategy to regulate electrodeposition in aqueous zinc metal batteries by reconstructing the electric double layer and regulating nanoscale zinc nuclei.
References:

S. Liu et al. Angew. Chem. Int. Ed., 2024, e202400045.

T. Zhang et al. Energy Environ. Sci., 2020, 13 (12), 4625-4665.

Figure 1
Theoretical View on Alternatives to Oxygen Evolution Reaction Processes
Authors: Basera Pooja , Jiang Chenyu , Ablid-Pedersen Frank , Manthiram Karthish , Bajdich Michal 
Published: December 2024

Our recent survey of oxygen bonding strength in the transition metal oxides revealed a broad range of reactivities resulting in a V-shape type behavior related to filling anti-bonding states. For metals with filling close to d0 to d10, the oxygen reactivity is generally weak [1]. While oxygen evolution reaction (OER) is well known for metal-oxides with moderately bonded oxygen such as in IrO2 and RuO2, chemistry of a weakly bonded metal-oxides is significantly less explored. At the same time, photo-electrochemical solar-fuel devices, such as one developed at Liquid Sunlight Alliance (LiSA), would strongly benefit from anodic reactions which are alternative to OER as a way to produce anodic products with added value and/or having lower onset potentials.
Very promising reactions currently being explored are water oxidation to peroxide, epoxidation of light olefins [2] and alcohol oxidation reactions [3]. In our theoretical analysis, we computationally re-evaluate this weakly bonded region and identify the switch from oxo bonded species species to peroxo one, previously known to occur in systems such TiO2. We compute the overall energetics of the above reactions and analyze which reactive oxygen species is preferential for each of the alternative reactions. We conclude with discussion of fundamental feasibility and limitations of alternative anodic reactions to OER.
This material is based on work performed by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under Award Number DE-SC0021266.
[1]. Comer, B. M.; Bothra, N.; Lunger, J. R.; Abild-Pedersen, F.; Bajdich, M.; Winther, K. T. Prediction of O and OH Adsorption on Transition Metal Oxide Surfaces from Bulk Descriptors. ACS Catal. 2024, 5286–5296.
[2] Chung, M.; Maalouf, J. H.; Adams, J. S.; Jiang, C.; Román-Leshkov, Y.; Manthiram, K. Direct Propylene Epoxidation via Water Activation over Pd-Pt Electrocatalysts. Science 2024, 383 (6678), 49–55. https://doi.org/10.1126/science.adh4355.
[3] Wei, L.; Hossain, M. D.; Boyd, M. J.; Aviles-Acosta, J.; Kreider, M. E.; Nielander, A. C.; Stevens, M. B.; Jaramillo, T. F.; Bajdich, M.; Hahn, C. Insights into Active Sites and Mechanisms of Benzyl Alcohol Oxidation on Nickel–Iron Oxyhydroxide Electrodes. ACS Catal. 2023, 13 (7), 4272–4282.
Oxidative Desorption Behavior of Sulfur Species from Pt and Pt Based Alloy Single Crystal Surfaces
Authors: Morooka Tetsuro , Aoki Makoto , Nakanishi Takuya , Ishikawa Atsushi , Masuda Takuya 
Published: December 2024

Pt and Pt-based alloys are the most widely used electrocatalyst for polymer electrolyte membrane fuel cells (PEMFCs) because of their very high hydrogen oxidation and oxygen reduction activities. However, trace amounts of S species in hydrogen fuel and air, especially in long tunnels and volcanic areas, often strongly adsorb on the Pt and Pt-based alloy surfaces, resulting in reduced electrochemically active surface area (S poisoning). Thus, understanding of adsorption/desorption behavior of S species at Pt and Pt-based alloy surfaces is very important to mitigate such S poisoning. In the present study, oxidative desorption behavior of S species from well-defined Pt and Pt-based alloy single crystal surfaces in acidic aqueous solutions were studied by electrochemical measurements, x-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculation.
Pt and Pt-based alloy single crystal surfaces were annealed by induction heating method [1, 2, 3] at various temperatures for 1 h under the flowing of Ar and H2 mixed gas, followed by cooling under the Ar and H2 flow for 7 min. The surfaces were then immersed in an aqueous solution of 1 mM Na2S for 1 h to yield S-adsorbed surfaces. After rinsing with water, electrochemical measurements were carried out in an aqueous solution of 0.1 M HClO4, followed by XPS measurements.
Bare Pt and Pt-based alloy single crystal surfaces showed characteristic current responses corresponding to adsorption/desorption of hydrogen and hydroxyl species as previously reported. After immersing in the 1 mM Na2S solution, those characteristic current responses completely disappeared due to the blocking of adsorbed elemental S species as evidenced by XPS. However, those characteristic current responses gradually recovered by repeating the potential cycles in the potential range between 0 V and 0.8 V or more positive, due to the oxidative desorption of S species. The recovery factor significantly depends on the face orientation, alloying foreign metal and surface modification. Among the Pt(111), Pt(110) and Pt(100) surfaces, Pt(111) surface showed the highest S oxidation capability. The S oxidation capability was further accelerated by alloying with several transition metals and coating with metal oxides. The details will be discussed.
References
[1] T. Masuda, S. Faridah, P. Singh, H. Naohara, K. Uosaki, Journal of Physical Chemistry C, 2013, 117, 15704-15709.
[2] T. Masuda, H. Fukumitsu, T. Kondo, H. Naohara, K. Tamura, O. Sakata, K. Uosaki, Journal of Physical Chemistry C, 2013, 117, 12168-12171.
[3] R. Devivaraprasad, T. Masuda, Langmuir, 2020, 36, 13793-13798.
Up-Scaling Solar Hydrogen Production: Development and Demonstration of Photoelectrochemical Reactors
Authors: Creasey George Henry , Moelich Arend W , Rodriguez Acosta John Wilman , Shalvey Thomas P , Garcia-Osorio Dora Alicia , McCallum Tristan W , O'Neil Liam , Zhu Jinjie , Halder Siddharth , Ai Ray , Major Jon , Cowan Alexander J , McGregor Craig , Kafizas Andreas G , Hankin Anna 
Published: December 2024

For commercially viable photoelectrochemical hydrogen production, considerable progress must still be made in the development and demonstration of up-scaled devices. The development of low cost and scalable photoelectrode materials that can harness light over a wide range of wavelengths, catalyse water oxidation/reduction, and are chemically, (photo)electrochemically and mechanically robust, remains a bottleneck on which research efforts are largely focused. The design and demonstration of up-scaled devices is equally important and must be addressed in parallel, to ensure material compatibility with the systems they will be used in. The constraining factors that must be considered in device design include: (i) electrode scale-up; (ii) modes of illumination; (iii) current distribution (and associated losses); (iv) the utilisation of a membrane; (v) heat and mass transport.[1] I will present the steps we have taken to address these.
Our up-scaled photoelectrochemical reactor has an irradiance area of 60 cm2 and is capable of splitting water and oxygen using only photon energies. The reactor was irradiated outdoors with natural sunlight during March, April and May 2024 at Stellenbosch University, South Africa (33.93° S, 18.86° E), while mounted on a 2-axis tracking platform. Light was directed laterally both into the (photo)cathode and photoanode compartments, which were separated by an ion-permeable membrane.
The reactor was operated in two modes:

Photoelectrochemical (PEC), with an FTO|WO3|BiVO4|NiFeOx photoanode and a FTO|Au|Sb2Se3|CdS|TiO2|Pt photocathode[2];

PV-assisted photoelectrochemical (PV-PEC), with an FTO|WO3|BiVO4|NiFeOx photoanode, Ni cathode and externally mounted c-Si PVs.

Two modes of illumination were compared:
(i) Direct irradiation, through the use of mirrors;
(ii) Concentrated irradiation (up to a factor of five), through the use of linear Fresnel lenses coupled with stepped Al waveguides.
This research seeks to elucidate challenges of developing up-scaled materials for water splitting, to facilitate the pathway to commercially viable photoelectrochemical hydrogen production. I shall discuss the experimental results from reactor testing, the performance under various modes of irradiation, and the effects of electrode materials, geometries and relative configurations within the reactor on its design.
Refs:
[1] A review of inorganic photoelectrode developments and reactor scale-up challenges for solar hydrogen production, Adv. Energ. Mater., 2021, 11, 2003286.
[2] Benchmark performance of low-cost Sb2Se3 photocathodes for unassisted solar overall water splitting, Nat. Commun., 2020, 11, 861.

Figure 1