bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lithium Ion Conduction in Single Lithium Perfluorosulfonylamides
Authors: Kubota Keigo , Matsumoto Hajime 
Published: February 2020

A liquid electrolyte of lithium ion battery (LIB) is usually composed of a lithium salt and a solvent, such as an organic solvent or a room temperature ionic liquid (RTIL), which is usually necessary to dissolve the lithium salts. Therefore, the electrolytes must contain characteristics of both of the lithium salt and solvent. For example, an organic electrolyte usually has high vapor pressure and flammability derived by the organic solvent. The solvent or the other additive materials are absolutely necessary for practical use but also complicate properties of the electrolytes.
We reported that a lithium (fluorosulfonyl)(trifluoromethylsulfonyl)amide (Li[(FSO2)(CF3SO2)N]), which is denoted as Li[fTfN], formed a molten salt above 100 ºC.[1] The Li[fTfN] melt is extremely simple construction as the electrolytes for the lithium secondary battery, only Li+ and fTfN–. Therefore, it is free from the effect of the solvents and its concentration of Li+ is extremely high (about 7.0 mol·dm–3) among liquid electrolytes. Charge-discharge in the single Li[fTfN] was successful with conventional electrodes for LIB, such as LiCoO2, LiFePO4[1] and graphite.[2]
The Li[fTfN] has many interesting characteristics compared with the conventional electrolytes of LIB, such as much high viscosity and superionic conductivity.[1] In this study, we focused on no concentration gradient in the Li[fTfN] when applying current. In the conventional liquid electrolytes, the concentration gradient of lithium salt is generated in the electrolytes when current is applied in order to maintain electroneutrality in the electrolytes. However, the concentration gradient of lithium salt is not generated in the single Li[fTfN] melt because this melt is a lithium salt itself. In chronoamperometry of the Li[fTfN] using the two-electrode lithium metal symmetrical sell, there is little difference between an initial current, which caused by Li+ and fTfN−, and a steady current, which caused by only Li+.[1] This indicates that the only Li+ migrate by difference of voltages and fTfN– does not diffuse by concentration gradient. Its conduction behavior is similar to a solid electrolyte. Therefore, it is expect that Li+ is not drained near electrode if large current is applied in high rate charge-discharge.
To the best of our knowledge, there is a few kind of single lithium salt which melts below melting point of lithium metal (180 ºC), such as the Li[fTfN] and bis(fluorosulfonyl)amide salt (Li[f2N]). These melts have possibility of electrolyte possessing high rate performance due to the no concentration gradient. In this presentation, the conduction behavior of Li+ in these low-melting single lithium melts.

Acknowledgement

This work was supported by the Advanced Low Carbon Technology Research and Development Program Specially Promoted Research for Innovative Next Generation Batteries (ALCA-SPRING) of Japan Science and Technology Agency (JST).
[1] K. Kubota, H. Matsumoto, J. Phys. Chem. C, 117, 18829 (2013).
[2] K. Kubota, H. Matsumoto, ECS Trans., 62, 231 (2014).
Copper-Based Electrocatalysts with Multinuclear Catalytic Sites for Oxygen Reduction Reaction
Authors: Kato Masaru , Muto Marika , Oyaizu Nobuhisa , Yagi Ichizo 
Published: February 2020

The oxygen reduction reaction (ORR) to water is catalyzed at cathodes in polymer electrolyte fuel cells (PEFCs). For widespread applications of PEFCs, low-cost cathode materials with high catalytic activity and durability are highly desirable. Since natural ORR catalysts such as multi-copper oxidases catalyze the ORR with almost no overpotential (ca. 20 mV)[1]and the enzymatic ORR occurs at a multinuclear copper complex, mimicking enzymatic active sites would allow us to develop non-precious metal-based ORR electrocatalysts for practical applications.
Herein we report our research progress in synthetic and mechanistic studies on copper-based electrocatalysts for the ORR.[3,4]Our findings suggest that the design and synthesis of multinuclear copper cores might be a key to develop highly efficient and durable copper-based electrocatalysts for the ORR.
References. [1] N. Mano, V. Soukharev, A. Heller, J. Phys. Chem. B, 110, 11180 (2006). [2] M.S. Thorum, J. Yadav, A.A. Gewirth, Ang. Chem. Int. Ed.,
48, 165 (2008). [3] M. Kato et al., Phys. Chem. Chem. Phys., 17, 8638-8641 (2015). [4] M. Kato, N. Oyaizu, K. Shimazu, I. Yagi, J. Phys. Chem. C, in press. DOI: 10.1021/acs.jpcc.5b11663
Size Effect of Single Nanoparticle Electrodes on the Electrochemical Interface and Charge Transfer Kinetics and New Insights into Their Size-Activity Relations
Authors: Fan Lixin , Gan Lin 
Published: February 2020

Understanding the particle size effects on the electrochemical reaction kinetics is of particular importance for rational design of nanoparticle materials for energy conversion and storages such as fuel cell electrocatalysts and battery materials. Our present knowledge on the size effects of nanoparticle catalysts is generally related to the impact of particle size on the atomic or electronic structures of nanoparticle surfaces. For electrocatalytic reactions, it is well known that the charge transfer kinetics not only depends on the electrode surface structure but also, perhaps more importantly, rely on the electrochemical solid-liquid interfaces, namely, the electric double layers (EDL). Effect of particle size on the latter aspect and thus the charge-transfer kinetics, however, has remained largely unexplored.
Exemplified by two redox reactions with different electron transfer kinetics (such as oxygen reduction reaction in fuel cells), we performed finite element analysis of the EDL potential distributions, concentration distributions of redox and intermediate species, and the overall voltammetry behaviors of single platinum (Pt) nanoparticle electrodes as functions of the nanoparticle size for the first time. Our results reveal significant influence of particle size on the potential drop distributions within the EDL of nanoparticle electrodes; decreasing particle size led to an increase of the potential at the compact layer, translating into apparent size effects on the charge transfer kinetics particularly for slow electrochemical reactions. These results provide important new insights into the size effect of nanoparticle materials for fuel cell electrocatalysis and battery electrodes.
Specific Response of Quinone Redox at 2-Aminoethanethiol Modified Electrode
Authors: Naito Kumi , Maeda Yuri , Yasui Takashi , Takada Kazutake , Yuchi Akio 
Published: February 2020

Self-assembled monolayers of alkanethiols on electrode surface have been the subjects of intensive studies in both fundamental interests of surface chemistry and their technological significance. The self-assembly is one of the most widely used techniques to construct ordered molecular structures and to control surface characteristics, due to its facile procedure. 2-aminoethanethiol has been used as an anchor to introduce functional molecules to electrode surfaces as it has a reactive amino group and its carbon chain is short.
We have found that a 2-aminotehanethiol modified Au electrode shows a specific electrochemical response to p-hydroquinone in aqueous solution. That is, a peak separation (ΔE
p) in the CV appeared to be very large at the first potential cycle, but it drastically decreased upon successive potential cycling. We have been studying condition where the specific response takes place and its mechanism.
Figure 1A shows typical CVs of an aminoethanethiol modified Au disk electrode in a 0.1 M sodium perchlorate solution containing 5 mM hydroquinone at 100 mV s-1. The ΔE
p for quinone redox was found to be 530 mV for the first cycle, indicating a slow electron transfer (Fig. 1A curve a). After application of +0.9 V vs. Ag/AgCl for 30 min at which hydroquinone is oxidized, the ΔE
p largely decreased to 120 mV (Fig. 1A curve b) and the CV overlapped with that of a bare electrode. On the other hand, application if –0.5 V was applied, the CV remained virtually constant. Interestingly, when the electrode was left in the solution at open circuit or –0.5 V for 3 h, the ΔE
p increased to the original value (530 mV). These results indicate that the changes in the ΔE
p is reversible and not originating from peeling of the film, and the increase can be attributed to an interaction between aminoethanethiol and hydroquinone, whereas the decrease is due to oxidation of hydroquinone. A Au electrode modified with 2-dimethylanimoethanethiol showed similar behavior (Fig. 1B), indicating that Schiff base formation from amino group of 2-aminoethanethiol and p-quinone is not the dominant cause of the changes in the electrochemical response.
At the current stage, we speculate two possible mechanisms for the changes in the electrochemical response. The first one is changes in structure of aminoethanethiol due to changes in an interaction with quinone, although it is known that short alkyl chains on the electrode surface do not block electron transfer. The second one is a chemical reaction between hydroquinone and aminoethanethiol, which produces derivatives with slow electrode reaction rate constant. We currently investigate those two possibilities with STM measurements for an aminoethanethiol modified electrode before and after the electrolysis and with NMR measurements for the reaction.

Figure 1
(Keynote) Artificial Photosynthesis: Progress, Science Outlook and Technology Prospects
Authors: Atwater Harry A 
Published: February 2020

The design of highly efficient devices that generate fuels directly from sunlight, water, and carbon dioxide is both a formidable challenge and an opportunity that, if realized, could have a revolutionary impact on our energy system. In the past five years, considerable progress has been made in scientific discovery of key materials and mechanisms needed to realize artificial solar fuels generators, and advances modeling and design have generated a now quite widely embraced conceptual paradigm for a solar fuels generator. While we still lack sufficient knowledge to design solar-fuel generation systems with the ultimate efficiency, scalability, and sustainability to be economically viable, considerable advances have been made, particularly for water-splitting solar fuels devices. I will describe work done in this area by the Joint Center for Artificial Photosynthesis. I will also survey outstanding scientific challenges to realization of artificial photosynthesis for generation of fuels and chemicals by reduction of carbon dioxide and discuss JCAP's approach and recent advances in carbon dioxide reduction.
Recent Progress in Aqueous Organic or Inorganic-Based Redox Flow Batteries at Pnnl
Authors: Li Bin , Nie Zimin , Kizewski James , Duan Wentao , Wei Xiaoliang , Wang Wei , Liu Jun , Reed David , Sprenkle Vincent 
Published: February 2020

Redox flow batteries (RFBs), as one of the most promising electrical energy storage systems, provide an alternative solution to the problems of balancing power generation and consumption. RFBs are designed to convert and store electrical energy into chemical energy and release it in a controlled fashion when required. In particular, aqueous RFBs are attracting more attentions because of their good safety, low cost and high power density comparing with non-aqueous RFBs. Therefore, aqueous RFB chemistries with appropriate redox potential, high soluble and low-cost active species are critically required.1

During the past few years, PNNL invented several aqueous RFB systems: inorganic and organic-based systems. Here, we will present the electrode development for zinc-polyiodide RFBs2 (inorganic-based). Two kinds of metal-organic frameworks (MOFs) acting as catalysts were in-situ grown at the cathode carbon electrode.3 The flow cell with MOFs showed largely improved energy efficiency. The chemical stability of MOFs in electrolytes was studied in detail. Also, we will introduce a kind of methyl viologen-based RFBs (organic-based). It represents a great potential to replace expensive vanadium flow batteries because of low-cost active materials. The cell performance and the chemical stability of electrolytes will be discussed.

References:

Soloveichik, Grigorii L. Chemical reviews 115.20 (2015): 11533-11558.

Li, B et al., Nature communications, 2015

Li, B et al., submitted, 2016
Fluorophosphate-Based Polyanion Cathode Materials for Rechargeable Magnesium Batteries
Authors: Masese Titus , Huang Zhen-Dong , Senoh Hiroshi , Sano Hikaru , Shikano Masahiro , Uchimoto Yoshiharu 
Published: February 2020

Rechargeable magnesium-ion batteries are promising candidates to compete with the state-of-the-art lithium-ion batteries for a plethora of large-scale energy storage devices.
The terrestrial reserves of magnesium are plentiful and magnesium metal is safe to handle under ambient atmosphere containing water and oxygen than metallic lithium. In addition, the multivalent nature of magnesium metal itself makes rechargeable magnesium-ion battery very attractive not only due to the inherent low cost and safety, but also as a high-energy density battery system.
However, in spite of the aforementioned advantages, the energy density of rechargeable magnesium batteries reported was low. The low energy density stems from the low voltage and capacity which is mainly constrained by the cathode material. A number of feasible cathode materials that can reversibly (de)insert magnesium ion have been reported in recent years, typical examples being the molybdenum chalcogenides[1] and transition metal oxides such as V2O5
[2]and MnO2
[3]; nonetheless, the energy density attained still remains unsatisfactory. Therefore, high energy density cathode frameworks are highly desirable for rechargeable magnesium battery system to be at par or even outperform the current lithium-ion battery technology.
In pursuit for alternative cathode materials, this study explores a promising broad class of poly(oxy)anion inorganic frameworks based on fluorophosphates[4] that exhibit multi-redox reactions (high theoretical capacity) and high redox voltage. The synthesis, crystal structure and electrochemical magnesium (de)insertion behaviour in representative fluorophosphates cathode materials based on environmentally-benign constituents such as MgFePO4F will be highlighted. Their analogues in the mineral world are hydroxyfluorophosphates, including triplite, panasqueiraite and magniotriplite [(Mg, Fe)2(PO4)(F, OH)], where F- can partially replace an OH- group. Complete substitution of F- is necessary to enhance electrochemical properties because the hydroxyl tends to undergo irreversible redox reactivity. Furthermore, the replacement of PO4
3- with PO4F4-in principle alters the charge balance and the dimensionality of the structure.

References

1. D. Aurbach et al., Nature, 407, 724-727 (2000).
2. D. B. Le et al., Chem. Mater., 10, 682-684 (1998).
3. N. Kumagai et al., J. Power Sources, 97, 515-517 (2001).
4. Z.-D. Huang et al., J. Mater Chem. A, 2, 11578-11582 (2014).
Novel High Energy Density Sodium Layered Oxide Cathode Materials - from Material to Cells
Authors: Smith Katherine , Treacher Joshua , Ledwoch Daniela , Adamson Paul , Kendrick Emma 
Published: February 2020

Lithium ion batteries have now been commercially available for the past twenty-five years. There has been a steady improvement in lithium ion battery technology throughout this period and lithium ion batteries are widely considered as the technology of choice to meet the energy demands of the future. However, there is growing research and commercial interest in other metal-ion battery technologies that could also meet certain areas of future energy demand. Sodium-ion technology has commanded an increasing research and commercial interest over recent years due to the high abundance and uniform distribution of sodium across the world, and the reported potential commercial advantages of lower cost, greater sustainability and improved safety characteristics of sodium ion batteries compared with their lithium-ion counterparts.
Sharp Laboratories of Europe Ltd have been developing a new sodium ion cell chemistry based upon a tin-containing nickel based layered oxide cathode and a hard carbon anode. Here we report on the challenges faced during the development of a new sodium-ion technology in moving from a new electrode material, through from half cell results to small full cell development and then larger scale full cell development. We discuss the optimisation of the material choice, electrolyte, electrode parameters and formation process on the gravimetric and volumetric cell energy density along with the lifetime and rate behaviour of the cells.
A Study on Long-Term Cycle Performance of Conventional Tin Anode for Sodium-Ion Batteries
Authors: Kim Changhyeon , Kim Huihun , Sadan Milan K , Cho Gyubong , Kim Ki-Won , Ahn Jou-Hyeon , Ahn Hyo-Jun 
Published: February 2020

Tin has been regarded as one of the most promising anode materials owing to its high theoretical specific capacity of 847 mAh g−1, based on the full sodiation of Na15Sn4. However, the pure tin anode has a severe problem of poor cycling properties, as it loses its initial capacity within the first 10 cycles. It is believed that the pulverization of tin induced a rapid degradation of capacity during cycling. The tin anode material expands to 520% of its original volume during sodiation and contracts to its original volume during desodiation. Several approaches have been investigated to overcome this problem. One approach involves stress release by utilizing a buffer layer, decreased tin size, or a thin film. Another approach involved the suppression of volume expansion by encapsulating tin nanoparticles into carbon and coating Al2O3 onto the tin nanoparticles. For example, ultra-small (8 nm) tin nanoparticles embedded in carbon showed 415 mAh g−1 of reversible capacity for 500 cycles, and tin nano-dots (1 ~ 2 nm) encapsulated in porous nitrogen-doped carbon nanofibers showed 483 mAh g−1 for 1300 cycles. Although these previous approaches succeed in improving cycle life, most preparation methods are too complex for commercialization as compared to that of the conventional electrode using tin nanopowder, a conducting additive, and a binder. However, a conventional electrode still showed poor cycling properties. Komaba et al. reported that a conventional electrode demonstrates capacity decay from 758 mAh g−1 to 21 mAh g−1 over the course of 10 cycles, even if using tin nanopowder (< 150 nm). The cycling properties of tin anode could be improved using a conductive binder or polyacrylate binder in short-term cycling of 20 cycles, but improved long-term cycle performance of a conventional electrode has not reported yet.
Previous studies indicate that the long-term cycling of tin electrode with high capacity could be improved by the release or suppression of accumulated stress in a tin due to volume change. In order to release stress of conventional electrode, the tin electrode should be designed using suitable binder, conductive additive, and its optimized structure. Therefore, we study on the long-term cycling of conventional tin anode for sodium-ion batteries by the control these components.
Analysis of Ion Transport in Glyme-Based Electrolyte Solutions for Li-Air Batteries
Authors: Saito Morihiro , Yamada Shinya , Tachikawa Yusuke , Ito Kimihiko , Kubo Yoshimi 
Published: February 2020

In order to elucidate the Li+ ion transport in glyme-based electrolyte solutions for Li-air batteries, LiCF3SO3(LiTfO) or LiN(SO2CF3)2(LiTFSI) dissolved glyme (triglyme(G3), tetra-glyme(G4) and pentaglyme(G5)) electrolytes were prepared, and the self-diffusion coefficients D of Li+ ion (7Li), anion (9F) and glyme (1H) solvent were measured individually by a pulsed-field gradient spin echo (PGSE-)NMR [1-3] in the temperature range of 30oC to 60oC. The viscosity η, density d and ionic conductivity σ were also measured to analyze the mechanism of ion transport in the glyme-based electrolytes. Moreover, molecular dynamics (MD) simulation was applied to reproduce the D values and investigate the dissociation of Li salts and solvation structure of Li+ion in the glyme solvents.
As the results, it was found that the glyme with shorter polyethylene glycol (PEG) chains gave lower η (Fig. 1) and higher D values (Fig. 2) and LiTFSI-based electrolytes exhibited higher σ values (Fig. 3) because of high apparent degree of dissociation α
app (Fig. 4), which were estimated by using Nernst-Einstein equation, for an increase in the amount of Li+ carriers. The trend was kept in the examined temperature range from 30oC to 60oC. However, the a value for the Li salts was decreased by an increase in the temperature, implying a reduction of the interaction energy between the Li+ ion and glyme solvents to form a metal complex. On the other hand, the a value was increased by the concentration of both Li salts in the electrolytes up to the molar ratio of 1:1 although the viscosity was also increased. Consequently, the highest σ values were attained both for 1 M LiTfO and LiTFSI-based electrolytes. From the results of MD simulation, the above trend of D values for ions and solvents were clearly reproduced and the larger amount of ion pairs of LiTfO was also confirmed than those of LiTFSI in the glyme solvents. The distance between Li+ ion and anion was much expanded for the LiTFSI compared with that for the LiTfO. Based on those results, we further investigated on the other new Li salt, LiN(SO2F)2(LiFSI), and influence of impurity such as H2O from air to the ion transports. The reports will be presented in the meeting.

This study was supported by JST “Next Generation Batteries Area in Advanced Low Carbon Technology Research and Development Program (ALCA)” and “A Tenure-track Program” from MEXT, Japan.

References
[1] M. Saito et al., Abstract in The 56thBattery Symposium in Japan, 3G25 (2015).
[2] K. Hayamizu et al., J. Phys. Chem. B, 103, 519 (1999).
[3] Y. Aihara et al., J. Chem. Phys., 113, 1981 (2000).

Figure 1