bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of LiCoO2 and Li4Ti5O12 Crystals in Lithium Ion Conductive Li2.2C0.75B0.25O3 glass for All-Solid-State Libs
Authors: Teshima Katsuya , Miyakoshi Tatsuya , Onodera Hitoshi , Matsumoto Mitsuhiro , Zettsu Nobuyuki 
Published: February 2020

All-solid-state lithium ion rechargeable batteries (LIBs) consisting of solid electrolytes have been desired for higher energy density, long term durability and safety. A great challenge of all-solid-state LIBs for practical use is reduction of the interfacial resistance. Effective interface modification techniques have been proposed, however, the interfacial resistance is still large because the charge transfer resistance at the active material/ solid electrolyte interface would be strongly affected by interfacial contact condition. Herein, we propose a new route to prepare smart interfaces for all-solid-state lithium ion batteries via the direct growth of electrode active material crystals in Li ion conductive glass.
Co3O4, Li2CO3, and Li3BO3 were used as a starting materials for LiCoO2 crystal growth in Li2-xC1-x+yBxO3+2y glass matrix. The volume fraction of LiCoO2 crystal was controlled to be >80% toward the glass matrix. The mixed powders was heated at designated temperature for 1 min to 5 h. Subsequently the powders were cooled to 500°C under temperature controlled conditions. The as obtained composites were structurally characterized by XRD, SEM-EDS, XRD, and TEM. All diffraction lines were in agreement with the ICDD data for LiCoO2. Since the diffraction lines of Li2CO3, and Li3BO3 were not observed, Li2-xC1-x+yBxO3+2y formed amorphous. SEM revealed the idiomorphic LiCoO2 crystal having barreled shape were homogeneously dispersed in the glass flax. Furthermore, the interface was atomically connected without any sub-phases formation, evaluated by TEM, suggesting that the interfaces provide seamless Li+ transportation pathways. Growth of Li4Ti5O12 crystals and futher electrochemical characteristics of these active material crystals will present in the ECS 227th Meeting.
Development of Ceramic-Polymer Composite Electrolyte for All-Solid Lithium Ion Batteries
Authors: Penumaka Rani V , Murakami Sho , Kim Youngsik , Zhu Likun 
Published: February 2020

In recent years, research on all-solid lithium ion batteries (LIBs) has increased considerably due to raised concerns relating to safety hazards such as the solvent leakage and flammability of liquid electrolytes used in commercial LIBs. All-solid LIBs use fast Li ion conducting solid electrolytes that do not carry the safety burdens of liquid electrolytes and are more effective. In addition, all-solid LIBs can increase the energy density of the entire battery pack by reducing the need for auxiliary systems such as safety monitoring systems. However, even with the highly ionic conductive solid electrolytes, it has been a struggle for a solid electrolyte LIBs to obtain similar specific capacity, rate capability, and cycle life to those of a liquid electrolyte LIBs. Studies conclude that these issues arise from the solid electrolyte’s inability to interface with the solid electrodes mainly due to the volume change of electrode materials during charge and discharge processes (1). In addition, it is difficult to manufacture on large scale the ceramic solid electrolyte LIBs, because the ceramic type solid electrolyte materials are hard and brittle.
To overcome this problem, a composite electrolyte was designed and fabricated using the combination of ceramic solid electrolyte and Li ion conducting organic polymer. The flexible polymer electrolyte can improve the interface stability and processibility for large cells. In this study, NASICON-type Li1.3Al0.3Ti1.7 (PO4)3 (LATP) was used as the solid electrolyte, which offers chemical stability and high conductivity at room temperature (2). Poly(ethylene oxide) (PEO) was used as the Li ion conducting polymer. The composite electrolyte was prepared by mixing LATP powders and the PEO binder with lithium salt (lithium bis(trifluoromethanesulfonyl)imide) (LITFSI). The conductivity of the composite electrolyte was studied by varying the composition at different temperatures. As shown in Fig.1, a stable composite film with good conductivity and flexibility was achieved with an optimum ratio of 75:25 of the LATP and the PEO binder. By using the composite electrolyte, all-solid LIBs were fabricated and studied. An initial discharge capacity of 92 mAh/g was achieved with 0.1 C rate at 60 °C. The detailed fabrication processes and charge-discharge characteristics of the all-solid LIBs will be reported.
Acknowledgments: This work was supported by US National Science Foundation under Grant No. 1335850.
References:
1. N. M. Asl, J. Keith, C. Lim, L. K. Zhu and Y. Kim, Electrochimica Acta, 79, 8 (2012).
2. H. Aono, E. Sugimoto, Y. Sadaoka, N. Imanaka and G. Adachi, Journal of the Electrochemical Society, 137, 1023 (1990).

Figure 1
Study on the Charging Behaviors of Lithium-Ion Batteries By the Simulation of Li Distribution in the Electrode Particles
Authors: Yang Naixing , Zhang Xiongwen , Li Guojun , Hua Dong 
Published: February 2020

The charging behaviors of lithium-ion batteries are closely related with the charging current and temperature. Generally, the constant current-constant voltage (CC-CV) mode is the most widely applied charging protocol for lithium-ion batteries. This paper establishes a multi-scale thermal-electrochemical model with considering the Li diffusion process in the electrode particles to investigate the battery charging performances. The change rules of the charging capacity and charging time are separately discussed based on the analysis of the transient characteristics of Li concentration inside the electrode particles when charging with the CC-CV mode.
It is known that the charged capacity is determined by the amount of the transferred Li between the negative and positive electrodes [1, 2]. The experimental and numerical results are compared in Fig.1. Fig.2 shows the distributions of Li concentration inside a carbon particle when battery is in charging with the CC-CV mode (4C→3.6V→0.02C) at 25°C. As the charging time increases, the gradient of Li concentration during the CC charging stage slightly decreases, while it decreases markedly during the CV stage.
The results show that the charged capacity in the CC stage decreases with the increase of the charging current when the current is lower than 4C, whereas it changes slightly in case of the charging current is higher than 4C; the CC charging time decreases with the increase of the charge current, while the change of the CV charging time is slight. For EVs application, the battery is recommended to only charge 90% of the total capacity, which can shorten the charging time significantly.

References

1. L.-x. Li, X.-c. Tang, Y. Qu and H.-t. Liu, Journal of Central South University of Technology, 18, 319 (2011).
2. N. Yang, X. Zhang and G. Li, Journal of Power Sources, 272, 68 (2014).

Figure 1
Iron(III) Oxalate Tetrahydrate: A New Positive Electrode for Li Batteries
Authors: Ahouari Hania , Tarascon Jean Marie , Recham Nadir , Rousse Gwenealle , Rodriguez-Carvaja Juan , Sougrati Moulay-Tahar , Courty Matthieu , Saubanere Matthieu 
Published: February 2020

Over the last two decades, energy storage devices and in particular lithium-ion batteries, have been the object of a steady growing demand due to their feasible implementation for automotive electric transportation (PHEV and HEV)[
1
]. However, this market requires the research of new electrode materials with higher energy density and greater power rate. When one looks back on history, the early nineties were solely devoted to oxide-based 3d-metal electrodes[
2
] and in the last 15 years three-dimensional frameworks built on transition metals and polyanions (XO4)n- have become subject of very intensive research[
3
].
LiFePO4 polyaionic compound offers low cost, environmental compatibility, high theoretical specific capacity (170 mAh/g) and has become the most praised material for the next generation of Li-ion batteries for EV’s [
3-4
].
Aside from the inorganics polyanionic compounds, we have recently shown the cost-wise attractiveness of some Fe-based phases having organic polyanions such as carbonates, oxalates, malonates, etc. These materials could be attractive electrodes due to their cost, low molecular weight and electronegativity. Herein, we report a new synthesis route to prepare Fe2(C2O4)3·4H2O and determine its crystal structure through X-ray powder diffraction coupled with neutron powder diffraction (Figure 1). We also show for the first time that iron(III) oxalate compound is electrochemical active versus lithium as it can reversibly insert 1.6 Li atom per formula unit at 3.35 V versus Li+/Li0 (Figure 2).
Beside reporting the synthesis and the crystal structure of Fe2(C2O4)3·4H2O phase, we will determine the structural changes driven by Li insertion using both in situ XRD and Operando Mössbauer measurements as will be discussed.

References

[1] M. Ati, M. T. Sougrati, G. Rousse, N. Recham, M. L. Doublet, J. C. Jumas and J. M. Tarascon, Chemistry of Materials
2012, 24, 1472-1485.
[2] J. M. Tarascon, W. R. McKinnon, F. Coowar, T. N. Bowmer, G. Amatucci and D. Guyomard, Journal Electrochemical Society
1994, 141, 1421-1431.
[3] C. Masquelier and L. Croguennec, Chemical Reviews
2013, 113, 6552-6591.
[4] N. Recham, J. Oró-Solé, K. Djellab, M. R. Palacín, C. Masquelier and J. M. Tarascon, Solid State Ionics
2012, 220, 47-52.

Figure 1
First Principles Study on Phase Stability in Li-Rich Layered Li2MnO3-LiMO2 (M=Mn, Ni, Co)
Authors: Lu Zhi , Morgan Dane , Wolverton Chris 
Published: February 2020

Lithium–rich layered oxides Li2MnO3-LiMO2 have attracted much attention as cathode materials in Li-ion battery recently because of their higher capacity (larger than 250 mAh/g), increased energy density and structural stability at high voltage. However, in order to be commercialized, there are still some unclear issues (structure complexity and reaction mechanisms) and challenges (first-cycle irreversible capacity loss, poor rate performance and voltage fade with cycling which is related to structural evolution).
Regarding their structure complexity, there is significant debate in the literature so far on whether these Lithium–rich layered cathode material form homogeneous solid solutions or Li2MnO3 nano-composite within a LiMO2matrix. It is important to get a clear picture of the actual detail structure, to understand and control their electrochemical performance. And without a detailed knowledge of the structure, it will be problematic to further explore failure mechanisms with cycling.
Recently in our research, the atomic order in Li-rich layered composites with composition xLi2MnO3-(1-x)LiMO2 is investigated with first-principles calculations using Generalized Gradient Approximation (GGA) +U method. The random solid solution structure model between Li2MnO3 and LiMO2 are created by Special Quasirandom Structures (SQSs) theory. After calculating the mixing energy, the miscibility gap is achieved and phase separation between Li2MnO3 and LiMO2 are predicted. Further study on the coherency strain energy shows that the strain energy is relatively small compared to mixing energy. Phase separation cannot be inhibited by strain.

Figure 1
Dilute Hydrogen Sulfide Sensing Characteristics of a Pt/GaN Schottky Diode
Authors: Xiao Jian-Feng , Hsu Chen-Pin , Wang Yu-Lin 
Published: February 2020

Hydrogen sulfide is a colorless, flammable and highly toxic gas with the characteristic foul odor of rotten eggs, often results from the bacterial breakdown of organic matters. Because of its toxicity, many personal safety gas detectors are set to alarm at 10ppm[i]. A number of sensors based on Schottky diode have been investigated as gas sensors since 1980s. In 2011, Professor Liu studied a Pt/AlGaN/GaN Schottky diode, which can exhibit ammonia detection limit lower than 35ppm NH3/air[ii]. There are also many papers research in H2S sensing with Schottky diode or metal oxide, most of their detection limit is higher than 10 ppm, expect one sensor made by thin film of CuO-SnO2, which can reach to 0.02ppm[iii].
The sensor studied in this paper contains four layers, which is showed in Figure 1 in detail. The Ohmic contact was formed by lift-off of e-beam evaporated Ti(200 Å)/Al(800Å)/ Ni(400Å)/Au(1000Å) and annealed at 850°C for 42 s under a flowing N2 ambient in a Premtek / ARTs 150. 100Å of Pt was deposited by e-beam evaporation to form Schottky contact as well as used as catalytic metal. Figure 2 shows three sets of Pt/GaN Schottky diode in different size and the size for the whole device is about 2×2mm. As the result of experiment, all of these three diodes are sensitive to H2S. Figure 3 shows real-time detection of 0.7ppm H2S in air. Figure 4 shows the relation between current change and concentration of H2S from 0.1-1ppm. All of the devices are tested in 200℃ and applied with 0.5ms width 1.5V pulse every second. With this Pt/GaN Schottky diode we can detect H2S down to 0.05pp.

[i] Agency for Toxic Substances and Disease Registry (July 2006)."Toxicological Profile For Hydrogen Sulfide". p. 154. Retrieved 2012-06-20.
[ii] T. Y. Chen, H. I. Chen, Y. J. Liu, C. C. Huang, C. S. Hsu, C. F. Chang, and W. C. Liu, “Ammonia sensing properties of a Pt/AlGaN/GaN Schottky diode,” IEEE Trans. Electron Devices, vol. 58, no. 5, pp. 1541–1547, May 2011.
[iii] Jun Tamaki , Kengo Shimanoe, Yoshihiro Yamada, Yoshifumi Yamamoto, Morio Miura, and Noboru Yamazoe,” Dilute Hydrogen Sulfide Sensing Properties of Copper Oxide-Tin Oxide Thin Film Prepared by Low-Pressure Evaporation” Solid State Sensors and Actuators, 1997 International Conference

Figure 1
Fabrication and Characterization of Well-Tunable and Titanium Thin-Film Liquid/Gas Diffusion Layers
Authors: Steen Stuart M. , Mo Jingke , Retterer Scott , Terekhov Alexander , Zhang Feng-Yuan 
Published: February 2020

A liquid/gas diffusion layer (LGDL) is located between the catalyst layer and current collecting flow field in proton exchange membrane (PEM) devices. Typically composed of carbon-based materials for PEM fuel cells (PEMFCs), this is unsuitable for PEM water electrolyzers (PEMWEs) due to the high anodic potential of the oxygen electrode that occurs during electrolysis, which creates a highly corrosive environment. Titanium has received considerable attention as a promising material to replace carbon LGDLs due to its high corrosion resistance at high positive overpotential, even in highly acidic and humid conditions. In addition, titanium provides high thermal/electrical conductivities and excellent mechanical properties. Current titanium LGDLs may be woven mesh, foams, and sintered fiber felt. Woven mesh are difficult to machine, and do not have the pore size controlled due to limitations of the material and available fabrication methods. Titanium felt on the other hand is similar in random structure to carbon paper, where shaved fibers of metal are sintered together to form a non-ordered porous material. In addition, their extra thickness increases significant electrical conductive path and fluidic resistance. Because of these challenges with the LGDLs, a thin-film LGDL with well-controllable pore morphology is highly desired in both PEMFCs and PEMWEs.
This presentation will highlight recent efforts to design and fabricate well-tunable and titanium thin film LGDLs using photolithography and etching techniques. The effect of mask size as well as different etchants on the etch rate and pore size of titanium is investigated. After fabrication, both performance & efficiency as well as electrochemical impedance spectroscopy is performed on the metallic LGDLs in order to evaluate their effectiveness in the anode side of a PEMWE. Ex-situ analysis is also performed before and after testing in order to characterize the morphological features of the LGDLs post etching and post testing. From the results of the fabrication and testing, new methods for the fabrication of well-tunable thin film LGDLs and the effect of controlling their parameters on the performance and efficiency of PEMWEs will be detailed.
Phase Field Simulation Coupling Microstructural Evolution and Crack Propagation during Performance Degradation of Solid Oxide Fuel Cells
Authors: Abdullah Taufiq , Liu Lin 
Published: February 2020

Both microstructural evolution and crack nucleation occur in Solid Oxide Fuel Cells (SOFCs) at elevated operation temperature (above 600°C), which cause severe performance degradation in electrochemical activity as well as structural integrity during their lifetime application. Nickel (Ni) coarsening of Ni-yttria stabilized zirconia (YSZ) in the anode of SOFCs is believed to lead to the microstructural evolution. In the meanwhile, severe thermal stress due to high operation temperature is one of the main factors responsible for crack propagation in the microstructure. Both microstructural evolution and crack nucleation have a significant impact on both electrochemical activity and structural integrity of SOFCs during operation. Based on theories of diffuse-interface and linear elastic fracture mechanics (LEFM), an integrated phase field model is established to couple electrode microstructural evolution and crack nucleation in SOFCs. Then, the model is applied to SOFCs with nonlinearly graded microstructures, which is proposed in our previous work (1), to explore the couple effects on SOFCs performance degradation. The preliminary results show that particle size and ratio, which dictates the triple phase boundaries (TPBs) contact angle, are ones of the most influential microstructural parameters in the microstructural evolution that affects SOFCs’ electrochemical activity. Different crack shapes are considered to reveal the effect of crack nucleation on SOFCs’ structural integrity. With combining the analysis of coupling effect of microstructural evolution and crack propagation on SOFCs’ performance degradation, it is expected the understanding of SOFCs’ performance degradation could be advanced. This work will provide one comprehensive evaluation computational tool for SOFC’s long-term degradation analysis and novel electrode design.
1. L. Liu, R. Flesner, G. Y. Kim and A. Chandra, Fuel Cells, 12, 97 (2012).
Alkene Difunctionalization Via b-Haloalkoxysulfonium Ions
Authors: Hayashi Ryutaro , Ashikari Yosuke , Nokami Toshiki , Shimizu Akihiro , Yoshida Jun-ichi 
Published: February 2020

Alkene difunctionalization via three-membered ring halonium ion intermediates is an important transformation in organic synthesis. The most straightforward method to generate the halonium intermediates is to use halogen cations, which are usually too unstable to accumulate in solution.
Recently, we reported that halogen cations stabilized by dimethyl sulfoxide (DMSO) were successfully generated and accumulated in solution by low-temperature electrochemical oxidation. Reactions of DMSO-stabilized halogen cations such as Br+ and I+ with alkenes gave b-haloalkoxysulfonium ions. Subsequent treatment of the b-haloalkoxysulfonium ions with triethylamine gave α-halocarbonyl compounds via Swern−Moffatt type oxidation. Here, we report that treatment of the b-haloalkoxysulfonium ions with different bases gives different products, i.e. the use of sodium hydroxide and sodium methoxide gives halohydrins and epoxides, respectively.
Electrosynthesis of Heterocyclic Compounds By Radical Cyclization in Environmentally Friendly Media
Authors: Mendes J.P. , Esperança J.M. S.S. , Esteves A. P. , Silva M. M. , Medeiros M.J. 
Published: February 2020

The formation of carbon-carbon bonds by radical cyclisation has become an important tool for the synthesis of natural products containing heterocyclic rings [1]. The majority of radical cyclisations in heterocyclic chemistry are still carried out using tributyltin hydride as the reducing agent. This has disadvantages, as the tributylin hydride is toxic and it is difficult to completely remove the tin species from the reaction mixture.
The electrochemical version of similar intramolecular processes - in reactions involving aryl or vinyl bromides [2], bromoacetals [2], or α-bromoamides [2] with double or triple bonds in the presence of nickel(II) complexes as catalysts - has been shown to be highly efficient. The reaction can be performed under mild conditions using relatively simple equipment. It also avoids the hazardous or toxic reagents used in the tributyltin hydride method.
Although most of the reactions have been reported in aprotic solvents, their toxicity, hazards and cost make them unattractive. This makes the search for non-toxic fluid alternatives highly desirable.
Ionic liquids (ILs) represent a class of alternative solvents currently receiving serious consideration, as they have environmental and technological benefits [3]. Their characteristics render them promising replacements for volatile organic solvents (VOCs).
As an extension of our previous research, we undertake further studies on analogs/derivatives of bromopropargyl esters as substrates. In the present work, we investigate the reductive intramolecular cyclization of bromopropargyl ethers derivatives, catalysed by electrogenerated (1,4,8,11-tetramethyl-1,4,8,11-tetraaza-cyclotetradecane)nickel(I), [Ni(tmc)]+ as the catalysts in N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium bis(trifluoromethylsulfonyl)imide,[N1 1 1 2(OH)][NTf2] and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C2mim][NTf2] by cyclic voltammetry and controlled-potential electrolysis. The results show that the reaction leads to the formation of the expected cyclic compounds, which are important intermediates in the synthesis of natural products with possible biological activities [4].

ACKNOWLEDGEMENTS

We are grateful to the Fundação para a Ciência e Tecnologia (PestC/QUI/UI0686/2013 and FCOMP-01-0124-FEDER-037302) for financial support of this work.

REFERENCES

1. B. Giese, “Radicals in Organic Synthesis: Formation of Carbon-Carbon Bonds”, Pergamon Press, Oxford (1986).
2. E. Dunach, M.J. Medeiros, S. Olivero, New J. Chem., 30, 1534 (2006).
3. Ionic liquids IIIB: Fundamentals, Process, Challenges, and Opportunities, ACS Symp. Ser. (Eds.: R. D. Rogers and K. R. Seddon), ACS, Washington DC, 2005.
4. P.K. Mandal, G. Maiti, S.C. Roy, J. Org.
Chem., 63, 2829 (1998).