bluuebunny/crossref_metadata_2025_split huggingface dataset:
Facile Synthesis of Anhydrous Metal Fluoride Nanocomposites Using Ammonium Fluoride and Their Application to High Performance Lithium-Ion Battery Cathodes
Authors: Chun Jinyoung , Kim Youngsik , Lee Jinwoo 
Published: February 2020

Among various metal compounds, metal fluorides (MFx) are one of the promising cathode materials for Li-ion batteries (LIBs) as they exhibit high theoretical conversion potentials as well as large specific capacities. However, only a limited number of synthetic method, generally involving highly toxic or inaccessible reagents, currently exist, which has made it difficult to produce well-designed nanostructures suitable for use as cathodes; consequently, harnessing their potential cathodic properties has proven challenging over the past several decades.
In this study, in order to address these critical issues and realize potential cathodic performance of MFx in LIBs, we have developed a new and facile bottom-up approach using ammonium fluoride (NH4F) to synthesize anhydrous MFx(CuF2, FeF3, and CoF2)/mesoporous carbon(MSU-F-C) nanocomposites. We discovered that various metal precursor nanoparticles pre-confined in mesoporous carbon can be directly converted to anhydrous MFx by simple heat treatment with NH4F under solventless conditions. Furthermore, we also demonstrate the versatility, mild toxicity, and efficiency of this synthetic method, and, using XRD analysis, propose a mechanism for the reaction. As the cathodes of LIBs, all MFx/MSU-F-C prepared in this study exhibited superior electrochemical performances, through conversion reactions. In the case of FeF3/MSU-F-C, it maintained a capacity of 650 mAh g−1
,FeF3 across 50 cycles, which is ~90% of its initial capacity; to the best of our knowledge, no such an excellent cycle performance of FeF3 with a high capacity through conversion reactions has previously been reported. CuF2/MSU-F-C and CoF2/MSU-F-C cells also retained 209 mAh g−1
,CuF2 (at the 20th cycle) and 400 mAh g−1
,CoF2 (at the 30th cycle) of discharge capacities, respectively. These results show excellent performance in comparison to previous studies; in particular, this is the first result which shows promising cycle properties of CuF2. We expect that this new synthetic method would open an avenue to application of metal fluorides to cathodes in LIBs and will be adopted by many scientists & engineers for their future research.
(Invited) Electrospun Electrolytes and Electrodes for Li-Ion Batteries
Authors: Croce Fausto 
Published: February 2020

The quest for more efficient and low environmentally impacting energy conversion and storage technologies has become a priority for modern society. In particular, rechargeable, high capacity and high power electric energy storage systems, if developed, would play a central role in accelerating the transition toward an electric transportation economy, which, in turn, would dramatically reduce the risks associated with the burning of fossil fuels. To this purpose, ‘ad hoc’ engineered functional materials that join improved electrochemical properties with scalable preparation process for electrodes and electrolytes are needed. The most promising of such materials are those with nanometric-scale dimensions, including nanoparticles and nanofibers. These materials, having very high surface to volume ratio, show enhanced bulk charge transport and faster electrodic reaction rates. Nowadays, new methods have emerged for manipulation, assembly and characterization of nanostructured materials, particularly regarding functional electrodes and electrolytes based on nanofibers. Among the methods for generating nanofibrous structures, electrospinning is a top-down approach proved to be simple, cost effective and versatile, which allows the fabrication of polymeric and inorganic nanofibers in a scalable process. Electrospinning is based on the application of an electric field to a drop of a viscous solution on the tip of a spinneret. The electric field elongates the drop to form a conical shape known as the Taylor cone. For an electric field critical value, the repulsive electrical forces between the charges in the fluid overcome the surface tension of the drop and a charged jet of the solution is ejected from the tip of the Taylor cone. The jet becomes unstable and rapidly whipping leading to the evaporation of the solvent and the formation of dry, continuous, ultra-thin fibers on the collector [Fig. 1]. The collected electrospun mats present peculiar properties, such as very high surface to volume ratio, low density, high pore volume and remarkable mechanical strength.
In this presentation, the electrospinning technique will be illustrated particularly regarding the optimization of the system and process parameters, which mostly influence the electrospun nanofibers. The characteristics of some gel electrolytes formed by electrospun polymeric separators based on PVdF and PEO will be discussed. Finally, the preparation by co-electrospinning followed by air stabilization and carbonization of nanosized, active, electrodic particles embedded in electrically conducting Porous Multichannel Carbon MicroTubes (PMCMT) will be described [Fig. 1] and the performances of composite electrodes prepared using Sn- PMCMT, Si-PMCMT and Li2S-PMCMT powders illustrated.
Fig.1

Figure 1
Separation of Reaction and Storage in Li-Air Battery
Authors: Takechi Kensuke , Mizuno Fuminori 
Published: February 2020

Non-aqueous Li-air battery has intensively been investigated due to its ultla-high energy density, however, its serious concerns have not been completely solved yet, such as severe cycle fading and low current density. The major cause of the issues can be attributed to a deposition of discharge product on the cathode surface because the deposition results in a clogging of the pore in the cathode preventing continuous steady discharge and in its chemical and/or physical electronic isolation from cathode even after charge.1 In other words, a fundamental difficulty which resides in Li-air architecture can be described as; ‘electrochemical reaction and discharge product storage take place at the same location, on the cathode’.
Based on the discussion, we simply came to the conclusion that we needed to separate ‘electrochemical reaction and discharge product storage’ to solve above-mentioned fundamental issues. In this presentation, we propose a new concept Li-air battery which discharge product (Li2O2) can be stored in its electrolyte instead of on the cathode (fig. 1). The new battery architecture can be realized by simply replacing its original electrolyte to a new composite one. The cathode is able to maintain itself in a steady state during discharge because the discharge product is not deposited on it, and the new Li-air has performed much higher current density and capacity than the regular (old) architecture Li-air (fig. 2). We also demonstrate performances of the new Li-air even in the ambient air operation.

Y. Hase, E. Ito, T. Shiga, F. Mizuno, H. Nishikoori, H. Iba, K. Takechi, Chem. Commun., 49, 8389 (2013).

Figure 1
Novel Ether- or Sulfur-Functionalized Ionic Liquids As Electrolyte Components in Advanced Lithium Batteries
Authors: Navarra Maria Assunta , Lombardo Lucia , D'Annibale Andrea , Appetecchi Giovanni Battista , Panero Stefania 
Published: February 2020

Although lithium batteries have tremendous potential, the flammability of the organic electrolyte commonly used hinders their consideration for large-scale applications, where the battery is expected to operate over a wide temperature range without compromising safety. To combat flammability, highly stable ionic liquids (ILs), entirely composed of ions and having negligible vapour pressure, have been widely investigated as electrolytes [1].
Tailored, in-house synthesized new ILs, based on cyclic quaternary ammonium cations, having no double bonds or acidic protons reacting with lithium, and bis(trifluoromethanesulfonyl)imide (TFSI) anion, will be here presented. A comparison between two families of ionic liquids, with ether- or sulfur-functionalized aliphatic side chains in the cation moiety, will be described. Their thermal and electrochemical properties, including the definition of the stability window, interface characteristics towards carbon-based and lithium electrodes, will be discussed. Electrochemical performances in advanced lithium cell configurations, adopting electrolytes based on the proposed ILs, will be finally presented. Tests in Li/S cells have revealed good reversibility of the polysulfides redox process and appreciable capacity, combined with good retention and coulombic efficiency leveling 99 %.
[1] M. A. Navarra, MRS Bulletin, volume 38, year 2013, pages 548 - 553: “Ionic liquids as safe electrolyte components for Li-metal and Li-ion batteries”.
(Invited) The Solid-State Lithium Secondary Batteries: Its Possibility Beside the Sulfide Electrolytes
Authors: Aihara Yuichi 
Published: February 2020

Lithium-ion battery was commercialized in 1991, and its market has grown tremendously for IT mobiles. Today, the demand for high energy density is rapidly increasing for automotive and stationary energy storage. In the history, lithium metal secondary battery has attracted great attention for digital media applications about thirty years ago. However, due to significant technical challenges such as dendrite formation during charge-discharge cycles, its development had faded and the interests shifted to lithium-ion batteries. From the view point of energy density, the interest is coming back and effort for the lithium metal and related alloys is intensifying.
In this presentation, our recent work on the fabrication of all-solid-state batteries and sulfide solid electrolyte development will be reported. The sulfide solid-state batteries have the advantages of (1) small grain boundary resistance, (2) fast kinetics at Li/solid electrolyte interface, (3) stable cycle with a lithium metal anode, (4), lack of convection of the electrolyte material, and (5) non-volatile and incombustible electrolyte. [1-3] We have demonstrated charge-discharge operation of solid state Li-S batteries, and verified its low activation energy of the charge transfer process at the anode. Further improvements are still needed in the loading-level of active materials and cell performance.
Besides the fabrication of the solid-state cells, our efforts on the materials development will be presented. In particular, some results on LiI substituted Li3PS4 solid electrolyte will be shown. This material is amorphous and exhibits >1mScm-1at 25℃.[4] Finally, challenges and outlook of our research and development will be discussed.

S. Ito, et al., J. Power Sources 248 (2014) 943.

M. Agostini, et al., Solid State Ionics 244 (2013) 48.

T. Yamada, et al., J. Electrochem. Soc.(2015) A646.

Y. Aihara, et al., elsewhere
(Invited) Electrochemical Synthesis of High Strength Regular Metal Foams and 3D Micro-Lattices
Authors: Mieszala Maxime , Hasegawa Madoka , Mischler Stefano , Michler Johann , Philippe Laetitia 
Published: February 2020

Three-dimensional metal micro- and nanostructures offer opportunities to develop multifunctional materials with unique combinations of material properties. Traditional strategies to improve the mechanical properties of materials consist of altering either the microstructure or the composition. Both strategies, albeit successful, tend to be rather incremental. The third approach is that of controlling not only the microstructure but also the architecture1. By combining the effect of the architecture with the effect of the microstructure, architectured cellular materials with enhanced mechanical properties are achieved.
Modern templating techniques, including colloidal crystal lithography2 and 3D laser lithography3, enable the creation of structures with well-defined sub-micron features. Used in combination with electrochemical routes, the deposition of nickel or copper micro-architectures is achieved with fine control of the microstructure and dimensions. Although electrodeposition is a well-established technique, metal electroforming of cellular micro-materials is demanding. Specific challenges include the electrodeposition onto non-conductive surfaces, adequate surface preparation, appropriate throwing power for electrolyte infiltration into submicron features or proper process optimization.
The present talk will cover our recent research activities on the fabrication of nickel and copper regular foams and micro-lattices synthesized by electrochemical processes aiming at achieving high strength and low density materials. Regular porous metal structures are produced by colloidal crystal templating of polystyrene (PS) microspheres. The PS templates are formed by sedimentation of PS microspheres. Under gravity and drying, the PS microspheres form a self-assembled multilayer with a face-centered cubic structure. The templating step is followed by either metal electrodeposition to obtain a metal inverse opal (Figure 1.a) or by electroless deposition of NiB to form a hollow-shell opal (Figure 1.b). The metallic micro-lattices (Figure 1.c) were fabricated by electroless deposition of NiB onto a surface-modified polymer template produced by 3D laser lithography. In situ micromechanical testing of these micro-architectures showed enhanced mechanical properties despite being low density. Increasing the metal coating in micro-lattices from 10 nm to 100 nm improve the mechanical performances by a factor of 3.5 while the density is only multiplied by 2.3.
References:

1 M.F. Ashby, Philos. Trans. A. Math. Phys. Eng. Sci. 364, 15 (2006).

2 A. Stein and R.C. Schroden, Solid State Mater. Sci. 5, 553 (2002).

3 J. Bauer, S. Hengsbach, I. Tesari, R. Schwaiger, and O. Kraft, Proc. Natl. Acad. Sci. U. S. A. 111, 1 (2014).

Figure 1
Deposition of Pt Nanoparticles on Ni Foam Via Galvanic Displacement
Authors: Tamasauskaite-Tamasiunaite Loreta , Zabielaite Ausrine , Balciunaite Aldona , Sebeka Benjaminas , Stalnioniene Irena , Buzas Vytenis , Maciulis Laurynas , Tumonis Liudas , Norkus Eugenijus 
Published: February 2020

In the present study the Ni foam was modified with Pt nanoparticles via the galvanic displacement technique. A thin electroless Ni sublayer was deposited on the Ni foam substrate. Then, Pt nanoparticles were deposited on Ni/Nifoam by its immersion into a platinum(IV)-containing solution for various time periods. The morphology, structure and composition of the prepared catalysts were examined by means of Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, X-ray Diffraction and Inductively Coupled Plasma Optical Emission Spectroscopy. The catalytic activity of Pt(Ni)/Nifoam with different Pt loadings was determined by measuring the amount of hydrogen generated directly from aqueous alkaline solutions of sodium borohydride and compared with that of Pt. The data on hydrogen generation volume with respect to time at different concentrations of sodium borohydride and different temperatures have been presented.
It was found that the Pt(Ni)/Nifoam catalysts show enhanced catalytic activity towards hydrogen generation as compared to that of Ni/Nifoam.
Acknowledgment

This research was funded by a Grant (No. TEC-06/2015) from the Research Council of Lithuania.
Electroless Metallization of Stereolithographic Photocurable Resins for 3D Printing
Authors: Bernasconi Roberto , Credi Caterina , Natale Gabriele , Tironi Marco , Levi Marinella , Magagnin Luca 
Published: February 2020

In the last few years the introduction of affordable 3D printing techniques like fused deposition modeling (FDM) and stereolithography (SLA) is slowly changing the way mass production has always been intended. The possibility to obtain complex shapes in a short time directly at home, without using conventional manufacturing techniques, is a revolutionary concept that is finding a lot of different applications. However some limitations exist for 3D printing, the most important one being the manufacture of metallic objects. Metals offer many attractive properties like electrical and thermal conductivity or a good mechanical resistance, and for this reason the 3D printing of metallic objects is a strategic research field in additive manufacturing. Some techniques able to directly print using metals are available, but many limitations are present in this case. For this reason the most used method to obtain bulk metallic parts is the use of the printed polymeric version as a mold to cast the final object. In most applications however only a thin layer of metal is required and different methods can be used to coat a printed part, including PVD and all-wet metallization. The latter is in general preferred due to the low cost and the optimal coverage in the case of critical shapes of the printed part. Optimized methods are available for the metallization of FDM printed objects [1], while in the case of SLA manufactured samples only some aspects of the plating process are treated in the existing literature [2, 3].
The present work investigates an optimized method to metallize parts obtained with SLA 3D printing by mean of an all-wet process based on electroless plating. The behavior of different proprietary and custom made photocurable resins printed using a commercial laser stereolithographic printer is investigated. The coatings employed include nickel-phosphorus and copper, two metals typically deposited via electroless plating on polymers. The metallization is characterized from the fundamental point of view on planar samples, while in a second time some examples of complex shapes metallization are provided. In particular the metallization of micrometric parts is studied. Finally the possibility to deposit other layers of different metals via electrodeposition on the first coating obtained by electroless plating is analyzed.
[1] R. Bernasconi et al.; ECS Trans., 66 (19), 23 (2015)
[2] A. Macor et al.; Rev. Sci. Instrum., 83, 046103 (2012)
[3] B. Luan et al.; Appl. Surf. Sci., 156, 26 (2000)
(Invited) Progress on Electroless Atomic Layer Deposition
Authors: Stickney John Lewellen , Benson David M. , Jagannathan Kaushik 
Published: February 2020

Atomic layer deposition (ALD) is a group of methods for the formation of nanofilms of materials, an atomic layer at a time using surface limited reactions. The majority of those methods are based on use of the vacuum environment. However there are methods such as sequential ionic layer adsorption reaction (SILAR) which uses the condensed phase, that is, aqueous solutions of precursor ions. In addition, this group has been working on an electrochemical form of ALD for 25 years. That work is referred to as electrochemical atomic layer deposition (E-ALD) or electrochemical atomic layer epitaxy (EC-ALE), and is based on using underpotential deposition (UPD) for surface limited reactions. The problem with using an electrochemical methodology for the formation of nanofilms is that many compatible with the conductive substrates normally used for E-ALD. This has stimulated investigations into the growth of materials using an electroless form of ALD (EL-ALD). The processes being explored are based on use of an adsorbed layer of a precursor, where the solution is then exchanged for a reducing agent, or vis versa. This cycle is then repeated to desired thickness. One example is the use of an adsorbed (or absorbed) layer of hydrogen as the reducing agent (usually on Pd). This is then used for surface limited redox replacement (SLRR) of the desired element. Another example is the use of Sn2+ adsorption followed by Pd2+, which oxidizes the Sn2+ to Sn4+ and forms Pd on the surface. Studies are underway to build this into a cycle for EL-ALD.
Magnetic Field and Substrate Effects on the Electrodeposition of High Magnetostrictive Cofe Films
Authors: Pillars Jamin Ryan , Langlois Eric Donald , Arrington Christian L. , Monson Todd 
Published: February 2020

Magnetostrictive CoFe films were investigated for use as magnetoelastic tags or sensors. The ability to electrodeposit these films enables batch fabrication processes to pattern a variety of geometries while controlling the film stoichiometry and crystallography. Previous research developed a chemistry and plating parameters to maximize magnetostriction with a stoichiometry range of Co0.7-0.75Fe0.3-0.25and 20-30nm grain size. To further optimize the magnetostriction of electrodeposited CoFe films, the effect of the substrate was examined using copper, gold, and nickel electrodeposited base layers with varying preferred orientations and grain sizes. X-ray diffraction spectroscopy and electron backscatter diffraction were used to determine the crystal structure and crystallite size. Additionally, a hard magnet setup was used to apply a magnetic field during electrodeposition of the CoFe alloy to control the alignment of the magnetic domains. Magnetic force microscopy was used to determine the magnetic structure of the films as a function of the applied field’s magnitude and direction. Magnetic field and substrate effects were then correlated to magnetostriction performance.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
Area-Selective Electroless Deposition of Gold Nanostructures with Various Morphologies on Silicon Assisted By Focused Ion Beam Irradiation
Authors: Itasaka Hiroki , Nishi Masayuki , Shimizu Masahiro , Hirao Kazuyuki 
Published: February 2020

Electroless deposition of metal onto semiconductor is an efficient technique to fabricate metal nanostructures for electronic, photonic, and plasmonic applications. We previously reported a new area-selective electroless deposition of gold nanostructures on a crystalline silicon substrate. A simple tetrachloroauric(III) acid (HAuCl4) solution using water or alcohol as a solvent is dropped on a crystalline silicon substrate preprocessed with a focused ion beam (FIB) or a femtosecond laser. Gold nanostructures selectively grow on the preprocessed area on the silicon substrate[1]. Hydrofluoric acid, which is commonly used for electroless deposition of metal on semiconductor, is unnecessary in our method. Our previous work revealed that silicon dangling bonds induced by the preprocessing reduce gold ions in the solution[2]:
3Si• + Au3+ + 3ROH → 3Si-OR + Au + 3H+ (R = H or CnH2n+1)
where Si• represents the silicon atom which has a single dangling bond and three covalent bonds with other silicon atoms. This reductive reaction requires hydroxyl groups of solvent molecules and initiates the nucleation of gold. However, the overall mechanism of the gold growth in our method is still unclear.
Here we focus on the growth stage of gold after the nucleation stage. For investigation of growth mechanism of gold, we quantitatively evaluate the amount of gold grown on FIB-irradiated silicon surface with a fixed microscopic area by measuring the thickness of gold. The quantitative evaluation indicates that once the gold/silicon interface is formed through the nucleation stage, electrons in crystalline silicon surrounding the FIB-irradiated silicon reduce gold ions in the solution across the interface. Therefore the difference in the Fermi level between silicon and the solution is the driving force in the growth stage. This mechanism is supported by a new two-step growth process introduced to our method, in which the exposure of the FIB-irradiated silicon substrate to HAuCl4 solutions is separated into the first and second steps. Once the gold/silicon interface is formed in the first step, the gold growth proceeds in the second step with or without silicon dangling bonds and hydroxyl groups of solvent molecules. Furthermore, our new method enables us to fabricate gold nanostructures with various morphologies by selecting the reaction condition in the second step.
References

H. Itasaka, M. Nishi, Y. Shimotsuma, K. Miura, M. Watanabe, H. Jain, and K. Hirao, J. Ceram. Soc. Jpn.
122,543 (2014).

H. Itasaka, M. Nishi, and K. Hirao, Jpn. J. Appl. Phys.
53, 06JF06 (2014).