bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Plasma Deposition of Functional Nanocomposites
Authors: Faupel Franz , Strunskus Thomas , Polonskyi Oleksandr , Elbahri Mady , Bonitz Michael , Kersten Holger
Published: February 2020

Nanocomposite films consisting of metal nanoparticles in a dielectric organic or ceramic matrix have unique functional properties with hosts of applications [1]. The present talk demonstrates how plasma and other vapor phase deposition techniques can be employed for tailoring the nanostructure and the resulting properties. Vapor phase deposition, inter alia, allows excellent control of the metallic filling factor and its depth profile as well as the incorporation of alloy nanoparticles with well-defined composition. The metallic nanoparticles typically form via self-organization during co-deposition of the metallic and matrix components due to the high cohesive energy of the metals and the low metal-matrix interaction energy. Various methods such as sputtering, plasma polymerization, and evaporation have been applied for the deposition of the matrix component, while the metallic component has mostly been sputter-deposited or evaporated. Moreover, gas aggregation cluster sources were utilized to obtain independent control of filling factor and size of the embedded nanoparticles [2,3]. Nanostructure formation was also studied by computer simulations [4]. In most applications, a high filling factor close to the percolation threshold is essential because the functional properties often require short range interaction between nanoparticles. Examples range from plasmonic composites [5,6] through high frequency magnetic cores [7] and sensors 8] to biocompatible antibacterial coatings with tailored release rate [9].

[1] F. Faupel, V. Zaporojtchenko, T. Strunskus, M. Elbahri, Adv. Eng.
Mater.
12, 1177 (2010).

[2] O. Polonsky, T. Peter, V. Zaporojtchenko, H. Biedermann, F, Faupel, Appl. Phys. Lett.
103 (2013) 033118.

[3] T. Peter, M. Wegner, V. Zaporojtchenko, T. Strunskus, S. Bornholdt, H. Kersten, F. Faupel, Surface & Coatings Technology 205, 38 (2011).

[4] J. W. Abraham, N. Kongsuwan, T. Strunskus, F. Faupel, and M. Bonitz, J. Appl. Phys. 117 , 014305 (2015).

[5] M. Elbahri, M. K. Hedayati, V. S. K. Chakravadhanula, M. Jamali, T. Strunkus, V. Zaporochentko, F. Faupel, Adv. Mater.
23, 1993 (2011).

[6] M. K. Hedayati, M. Javaherirahim, B. Mozooni, R. Abdelaziz, A. Tavassolizadeh, V. S. K. Chakravadhanula, V. Zaporojtchenko, T. Strunkus, F. Faupel and M. Elbahri, Adv. Mater.
23, 5410 (2011)

[7] H. Greve, C. Pochstein, H. Takele, V. Zaporojtchenko, F. Faupel, A. Gerber, M. Frommberger, E. Quandt, Appl. Phys. Lett.
89, 242501 (2006).

[8] C. Hanisch, N. Ni, A. Kulkarni, V. Zaporojtchenko, T. Strunskus, F. Faupel, J. Mater. Sci.
46, 438 (2010).

[9] T. Hrkac, C. Röhl, R. Podschun, V. Zaporojtchenko, T. Strunskus, H. Papavlassopoulos, D. Garbe-Schönberg, F. Faupel, Mater. Sci. Eng. C
33, 2367 (2013).
Role of Low-Energy Ion Impact in Plasma Deposition of Cubic Boron Nitride Films
Authors: Murata Kazuma , Torigoe Masataka , Teii Kungen , Matsumoto Seiichiro
Published: February 2020

Cubic boron nitride (cBN) is potentially expected as the semiconductor for high temperature condition due to the large band gap, high breakdown field, and high resistance to oxidation. cBN films have been synthesized from vapor phase using a variety of physical vapor deposition such as sputtering and ion beam deposition rather than plasma-enhanced chemical vapor deposition. However, high-energy (>50 eV) ion bombardment for cBN formation results in low-quality cBN films and thus obstructs their electrical applications. In our previous studies, high-quality cBN films were deposited under low-energy ion bombardment (<40 eV) by plasma-enhanced chemical vapor deposition using the chemistry of fluorine. The mean ion energy for cBN formation was reduced greatly, then the resulting films consisted of micron-sized grains with crystallographic morphology. In this study, the deposition mechanism of our cBN films is examined in terms of ion energy, ion flux, and ion to depositing boron flux ratio onto the substrate.

The ion energy and the ion to boron flux ratio are determined from the sheath potential and the ratio of incident ion flux to net deposited boron flux, respectively. For negative substrate biases where sp2-bonded BN phase only or no deposit is formed, both the ion energy and the ion to boron flux ratio are high. For positive substrate biases where cBN phase is formed, the ion energy and the ion to boron flux ratio are estimated in the range of a few eV to 35 eV and 100 to 130, respectively. The impact of negative ions is presumed to be negligible due to their low kinetic energy. The impact of positive ions with high ion to boron flux ratios is primarily responsible for reduction of the ion energy for cBN film deposition. [1] K. Teii and S. Matsumoto, Thin Solid Films 576, 50-54 (2015).
Plasma Synthesis of Platinum-Palladium Alloy Nanoparticles and Their Application to the Counter Electrode of Dye-Sensitized Solar Cells
Authors: Lee Woo-Yeol , Dao Van-Duong , Choi Ho-Suk
Published: February 2020

Dry plasma reduction (DPR) is an excellent approach for easy synthesis of PtPd alloys with different sizes, shapes (nanoparticles, nanorods, microrods, etc.), and distributions on fluorine-doped tin oxide (FTO) substrates through simply controlling the volume ratio of the Pt and Pd precursor solution under atmospheric pressure near room temperature. These alloys are optimized for use in highly efficient counter electrodes (CEs) of dye-sensitized solar cells (DSCs). In order to combine both high conductivity and ultrahigh catalytic activity in the regeneration of iodide ions from triiodide ions, seven different CEs are prepared through the immobilization of Pt, Pd, and PtPd alloys from solutions with different volume ratios of Pt to Pd precursors (1:0, 0.9:0.1, 0.7:0.3, 0.5:0.5, 0.3:0.7, 0.1:0.9, and 0:1) on the surface of fluorine-doped tin oxide (FTO) substrates via DPR. Dye-sensitized solar cells (DSCs) utilizing a bimetallic Pt0.5Pd0.5 nanorod counter electrode exhibit better performance than those of DSCs fabricated with Pt and Pd electrodes. The obtained results establish a foundation for the use of PtPd alloy CEs as well as the economic utility of Pt in efficient and low-cost DSCs.
An Alternative Pre-Treatment for Metallization of Polymeric Materials and Its Applications
Authors: Oriani Andrea Vittorio , Cojocaru Paula , Magagnin Luca
Published: February 2020

Metallization of polymers is a challenging process due to the intrinsic difference in the chemical nature of Polymeric and metallic materials. This leads, in the best scenario, to metallic deposits having poor adhesion to the polymeric substrate1. Neglecting wet processes2, that are based on hazardous chemicals (as chromic acid) and limited to specific polymers, plasma activation has been considered a promising option for more than thirty years. In the past, pioneering studies demonstrated that low pressure plasma is a valid alternative pre-treatment to chemical etching. This is due to the ability of plasma to graft nitrogen-containing functionalities that bind to palladium in the activation bath3–5. Technological advancement in the field of plasmas allowed developing open air systems, thus reducing operational costs and dimensional limitations. Since, in principle, plasma parameters can be tuned to be effective on different classes of polymers6,7, this pre-treatment allows electrochemical metallization of polymers that couldn’t be plated due to the ineffectiveness of wet chemical etching.

In this study open-air roll-to-roll dielectric barrier discharge (DBD) equipment was used to pretreat different polymers including Polyetheretherketone (PEEK), Ethylene ChloroTriFluoroEthylene (ECTFE) and Poly Vinyldene fluoride (PVDF) films with nitrogen-based plasma. The plasma modified surface of the films was therefore coated with metal by means of a commercial electroless copper or nickel lines or homemade silver baths. Different thickness values have been considered for the metallic coating. While thin deposits (up to about 250nm) were obtained by electroless only, thicker coatings were obtained performing electrodeposition on top on the metallic layer previously obtained.

Specific characterization of the metallic-coated polymers was performed depending on their final application: this spans from barrier layer to fluids to flexible concentrator mirror for solar thermodynamic. Further studies were performed to understand the nature of the modification induced by plasma to the polymer surface, both from a chemical and morphological point of view, in the first case by means of XPS and in the second by AFM. Nucleation and growth of the metallic layer was studied by SEM. Adhesion between polymer and metal was studied by cross cut test (ASTM D3359), which confirmed excellent adhesion levels.

References

1. J. M. Burkstrand, J. Appl. Phys., 52, 4795 (1981).

2. R. R. Rye, A. J. Howard, and A. J. Ricco, Thin Solid Films, 262, 73–83 (1995).

3. M. Charbonnier, M. Alami, M. Romand, L. De Sciences, and U. C. Bernard, 143 (1996).

4. M. Alami, M. Charbonnier, and M. Romand, Plasmas Polym., 1, 113–126 (1996).

5. M. Charbonnier, M. Alami, and M. Romand, J. Appl. Electrochem., 28, 449–453 (1998).

6. S.J. Cho, S. P. Shrestha, and J.H. Boo, Curr. Appl. Phys., 11, S135–S139 (2011).

7. M. Šimor et al., Surf. Coatings Technol., 172, 1–6 (2003).
Composition, Structure and Properties of Electroless Deposited Rhenium-Rich Re-Co Thin Films
Authors: Duhin Alla , Inberg Alexandra , Eliaz Noam , Gileadi Eliezer
Published: February 2020

Rhenium (Re) is a promising refractory metal that has unique combination of properties. Compared to other refractory metals, Re has the greatest tensile strength and excellent creep resistance over a wide range of temperatures (up to ~2000°C). Pure Re does not have a ductile-to-brittle transition temperature. Moreover, unlike other refractory metals, Re does not form stable carbides. Thus, it is potentially attractive coating on different carbon material.

Electroless plating is relatively simple method for generating thin metallic and metal alloy films on conductive and nonconductive surfaces. The ability of electroless plating to coat the inside of holes and recesses without using external current source or vacuum technology equipment makes it an ideal coating technology for many applications. In this study, high Re content (more than 65 at.%) Re-Co coatings were prepared by electroless deposition. The pH dependence of process kinetics, film microstructure and composition was studied. The obtained films were characterized by HRSEM, AFM, XPS and XRD methods. It was shown that as deposited films have amorphous structures with microhardness value of 600 - 620 HV. Crystalline hcp structure of Re-Co coating was detected only after annealing at 550 oC. Thin coatings (250-500 nm) have demonstrated good corrosion protection of copper in salt medium reducing corrosion current at list by one order of magnitude. The annealed deposits have shown improved mechanical and electrical properties. Such films exhibit ferromagnetism and could be applied in mobile magnetic components where soft-magnetic response combined with mechanical stability is required (MEMS devices).
Deposition of Ni-Based Carbon Nanotube Composite Coatings By Using Laser Enhanced Electroless Plating
Authors: Suzuki Tsunehisa
Published: February 2020

1 Introduction

In recent years, the mask-less direct metal patterning on 3D shape plastic substrates has received considerable attention from the perspective of potential applications to such as 3D-molded interconnect device (3D-MID). 2-shot injection molding and Laser direct structuring (LDS) are the leading technology in this field. However, these technology are not direct metal patterning. In the case of LDS, The laser-activatable thermoplastic doped with a special additive was required for making a sensitized-activated surface by laser. When the thermoplastic was irradiation by laser beam, it was activated. A physical-chemical reaction forms metallic nuclei. These act as a catalyst for electroless plating. The metallization on activated pass was performed by electroless plating after laser-activation.

Some recent researches have investigated the laser enhanced electroless plating and have reported that they could successfully and directly formed metal patterning on the plastic substrates by the laser enhanced electroless plating. The metallization on activated pass were performed by electroless plating after laser-activation. However, the effects of the laser wavelength and additives in plating bath is not clear. In this study, their effects on the laser enhanced electroless plating were investigated. Carbon nanotubes (CNTs) were used as additives for improving laser absorption.

2 Experimental Procedure

Polyimide films as substrates were immersed in low phosphorus electroless nickel plating bath (Meltex, NI-426, 1-3% phosphorus). The polyimide films were not sensitized and were not activated. Laser beam irradiation performed on the substrates through quartz glass rods at room temperature. Laser wavelengths of 405nm, 532nm, 980nm were chosen. CNTs (Showa denko, VGCF-H, 0.4g/L) were added in the plating bath.

 3. Results and discussion

In the case of non-addition of CNTs, no nickel deposited on the polyimide film by laser irradiation of 405nm (0.15W), 532nm (1.5W), 980nm (6W) in wavelength. Non-deposition results from non-pretreatment, such as sensitizing and activating, and from the less laser absorption of substrates.

In the case of addition of CNTs, Island-like nickel deposited on the polyimide films by using 980 nm Laser beam. The nickel deposits were nickel-based CNT composites. CNTs improved the absorption of Laser and led local heating on the substrates so that the composite coatings formed on the non-pretreated substrates.

Figure 1
(Invited) The Interaction of Organic Additive in Magnetic Alloy Plating
Authors: Sun Ming , Jiang Ming
Published: February 2020

Organic additives can play an important role in thin magnetic alloy electrodeposition. To understand how the additive interacts with the film nucleation/growth, then alters the film property still remains as the very interesting topic.

In this study, we have evaluated several sulfur-containing organic additives with different structures in NiFe or CoFe electrodeposition electrolytes. First, the molecule adsorption on metal surface via unsaturated bonds are evaluated and compared; then, post hydrogenation reduction products of those compounds are verified in the deposit, to identify if the additive active function groups are actually desorbed from surface, or incorporated in deposit; lastly, the associated film properties are studied and compared.
(Invited) Electrodeposition of Thermally Stable Soft Magnetic Materials
Authors: Gong Jie , Riemer Steve , Tabakovic Ibro , Kautzky Michael
Published: February 2020

Advanced reader technology requires high reader annealing temperature (300-450°C) to achieve good TMR ratio, to realize high density and low noise reader performance. 1) However, during the reader stack anneal, the bottom shield will also be exposed to the high temperature and possibly a cross magnetic field. Generally, the bottom shield is regular electrodeposited Permalloy Ni80Fe20 prepared from an electrodeposition solution containing saccharin additive. The significant grain growth of the NiFe bottom shield would cause deterioration of the magnetic properties as annealing temperature increases over 300°C, resulting in disordered shield domain structures and high reader noise.   As one of the paths to improve the thermal stability, we have been studying and developing by using a third element to pin the grain growth caused by thermal annealing, while still keeping good magnetic softness. In this work nanocrystalline NiFeX (X=Co, Mo, O etc) films were prepared by electrodeposition, which can be stable up to 450°C. The relationship between preparation method and magnetic properties, domain structure, microstructure, crystal structure, corrosion resistance, and their thermal stability were studied.   Figure 1 shows the comparison of the microstructure and domain structure of regular Permalloy and the thermally stable NiFeO after 400C 2hr annealing.   Reference: 1) S. Ikeda, J. Hayakawa, Y. Ashizawa, Y. M. Lee, K. Miura, H. Hasegawa, M. Tsunoda, F. Matsukura, and H. Ohno, Appl. Phys. Lett., 93, 082508 (2008).

Figure 1
Superconformal Bottom-up Cobalt Deposition in High Aspect Ratio through Silicon Vias
Authors: Josell Daniel , Silva Manoj , Moffat Thomas P.
Published: February 2020

This work demonstrates void-free cobalt filling of 56 mm tall, annular Through Silicon Vias (TSVs) using a mechanism that couples suppression breakdown and surface topography to achieve controlled bottom-up deposition. The chemistry, a Watts electrolyte containing a dilute suppressing additive, and processes are fully detailed. The impact of deposition potential and additive concentration on the filling of the patterned features is presented. Voltammetric measurements on planar substrates, including the impact of rotation rate and suppressor concentration on the rate of metal deposition and potential of suppression breakdown, are used to quantify the interplay between metal deposition and suppressor adsorption. The derived kinetics are then used to quantitatively predict the observed bottom-up filling in the TSVs using the S-shaped negative differential resistance (S-NDR) mechanism for superconformal deposition; the predictions capture the experimental observations. This work extends understanding and application of the additive-derived S-NDR mechanism, including previous demonstrations of superconformal filling of TSVs with nickel as well as copper, zinc and gold.
Lifecycle Characterization of a High Magnetostriction Cobalt Iron Electroplating Chemistry
Authors: St. John Christopher R. , Pillars Jamin Ryan , Hollowell Andrew E , Finnegan Patrick , Langlois Eric Donald , Arrington Christian L.
Published: February 2020

Electrodeposition of iron alloy metals is problematic due to the undesired oxidation of Fe+2 to Fe+3 [1]. A custom cobalt iron electroplating chemistry targeting properties of magnetostriction was used at the beaker scale 80 mL in size. The chemistry is stable for long periods of time, maintains current efficiency, and yields the desired atomic ratios in the deposited cobalt iron film with high values of magnetostriction. However, upon scaling to a 2.5-liter chemistry needed to accommodate four to six inch wafer fabrication, the bath deteriorates much more quickly over time. The current efficiency drops and oxygen is deposited into the film. This is undesirable as the atomic ratio changes the properties of the material and the resulting structures. An investigation into counteracting the undesired iron oxidation in the chemistry was undertaken in order to characterize the deterioration and to prevent this deterioration from occurring.

Our experiments tracked on a weekly basis the decrease of current efficiency within the chemistry, along with the stoichiometry of the deposited cobalt iron and the resulting magnetostriction of the films. Various chemistry storage concepts were tested to determine the effect on current efficiency. When fresh, both the beaker and 2.5-liter sized chemistries electroplate near 80% current efficiency, with a majority of wasted current attributed to hydrogen gas formation. As the chemistry ages, much of the decrease in current efficiency is believed to occur as a result of iron oxidation. Both the solution and the plated films take on a darker color common with oxygen poisoning. During plating, nitrogen is bubbled into the bath in order to reduce this issue. However, it takes the beaker scale approximately 70 days to drop below a usable efficiency, while the 2.5 liter wafer-scale takes approximately 35 days to do the same.

 

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. SAND2015-10657A

Tabakovic, I.; Riemer, S.; Jayaraju, N.; Venkatasamy, V.; Gong, J. Electrochim Acta 2011, 58, 25-32.
Electrodeposition of Ag-Ni-W Alloys
Authors: Kola Avinash R. , Podlaha Elizabeth J
Published: February 2020

The induced codeposition of tungstate has been widely examined in the presence of nickel, cobalt and iron ions.1 On the other hand, more noble elements, such as Ag, can also induce the reduction of tungstate ions, but to a lesser extent, resulting in silver-rich alloys, by either electrodeposition2 or electroless deposition.3,4 Since both nickel and silver species can induce tungstate, the combined effect is investigated here. Electrodeposited Ag-Ni-W alloys from a stable, thiourea-citrate electrolyte, is examined using rotating cylinder electrodes. The deposit composition was determined with x-ray fluorescence, and used to calculate partial current densities. The increase of nickel ions to a Ag-W electrolyte did not further induce the reduction of tungstate ions, but inhibited it. To probe if the type of nickel species were responsible for affecting the tungsten rate, citrate concentration in the electrolyte was also varied. A significant factor in inducing tungsten was attributed to the presence of silver species compared to nickel species suggesting a thermodynamic control for tungstate reduction.

 

Acknowledgements

The authors wish to thank the AESF foundation and Tyco Electronics Connectivity Ltd. for partial support of this project.

 

References

1. N. Tsyntsaru, H. Cesiulis, M. Donten, J. Sort, E. Pellicer, and E. J. Podlaha_Murphy, Surf. Eng. Appl. Electrochem., 48, 491 (2013).

2. A. Kola, X. Geng, and E. J. Podlaha, J. Electroanal. Chem., 761, 125 (2016).

3. Y. Shacham-Diamand, A. Inberg, Y. Sverdlov, and N. Croitoru, J. Electrochem. Soc., 147,3345 (2000).

4. E. E. Glickman, V. Bogush, A. Inberg, Y. Shacham-Diamand, and N. Croitoru, Microelectron. Eng., 70, 495 (2003).
(Invited) In-Situ Analysis of Lithium Ion Batteries
Authors: Ogumi Zempachi
Published: February 2020

Twenty-five years have passed since the first lithium ion battery (LIB) was commercialized, which work on the basis of ion shuttle mechanisms. Reactions in LIBs are very simple at first glance; insertion and extraction of Li+at positive and negative electrodes, and electron transfer occurs through a schottky contact between current collectors and active masses.

When we look insight of the reaction, the situation is not so simple as the first glance. Even during insertion and extraction of positive ions, i.e. Li+, charge neutrality through the system must be retained, which means that the valences of the elements, mainly transition metals, composing the host lattice must change during the reaction. The valence change causes structural changes in the lattice, namely, phase transition should occur.

Carbon materials, generally graphite, are used as the negative active mass in LIB. The fully charged state of graphite shows the potential as low as that of lithium metal, 90 – 200 mV vs Li/Li+. Organic species composing the electrolyte and binder of LIB are inherently unstable against such reductive circumstances. Nevertheless LIB shows stable and long life compared with other rechargeable batteries and is now produced in an enormous scale and widely used. This is due to the surface stabilization of the graphite negative electrode by the formation of a passivating film called SEI.Its energy density has increased over twice since the commercialization. There remain some issues to enhance the property and extend the application of LIBs.

Innovation in materials for LIB is essential for advancing LIB properties but it is no less important to clarify reactions occurring in LIBs. The latter would supply information and cues to develop innovative materials for future LIBs.

Reactions proceeding inside LIB range widely in scale of time and space. A variety of analytical technologies including FT-IR, Raman, SPM, NMR, SR-X-ray diffraction and absorption, neutron diffraction, SEM, TEM, EC-MS have been developed and used to elucidate reactions inside LIBs in situ and ex situ.

The author’s group has developed some of these technologies, some of that are summarized and explained here.

There are plenty of analytical technologies further-more that have high potential for clarifying reactions of batteries. Main battery reactions should be focused and in addition to the main reactions side reactions and slow reactions that give major influences on life and safety of battery required to be solved.

Each analytical technology has some merits and demerits in focusing on reactions to be clarified. Adequate technologies should be selected depending on the phenomena to be solved.

Figure 1
in-Operando Imaging Studies on Dynamics of Sulfur/Polysulfides in Li-S Batteries
Authors: Wu Nae-Lih
Published: February 2020

Lithium-sulfur (Li-S) battery is a promising rechargeable battery system that has both high theoretical capacity and energy density. Moreover, sulfur (S) is inexpensive and nontoxic, making Li-S suitable for large-scale energy storage applications. Sulfur (S8) lithiation during the operation of Li-S battery is a multi-step electrochemical process that involves different lithium polysulfide (Li2Sn) intermediates. The long-chain polysulfides (PSs) are highly soluble in the aprotic organic electrolyte. There has been a broad consensus that polysulfide dissolution is strongly linked to the key performance indexes, such as columbic efficiency, self-discharge, capacity fading and etc., of Li-S batteries.  Re-deposition of S/PS takes place during de-lithaition, which has never been investigated in the literature but is believed to play equally important part as the dissolution process in affecting the cycle stability of the S electrode. We carry out in this work operando observations at two different scales on the dynamics of dissolution and re-deposition processes of polysulfide/S particles during the operation of Li-S batteries. In-operando synchrotron transmission X-ray microscopy (TXM) has been used to monitor in real-time the dynamics of the S/PS dissolution and re-deposition  based on the dimensional variation of the micron-sized S-containing active particles. On the other hand, in-operando optical microscopy has been used to reveal the large-scale motion of the polysulfides within a model cell. The combined information from these two in-operando studies provides valuable evidences that unravel the existence of unprecedented chemical-reaction driven charge-transfer mechanisms for S lithiation/delithiation.

Figure 1
Using Thin Films to Study Capacity Fade Mechanisms Observed in Conventional LiV3O8 cathodes
Authors: Kercher Andrew Keith , Sarbada Varun S.V. , Zhang Qing , Takeuchi Kenneth J , Marschilok Amy C , Hull Robert , Dudney Nancy J , Takeuchi Esther S
Published: February 2020

Capacity fade mechanisms can be difficult to pinpoint in conventional composite cathodes for Li-ion batteries. Capacity fade associated with the cathode can be caused by: (1) irreversible reactions involving the active material, possibly with the electrolyte, (2) degraded integrity of the composite structure, or (3) anode contamination by cathode dissolution products. Post-cycling characterization can be difficult, because these potential capacity fade mechanisms would occur in a complicated cathode structure with: porosity, possible microcracks, irregular surfaces, and multiple particulate phases (active material, binder, and conducting additive).

Thin film cathodes were used to study how LiV3O8 (LVO) microstructure affects cycling performance without the added complications associated with a conventional composite cathode structure. Thin film cathodes were produced by magnetron sputtering a Pt current collector layer and an LVO layer onto alumina disks. The thin film geometry with its uniform layered structure was well suited for analysis of pristine and cycled LVO cathodes by several characterization techniques, including transmission electron microscopy, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy.

The cycling performance of heat-treated thin film cathodes was directly compared to that of conventional composite cathodes with heat-treated sol-gel derived LVO powder. Thin film and sol-gel derived LVO cathodes showed excellent microstructural and electrochemical agreement as a function of heat-treatment temperature. Depending on heat-treatment temperature, the microstructure ranged from amorphous (as-deposited or low temperature heat-treatment) to coarse-grained crystalline material (higher temperature). The maximum specific capacity and the maximum capacity fade were both observed for LVO nanocrystalline material fired at intermediate temperature, where reduced capacity and reduced capacity fade were observed for higher and lower firing temperatures. Capacity fade was linked to vanadium dissolution, where amorphous LVO cathodes showed much lower vanadium dissolution than nanocrystalline LVO material.

This work was supported as part of the Center for Mesoscale Transport Properties, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0012673.
(Invited) In-Situ and Operando Structure Analysis of Lithium Battery Reactions Using Neutron Scattering
Authors: Kanno Ryoji , Taminato Sou , Yonemura Masao , Shiotani Shinya , Kamiyama Takashi , Torii Shuki , Nagao Miki , Ishikawa Yoshihisa , Mori Kazuhiro , Fukunaga Toshiharu , Onodera Yohei , Naka Takahiro , Morishima Makoto , Ukyo Yoshio , Adipranoto Dyah Sulistyanintyas , Arai Hajime , Uchimoto Yoshiharu , Ogumi Zempachi , Suzuki Kota , Hirayama Masaaki
Published: February 2020

Among the in situ and operando techniques proposed for elucidating the reactions, a structural analysis would provide essential and fundamental information. The high-intensity and high-resolution diffraction is one of the best techniques for observing the changes in the cell components during operation, which may provide clues that help us to recognize the significant issues affecting the deterioration of the battery. However, the operando systems are rather difficult to apply in the commercial-size cells. Many approaches have therefore been proposed based on stationary neutron and high energy X-rays, and structural changes in the electrode materials have been detected under slow reaction kinetics conditions or a repeated data accumulation process. However, comprehensive observations that can detect deterioration-related changes in the components under actual operations remain difficult.

We developed an experimental system that uses high-intensity time-of-flight (TOF) neutrons and a high-resolution SPICA diffractometer. The structure changes in the cathode and anode materials were analysed at each charge-discharge reaction step. The new measurement system could provide information for a wide range of reactions related to real battery operation conditions.

Acknowledgements

This work was supported by the Research and Development Initiative for Scientific Innovation of New Generation Batteries (RISING) project of the New Energy and Industrial Technology Development Organization (NEDO).
Long Duration Studies of Lithium Battery Materials Using Synchrotron X-Ray Powder Diffration
Authors: Baker Annabelle , Day Sarah , Tang Chiu C.
Published: February 2020

The use of in-situ X-Ray Powder diffraction for the study of new battery materials has grown in recent years, providing an insight into the effects that charge/discharges cycles have on cathode materials. These experiments are often limited to short periods of time and therefore only allow for one full charge/discharge cycle/multiple fast cycles to be observed. The result is that material characteristics may be well understood for the first cycle but little is known about the long term processes that ultimately lead to failure of the cell over longer timescales.

The Long Duration Experiment (LDE) Facility on Beamline I11 at Diamond Light Source is the first of its kind, housing experiments that require periodic, in-situ monitoring over periods of months to years. It is an ideal facility for the long term study of battery materials, allowing data to be collected over many cycles. To conduct these experiments a new cell had to be developed that would allow the transmission of X-rays, while also remaining impermeable to air and moisture for a long period of time. Previous in-situ diffraction experiments of battery materials have generally involved using unconventional cells. While these are effective, they are often not stable for long periods of time and are not true representations of real-life battery systems. By modifying a standard CR2032 coin cell case, we have been able to produce a cell that fits this purpose. Laser thinning was used to reduce the thickness of a small section of the cell to 50μm, allowing sufficient X-ray transmission without compromising the integrity of the cell.
Compton Scattering Imaging for Operando Observation of Battery Cell
Authors: Itou Masayoshi , Sakurai Yoshiharu , Suzuki Kosuke , Sakurai Hiroshi , Orikasa Yuki , Uchimoto Yoshiharu
Published: February 2020

We propose an X-ray Compton scattering imaging technique based on synchrotron radiations for observation of lithium migration and internal structure change in battery cells under in-situ and operation conditions.

This technique uses high-energy monochromatic X-rays as the probe, and detects Compton scattered X-rays from a certain volume element inside a battery cell. Because the energies of both X-rays are higher than 100 keV with high penetration power, it is possible to observe the inside of battery cells. The intensity of Compton scattered X-rays is proportional to electron density and the energy profile of Compton scattered X-rays provides the electron momentum density distribution, both of which enable us to analyze the internal structure and lithium concentration inside the battery cell. In this presentation, we demonstrate the capability of the X-ray Compton scattering technique by visualizing both the migration of lithium ions in the positive electrode and the structural change due to the volume expansion of the electrode [1, 2].

This work was supported by Japan Science and Technology Agency.

[1] K. Suzuki et. al., J. Appl. Phys. 119, 025103 (2016)

[2] M. Itou et .al., J Synchrotron Radiat. 22, 161-4 (2015)
In-Operando Imaging of Electrodeposition and Dendrites Using Nanoscale X-Ray Computed Tomography
Authors: Choi Paul , Kedlaya Vinayak , Mandal Pratiti , Frisco Sarah , Whitacre Jay , Litster Shawn
Published: February 2020

The widespread implementation of lithium-ion batteries in systems ranging from portable electronics to electric vehicles has generated a remarkable demand for batteries with improved durability and performance. In order to satisfy said demand, the issue of dendrite formation must be addressed; dendrite growths inside batteries have been observed to create an internal short circuit that results in catastrophic failure.1 Consequently, dendrite propagation not only poses a significant safety hazard to existing lithium-ion batteries, but also is detrimental to the development of next-generation lithium based energy storage technologies such as lithium-air batteries. A better understanding of dendrite nucleation and growth behavior through direct visualization is crucial to developing effective dendrite mitigation techniques. Prior studies observed these phenomena using electron microscopy2 and micro-scale resolution X-ray computed tomography (micro-CT).3,4 These approaches present distinct challenges, including the vacuum environment of electron microscopes2,5 and insufficient resolution of micro-CT to image nucleation events.3

An interesting alternative is the use of the nano-scale resolution X-ray CT (nano-CT) that allows for three-dimensional observations within opaque materials at high resolution (50 nm) with any electrolyte with controlled environmental conditions. In this study, an in-operando cell for nano-CT imaging was designed and fabricated, in which the working electrode is prepared on a metal wire placed within electrolyte contained by a sealed capillary. This work addresses the particular challenges of preparing in-operando electrochemical cells for lab-scale nano-CT instruments, which include sealing, limited cell size, and the beam path length through the sample. Additional considerations include the development of high temporal resolution 4D (3D plus time) reconstruction algorithms to address the longer exposure times of lab-scale instruments. Preliminary experiments demonstrating these capabilities include the imaging of dendritic copper electrodeposition using copper wires and aqueous copper sulfate electrolyte. Figure 1 shows the images of the in-operando copper dendrite growth acquired using the nano-CT with a 65 mm field of view and an exposure time of 10 s. The results in Figure 1f show that following the initial cell transient, the cell current increases with the corresponding increased surface area of the dendrites.

References

1. P. G. Balakrishnan, R. Ramesh, and T. Prem Kumar, J. Power Sources, 155, 401–414 (2006)

2. J. K. Stark, Y. Ding, and P. A. Kohl, J. Electrochem. Soc., 160, D337–D342 (2013)

3. K. J. Harry, D. T. Hallinan, D. Y. Parkinson, A. A. MacDowell, and N. P. Balsara, Nat. Mater., 13, 69–73 (2014)

4. D. S. Eastwood et al., Chem. Commun. (Camb)., 51, 266–8 (2015)

5. W. Xu et al., Energy Environ. Sci., 7, 513–537 (2014)

Figure 1
EIS Analysis of Commercial Lithium-Ion Battery on Accelerated Degradation for Long-Term Charge-Discharge Cycling
Authors: Mukoyama Daikichi , Nara Hiroki , Yokoshima Tokihiko , Momma Toshiyuki , Osaka Tetsuya
Published: February 2020

A lifetime of batteries is one of the most important issues for energy storage systems. Non-destructive measurement methods are demanded on accelerated testing in the development of a lithium ion battery (LIB) for longer lifetime, in order to provide shortening development period and reducing development cost. Electrochemical impedance spectroscopy (EIS) is the effective method of non-destructive investigation for batteries. We already proposed an equivalent circuit for a wide range of impedance spectra. [1,2]The electrochemical impedance of the electrodes in a commercial LIB at various states was analyzed to evaluate by this circuit. In this study, we focused on an analysis of accelerated degradation of the LIB for the long term charge-discharge cycling.

A commercially available pouched LIB with a nominal capacity of 5 Ah for an electric assist bicycle was used in this work. The batteries were charged and discharged with a constant current (CC) protocol between 3.0 and 4.2 V with a rate of 2 C at 25 °C and 45 °C. The discharge capacities of LIBs were measured with a rate of 1/3 C at 25 °C. The impedance of the batteries was measured by Biologic VMP3 with AC signal amplitude of 0.4 A in the frequency range from 100 kHz to 10 mHz at 25 °C. Before the impedance measurement, the batteries were charged at a rate of 1/3 C to 4.2 V, and were maintained for 3 h.

During continuous charge-discharge cycling of LIB under 25 °C and 45 °C, the discharge capacities gradually decrease to less than 65% after 9,700 cycles and 2,400 cycles, respectively (Fig. 1). The variety of frequency responses accompanying the capacity degradation at 25 °C is shown in Fig. 2 (a). The frequency responses at 10 mHz increased with charge-discharge cycles, EIS analysis using equivalent circuits imply that the major factor of LIB degradation is the active material degradation of the cathode. On the other hand, frequency responses accompanying the capacity degradation at 45 °C showed the almost same increase tendency in Fig. 2 (b). We will present the EIS analysis using equivalent circuit on accelerated testing with charge-discharge cycles in detail.

This work was partly supported by “Research & Development Initiative for Scientific Innovation of New Generation Batteries” and “Development of Safety and Cost Competitive Energy Storage System for Renewable Energy” from NEDO, Japan.

References:

T. Osaka, et al., J. Power Sources, 205 (2012) 483-486.

D. Mukoyama, et al., Chem. Lett., 41 (2012) 444-446.

Figure 1
An Inverse Model of Acoustics in Batteries for Determining Structural Changes, State of Charge and State of Health
Authors: Davies Greg , Hsieh Andrew , Steingart Daniel A
Published: February 2020

There has been recent interest in using acoustic techniques as a diagnostic tool for batteries. Studies have shown that significant changes in the acoustic fingerprints of batteries occurs during cycling [1,2]. These shifts can be correlated with electrochemical and physical phenomena within the cell. Ideally, the goal is to determine battery properties based on the acoustic fingerprint of a cell without a prior understanding of the state of health or charge of the cell. Furthermore, we would seek to understand acoustic behaviour as cells degrade or approach catastrophic failure. Here we present modeling developed to understand acoustic and electrochemical interactions in a cell. A forward model of a cell subject to acoustic signals is presented, which captures some critical characteristics of the system. Then, an associated inverse method is presented, which seeks to back out critical material characteristics relevant to cell state of charge, state of health and potential failure modes.

1. A. G. Hsieh et al., Energy Environ. Sci., 8, 1569–1577 (2015).

2. S. Bhadra, A. G. Hsieh, M. J. Wang, B. J. Hertzberg, and D. A. Steingart, J. Electrochem. Soc., 163, A1050–A1056 (2016).
Non-Destructive Analysis of Lithium-Ion Battery Using Isothermal Electrochemical Calorimetry
Authors: Kobayashi Yo , Kato Hisashi , Miyashiro Hajime , Mita Yuichi
Published: February 2020

The thermal response of highly reversible reaction such as lithium-ion battery materials is derived from the change in entropy (ΔS) of the system. In particular, we can directly observe the arrangement of mobile lithium ions because the origin of ΔS is due to the configurational entropy of lithium ions in operation. A temperature dependence of open circuit voltage (dE/dT) is known as another popular tool to determine ΔS. However, dE/dT analysis is just an information of the static condition like a snap shot. On the other hand, the electrochemical calorimetry is an analysis tool to observe the direct motion of lithium ions during charge and discharge. It is like a motion picture so that we can also determine the transitional phenomena of the mobile lithium ions in the host structure. We applied electrochemical calorimetry to commercial lithium-ion systems, and determined the degradation mechanism with cycle operation. We will also show a clear difference of observed ΔS between dE/dT and electrochemical calorimetry, and confirm the advantage of electrochemical calorimetry.
(ECS Charles W. Tobias Young Investigator Award) Advanced Materials Diagnosis and Characterization for Enabling High Energy Long Life Rechargeable Batteries
Authors: Meng Ying Shirley
Published: February 2020

High energy long life rechargeable batteries is considered as key enabling technology for deep decarbonization. Advanced materials characterization tools are essential for scientists and engineers to understand operation and degradation mechanisms in batteries, in order to propose solutions and strategies for improvement. Scanning electron microscopy and electron energy loss spectroscopy (STEM/EELS) offers unprecedented spatial resolution, which has enabled nanoscale imaging and chemical analysis of battery materials - their surfaces, grain boundaries and phase boundaries. Combining the state-of-the-art in situ operando analytical electron microscopy with first principles (FP) computational data analysis, we reveal some insights that could not be possible to see in the past. On the other hand coherent x-ray diffraction imaging (CXDI), a lensless form of microscopy capable of discerning electron density and strain with 10 nm resolution, can be used to map the strain evolution of a single cathode particle in a functional battery material as it is cycled in-situ. The evolution of compressive/tensile strain reveals a number of interesting phenomena. By combining electron based and X-ray based novel imaging techniques, I hope to showcase the state-of-the-art diagnostic tools developed for probing and understanding electrode materials in operando.
Electrodeposition As an Approach for Fabricating High Performance Battery Electrodes
Authors: Marschilok Amy C , Takeuchi Kenneth J , Takeuchi Esther S
Published: February 2020

Conventionally, battery electrodes are prepared from physical mixtures of conductive additives, polymeric binders, and electroactive active material particles which are usually coated onto metal foil current collectors. The three passive components serve distinct functions, where the current collector provides structural support, the binder maintains physical adhesion throughout the composite, and the conductive additives establish an interconnected conduction network. Minimizing the mass of passive material in the electrode is desirable to maximize functional gravimetric capacity. To maximize energy density and rate capability, obtaining a continuous conductive pathway with open pores for fast ion transport is critical.

Electrodeposition is presented here as a design strategy for lightweight, high performing, high energy density battery electrodes. Opportunity for removal or reduction of passive components will be discussed. Examples of direct deposition of electroactive particles onto a three-dimensional, lightweight, conductive substrate will be described, along with functional testing of the resulting composite electrodes for beyond lithium-ion batteries (i.e. magnesium-ion batteries and metal air batteries). Benefits of the electrodeposition based fabrication strategy, including quantitative control over active material loading, and opportunity to realize continuous electrical contact by design, will be highlighted.