bluuebunny/crossref_metadata_2025 huggingface dataset:
The Study of Dissolved Oxygen Control in TSV Electroplating Deposition
Authors: Kim Dae-Gil , Lee Dosun , Kim Sang-Yun
Published: February 2020

As the device size have been continuously scaled down, it is difficult to have a reliable semiconductor device. TSV (Through Silicon Via) is one of the promising candidates to solve the problem.

In TSV, it is one of the important techniques to fill the hole without defect as a conductive material [1].

The copper (Cu) is commonly used as a filling material because Cu has good electrical conductivity and excellent signal transfer characteristic in the GHz band.

The electroplating (EP) is widely used for proper filling way due to its fast speed and low cost. [2].

In TSV EP, as the aspect ratio of the TSV filling is increased, it is a also critical issue to maintain fast and constant bottom-up filling rate without void.

In this study, the relationship between the bottom-up rate of TSV EP and key process parameters was analyzed. In particular, we focused on the dissolved oxygen (DO) in the electrolyte and experimented the relationship between bottom-up filling rate and DO.

Fig.1 shows the bottom-up filling rate as functions of a VMS additive "A", "S" and the DO concentration. In Fig. 1, the effect of the DO concentration is more sensitive than other additives in view of the filling rate.

Equ.1 describes Fig.1

Equ.1 shows the additive oxygen present in the VMS which reacts with Accelerator Acc. As a result, the amount of Acc. is reduced. DO concentration control the oxidation-reduction reaction in EP Process which results in the reduced Bottom-up Rate. [3,4].

Fig.2 shows the simplified picture of the degasser mounted on the VMS supply line where the gas molecules dissolved in the VMS are removed by vacuum. Consequently, the concentration of DO can be lowered.

Fig.3 shows the TSV filling images as functions of the device type and DO concentration. As shown in Fig. 3, the stable characteristics of TSV filling are developed by keeping the DO concentration less than 1.0ppm.

In this paper, we investigated the relationship between TSV bottom-up rates and DO concentration. From experimental results, we found that it is essential to keep the DO concentration less than 1ppm. We installed degasser for the VMS in order to obtain a constant low DO concentration. As a result, we were able to achieve the stable TSV bottom-up rate and yield improvement.
Pattern Formation in the Mercury Beating Heart System
Authors: Ocampo-Espindola Jorge Luis , Ramírez-Álvarez Elizeth , Montoya Fernando , Rivera Marco Antonio
Published: February 2020

In this work is presented a phenomenological study of the mercury beating heart (MBH) in a configuration of three electrode electrochemical cell, where the mercury drop is the working electrode. We report the occurrence of a traveling wave on the MBH system as result of the chemo-mechanical processes taking place.

Under fixed potential conditions the drop changes its shape and rotates simultaneously. Using image processing, it was possible to gain information about angular velocities, changes in perimeter of the drop and periodicities in the spatiotemporal changes observed. Furthermore when a sinusoidal potential is applied, the mercury drop exhibit geometrical shapes and complex surface structures. Here the characterization study was realized by observing a wide range of frequencies and amplitudes of a sinusoidal wave potential signal. As frequency increases, shapes with higher number of peaks and more complex surface structures appear. A possible resonant coupling of some traveling waves, originated by the electrochemical process and shaped by the mercury hydrodynamic, results in these complexes surface structures.
New Insights on Naproxen Quantification Using Voltammetry and Graphite Electrodes: Development of an Optimized and Competitive Methodology
Authors: Aguilar-Lira Guadalupe Yoselin , Álvarez-Romero Giaan Arturo , Rojas-Hernández Alberto , Páez-Hernández María Elena , Rodríguez-Ávila Jose Antonio , Romero-Romo Mario Alberto
Published: February 2020

The non-steroidal anti-inflammatory drugs (NSAID’s) comprise a group of compounds bearing different chemical structures, displaying primarily an inhibition capacity of the prostaglandins synthesis through inhibition of the enzyme cyclo-oxygenase [1]. These medicaments share similarly undesirable pharmacological actions and effects. Naproxen is found among the group of widely prescribed and well-known pharmaceuticals, Figure 1, which exhibit anti-inflammatory analgesic and anti-pyretic properties [2]. The fact that naproxen is much more commonly used with and without appropriate medical prescription has made it necessary to implement stricter quality controls for this drug; during the last years it has also been considered an emerging contaminant in residual waters systems.

Figure 1. Naproxen’s chemical structure

Naproxen, acid ((S)-2-(6-methoxy-2-naftyl) propanoic acid) is a non-steroidal anti-inflammatory drug, frequently used to diminish pain, fever, inflammation and the stiffness provoked through osteoarthritis, rheumatoid arthritis, and other illnesses [3]. Naproxen is considered an NSAID of the propionic acid group with a pKa of 4.2, it is liposoluble, practically insoluble in water at pH < 4, though when the pH > 6, the reverse is true [1].

The present work discuses new findings in the electrochemistry of naproxen over graphite electrodes. This new approach, along with a formal optimization of the variables related with differential pulse voltammetry, allows the proposal of a simple and competitive low-cost method to carry out naproxen’s voltammetric quantification. Naproxen’s indirect quantification through an adsorption anodic wave was performed at a graphite bar electrode using differential pulse voltammetry. An anodic current maximum was recorded at a potential of -0.3 V referred to a saturated Ag/AgCl reference electrode, in the presence of 0.1 mol dm-
3 phosphates buffer at pH 7. A calibration plot was done, having a correlation coefficient of 0.990, with a sensibility of 4.19 ± 0.62 µA cm3 µg-
1, with detection and quantification limits of 0.68 and 3.3 µg cm-3, respectively, and a quantification interval of 3.3 - 28.18 µg cm-
3. The method proposed was adequate for naproxen quantification in pharmaceutical samples.

References

[1] P. Todd, S. Clissold, Naproxen. A reappraisal of its pharmacology, and therapeutic use in rheumatic diseases and pain states, Drugs 40 (1) (1990) 91-137.

[2] B. Raskin, Gastrointestinal effects of nonsteroidal anti-inflammatory, Therapy Americ. J. Medic. 106 (1999) 3S–12S.

[3] C. Boynton, C. Dick, G. Mayer, NSAIDs: An Overview, J. Clin. Pharmacol. (28) 6 (1998) 512-517.
Effects of the Cross-Linking Agent on Electrochemical Performances of the Lithium Metal Polymer Batteries Prepared by In-Situ Thermal Polymerization with Trimethylolpropane Treiacrylate
Authors: Jeong Jiseon , Lee Hoogil , Shin Gyuho , Cho Insung , Choi Jaecheol , Ryou Myung-Hyun , Lee Yong Min
Published: February 2020

All-solid lithium metal polymer batteries (LMPBs) consisting of lithium transition metal cathodes, polymer electrolytes and lithium (Li) metal anodes have long been investigated for over two decades to achieve higher level of energy density compared to those of lithium-ion batteries (LIBs) [1-2]. Unfortunately, however, LMPBs have failed to come to the market because of their low level of standard to use; relatively poor ion conductivity level (<10-3 Scm-1) and high interfacial resistance. In order to improve these bottlenecks, gel polymer electrolytes (GPEs) were developed by adding solvents into pure solid polymer electrolytes (SPEs).

In this study, we developed the novel GPE systems based on in-situ thermal polymerization process, which play as polymer electrolytes within pores of microporous polyethylene separators and polymeric binders for cathode at the same time. GPEs were synthesized via in-situ thermal polymerization process, and thus it is remarkably economical and easy to handle. We found optimum ratio of cross-linking agent for GPEs, and evaluated cell performance of LMPBs employing the same. Furthermore, we evaluated the effects of GPEs upon surfaces of Li metal anodes and cathodes by monitoring the morphological changes of them by electron scanning microscopy (SEM) as a function of cross-linking agent concentration.

Acknowledgements

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (2010-0025738).

References

[1] J.Y. Lee et al., Journal Solid State Electrochem 14 (2010) 1445–1449

[2] J.Y. Lee et al., Journal of Power Sources 174 (2007) 603–606
Catalytic Activity of Spherical Meso-Porous Pt Films-Deposited Fluorine-Doped Tin Oxide Substrate Covered By Multi-Walled Carbon Nanotube for Iodine Reduction
Authors: Endo Michinori , Aoyama Hiroyuki , Matsunaga Mariko
Published: February 2020

Platinum (Pt) is known to be one of the best catalysts for various electrochemical reactions although it is an expensive rare metal. Therefore, a investigation on reducing consumption of Pt is of great interest by many researchers. For this purpose, we recently focus our attention on a mesoporous Pt film which posses not only a large surface area but also extremely high catalytic activity for methanol oxidation [1].

To make most of the mesoporous Pt film effectively, we focus our attention to moderately small spherical configuration. Spherical configuration increase the active surface area for electrochemical reactions. However, the interface between Pt particles and the substrate is considered to yield high interfacial resistance because of the limited point contacts. Therefore, in this study, Multi-Walled Carbon Nanotube (MWCNT), which is superior in mechanical strength and electric conductivity, a specific thermal conductivity, and the large surface area, was deposited to bypass the spherical mesoporous Pt film and the substrate as depicted in Fig.1. In this presentation, the redox reaction of the iodide ions will be mainly discussed for the application to dye-senstized solar cell.

MWCNT/mesoporous Pt composite film was prepared by two steps. At first, the mesoporous Pt was deposited on TiO2/ Fluorine-doped Tin Oxide (FTO) substrates, and then the surface was wholly covered by MWCNT. The electrodeposition was performed in a three-electrode cell by chronoamperometry: various FTO substrates are used for working electrode, platinum wire for counter electrode, and an Ag/AgCl electrode for reference electrode. For the electrolyte, 20 mM K2PtCl4aqueous solution resolving 1.0 wt % Brij58 (Aldrich) was utilized. 10 mg/mL of CNT solution resolving sodium dodecylbenzenesulfonate was dropped on the mesoporous Pt film and dried at room temperature.

The spherical mesoporous Pt film was demonstrated to deposit at the potential of -0.1 V when a TiO2/FTO is used as substrate. Cyclic voltamograms of the bare TiO2/FTO substrate, and the TiO2/FTO substrates modified with the composite film, the spherical mesoporous Pt film, and the MWCNT film, respectively were measured in an acetonitrile solution consisting of 0.1M TBAP, 1 mM I2, and 0.1 M LiClO4. As shown in Fig.2, the reduction peak current corresponding to iodine reduction for the composite film showed approximately three times larger than that for the both substrates modified only with the spherical mesoporous Pt film and the MWCNT film. These results revealed that the composite film can be the best catalyst for iodine reduction.

[1] H. Wang et al., Chem. Mater., 2012, 24, 1591-1598.
Voltammetric Determination of Cisteine by Carbon Paste Electrode Cu-Hg Amalgamated
Authors: Molina Mayela , Gil Paulina Obdulia , Roa Gabriela , Macedo Guadalupe , Balderas Patricia
Published: February 2020

Plants have a defense mechanism for dealing with heavy metals, so that they are produced rapidly due to the high toxicity of the heavy metals. By this plant defense mechanism occurs, phytochelatins which are polypeptides , wherein a glutamic acid is linked to a cysteine via a γ - peptide bond, so that they have an ability to form bonds with metals through group SH in the portion of the cysteine .

So it is very important find cheap and easily applied for the determination of phytochelatins methods. In literature are reported reported to an amalgam of Cu-Hg was efficient for determining phytochelatins by complexation of Cu+ with thiol groups by electrochemical methods such as voltammetry and polarography cathodic stripping voltammetry, [1].

So in this work is to obtain a carbon paste electrode (CPE) modified with a Cu-Hg amalgam by electrolysis to develop a methodology for the determination of cysteine .

The solutions used to obtain copper and mercury amalgam was a 0.05M concentration by applying a potential of -0.8V. Amalgam characterization was performed by cyclic voltammetry , wherein the support electrolyte was a borate buffer of pH 8.1 0.05M in which electrochemical processes typical Cu oxidation and ensuring Hg amalgam was performed properly observed .

Subsequently technique cathodic stripping voltammetry (SCV) used for applying different potentials cysteine reservoir (Ed -0.28V) for 300 s and a potential sweep -0.1V to -1.0V. The graphics shows a reduction peak at -520mV associated Cu complex formation of cysteine-SR.

The technique has been applied so far has proven to be very efficient since according to literature marked the peak potential is reported in the literature.

This technique can be used as is relatively easy to perform and the data shown are very sensitive to very small quantities, although this technique is still used to determine concentrations of cysteine smaller. For later use it with a real sample in the determination of phytochelatins in mosses.

Works cited

[1] Y. B., S. I. y N. L., «Voltammetric determination of phytochelatins using Copper solid amalgam electrode,» Talanta, pp. 1253-1258, 2003.
Free Platinum Electrcatalyts Based on Sulfur Doped Carbon Nanotubes as Electrocatalyst in Fuel Cells
Authors: Montiel-Macias Elizabeth , Alonso-Lemus Ivonne , Verde Gomez Ysmael , Balbuena Perla B
Published: February 2020

Fuel cells are recognized as an attractive alternative for clean energy generation. However, their commercialization has been limited by the high cost of their components. Platinum supported on carbon (Pt/C) is considered a conventional electrocatalyst due to their high electrocatalytic activity. Recent research work has shown that free platinum electrocatalyst based on carbon supports doped with heteroatoms (e.g. B, N, P and S) have similar electrocatalytic activities that conventional Pt/C for oxygen reduction reaction. On the other hand, carbon nanotubes have unique properties that make them excellent candidates for use as electrocatalyst support. This work presents the synthesis of carbon nanotubes doped with sulfur (S-CNTs). All free platinum electrocatalyst were prepared by chemical vapor deposition, toluene and thiophene were used as carbon and sulfur sources, respectively. Physical characterization was done by X Ray diffraction, scanning electron microscopy and nitrogen adsorption analysis in order to determinate structural, morphological and textural properties of the materials, respectively. Elemental composition was estimated employing energy dispersive spectroscopy. Finally, electrocatalytic activity for these materials was analyzed by cyclic voltammetry and rotary disk electrode techniques.
Effect of Surface Morphology and Pore Structure on the Water Electrolysis, O2 Evolution Activity of Sb-Doped SnO2 Supported IrO2
Authors: Karimi Parisa , Peppley Brant , Bazylak Aimy , Halliop Ela
Published: February 2020

Nanoparticle IrO2 supported on Antimony doped Tin Oxide (ATO) is a very active electrocatalyst for the oxygen evolution in polymer electrolyte water electrolysis. Using the modified polyol method [A. Marshal and et al. /Material Chemistry and Physics, 94 (2005) 226] nanoparticles of IrO2 were synthesized and deposited on commercial antimony doped tin oxide (ATO). This synthesis involves the reduction of a metal precursors (IrCl2) in ethylene glycol containing a suspension of ATO. Nanoparticle catalysts were characterized by cyclic voltammetry (CV) and steady state polarization analysis in 0.5 M H2SO4 solution. The CV voltammograms for IrO2/ATO catalyst showed clear broad peaks for oxidation and reduction of IrO2, with peaks at 0.72 V and 0.82 V respectively. The catalyst morphology, surface area and the pore structure were studied using BET nitrogen physisorption, mercury porosimetry, Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM). The BET surface area was found to be 59.4 m2/gr and the total porosity (interparticle and intraparticle porosity) of the catalyst was found to be 4.45 %. A narrow particle size distribution for the IrO2 phase in the range of 1 to 3 nm was determined by examining and analyzing the TEM images. X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were also done to provide information on the crystal structure and thermal properties. Polarization curves for membrane electrode assemblies (MEAs) fabricated using this catalyst will be presented. The importance of the pore structure in providing good catalytic activity and mass transport in the two-phase flow process will be discussed.
Enhanced Hydrogen Separation in Multilayered Ni-Zr Thin-Film
Authors: Park Sung Bum , Yun Deok-hwan , Park Yong-il
Published: February 2020

Hydrogen separation devices are attracting increasing interest as potential devices for the industrial production of hydrogen. In particular, metal thin films are promising because they can satisfy the requirements of a typical hydrogen-purification process. Palladium alloys are the only metals that satisfy all these requirements; however, palladium is prohibitively expensive. Therefore, the development of new thin alloy films by a minimal addition of Pd or the development of non-Pd-based thin film alloy becomes increasingly important. We have been interested in the outstanding features of amorphous alloys, which are superior to crystalline alloys in terms of, for example, mechanical properties and excellent immunity from corrosion. In this study, an amorphous multilayered Ni-Zr alloy thin film was prepared by a sputtering technique. Hydrogen permeation properties through those alloy thin films were examined. Moreover, hydrogen solubility and diffusivity were also measured in order to discuss the mechanism for hydrogen permeation. The existing Pd-based metal alloy's permeable membrane and characteristics were comparatively analyzed by measuring microstructure, hydrogen transmittance and mechanical strength, etc. of the manufactured permeable membrane.
Battery Division Research Award: From Insertion-compound Electrodes to Conversion-reaction Electrodes for Energy Storage
Authors: Manthiram Arumugam
Published: February 2020

The current lithium-ion technology is based on insertion-compound cathodes and anodes. Layered and spinel oxides and olivine phosphates are the leading insertion-cathode hosts while graphite is the sole insertion-anode host at the present time. Each of the three cathode systems in play offers advantages and disadvantages while exhibiting rich but complex structural/chemical behaviors, and their adoption in practical cells is determined largely by the type of application. This presentation will focus on the challenges and prospects of transitioning from insertion-compound electrodes to next-generation, high-capacity, conversion-reaction electrodes.

First, an overview of how low-temperature synthesis and processing (e.g., chemical lithium extraction and microwave-assisted solvothermal synthesis) approaches have assisted to develop a fundamental understanding of some of the complex behaviors of the three classes of cathodes. For example, with the use of low-temperature synthesis processes, the roles of the position of the transtion-metal:3d energy relative to the top of the oxygen:2p band, degree of metal-oxygen covalence, morphology and surface crystal planes, surface compositions, isovalent and aliovalent cationic and anionic doping on the electrochemical performances (e.g., capacity, irreversible capacity loss in the first cycle, rate capability, and cycle life) will be pointed out with representative examples.

Second, the potential of alternative, conversion-reaction, nanocomposite alloy anodes to overcome the safety issues of the graphite anode will be presented. Specifically, the use of facile mechanochemical reactions to realize nanoengineered alloy anodes both for lithium-ion and sodium-ion batteries will be discussed.

Third, novel electrode architectures as well as innovative cell designs to overcome the persistent problems of the conversion-reaction sulfur cathode will be presented. Specifically, approaches to enhance the electrochemical utilization of sulfur and suppress the migration of dissolved polysulfide ions to the anode will be discussed both with lithium-sulfur and ambient-temperature sodium-sulfur cells. Also, approaches to stabilize the lithium-metal anode surface in a polysulfide-rich environment will be outlined.

Fourth, to overcome the formidable challenges of aprotic lithium-air cells, the possibility of hybrid lithium-air cells in which a solid electrolyte separates the lithium-metal anode in an aprotic electrolyte from the air electrode in an aqueous catholyte will be briefly presented. Specifically, the design and development of inexpensive, efficient catalysts for the oxygen reduction reaction and oxygen evolution reaction will be discussed.
In-Situ Synthesis of High Voltage Cathode Li2FeMn3O8 in Garnet Scaffold for Solid State Battery Application
Authors: Dai Jiaqi , Hitz Gregory , Han Xiaogang , Gong Yunhui , Thangadurai Venkataraman , Wachsman Eric D. , Hu Liangbing
Published: February 2020

Introduction

The safety concern of Li-ion batteries due to the potential leakage and the flammability of the electrolyte severely hinders applications. The emergence of all-solid-state batteries, consisting of solid state electrodes and solid state ionic conductor electrolyte, will solve this safety problem because it eliminates the problematic liquid electrolytes.

One key issue that needs to be addressed in constructing such a battery is the contact between electrode and electrolyte. Different from liquid electrolytes that can submerge the cathodes, it is difficult for solid state electrolyte to have a sufficient touch with electrodes. A common cathode-side fabrication method is to mix the electrolyte powder with cathode powder and electronically conductive materials, yielding a point-to-point contact. This contact configuration limits the number of effective pathways of li-ion diffusion, therefore hurts the performance of the battery.

solves the aforementioned problems. Starting with precursor solutions, reactants are homogenously mixed at a molecular level, and are much easier to get into the scaffold than powders. Additionally, in-situ synthesis allows the high voltage cathode material to adhere to the surface of the electrolyte scaffold, yielding a face-to-face contact. This enlarges contact area, creating more pathways for Li-ion diffusion and improves the conductivity between the cathode and the electrolyte.

Experimental Methods

The high voltage cathode Li2FeMn3O8 (LFMO) is synthesized by glycine-nitrate combustion. Precursor solution containing metal nitrates and glycine with an optimized ratio is infiltrated into the porous garnet electrolyte scaffold. After drying at 300℃ combustion takes place. The pellet is subsequently annealed at 700℃ to achieve the desired LFMO phase. Finally, carbon nanotube ink is infiltrated to the scaffold to form a conductive network over the cathode.

Results

Fig. 1a shows a schematic of the cathode. With the conductive network and improved contact of cathode and electrolyte, it is expected to have an improved performance. As is shown in Fig. 1b, the cathode adheres to the surface of the scaffold, forming a face-to-face contact.

The LFMO cathode has been tested in LFMO/Li coin cell with LiPF6/ FEC electrolyte. Fig.2 a) gives the XRD spectrum of the cathode prepared by glycine-nitride combustion method. The spectrum matches with JCPDS#48-0258, indicating a Li2FeMn3O8 phase. Fig.2 b) shows the cycling performance of the cathode. It can be seen from the voltage profile of the tested cell that LFMO has two plateaus at around 4.1V and 4.9V, with capacity being 104mAh/g.
Enhanced Electrochemical Performance of Monoclinic LiMnBO3-Based Li Storage Material Via Partial Substitution
Authors: Kim Jae Chul , Seo Dong-Hwa , Li Xin , Ceder Gerbrand
Published: February 2020

We developed a new electrochemically active Li storage material based on a polyanionic framework. By replacing a portion of Mn with Fe and Mg in monoclinic lithium manganese borate (LiMnBO3), a phase-pure LiMn0.5Fe0.4Mg0.1BO3 was successfully synthesized. A C/50-rate galvanostatic discharge delivered a near theoretical capacity of 201 mAh g-1 at room temperature with much improved rate capability, 120 mAh g-1 at a 1C discharge, compared to other borate chemistries. We explained this superior Li storage activity in relation to the topological effect of substitution, which leads to facile Li diffusion and stabilizes the structure. Combining with the inherent stability of the borate group against oxygen evolution, we believe that the enhanced electrochemical properties achieved in this study makes the LiMn0.5Fe0.4Mg0.1BO3 compound a strong contender as a new cathode material for Li-ion batteries and will bring more attention to the lithium transition metal borate chemistry.
Electrochemical Characterization of LiCoO2 Composite Particles by Single Particle Measurement
Authors: Munakata Hirokazu , Annaka Koji , Yamada Yuto , Kanamura Kiyoshi
Published: February 2020

Active materials for rechargeable lithium-ion batteries are generally coated with polymer binder and conductive carbon on a current collector and evaluated as a porous composite electrode. However, the use of composite electrode makes it difficult to understand the intrinsic electrochemical properties of active material since the electrode structural factors such as porosity and thickness are included in the electrochemical response of composite electrode. In order to prevent such misunderstanding, single particle measurement is one of useful tools. In the case of single particle measurement, a micro current collector is used to establish electrical connection to an active material particle. Thus, the structural factors of composite electrode can be neglected, resulting in precise understanding the intrinsic electrochemical properties of active materials. In this study, LiCoO2 was focused and its electrochemical properties, particularly the cycleability at high temperatures was investigated by single particle measurement. Furthermore, the cluster particle of LiCoO2 composite electrode was also evaluated in order to investigate the effects of PVdF binder and conductive carbon on the cycleability of LiCoO2. As shown in Figure 1, the rate capability of cluster particle was low compared with LiCoO2 single particle, namely the discharge capacity was decreased at high discharge rates. This difference is expected to be due to the blocking effect of PVdF binder on Li+ diffusion to LiCoO2 particle from an electrolyte solution. In contrast, the capacity retention in charge-discharge cycle test (Figure 2) was significantly improved in the cluster particle. This result suggests that LiCoO2 is stabilized by PVdF binder and conductive carbon.
Silicon Nanoparticles - Polymer - Carbon Composite As Anode for Lithium Ion Battery
Authors: Zhong Lanlan , Hernandez Jesus , Mangolini Lorenzo
Published: February 2020

Silicon is a very promising anode material for next generation lithium ion battery due to its high lithiation capacity. Despite the intense research that has focused on silicon, this material has yet to demonstrate a performance that is compatible with commercial applications. The main shortcomings obstructing its commercializing are (a) the large volume change during lithiation/delithiation which leads to failure of the material, (b) its poor charge transport properties and (c) the formation of an unstable and/or insulating solid-electrolyte interphase on the active material surface. We propose a novel processing technique that allows addressing these problems using a simple and scalable manufacturing protocol. Silicon nanoparticles with an average particle size of ≤10 nm were produced by plasma enhanced chemical vapor deposition (PECVD) and then functionalized with 12-carbon long aliphatic chains. The resulting silicon ink was composed with polyvinylpyrrolidone (PVP) and carbon nanotubes (CNTs) to give a printable dispersion which was then coated onto copper foil and annealed to produce a binder-free anode for lithium ion battery. This unique electrode structure has an average charge/discharge capacity of ~1000 mAh/g (normalized over the total weight of the coated material) for >200 deep cycles (from 1.5 to 0V) and coulombic efficiency exceeding 99.6% after few cycles. Control experiments for the same anode without PVP suggests that the presence of the polymer during thermal annealing inhibits the particle size growth and covers the silicon particles with a layer of carbon contained material, thus enhancing the stability of the anode structure. Preliminary results regarding the extension of this approach to other materials (conductive polymers and graphene flakes) will also be discussed.
Atomistic Mechanisms of Phase Boundary Evolution during Initial Lithiation of Crystalline Silicon
Authors: Kim Sang-Pil , Datta Dibakar , Shenoy Vivek B.
Published: February 2020

In lithium-ion batteries, the electrochemical reaction between Li and Si causes structural changes in the negative electrode. The dynamics of lithiation of Si can be further complicated by the crystalline-to-amorphous phase transition. In situ TEM experiments show that a sharp interface, known as phase-boundary, is formed in between c-Si and a-LixSi during initial lithiation. Despite intensive study of the mixing mechanism during lithiation of Si negative electrode, the atomistic investigation of the formation and propagation of phase boundary for different orientation of Si remains unclear. We, therefore, performed molecular dynamics simulations to characterize the structural evolution of the phase boundary with a newly developed reactive force field (ReaxFF) potential for Li-Si. Our results confirm the phase boundary formation in between c-Si and a-LixSi. Structure and dynamics of the phase boundary depend on the crystalline phase of the Si. In particular, the location of the (111) plane plays a key role in crystal-toamorphous phase transformation. A relatively thick phase boundary is developed at the (100) surface, while an atomically sharp interface of negligible thickness is formed at the (111) surface. An amorphous phase of lithiated Si is developed beyond the phase boundary, in which the ratio of lithium to silicon atoms is steady at 0.8. Partial RDF studies revealed that the structures of the phase boundary and the lithiated Si region are c-LiSi and a-Li15Si4, respectively.
Enabling the Next Generation of High Energy Lithium-Ion Battery Cathodes
Authors: Croy Jason R. , Long Brandon R. , Park Joong Sun , Gallagher Kevin G. , Balasubramanian Mahalingam , Miller Dean , Thackeray Michael M.
Published: February 2020

Lithium-ion (Li-ion) battery chemistries have driven the portable electronics market for almost 25 years and are now poised to significantly impact the light-duty transportation and grid storage sectors as well. The versatility and proven record of Li-ion systems makes them an irresistible choice from a practical standpoint. However, each application continuously demands more from every new generation of battery products; the highly correlated parameters, energy, power, safety, cycle life, and cost, are constantly being pushed to their limits. Although much of the current effort in energy storage research is aimed at transformational gains, novel Li-ion systems, yet to be explored, have the potential of making continual and significant incremental impacts on next-generation technologies.

This presentation will discuss insights into the atomic-level structure and transformation mechanisms of lithium-transition-metal-oxide cathode materials. These mechanisms explain, in part, the failure modes of layered cathodes at high states of delithiation. Furthermore, a discussion on a variety of elemental and structural compositions will be given. For example, unique layered, layered-layered, spinel, and layered-layered-spinel structures and chemistries will be presented that are pushing the boundaries of current Li-ion technology.

Future directions and research in further enabling these new systems will also be discussed.

Acknowledgment

Support from the Vehicle Technologies Program, Hybrid and Electric Systems, in particular, David Howell, Peter Faguy, and Tien Duong at the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, is gratefully acknowledged.

The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up, nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.
The Effect of Al and Fe Substitution on the Structure and the Electrochemical Properties of NMC Type Positive Electrode Materials for Lithium Ion Batteries
Authors: El Mofid Wassima , Ivanov Svetlozar , Bund Andreas
Published: February 2020

Positive electrode materials combining the advantages of nickel, manganese and cobalt such as higher reversible capacity, lower cost, and less toxicity [1–4] are currently in the focus of research for lithium ion batteries. The relevant electrochemical performance of NMC type cathode materials (LiNixMnyCo1−x−yO2) has been widely discussed in literature. Al, Mg and Cr seem to be promising candidates for the partial substitution of Co in these materials [5-9] in order to further improve the electrochemical performance by decreasing the cation mixing in the structure.

The current study discusses three NMC type materials obtained by cationic substitution of cobalt with aluminum and/or iron in the starting material LiNi0.6Mn0.2Co0.2O2. The three compounds with the following compositions LiNi0.6Mn0.2Co0.15Al0.5O2 (NMCA), LiNi0.6Mn0.2Co0.15Fe0.5O2 (NMCF) and LiNi0.6Mn0.2Co0.15Al0.025Fe0.025O2 (NMCAF) were synthesized by the self-combustion method using sucrose as fuel. These materials belong to α-NaFeO2-type structure (space group R-3m) with hexagonal ordering. Rietveld refinement analysis of the XRD patterns revealed a very low cationic mixing for the double substituted material NMCAF (5%) compared to the non-substituted material (13%) suggesting a higher structural stabilization for the double substituted compound. Galvanostatic cycling measurements indicate improved electrochemical performance, good cycling stability and higher reversible capacity preferentially for NMCAF (190 mAh.g-1), NMCF (167 mAh.g-1), NMCA (145 mAh.g-1) then NMC (140 mAh.g-1).

References:

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[7] Zhang B, Li L, Zheng J, J. Alloy. Compd. 520 (2012) 190.

[8] Idemoto Y, Kitamura N, Ueki K, Vogel SC, Uchimoto Y, J. Electrochem. Soc. 159 (2012) A673.

[9] Luo W, Zhou F, Zhao X, Lu Z, Li X, Dahn JR, Chem. Mater. 22 (2009) 1164.
Design of Solid Electrolyte Interphase to Improve Li-Ion Battery Cycle Efficiency
Authors: Lu Peng , Kim Jung-Hyun , Xiao Xingcheng , Harris Stephen J
Published: February 2020

Among the many challenges to enable large scale commercialization of Li-ion batteries in plug-in hybrid electric vehicles (PHEVs) and full electric vehicles (EVs), formation of high quality solid electrolyte interphase (SEI) is one critical issue to achieve long term battery durability and safety. As a nano-meter scale thin film which natively forms on the negative electrode due to electrolyte reduction, SEI is a complex system composed of various lithium salts and organic reduction products. Most published works have focused on identifying the SEI composition, but the understanding of correlation between SEI properties and battery performance is still lacking.

Previously, we have identified that SEI impedance is closely related with its composition. Briefly, the inorganic components (e.g. Li2O and Li2CO3,
etc) constitute a low impedance and less porous part of SEI, while the organic reduction products tend to be more porous and resistive.1 In this talk, we will advance the findings and evaluate characteristic Li salts using isotope exchange method. Typical SEI components, e.g. Li2CO3, LiF, etc. are found to behave differently in passing Li. With these understandings, we will also demonstrate that the SEI composition can be modified by surface functionalization and coating on graphite electrode. By designing the SEI chemistry, the electrode/electrolyte interface is more stable and the cycling efficiency can be improved.

Figure. Isotope profiles of three Li salt thin films after soaked in 1M 6LiClO4 (DMC) solution for 30s. The natural abundance of 6Li:7Li is ~0.08. The different isotope ratios in the films indicate that SEI components may behave differently in passing Li.

Reference 1. Lu, P., Li, C., Schneider, E. W., Harris, S. J., J. Phys. Chem. C, 2014, 118, 896-903
Improvement of Electrochemical Performance of Li-Rich Cathode Material with Specific Morphology for Lithium Ion Batteries
Authors: He Xin , Wang Jun , Li Jie
Published: February 2020

Li-rich cathode materials (Li2MnO3-LiMO2) have been reported as promising cathode materials since they can deliver high specific capacity and perform with a very good rate capability [1]. Considering the relatively high content of Mn and low content of Ni and Co, Li[Li0.2Mn0.56Ni0.16Co0.08]O2which is a solid solution between Li2MnO3 and LiMn0.4Ni0.4Co0.2O2 with mole ratio of 5:5, fulfills the requirements of a next-generation cathode material very well: low cost, higher energy density and safe. However, high cut-off voltages of up to 4.6-4.8 V are required during charge to obtain high specific capacity as well as high energy.

The morphology of a material has obvious influence to its electrochemical properties, especially for nanostructure materials. In this work, the specific morphology of Li[Li0.2Mn0.56Ni0.16Co0.08]O2, has been successfully synthesized by high temperature annealing assisted by molten salt. XRD characterization proved that it belongs to the R-3m layered structure with the monoclinic Li2MnO3-like (C2/m) super lattice. The electrochemical experiments proved that the specific structure like spherical (Figure 1A) or porous (Figure 1B) could increase the rate capability and improve the cycle performance [2]. The morphology control during synthesis is a significant way to improve the performance of Li-rich cathode in lithium-ion batteries, and is a promising candidate for the realization of high voltage lithium and lithium-ion batteries.

Reference

[1] J. Li, R. Klöpsch, M. C. Stan, S. Nowak, M. Kunze, M. Winter, and S. Passerini. J. Power Sources, 196 (2011) 4821

[2] X. He, J. Wang, R. Klöpsch, S. Krueger, H. Jia, H. Liu, B. Vortmann, and J. Li. Nano Research, 7 (2014) 110.

[3] J. Wang, X. He, R. Klöpsch, S. Wang, B. Hoffmann, S. Jeong, Y. Yong and J. Li. Energy Technology, 2 (2014) 188
Influences of Dopants on the Properties of LiMnO2 and Li2MnO3 in Olo Cathode for Li Ion Batteries
Authors: Kong Fantai , Longo Roberto C , Park Min-Sik , Yoon Jaegu , Yeon Dong-Hee , Park Jin-Hwan , Wang Weihua , KC Santosh , Doo Seok-Kwang , Cho Kyeongjae
Published: February 2020

The over-lithiated-oxides (OLOs), a composite of layered structures of Li2MnO3 and LiMO2 (M = Mn, Fe, Co, Ni), have shown much higher storage capacity than the traditional layered oxides for Li ion battery cathode because of the Li2MnO3 phase. However, Li2MnO3 is not stable after the 1st charge-discharge cycle and will partly transform into layered LiMnO2, which indicates that the practically used phase is a mixture of both Li2MnO3 and LiMnO2. During the subsequent cycles, the OLO voltage decreases due to the phase transition of layered LiMnO2 into spinel. Experimentally, the effective dopants satisfying multiple cathode materials requirements of thermodynamic stability, optimized voltage and improved kinetics based on ionic and electronic conductivities are investigated to overcome the voltage degradation and to improve the power capacity. In this work, redox potential, lithium ion diffusion and charge carrier transportation of both phases are examined in details using the ab initio density-functional theory (DFT) simulations. The calculations find, due to the Jahn-Teller effect of Mn3+ atoms, Li vacancy migration in LiMnO2 has special behaviors and hole polaron and electron polaron will form in LiMnO2 and Li2MnO3 phases, respectively. Based on the understanding of the pure phase properties, the effects of 10 cationic (Mg, Ti, V, Nb, Fe, Ru, Co, Ni, Cu, Al) and 2 anionic (N, F) dopants on the redox potential, ionic and electronic conductivity are investigated. These DFT findings could provide conceptual guidance in the experimental search for the effective dopants enabling the practical application of OLO cathodes.
Degradation Diagnosis of Aged Li4Ti5O12/LiFePO4 Batteries
Authors: Castaing Rémi , Reynier Yvan , Dupré Nicolas , Schleich Donald , Jouanneau Séverine , Guyomard Dominique , Moreau Philippe
Published: February 2020

Lithium-ion batteries longevity is of major concern for electric transportation applications. It is therefore necessary to understand the performance decay of a battery subject to aging conditions. Degradation mechanisms of the electrodes are generally divided into three families: (i) irreversible loss of active material, (ii) parasitic reactions leading to a loss of cyclable lithium or electrons, (iii) increase in resistance due to passive films formation and loss of contact [1, 2].

Lab-scale Li4Ti5O12/LiFePO4cells were submitted to accelerated aging during 4 to 5 months. All the cells exhibit capacity fade whose extent is not correlated with the aging condition. In order to understand aging phenomena, cells were disassembled at the end of cycle life and the recovered electrodes were analyzed using electrochemistry, electron microscopy, XRD and MAS-NMR. Positive and negative electrodes show no loss in active material and no change in electrochemical activity, active material structure and composite electrode structure. This rules out any irreversible electrode degradation. Lithium stoichiometry estimated by both XRD and electrochemistry is unexpectedly low in the positive electrode when the aging is stopped at full discharge. That indicates a loss of cyclable lithium or electrons leading to cell balancing evolution [3]. That loss has been caused by parasitic reactions occurring at both electrodes, in accordance with their rich surface chemistry evidenced by MAS-NMR.

This surface chemistry is fully characterized by MAS-NMR both qualitatively and quantitatively, using an original calibration method (see Fig. 1) [4]. Correlations are drawn between the quantity of diamagnetic lithiated species deposited on the surface of both electrodes (mainly LiF) and the loss of cyclable lithium or electrons undergone by the cell. This study attempts to develop a parasitic reaction pathway that explains the loss of cyclable lithium or electrons encountered under these aging conditions.

References:

[1] J. Vetter, P. Novák, M. Wagner, C. Veit, K.-C. Möller, J. Besenhard, M. Winter, M. Wohlfahrt-Mehrens, C. Vogler, A. Hammouche, Journal of Power Sources 147 (2005) 269.

[2] A. Barré, B. Deguilhem, S. Grolleau, M. Gérard, F. Suard, D. Riu, Journal of Power Sources 241 (2013) 680.

[3] M. Kassem, C. Delacourt, Journal of Power Sources 235 (2013) 159.

[4] M. Cuisinier, J. F. Martin, P. Moreau, T. Epicier, R. Kanno, D. Guyomard, N. Dupré, Solid State Nuclear Magnetic Resonance 42 (2012) 51–61.

Figure 1: Calibration of NMR-MAS 19F signal with LiF-electrode mixtures.
Structural and Spectroscopic Studies on Electrolytes Containing Novel Salts Dedicated to Lithium-Ion Batteries
Authors: Jurkowska Barbara , Szablowska Aneta , Jankowski Piotr , Gajewska Agnieszka , Poterala Marcin , Kalita Michal Jan , Dranka Maciej , Zukowska Grazyna Zofia , Zachara Janusz
Published: February 2020

Lithium anode an Li-ion batteries are chemical power sources of high energy and power density. In other words, such batteries can be light, small and relatively efficient. Therefore, they can be used in several power-demanding devices, like laptops, tablets, smartphones as well as cameras. Despite of this commercial success, the scientific works oriented on development of these power sources are still conducted. The most important problem, which still needs to be solved, is stability of the battery and battery life length. This is related to the stability of the electrolyte-electrode interfaces.

Due to this, the importance of the research on novel salts for batteries' electrolytes grew more and more important. The focus was put on looking for novel lithium salts which dissociate well in aprotic solvents and are electrochemically and thermally stable.

In the present study, spectroscopic and structural properties of the solvates of the lithium salts with fluorine-free heteroaromatic anion are researched. The main impact is put on complexes of the salts with dimethyl ethers of ethylene glycol oligomers (glymes) and organic carbonates.

Correlation between crystal structures, obtained from X-ray diffraction experiments on the single crystals with vibrational spectroscopy data (FTir and Raman) should make the prediction of the cation-anion-solvent molecule interactions in the liquid systems possible.

The discovering and understanding of phenomena related to the organization of such systems in the solid state is crucial for the elaboration of novel electrolytes. Gained knowledge will be helpful in the design of novel compounds with defined properties and in optimization of the working systems.
Impedance Growth with Lithium Titanate Based Cells; Understanding and Mitigation
Authors: Greszler Thomas A , Chen Yvonne , Deveney Bridget , El Ouatani Loubna , Tessier Cécile
Published: February 2020

SAFT has successfully applied Li-ion electrochemistry to defense, space, and commercial applications which require very high power. In fact, by optimizing both the electrochemical and electro-mechanical cell design, Saft has developed a range of Li-ion products that can deliver up to 10 kW/kg of power for 10 seconds and over 30 kW/kg of power for a fraction of a second. There are, however, still inherent limitations for high power applications with traditional Li-ion chemistry. Particularly, even with an optimized cell design, cycle life can be limited for applications which require very rapid charging due to both Lithium plating and electrolyte decomposition on the graphitic negative electrode. Lithium titanate oxide (LTO), due to operation above both the lithium plating and solvent reduction potentials, minimizes these phenomenon and can potentially provide extremely long cycle life. Saft is working, with DOE/USABC funding, to industrialize LTO based technology for high power applications. Results will be presented including power capability, high temperature impedance growth, capacity fade, and gas generation. In particular, impedance growth, which is a major obstacle to large scale use of LTO, will be discussed including mechanistic understanding and methods of mitigation.