bluuebunny/crossref_metadata_2025 huggingface dataset:
Fujimi’s New SiC CMP Slurry Development
Authors: Hirano Shinya , Takami Shinichiro , Noguchi Naoto , Ishibashi Tomoaki , Ito Yasuaki , Oda Hiroyuki , Arakawa Shigekazu , Mori Yoshio , Greene Bill , Sanford James , Riesen Jon , Kato Tomohisa
Published: February 2020

Introduction

Since silicon carbide (SiC) is a very hard substrate and is stable both chemically and physically, wafer processing is costly and takes a lot of time. Particularly, in the chemical mechanical polishing (CMP) process, which is the final wafering process, significant improvement in performance such as surface quality and productivity is required for high volume commercial production.

At Fujimi, we have developed a high removal rate slurry of over 1.5 μm per hour on the Si-face under neutral pH and conventional CMP processing conditions. We have also proven that the slurry had a nice behavior in removal rate performance based on Prenston equation, that is, removal rate was proportional to the pressure and velocity of substrate. Furthermore, our testing result has shown great surface morphology such as no scratches and no latent scratches beneath the surface. Low surface roughness was achieved under 0.1nm of RMS at 10x10μm area.

Fujimi has introduced this new SiC slurry at the Advanced Industrial Science and Technology (AIST) as a suitable stock polishing slurry to remove surface damage coming from previous grinding or lapping steps. We have demonstrated the benefit of a two-step CMP process which applies a stock step using the higher removal rate slurry followed by a fine step using our Colloidal silica type slurry. As a result, the combination process could realize to produce the SiC epi-ready wafer with fine quality surface in shorter process time than conventional process [1].

Results and Discussion

In this study, we will discuss our SiC slurry development technologies. At Fujimi, we can control the size and shape of the abrasive grains. Utilizing our expertise in chemical and additive formulation, we can modify our slurries to meet our customers’ various performance criteria.

In Figure 1, it shows a test result example in which the removal rate of the Si-Face was improved. These improved performances depended on the type of additive used in the slurry.　Test was performed using substrates of 4-inch 4H-N SiC (4°off) Si-face substrates with exactly the same polishing process and pad condition for all slurries.　Slurry A was a result of high speed conventional slurry used by AIST [1] as a reference slurry. Slurry B was a newly developed slurry with improved abrasive grains dispersion. Slurry C was also a newly developed slurry focusing on the improvement of oxidation efficiency. As a result, it was possible to achieve a polishing removal rate over 2 um / hour as well as maintain low surface roughness at the same time.

[1] S. Hirano et al., Journal of the Japan Society for Abrasive Technology, 60, (2016)353

Figure 1
Effects and Characterizations of Pulse Electrodeposition Parameters of Silver on Surface Roughness and Scattering Parameters of Horn Antennas
Authors: Başaran Caner , Karakaya Ishak
Published: February 2020

Electronic conductivity is a parameter that exhibits the free-electron transportation ability of a material. The radiation efficiency of reflector type antennas and insertion loss of waveguide transmission lines are directly related to the conductivity of the materials used to construct such structures. Signal quality of antenna and waveguides in the transmission of electromagnetic waves are also very much dependent on the surface finish that has good conductivity [1].

The use of pulse currents produces homogenous deposits of better surface finish than direct current [2,3]. Effects of pulse parameters on the surface properties of silver coatings of the copper base material have been analyzed in terms of surface roughness and S-parameter (scattering parameter). Grain morphologies of silver coatings were characterized by SEM and XRD. The duty cycle, frequency and the average current density were selected as three pulse parameters. Three levels were selected for each parameter in the experimental design. A relationship was developed for surface finish in terms of duty cycle, average current density and pulse frequency. The S11 scattering parameter observations were made relative to a gold-plated reference coupon. It was analyzed that smoother surfaces had more reflection power in terms of S11 parameter thus decreasing the loss of radiation. Therefore, the results may be used to develop a silver coating procedure to improve signal quality of antenna and waveguides in the transmission of electromagnetic waves.

[1] Balanis, C. A. (1989), “Advanced Engineering Electromagnetics”, John Wiley & Sons

[2] Chandrasekar, M.S. and Pushpavanam, M. (2008) ‘Pulse and pulse reverse plating—Conceptual, advantages and applications’, Electrochimica Acta, 53(8), pp. 3313–3322.

[3] Arslan, B., Demirci, G., Karakaya, İ. and Erdoğan, M. (2015) ‘Formation of gold-plated electroformed copper structures’, Advances in Materials and Processing Technologies, 1(3-4), pp. 384–393.
High Temperature Oxidation Resistance of Cr Coatings on 22MnB5 Steel Electroplated in Trivalent Cr Baths
Authors: Huang Chao-Yu , Lin Chao-Sung
Published: February 2020

22MnB5 steel is one kind of advanced high-strength steels commonly used for vehicles to enhance passengers’ safety and reduce carbon dioxide emission[1]. However, 22MnB5 steel is vulnerable to high-temperature oxidation and a protective coating is essential to inhibit oxidation during hot stamping process. For example, hot-dip Al-10 wt % Si coating has been extensively applied on press hardening steel although it does not provide sacrificial protection on the steel parts[2]. In contrast, hot-dip Zn coating, which confers sacrificial protection, tends to suffer oxidation and liquid metal embrittlement during hot stamping[3, 4].

This study investigated the structure and properties of Cr coatings on 22MnB5 steel electroplated in a trivalent Cr (Cr(III)) bath. The DC electroplating was conducted in a chloride-based Cr(III) electrolyte with and without the addition of sulfur-containing organic compounds. The morphology, microstructure, and composition of the Cr coating were characterized using scanning electron microscope (SEM), X-ray diffraction (XRD), and electron dispersive spectroscopy (EDS). The thickness of the deposit before and after high-temperature heat treatment (900℃ for 5 min in air) was measured using cross-sectional SEM.

Experimental results show that the sulfur-containing organic compound in the electrolyte reduces the carbon content and increases the sulfur content of the Cr coating, which, in turn, reduces the residual stress of the coating. As a result, a crack-free Cr coating can be obtained in the electrolyte with the organic additive. In contrast, many cracks develop on the Cr coating plated in the electrolyte without the organic additive. After the heat treatment at 900℃ for 5 min, extensive oxidation was observed on the crack-free Cr coating, but not on the Cr coating with cracks. It is likely that the presence of sulfur in Cr coating deteriorates the oxidation resistance. Crack openings of the Cr coating free of sulfur are filled with compact oxides after 900℃heat treatment for 5 min. The steel substrate with a Cr overlay remains intact, indicating the Cr coating prevents the steel substrate from oxidation at 900℃.Finally, a 2-mm-thick Cr coating can be electroplated in the Cr(III) bath without the organic additive at a current density of 10 A/dm2and a plating time of 1 min and effectively protects the 22MnB5 steel from high-temperature oxidation.

Reference

[1] H. Karbasian, A.E. Tekkaya, Journal of Materials Processing Technology, 210 (2010) 2103-2118.

[2] D.W. Fan, H.S. Kim, J.-K. Oh, K.-G. Chin, ISIJ international, 50 (2010) 561-568.

[3] C.W. Lee, D.W. Fan, I.R. Sohn, S.-J. Lee, B.C. De Cooman, Metallurgical and Materials Transactions A, 43 (2012) 5122-5127.

[4] M. Razmpoosh, A. Macwan, E. Biro, D. Chen, Y. Peng, F. Goodwin, Y. Zhou, Materials & Design, (2018).
Influence of ZrO2 Incorporation into Coating on Electrochemical Response of Low-Carbon Steel Processed By Plasma Electrolytic Oxidation
Authors: Lee Kang Min
Published: February 2020

The carbon steel is one of the most widely used metals material in engineering with good properties, such as high strength, high toughness, good mechanical properties and low cost. The surface treatment of the steel is essential, however, before use it in industry due to the low corrosion resistivity of steel substrate, which is a problem to use in high humid environment. Meantime it is important to improve the wear resistance and the interfacial adhesion of the coating. Since the thick alumina coating is one of most effective anti-corrosion layer which has high corrosion resistance relatively with the metals, the alumina coating on the steel substrate is good way to improve corrosion resistance. Among the ceramic coating technique for fabrication the alumina layer, such as chemical vapor deposition, magnetron sputter and ionization-assisted beam, plasma electrolytic oxidation (PEO) has been investigation as a new electrochemical surface treatment.

PEO process is a unique process that utilized electrochemical reactions to form an oxide layer on a metal surface. The PEO process has been reported to attractive combination of wear resistance and corrosion resistance as well as enhancing thermal property of coating layer. However this advanced coating technique has been performed only if material was valve metals, such as Mg, Al, Ti, Nb and etc. and only a few papers of PEO processed steel have been published. Although several researchers performed PEO process on the steel substrate, the specimen was pretreated by plasma spray, laser re-melting or chemical vapor deposition, therefore it was not convenience to widely use in engineering due to the very high cost and thermal shock to the substrate.

The structure and morphology of coating layer formed by PEO process, on the other hand, is influenced on experiment conditions which are composition and concentration of electrolyte, current density and condition of substrate, in particular, composition of electrolyte effect on forming oxide layer. Recently, the incorporation of second oxide nanoparticles into the oxide layer generated by the PEO process in order to improve functionality has received considerable attention. Our previous work has demonstrated that incorporated ZrO2 nanoparticles into oxide layer may enhance the resistance against pitting corrosion.

In this study, we conducted PEO process on A36 carbon steel without any pretreatment and successfully formed an incorporated alumina layer with 200-400 nm size of ZrO2 nanoparticles on the carbon steel and prepared comparison specimen which is unincorporated alumina coating with any others during PEO process. The microstructure and phase of coating layers were investigated and corrosion behavior was evaluated by electrochemical impedance spectroscopy.
Electrochemical Behavior and Extraction of Yttrium on Cu Electrode in LiCl-KCl Eutectic
Authors: Li Wenlong , Han Wei , Li Mei , Yang Xiaoguang , Sun Yang
Published: February 2020

The electrochemical behaviors of Y(III) were investigated on inert W and reactive Cu electrodes in LiCl-KCl eutectic by electrochemical technique at 773K. On an inert W electrode, the apparent standard potential of Y(III)/Y(0) couple was studied at different concentration of Y(III) ions using cyclic voltammetry. The result shows the apparent standard potential of Y(III)/Y(0) couple has a dependent on the concentration of Y(III) ions. On a reactive Cu electrode, cyclic voltammetry, stripping voltammetry and square wave voltammetry experiment results indicated that the deposition potential of Y (III) shift toward more positive values than that on W electrode because of the formation of Cu-Y intermetallic compound. Five Cu-Y intermetallic compounds, Cu6Y, Cu4Y, Cu7Y2, Cu2Y and CuY, were found to be formed by transient and steady electrochemical methods. Based on open circuit chronopotentiogram, the intermetallic compounds of Cu7Y2 is easier to form and more stable than the others because its platform is longer. Potentiostatic and galvanostatic electrolysis was conducted on Cu electrode to extract metallic yttrium. Furthermore, the cyclic voltammetry curves showed that the redox signals observed before electrolysis almost disappeared after electrolysis. In addition, the concentration of Y(III) ions in LiCl-KCl melts were detected by inductive coupled plasma atomic emission spectrometer before and after electrolysis, and the current efficiency for the electroextraction of Y was estimated. The results showed that Y(III) ions could be effectively extracted using reactive Cu electrode. Finally, the electrolysis products were characterized by scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). The results showed that yttrium and copper can form Cu-Y intermetallic compounds during electrolysis and the thickness of alloy layer is about 50 mm.

Acknowledgement

The work was financially supported by the National Natural Science foundation of China (11675044, 11575047, 21790373, 21271054 and 21173060), the Major Research plan of the National Natural Science Foundation of China (91326113 and 91226201), and the International Exchange Program of Harbin Engineering University for Innovation−oriented Talents Cultivation.

Figure 1
Electrochemical Behavior of Nd and the Preparation of Mg-Al-Nd Alloys in LiCl-NaCl Molten Salt
Authors: Zhang Yingchun , Han Wei , Li Mei , Yang Xiaoguang , Sun Yang
Published: February 2020

The electrochemical behaviors of Nd(Ⅲ) ions and the mechanism of Mg-Al-Nd alloys by co-reduction were studied in LiCl-NaCl-MgCl2 melts by cyclic voltammetry(CV). The results of CV indicates that Nd(Ⅲ) ion was reduced to Nd atom in two steps exchange 3 electrons: Nd(Ⅲ)+e-=Nd(Ⅱ) and Nd(Ⅱ)+2e-=Nd(0). The diffusion coefficients of Nd(Ⅲ) was calculated and found to be 4.92×10-5 cm2 s-1. Mg-Al-Nd alloy samples prepared by galvanostatic electrolysis were analyzed by XRD and SEM-EDS. Results indicate that when there is no Nd2O3 in the melts, the alloying phases are mainly Al12Mg17, Al0.58Mg0.42 and Mg phases. When 0.35% Nd2O3 was added into the melts, only Al2Nd and Mg phases exist in the alloy; Nd element mainly distributes at grain boundary, Al element distributes in grain boundary and cell, and Mg elements distribute in the whole alloy as the matrix of the alloy.

Acknowledgement

The work was financially supported by the National Natural Science foundation of China (11675044, 11575047, 21790373, 21271054 and 21173060), the Major Research plan of the National Natural ScienceFoundation of China (91326113 and 91226201), and the International Exchange Program of Harbin Engineering University for Innovation−oriented Talents Cultivation.
Size-Effects of Micropattern on Lithium Metal Surface on the Electrochemical Performance of Lithium Metal Secondary Batteries
Authors: Kim Dohwan , Park Joonam , Jin Dahee , Ryou Myung-Hyun , Lee Yong Min
Published: February 2020

As lithium (Li) metal has a low reduction potential (-3.045 V vs. SHE) and a high capacity per weight (3860 mAh g-1), Li has been researched continuously as one of the fine secondary battery anode materials. However, there are some electrochemical issues that Li metal’s charge/discharge efficiency is lower than those of conventional carbon-based anode materials, and Li is intensively grown at a specific region of the Li surface and form a dendritic dendrite. Dendrites not only increase the dead Li but also lead to an internal short to cause a battery explosion. In order to solve this problem, this research group has reported that micropatterns can be formed on the surface of Li metal to successfully control Li plating/stripping position behavior

In this study, we investigated how the pattern controls the shape of Li according to the charging/discharging current density, and the effect of the pattern size change on the electrochemical properties of the battery. Micropatterns of two sizes, 50 and 80 μm, are designed to have an available capacity of 1.06 and 2.44 mAh cm-2, respectively. We fabricated a micropatterned Li metal with two effective capacities and made a Li/Li symmetric cells to analyze the overpotential characteristics. The overpotential characteristic of 80 μm-patterned Li was lower than that of 50 μm-patterned Li during long charge. Also, full cells (LiNi0.6Co0.2Mn0.2O2 / 2 mAh cm-2) were fabricated with each patterned Li metals. As a result, 80 μm-patterned Li showed stable morphologic behavior inside pattern and exhibited much better electrochemical performance.
In-Situ Dilation Observation of Si-Based Electrode Adopting the Thermally Treated Poly (amid-imide) As a Binder for Lithium Rechargeable Battery.
Authors: Park Hyeong-Il , Lee Dong Geun , Chung Dong Jae , Sohn Myungbeom , Youn Donghan , Park Cheolho , Kim Hansu
Published: February 2020

Real time dilation observation of a Si-alloy based electrode using the poly (amide-imide) (PAI) as a binder was investigated to understand the effects of thermal treatment of PAI binder on the electrochemical performance of the Si-alloy electrode using an in-situ electrochemical dilatometer device. In-situ dilation measurement of the electrode during lithiation and delithation showed that the volume changes of the Si-alloy electrode were suppressed by thermal treatment over 300 ºC, which well agreed with the improved electrochemical performances of the Si-alloy electrode thermally treated at the same temperature. Differential dilation plots of the Si-alloy electrodes revealed more detailed changes in the volume of the Si-alloy electrode, thus showing that the enhanced mechanical strength of thermally treated PAI effectively could control the expansion and contraction of the Si-alloy electrode and ensure a more stable cycle performance of the Si-alloy electrode. More detailed study of Si-alloy electrodes using thermally treated PAI binder will be discussed in this presentation.
Onion-like Synergetic Multilayer Coating for High-Stability Silicon Monoxide Anode in Lithium-Ion Batteries
Authors: Tan Tian , Lee Pui-kit , Yu Denis Yau Wai
Published: February 2020

Silicon monoxide (SiO) is a potential next-generation high-capacity anode material for lithium-ion batteries. However, SiO undergoes severe volume change during charge and discharge, which leads to mechanical failure and thus fast capacity decay. Nano-structuring has been reported as an effective method to improve cycle stability of SiO by preventing particle pulverization and increasing void content to accommodate the large volume change. Though, nano-particles are difficult to handle and energy-intensive to manufacture in large scale. In addition, the larger surface area facilitates side reactions between active material and electrolyte. Therefore, the use of micron-size materials is desirable.

Herein, we engineer a multilayer surface coating on micron-sized (5 µm) carbon-coated SiO particles (SiO@C) to enhance the stability of the electrode during charge and discharge. The layer of carbon on SiO@C enhances its electrical conductivity. The material is treated with ultra-violet irradiation to generate -OH functional groups on its surface. The resulting particles are treated with an organosilane self-assembled monolayer (SAM) with (3-aminopropyl)triethoxysilane (APTES). The powder is then further combined with imide monomers and heat-treated to form a robust chemical bonding between the amine (-NH2) functional group of the SAM and the dianhydride group of the polyimide (PI) on the surface. The resulting SiO@C@UV@NH2@PI composite possesses excellent mechanical stability, where the high-modulus PI layer suppresses volume change, particle pulverization and electrode cracking during charge and discharge. In addition, the PI coating reduces side reactions between the electrolyte and the active material and improves the Coulombic efficiency of the electrode.

Our study demonstrates that the SiO@C electrode with the multilayer coating exhibits a stable capacity of 1310.7 mAh g-1 after 100 cycles at 150 mA g-1, and a capacity of 910.3 mAh g-1 (capacity retention 94.2%, with respect to the 2nd cycle) under 1 A g-1 after 300 cycles. In comparison, SiO@C electrode without surface coating gives only a reversible capacity of 247.1 mAh g-1 after 100 cycles, with a 15.1% capacity retention (see Figure 1a). Figure 1b shows a comparison of the thickness change of the two SiO electrodes during charge-discharge, verifying that the multilayer coating can reduce volume expansion. Further characterizations of the surface-coated material to identify the mechanism of the improvement are underway and more data will be presented at the meeting.

Figure 1
The Application of Magnesiothermic Reduction of Silica to Produce Porous Silicon for Lithium Ion Batteries
Authors: Entwistle Jake , Patwardhan Siddarthh
Published: February 2020

Increasing demand for portable power applications are pushing conventional battery chemistries to their theoretic limit. Silicon has the potential as an anode material to increase lithium-ion cell capacity. The associated volume change of lithiation leads to a decline in capacity during cycling and low lithium diffusion rates within silicon limit high rate discharging. Many silicon morphologies and nanostructures have been studied including porous architectures. Porous morphologies can potentially address the poor cyclability and rate capabilities simultaneously. The template assisted synthesis ‘magnesiothermic reduction’ of silica to silicon offers a facile and scalable synthesis route to porous silicon structures. However, our review of the recent progress of this method indicates a distinct lack of mechanistic understanding of this phenomenon. To better understand the processes, we have systematically studied the process conditions using a model silica system. Further, we performed a complete characterisation of both the reactant and product structures in order to map how reaction conditions affect the properties of the electrode materials. Finally, we will present the battery performance of these porous silicon structures and compile a processing-structure-property-performance relationship.

Figure 1
Red Phosphorous-Span Composite Anode through Electrostatic Spray Deposition for High Performance Lithium-Ion Batteries
Authors: Rabiei Baboukani Amin , Khakpour Iman , Adelowo Ebenezer , Drozd Vadym , Wang Chunlei
Published: February 2020

Li-ion batteries (LIB) have a combination of high energy and power density, making it the technology of choice for portable electronics, power tools, and hybrid/full electric vehicles. Phosphorous based material is very promising for high performance Lithium-ion battery application due to its high theoretical capacity (2569 mA h g-1) but suffers from poor conductivity (10-12 S m-1). It was reported that poor electrochemical stability with significant capacity fading was observed immediately after the first cycle because of the large volume change of almost 300 percent. In this study, we synthesized a novel red phosphorous/sulfurized polyacrylonitrile (SPAN) composite via electrostatic spray deposition (ESD) for LIB. The electrochemical performance of the hybridized composite were evaluated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge-discharge tests. Electrochemical characterizations revealed that the Red Phosphorous-SPAN composite delivers a high specific capacity of ≈1515 mAh g-1 at a current density of 200 mA g-1 with good cycling performance (92% capacity retention after 100 cycles) which is prominent in the anode materials for LIBs. This presentation will give the details of the methods used to produce the novel anode materials and their electrochemical characterization as LIB anodes.
Pre-Electrochemical Treatment Effect of Cu Eqcm Electrode on Lithium Electrodeposition/Dissolution Processes
Authors: Kondo Toshihiro , Smaran Kumar Sai , Ohama Ayano , Niida Asako , Nishihara Kaho
Published: February 2020

Lithium has been extensively expected as one of the most ideal anode materials of the next generation lithium-based batteries, because of its higher theoretical specific capacity (3860 mA h g-1) and its most negative redox potential (-3.04 V vs. SHE). On the lithium anode surface, however, it is well known that the dendrite, which further leads to poor performance and short circuit, forms. In addition, solid electrolyte interphase (SEI), which is generated by decomposition of electrolytes and/or solvents, also accumulates on the anode surface during the anode reaction. An ideal SEI layer is expected to be higher and lower conductive for lithium ion and electron, respectively, and it is flexible and has a relatively uniform flat surface with an appropriate thickness, in order to avoid dendrite formation [1].

During the electrochemical reaction, on the other hand, electrochemical quartz crystal microbalance (EQCM) technique gives us information not only of mass change on the electrode surface but also resonance resistance change, which shows surface area change of the electrode [2,3] and/or density and viscosity change at the electrode/electrolyte solution interface [4,5]. Using this technique, we found that the pre-electrochemical treatment of Cu EQCM electrode strongly effects on the lithium electrodeposition/dissolution processes.

Acknowledgements

This work was totally supported by the Advanced Low Carbon Technology Research and Development Program (ALCA), specially promoted research for innovative next generation batteries (SPRING) from the Japan Science and Technology (JST).

References:

[1] X.-B. Cheng, R. Zhang, C.-Z. Zhao, F. Wei, J.-G. Zhang, Adv. Sci.3 (2016) 1500213.

[2] K. Kanamura, S. Shiraishi, Z. Takehara, J. Electrochem. Soc.147 (2000) 2070.

[3] D. Aurbach, M. Moshkovich, Y. Cohen, A. Schechter, Langmuir15 (1999) 2947.

[4] K. Naoi, M. Mori, Y. Naruoka, W. M. Lamanna, R. Atanasoski, J. Electrochem. Soc.146 (1999) 462.

[5] N. Serizawa, S. Seki, K. Takei, H. Miyamoto, K. Yoshida, K. Ueno, N. Tachikawa, K. Dokko, Y. Katayama, M. Watanabe, T. Miura, J. Electrochem. Soc.160 (2013) A1529.
Quantifying Reaction Products of Silicon Monoxide Electrodes during Initial Cycle in Lithium-Ion Batteries
Authors: Yu Denis , Tan Tian , Lee Pui-kit
Published: February 2020

Silicon monoxide (SiO) is a potential high-capacity anode material for lithium-ion batteries. However, its low initial Coulombic efficiency hinders its adoption in commercial batteries. The irreversible capacity of SiO is typically attributed to the formation of lithium silicate (such as Li4SiO4), lithium oxide (Li2O) and solid electrolyte interphase (SEI), but the amount of each product is typically not quantified. Here, we use an electrochemical approach, depth of discharge test, which we developed earlier [1] to estimate the amount of reaction products. Based on the first cycle discharge-charge capacities as well as the proportion of reversible capacity at different state of discharge (see Figure 1a and 1e), the lithiation mechanism of pristine SiO1.12 is estimated to be:

SiO1.12 + 3.10 Li+ + 3.10 e- → 0.63 Li3.75Si + 0.15 Li2O + 0.11 Li4SiO4 + 0.26 SiO2

where inactive SiO2 in the material accounts for the lower-than-theoretical capacity, Li4SiO4 takes in lithium but cannot release them back, while Li3.75Si and Li2O give partial reversibility upon delithiation.

We found that the amount of reaction products depends strongly on how the material is treated. Table I summarizes the corresponding reaction mechanisms [2]. In particular, while carbon-coating (SiO@C) increases the reversible capacity (y) as it increases its electrical conductivity which allows easier access to the lithium from Li2O, larger irreversible capacity is also observed with more Li4SiO4 formation. On the other hand, disproportionation (d-SiO@C-900°C and 1000°C) decreases the irreversible capacity in the initial cycle with the formation of large cluster of SiO2 which is electrochemically inactive. Though, the reversible capacity is reduced. Our results suggest that there are opportunities to further improve the first cycle efficiency of SiO by finding ways to control the reaction products during the initial lithiation process. More results and discussions will be presented at the meeting.

References:

P.-K. Lee, Y. Li, D. Y. W. Yu “Insights from studying the origins of reversible and irreversible capacities on silicon electrodes” J. Electrochem. Soc. (2017) 164, A6206-A6212.

T. Tan, P.-K. Lee, D. Y. W. Yu, “Probing the reversibility of silicon monoxide electrodes for lithium-ion batteries” J. Electrochem. Soc. (2019) 166, A5210-A5214.

Figure 1
Understanding the Effects of Ultra-Thin Al2O3 Coatings Prepared By Atomic Layer Deposition on Lithium Ion Battery Cathode Materials
Authors: Kang Donghyeon , Mane Anil U. , Elam Jeffrey W. , Barry Edward F. , Warburton Robert , Greeley Jeffrey
Published: February 2020

Although various cathode materials possessing high capacity have been developed to date, most of them are still suffering from early capacity fading. Several strategies such as doping, surface treatment and coating have been adopted to minimize this problem. Among a variety of coating strategies, atomic layer deposition (ALD) is regarded as the best technique for coating of cathode materials. ALD is a thin-film growth technique that offers the unique capability to coat complex, three-dimensional objects with precise, conformal layers by atomic-level control over thickness and composition. Over the last decade, ALD has emerged as an effective strategy for coating cathode materials to enhance the overall performance Li-ion batteries.

ALD Al2O3 coatings prepared using trimethyl aluminum (TMA) and H2O have been evaluated previously on cathodes including LiCoO2 (LCO), LiMn2O4 (LMO), and Li(NixMnyCoz)O2 (NMC), and the effect of the coating on cycling stability was found to vary between these different materials. Moreover, our recent study of TMA/H2O chemistry on LMO revealed a unique nucleation mechanism leading to unexpected products and altered electrochemical behavior. In an effort to better understand these observations, we are exploring Al2O3 ALD using a range of aluminum precursors (TMA, tris(dimethylamido) aluminum, aluminum trichloride, dimethyl aluminum isopropoxide, and aluminum triisopropoxide) and a variety of cathode materials (LCO, LMO, and several NMCs). We discovered that the ALD aluminum precursor reduces cations on the cathode surface, and the degree of reduction depends on the relative Lewis acidity of the precursor ligands, and on the composition of the cathode surface. In this presentation we will elaborate on these findings and describe the correlations between the chemistry of the ALD-modified cathode surface and the resulting electrochemical behavior and cycling performance.
Low Cost, Scalable Active Material Coating for Higher Energy Density Li-Ion Batteries
Authors: Lang Christopher M. , Moran Peter D. , Herb Jake T.
Published: February 2020

Higher energy density batteries are required to power next generation technologies. New cell design techniques are required to minimize the mass fraction of inactive components and achieve improved energy density. This presentation will discuss Physical Sciences Inc.’s (PSI’s) efforts to construct cells offering a 25% increase in cell energy density over the state of the art. This talk will focus on a low cost, rapid high active (HA) coating technique that enables electrode active material content >98.5%. PSI has demonstrated that extended cycling at elevated voltages (4.4 V) can be achieved with less than 10% fade over 1000 cycles. PSI will show this technology is scalable and applicable to the entire range of commercial active materials. Test results from multi-Ah pouch cells built for multiple applications will demonstrate the flexibility of the PSI technology.
Li Dendrite Nucleation from First Principles Perspective
Authors: Kamphaus Ethan P , Balbuena Perla B.
Published: February 2020

Given the demands of modern society, current chemical energy storage needs significant improvement. Advanced battery technology research has focused on the use of Lithium metal anodes to increase performance for Li-ion, Li-sulfur and Li- air batteries. Unfortunately, the use of these anodes causes several problems for battery operation such as the formation of dendrites. In the cycling of lithium anodes, the lithium will be deposited in a way that lithium metal tendrils or spikes grow on the surface of the electrode. These dendrites can cause the short circuiting and other mechanical problems that hurt performance and can even lead to significant safety concerns. Researchers have been focusing counteracting dendrite growth and formation from an experimental and practical approach but there has been a lack in fundamental understanding of how lithium dendrites form and grow. We used first principles simulations to study the nucleation, growth and properties of lithium clusters to determine the basic principles that govern dendrites. By exploring the reduction chemistry with small clusters, general principles can be derived that will help intelligently guide experimental and other modeling research to better battery design. We found that the reduction of Li ions is highly favorable regardless of position on the nucleating cluster which indicates that other factors are more important to the direction of cluster growth like the electrostatic potential that corresponds to a given electronic density distribution. With this information, the evolution of lithium clusters was investigated to connect clusters to dendrites as well as the influence of a copper substrate and SEI species. These models provide a methodology that gives a base for further study of dendrite fundamentals that can be easily extended to engineer high performance battery technology.
Multi-Paradigm Modeling Approach to Simulate the Link between the Fabrication Process and the Performance of Li-Ion Batteries
Authors: Ngandjong Alain Cabrel , Rucci Alexis , Primo Emiliano , Lombardo Teo , Chouchane Mehdi , Su Zeliang , Shodiev Abbos , Franco Alejandro A.
Published: February 2020

In this work we present a multi-paradigm modeling approach simulating the link between the fabrication process of lithium-ion battery electrodes and their electrochemical performance at the cell level. The approach combines discrete particle (Coarse Grained Molecular Dynamics) and continuum (PDE-based) mathematical models. Discrete particle models were used to simulate slurry preparation, drying, and calendering step in strong correlation with experimental results. Experimental data such as the slurry formulation, the viscosity vs. the shear rate, the density and the porosity of the dry electrode were used to validate our model for the slurry and the dried electrode state. Different compositions were studied, in order to reproduce experimental trends, and validate our force fields parametrization. The final electrode structures obtained after drying were compared to tomography characterizations and used to simulate the electrochemical performance of the electrodes, and compared with experimental results. In this presentation, for demonstration purpose, we focus on the case of the NMC as active material.

References

[1] Ngandjong, A.C., Rucci, A., Maiza M., Shukla, G., Vazquez-Arenas J., Franco, A.A., J. Phys. Chem. Lett., 8 (23) (2017) 5966.

[2]
ERC Consolidator Project ARTISTIC (Advanced and Reusable Theory for the In Silico-optimization of composite electrode fabrication processes for rechargeable battery Technologies with Innovative Chemistries), grant agreement #772873 (https://www.u-picardie.fr/erc-artistic/).
2D Layered Manganese Oxide Nanosheets as a Bifunctional Electrocatalyst for Zn-Air Batteries
Authors: Kosasang Soracha , Ma Nattapol , Sawangphruk Montree
Published: February 2020

The sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a crucial issue that limits a practical utilization of metal-air batteries. Manganese oxides with various structures, δ-, β-, α-, or γ-MnO2, have been studied and reported as electrocatalysts for the ORR and/or OER. Here, we have suggested birnessite-typed layered manganese oxides (δ-MnO2) with their sheet-like structure and interlayer spacing of ca. 7 Å containing different alkaline intercalated cations within the layers as bifunctional electrocatalysts. Surprisingly, the experimental results together with a fundamental explanation by density functional theory (DFT) calculations show that the intercalated cations between layers of the birnessite (Bir) play an important role on the ORR and OER catalytic activities which have the activity trend as follow: Li-Bir > Na-Bir > K-Bir > Rb-Bir > Cs-Bir.[1] Apart from the fundamental study, primary Zn-air batteries with these materials are also demonstrated. Zn-air battery with the Li-Bir catalyst shows the highest performance among these catalysts. Moreover, we also integrated the Li-Bir with reduced graphene oxide (rGO) as a composite to improve the electronic conductivity of the MnO2. The mechanical rechargeable Zn-air battery with Li-Bir/rGO composite as an air electrode demonstrates better performances than the Zn-air battery with a pristine Li-Bir catalyst. Interestingly, even the Zn-air battery with the Li-Bir/rGO composite (0.687 V) shows higher potential gap between discharge and charge potentials than state-of-art Pt/C+RuO2 (0.667 V) in the first cycle (2 hours per cycle), however, the Zn-air with our composite catalyst exhibits smaller potential gaps of 0.697 V and 0.719 V (0.720 and 0.761 V for Pt/C+RuO2) at the second and third cycles, respectively. In addition, our mechanical rechargeable Zn-air battery displays an impressive cyclability of discharge-charge processes (10 minutes per cycle) of 500 cycles or over 83 hours at a current density of 2 mA cm-2. Therefore, the Li-bir/rGO composite could be used as a bifunctional electrocatalyst in a practical application for Zn-air batteries.

Reference

[1] S. Kosasang, N. Ma, P. Wuamprakhon, N. Phattharasupakun, T. Maihom, J. Limtrakul, M. Sawangphruk, Chem. Commun.
2018, 54, 8575.
Activated Carbon-Based Electrodes with Engineered Microstructure for Capacitive Deionization (CDI) of Aqueous Solutions
Authors: Mueller Caroline , Salamat Yasamin , Stanczyk Thomas , Soheilian Rasam , Erb Randall , Hidrovo Carlos H.
Published: February 2020

Capacitive Deionization (CDI) is a relatively novel technique which uses an external electric field to remove ionic species from water streams and adsorb them onto a highly porous material. In this system, the interplay between the transport phenomena taking place in the microstructure of the porous electrode and in the bulk flow is of paramount importance as it determines the concentration profile of the effluent. Microporosity and tortuosity of the electrodes dictate the motion of the species in the porous medium and set its adsorption capacity and resistivity. In this work, to achieve systems with better electrosorption and energetic performance, activated carbon electrodes with engineered microtopology are manufactured by employing magnetic field manipulation. By properly arranging the location of the macropores, the fabricated materials allow ions to freely diffuse within the electrode. Along with the electrochemical characterization methods, adsorption and energetic efficiency of the manufactured electrodes are evaluated using the proposed comprehensive figure-of-merits. The obtained results provide new insights into the effects of porous geometry on the microscale electro-sorption and diffusion of ionic species within the porous electrode and their correlation with the macroscale advection and diffusion in the bulk flow of CDI units. The adopted manufacturing process also leads towards development of large-scale production of carbon-based electrodes with controlled microstructures for different applications.
Tailoring Mesoporous Silica Nanoparticles and Thin Films: Synthesis, Characterization and Electrochemical Applications
Authors: Weldekidan Ephrem Terefe , Hornebecq Virginie , Lebouin Chrystelle
Published: February 2020

Mesoporous silica materials have played great roles in widespread application areas like adsorption, catalysis, and separation due to their high surface area, large pore volume and tunable pore size and structure. One of the approaches for extending the application of mesoporous silica materials is tailoring their wall with various functional groups. However, the conventional post-grafting method results in lightly dense, heterogeneously distributed and less accessible functional groups.

In our work, a new method that leads to dense and uniform functionalization of the wall without clogging of the pores has been employed. The hybrid silica-based materials are fabricated either through diblock copolymer templated sol-gel method or through electro-assisted self-assembly method. In the former case, since the template is self-assembled functional amphiphilic diblock copolymer, the selective removing of the hydrophobic block results in porous and PEO functionalized silica materials. Textural and structural properties of the hybrid porous materials will be presented. Furthermore, their application in the area of Li-ion battery as solid composite polymer electrolytes will be discussed. In the later case, surfactant templated mesoporous silica films have been fabricated on conductive substrates via electro-assisted self-assembly method. Hexagonally well-ordered and vertically oriented mesochannels with a diameter of 3nm are obtained in a large domain across the resulted films. The permeability, morphology and nanostructure of the films will be presented.

Figure 1
Assessment of Arrays of Permanent Nanomagnets Produced By Bi-Metal Deposits within Porous Silicon
Authors: Rumpf Klemens , Granitzer Petra , Gonzalez-Rodriguez Roberto , Coffer Jeffery L , Poelt Peter , Michor Herwig
Published: February 2020

This work presents the investigation of the magnetic behavior of bi-metal nanostructures within nanostructured silicon with the aim to exploit the magnetic properties of both metals and gain control of the exchange coupling between the two metals especially with respect to their volume ratio. Furthermore a variation of the structure size and the proximity of the metal deposits modify the exchange coupling and thus the energy product. Finally nanocomposite systems with an energy product as high as possible should be achieved to give rise to on-chip applications using permanent nanomagnets, especially arranged in arrays.

Magnetic nanostructures of two different metals are deposited within nanostructured silicon to control the magnetic switching behavior of the silicon/metal nanocomposite. Two different templates, porous silicon and porous silicon nanotubes are utilized to achieve such nanocomposites. The morphology (pore diameter, tube diameter) of the two systems is comparable. In the case of the utilization of porous silicon templates a mesoporous morphology with average pore diameters of 50 nm is used and these oriented and separated pores are filled with two different metals, namely Ni and Co. The two metals are deposited alternatingly by electrodeposition. A further approach is the chemical growth of Co nanoparticles within porous silicon nanotubes (SiNTs) and the additional deposition of a Ni layer on the outer surface of the tubes. The inner diameter of the silicon tubes is around 50 nm and the wall thickness is about 10 nm. Since the silicon wall of the tubes offers a porous structure the Co particles, which are localized near the pore surface on the wall of a given nanotube, can touch the Ni layer. An alternative structure involves the deposition of an additional Si layer, after the growth of Co particles inside the tubes, as a spacer before the Ni deposition.

The morphology of the deposited bi-metal Ni/Co structures is figured out by SEM and EDX, magnetic measurements are performed by SQUID magnetometry.

In the presented work the dependence of the magnetic properties of a nanostructured silicon/bi-metal nanocomposite on the volume ratio of the metals, on the proximity of the nanostructures and also on the size of the metal deposits is figured out. If the distance between the deposited bi-metal structures is small enough magnetic exchange coupling between them [1] is present which can be explained by the obtained magnetic data. By tuning the bi-metal deposition an optimized energy product [2] is achieved which gives rise to self-assembled nanocomposite systems containing permanent nanomagnets and arrays of them, respectively for on-chip applications.

[1] R. Skomski, J.M.D. Coey, Permanent Magnetism, 1st Edition, CRC Press, Taylor and Francis Group, 1999.

[2] R. Skomski, P. Manchanda, P.Kumar, B. Balamurugan, A. Kashyap, D.J. Sellmyer, IEEE Trans. Mag. 49, 3215, (2013).
Transport Limitations of Sodium-Ions in Type-II Clathrates
Authors: Li Xuemin , Steirer Kenneth , Krishna Lakshmi , Xiao Chuanxiao , Fink Kae , Santhanagopalan Shriram
Published: February 2020

The development of material for room temperature sodium ion batteries with high cycling stability is of great significance. Clathrates are potential sodium ion conductors with the properties of cage-like frameworks. It is predicted that the open cages can easily accommodate alkali ions with negligible volume changes. In this paper, we evaluated the type II clathrate performance in sodium ion batteries. Slightly elevated testing temperature (45 oC) can improve the cell capacity and rate performance due to the improved ionic conductivity. Side reactions on the solid electrolyte interface and loss of active materials during the first sodiation process contribute to the low Coulombic efficiency of the first cycle. Electrode morphology and elemental mapping analysis for clathrate electrodes at different states corroborate the above analysis.

References:

J. Yang and J. S. Tse, Journal of Materials Chemistry A, 1, 7782 (2013).

N. Wagner, A., R. Raghavan, R. Zhao, Q. Wei, X. Peng and K. Chan Candace, ChemElectroChem, 1, 347 (2013).

A. Marzouk, P. B. Balbuena and F. El-Mellouhi, Electrochimica Acta, 207, 301 (2016).

T. Langer, S. Dupke, H. Trill, S. Passerini, H. Eckert, R. Pöttgen and M. Winter, Journal of The Electrochemical Society, 159, A1318 (2012).

K. S. Chan, M. A. Miller, C. Ellis-Terrell and C. K. Chan, MRS Advances, 1, 3043 (2016).