bluuebunny/crossref_metadata_2025_split huggingface dataset:
Robust Design of Silicon/Graphite Composite Via Atomic-Scale Rearrangement for High Performance Lithium Ion Batteries
Authors: Lee Taeyong , Cho Jaephil 
Published: February 2020

State-of-the-art lithium-ion battery (LIB) technology are still challenged with many other requirements, including high-energy density, long cycle life, safety and cost by the increasing demand of the electric vehicle energy-storage market. Moreover, key to success for commercialization of EVs is reducing the charging time of the batteries. In general, the conventional graphite has shown not only low electrochemical performance but also safety problems arisen from the metallic lithium plating at the surface of the anode electrode at the high current density (4mA/cm2) due to a sluggish kinetics during intercalation reaction and working voltage potential neighboring almost 0V (versus Li/Li+). Alternatively, among the alloy-type anodes, silicon is considered as promising anode material due to the high gravimetric capacity of 3572 mAh g-1 and proper lithium-alloying potential (0.22 V vs. Li/Li+) to prevent unwanted lithium plating. However, to the best of our knowledge, the majority of previously reported Si anodes do not demonstrate the rate capabilities at high electrode density (g/cc) due to the large volume changes (>300%) and low electrical conductivity of Si anodes.
Herein, we have proposed a composite consisting of a nanoscale silicon coating layer on graphite/carbon nanofibers through nickel-catalyzed-CNF growth on the graphite by chemical vapor decomposition (CVD) using both ethylene (C2H4) and silane (SiH4) gas. The chemical Si-C bonding by atomic rearrangement of CNF and a-Si layer prevents the exfoliation of the active Si layer from the surface of CNF during cycles. For practical viability, all electrochemical tests were performed in the full-cell as well as in the half-cell configurations with high energy density (> 1.6g cc-1), high areal capacity (3.3 mAh cm2) and limited binder composition (< 4wt %). As a result, by increasing electrical conductivity of silicon/graphite composite and existing high stability of ultrathin Si layer, our composite shows remarkable improvement in electrochemical performances even at high current density with those of the conventional graphite.
Designing High Power Lithium Ion Cells
Authors: Lain Michael J. , Brandon James , Kendrick Emma 
Published: February 2020

Applications like hybrid electric vehicles (HEV) require batteries with high volumetric and gravimetric power densities, in both charge and discharge modes. Lithium ion cells are now being designed with different power : energy ratios, for specific applications. Many cells are rated for high rate discharge (> 10 C), but not for high rate charge (< 2 C). However, even 10 C is not enough.
A selection of commercial lithium ion cells, mainly cylindrical 18650 cells, were disassembled and characterised. The cells had a variety of different power : energy ratios, and this was correlated with key design parameters. For example, cells with a high power density had relatively low coat weights and areal capacities, and used active materials with a smaller particle size. However, most of the cells had the same tag arrangement, when high power cells were predicted to use more tags.
Having disassembled the cells, the harvested electrodes were tested in coin cell half cells. The tests included resistance measurements, continuous discharge tests at relatively low rates, and pulse charge and discharge tests at high rates. During lithiation pulses, all the anode voltages went negative of zero volts vs. Li/Li+ by around 5 C. However, the reaction still appeared to be under solid state diffusion control, based on the linearity of the voltage vs. time0.5 GITT plots.
These and other results will be presented at the meeting.
(Invited) Understanding Interfacial Reactivity in Li-Ion Battery Cathodes and the Effect of Surface Modifications
Authors: Cabana Jordi 
Published: February 2020

Reactivity at interfaces between Li-ion battery cathodes and electrolytes imposes limitations to activity and durability. Before solutions can be devised, it is indispensable to precisely define the underlying chemical mechanisms. Interfacial instability is driven by the formation of highly oxidized species on the surface of the cathode particles, but these mechanisms are inherently local and they depend on their morphology and chemistry. A combination of X-ray absorption spectroscopy and X-ray microscopy will be presented to establish the changes undergone by cathode particles at different points of the charge, revealing the consequences of interfacial reactions at very high spatial resolution.
Modifying the surface of the cathode particles with redox-inactive cations is an established strategy to prevent these undesired reactions and increase electrode durability generally. Developments will be discussed in the manipulation of chemical assembly to achieve the highest level of sophistication in this approach, through core-(epitaxial) shell architectures at the level of primary particles. The nanostructures are produced via colloidal methods that generate objects with high chemical and morphological definition. As a consequence, they constitute valuable models to evaluate effect of surface modifications on cathode-electrolyte interfacial interactions. The presentation will establish comparisons of the changes at the surface of cathode particles depending on the presence and identity of a passivating shell. These comparisons inform the definition of mechanisms of stabilization, which will be subsequently used to propose further avenues of design towards cathodes with high capability for energy storage with long life.
Thin Film Lithium Niobites with Intrinsic High-Rate Performance for Lithium-Ion Batteries
Authors: Lee Dong-Chan , Shank Joshua C. , Doolittle W. Alan , Alamgir Faisal M. 
Published: February 2020

Lithium-ion batteries have been broadly favored as one of the best energy storage systems which have various classes of electrode materials being studied to satisfy the demand on improved electrochemical performance. As a similar class to titanium-based oxides, niobium-based oxides continue to be considered as promising electrode materials with multiple pairs of Nb redox couples, which can deliver more capacity than Ti-based oxides depending on their phase and charge/discharge condition. Among several phases of niobium oxides, lithium niobite (LiNbO2) has attracted scientific attention as a mixed ion-electron conductor proposing its use for the optical application as well as memristor and superconductor. Nevertheless, the research on lithium niobites still lacks, especially for the use as energy storage materials in lithium-ion batteries.
By sputter deposition, 1.1-micron-thick lithium niobite membranes were fabricated for thin film electrodes. The characterization using XRD and XPS with consecutive etching confirmed the unique (101)-oriented crystalline arrangement of as-synthesized thin film electrodes and elucidated their initial lithium deficiency. Free of conducting agent and binder, the electrodes exhibited high capacity utilization and stable retention over 400 cycles. They also presented remarkable high-rate performance even at 14 A/g of extremely high current density (ca. 70C) and demonstrated a full recovery of capacity at the subsequent moderate rate. It was revealed the unit parameter change originated from the insertion and desertion of lithium cations occupying the octahedral sites between (NbO2)n- layers of edge-shared NbO6 trigonal prisms. None of phase evolution or extinction during the cycling implies that the major capacity contribution of lithium niobite comes from the single-phase intercalation reactions, which was supported by voltage profiles as well. Post-mortem analysis using XPS with Ar ion etching enabled to suggest that besides the main intercalation reaction, from Li0.5NbO2 to LiNbO2, about 9.3% of LiNbO2 undergoes a conversion reaction to Nb.
The Interplay of Electrode Heterogeneity, SEI Growth, and Li Plating in Li-Ion Batteries
Authors: Pouraghajan Fezzeh , Sun Fei , Mazzeo Brian , Wheeler Dean 
Published: February 2020

Newman-type or macrohomogeneous cell models have had a significant contribution toward designing and optimizing Li-ion batteries. In order to lower the computational cost and accommodate limited experimental information, this model assumes that battery electrodes are functionally homogenous. However, this assumption can be far from reality even for commercial-quality electrodes, due to variability in microstructure that arises during the manufacturing process.
Previous work in our group showed that electrode heterogeneity can lead to non-uniform distribution of current density, positive and negative electrode states of charge, and charge/discharge capacities [1]. Consequently, heterogeneity can cause faster degradation of materials, prevent maximum utilization of active materials, and even lead to catastrophic failure of the cell.
Among the different modes of cell aging, solid electrolyte interphase (SEI) growth and Li plating are considered mainly responsible for capacity fade due to loss of active Li. In this study, we will discuss how electrode heterogeneity can lead to non-uniform SEI growth and Li plating, and how the growth of this resistant layer affects the level of heterogeneity, performance, and lifetime of the cell.
To better understand the interplay of the electrode’s heterogeneity and cell aging, we use a combination of a Newman-type model and an equivalent-circuit model for an NMC cathode and graphite anode. The equivalent-circuit model consists of three parallel resistances, each represent high, medium, and low conductivity regions in an electrode film.
This research was funded by the BMR program of the US Department of Energy.
[1] Forouzan et al., J. Electrochem. Soc. 165, A2127-A2144 (2018).
Development of Physical Property Measuring Device for 3D Food Printer Gel
Authors: Ishigaki Ryo , Kawakami Masaru , Furukawa Hidemitsu 
Published: February 2020

In recent years, research and development of 3D food printers have been actively conducted, and it is expected to change the future food problems immensely and the way of food manufacturing and processing.
In the Food Layer Manufacturing(FLM) 3D food printer, the molding conditions must be set for physical properties of the each material. In the previous study, researches were conducted on the relationship between viscosity and molding conditions by rheometer or viscometer, and it is reported that the modeling accuracy improves as viscosity increases. However, since it is difficult to use a rheometer or a viscometer at each household, a simple physical property measuring device is necessary. Therefore, in this study, we will investigate whether the shaping conditions can be determined from the concentric circle spreading out of the container after vibrating the gel contained in the cylindrical container with the diaphragm. Also, We will confirm whether or not it is possible to measure simple kinematic viscosity of a high viscosity material by checking the presence or absence of concentric circle spread and viscosity relationship.
Wireless Stretchable Hybrid Electronics for Smart, Connected, and Ambulatory Monitoring of Human Health
Authors: Kim Yun-Soung , Mahmood Musa , Kwon Shinjae , Herbert Robert , Yeo Woon-Hong 
Published: February 2020

Continuous ambulatory cardiac monitoring using electrocardiogram (ECG) can reveal a range of essential health conditions. However, commercially available devices rely on bulky wires, rigid sensors/electronics and cause great discomfort that disrupts one’s lifestyle and prevents long-term use. Moreover, standard gel-based electrodes are prone to degradation over long-term use and can causing allergic skin reactions. Also, research-level skin-wearable devices, while excelling in few aspects, fall short as concept-only presentations, due to the fundamental challenges in active wireless communication and integration as a single device platform.
Here, we introduce a fully wireless, low-profile, multifunctional stretchable hybrid electronic (SHE) device that offers smart, connected, and ambulatory health monitoring. As shown in Figure 1, the low-modulus, elastomeric system construction provides the gentle, yet sufficient, device adhesion to skin, obviating the need for straps, tapes, or adhesives, and demonstrates a type of monitoring scheme inconspicuous not only to the observer, but also to the user. Integration of a set of stretchable nanomembrane sensors with a highly flexible, membrane-based wireless circuit enables the continuous, long-range (up to 15 m) monitoring of ECG, heart rate, respiratory rate, and physical activities. Implementation of convolutional neural networks and algorithms for real-time classifications of multi-modal physiological signals demonstrates the device feasibility for multi-faceted clinically relevant analysis. In vivo demonstrations involving human subjects both with and without cardiac conditions reveal the feasibility of the device as a continuous, ambulatory, and multifunctional health monitor with emphasis on real-time detection of cardiac abnormalities. Further in vivo demonstration of SHE applied on athletes during treadmill exercises validate the versatility of SHE in both clinical and research environments.
Figure 1: Overview of SHE. (A) Photograph showing the stretchable hybrid electronics applied on human chest. (B) Blow-up render detailing the structural components of SHE including the thin-film stretchable skin electrodes, hyperelastic membranes, mechanical decoupling chamber, stretchable connector, and flexible data acquisition unit.

Figure 1
Microfluidics Enhanced Performance of Electrochemical Devices
Authors: Stetter Joseph R. 
Published: February 2020

The design of electrochemical [amperometric] gas sensors [the AGS] involves consideration of materials, geometry, structure and methods of operation as well as supporting electronics; in other words it is a systems problem to make a practical sensors within size and cost constraints that will meet all performance requirements for a given market. This work examines the construction of an AGS for atmospheric pollutants [Ozone, CO, NO2] that combines microfluidic sample inlet with cell designed to operate over a wide range of RH, Pressure, and Temperature encountered in smart cities, IoT deployment. Not only is ppb sensitivity required, but also multiyear stability of both span and background currents as well as a MTBF [mean time between failure] measured in decades. The approach to design, fabrication, testing, and deployment as well as field data are presented. Overall assessment of the advantages of electrochemistry as well as limitations and challenges are discussed.	to be entered later
Effect of Alcohol Addition to Sulfuric Acid on Efficiency for Formation of Anodic Alumina
Authors: Matsumoto Mikimasa , Hashimoto Hideki , Asoh Hidetaka 
Published: February 2020

Anodization of aluminum in electrolytes containing alcohols as an additive has been studied for improvement of coating properties such as corrosion and wear resistance, and hardness. The influence of the addition of alcohols on the pore arrangement in anodic alumina was also investigated. However, the essential understanding of the effect of alcohol addition is still insufficient. In this study, we used the sulfuric acid-based electrolyte containing various alcohols (e.g., methanol, ethanol, glycerol, and ethylene glycol) as an additive and investigated the effects of types and concentrations of alcohols on the efficiency for the oxide formation and the structure of the porous alumina.
High purity aluminum sheets were used as a starting material and anodized at constant current of 100 A m-2 in 1.5 mol dm-3 sulfuric acid with alcohol concentration in the range of 0~50 vol%. The formation of porous alumina film on the aluminum substrate was investigated by measuring voltage transient. In the case of ethanol concentration less than 10 vol%, voltage-time curve shows the steady-state voltage of approximately 15.7 V. When ethanol concentration exceeded 20 vol%, the steady-state voltage obviously increased with increasing ethanol concentration. In sulfuric acid without ethanol addition, the surface layer of oxide film was excessively dissolved after anodization for 220 min. The film thickness was approximately 65 μm. While using sulfuric acid with 50 vol% ethanol, chemical dissolution of the outer surface was significantly suppressed and the film thickness increased from 65 μm to 70 μm at the same anodization time, i.e., the same electric charge. Even in other type of alcohols, chemical dissolution of oxide was suppressed, resulting in improvement of coulombic efficiency for the oxide formation. The variation of dissociation constant of the electrolyte by addition of alcohols might affect the chemical dissolution and formation efficiency of anodic film.

K. Kuroda, M. Ozawa, J. Met. Finish. Soc. Jpn.,
15, 3 (1965).

Y. Li, M. Zheng, L. Ma, W. Shen, Nanotechnology, 17, 5101 (2006).
Cu/Zn SOD Detection By Catalytic Amplification for the Design of a Cancer Biosensor
Authors: Sanchez Annelis O 
Published: February 2020

High levels of SOD2 are related to an increased frequency of invasion and metastasis of certain types of cancer (i.e. fibrosarcoma). Early detection of SOD2 in the circulatory or lymphatic system can help diagnosis and prognosis of these types of cancer. A highly sensitive method is required for detecting very low concentrations of this enzyme. The herein project detects collisions of a single CuZn SOD enzyme on the electrode’s surface. This detection is possible due to a catalytic amplification process occurring over the enzyme’s surface. The current transient is generated when the oxidation process occurs over the surface of the individual nanoparticle (CuZnSOD in this case) when this one impacts the ultramicroelectrode’s (UME) surface. The current blip generated is then use to calculate the enzyme's size. According to theoretical calculations, CuZn SOD has approximately 4 nm diameter. This number correlates with the size obtained by the electrochemical technique, and transmission electron microscopy (TEM) images.
Figure 1. Amperometric i vs t curve of a 0.089 fM CuZnSOD solution in phosphate buffer pH = 7.8 applying a potential of E = 0.2 V. Three electrode cell was used: a 10 μm Pt UME as the working electrode, Ag/AgCl as the reference electrode, and a Pt wire as the counter electrode.

Figure 1
Electrochemistry on Tribocharged Polymers
Authors: Zhang Jinyang , Ciampi Simone 
Published: February 2020

Static electrification of insulators is a familiar topic: hair attracted by a party balloon or ink or laser printers transferred to a toner1. Contact electrification develops on the surface of insulators which are brought in and out of. Statically charged surfaces has been known to mediate redox work, but the scope in electrochemistry of charged dielectrics remains poorly understood. In 2008, Liu and Bard demonstrated that metal ions can be reduced to elemental metal on a charged polytetrafluoroethylene surface and they proposed that charge carries are electrons2. However, in 2011, Bartosz A. Grzybowski demonstrated a random “mosaic” of each polymer surface after contact and separated, suggesting that polymer fragments are responsible of the electrification process3. Here we report that the magnitude of electrochemical work on electrostatically-charged polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE) and polyvinyl chloride (PVC) samples is material-dependent. We show that the magnitude of redox work mediated by a charge insulator is governed by a trade-off between its ionization energy (IE) and electron affinity (EA)4. Using XPS, AFM and TEM we have quantified metal deposition on electrostatically-charged PDMS, PTFE and PVC samples. Quantum chemical methods are used to show that anions are the effector of the redox work and polymer, with plastics of the largest negative value of EA (making negative charges unstable) but that at the same time it will ionize into cationic fragments with relative ease, leads to surfaces able to mediate redox work to the largest extent. This work extends our understanding of the molecular nature of static electricity and may find applications in single-electrode electrochemistry and in the study of electrostatic catalysis on chemical reactivity.
References

Childress, C. O.; Kabell, L. J., Electrostatic Printing System. US Patent No. 3,081,698, 163: 1963.

Liu, C.-Y.; Bard, A. J., Electrostatic Electrochemistry at Insulators. Nat. Mater.
2008,
7 (6), 505–509.

Baytekin, H.; Patashinski, A.; Branicki, M.; Baytekin, B.; Soh, S.; Grzybowski, B. A., The Mosaic of Surface Charge in Contact Electrification. Science
2011,
333 (6040), 308–312.

Zhang, J.; Rogers, F.; Darwish, N.; Gonçales, V. R.; Vogel, Y. B.; Wang, F.; Gooding, J. J.; Peiris, M. C.; Jia, G.; Veder, J.-P., Electrochemistry on tribocharged polymers is governed by the stability of surface charges rather than charging magnitude. Journal of the American Chemical Society
2019.

Figure 1
(Invited) Gender Bias in STEM Workplaces
Authors: Rincon Roberta 
Published: February 2020

While we have seen an increase in women’s representation in certain STEM fields such as biology and chemistry, many engineering and technology professions have seen relatively slow increases (and, in some cases, decreases) in women’s participation. Though an increasing number of women are choosing STEM careers, many experience frustrations when trying to move up into more senior positions. Achieving gender equity in STEM requires addressing issues affecting women’s inclusion and advancement in the workplace, particularly the impact of gender bias.
A recent study found that 27% of women in the U.S. feel that their careers are stalled in STEM, with over 30% indicating thoughts of leaving their jobs within the year.1 And women in the U.S. are not alone: Women around the globe are struggling to reach higher level positions in their STEM careers, with 47% of women in China and 55% of women in India indicating that a women will never get a top position in her company, no matter how able or high-performing.2 Research indicates that one of the primary reasons for women’s attrition from the STEM workforce is workplace climate and culture. For example, one study found organizational climate was the primary factor for 30% of women who left the engineering profession, with nearly half citing working conditions such as a lack of advancement or salary.3

Addressing gender bias in the STEM workplace will help to close the gender gaps that exist in the STEM workforce. It is not just the right thing to do: Reducing women’s attrition in STEM is necessary to help meet the growing global demand for STEM talent. Studies also show that gender-balanced teams are more innovative, and companies with greater levels of gender diversity in upper management see greater financial performance than their less-diverse counterparts.4,5

Hewlett, S. A., Sherbin, L., Dieudonne, F., Fargnoli, C., & Fredman, C. (2014). Athena Factor 2.0: Accelerating Female Talent in Science, Engineering & Technology: Executive Summary.

Ibid.

Fouad, N. A., Singh, R., Fitzpatrick, M. E., & Liu, J. P. (2012). Stemming the tide: Why women leave engineering.

Kelly Services. (2016). Women in STEM: How and why an inclusive strategy is critical to closing the STEM talent gap.

McKinsey & Company. (2018). Delivering through diversity.