bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Gold Nanostructures and Their Activity Against Dopamine
Authors: Silva Juan Francisco , Ramirez Sara , Silva Nataly , Oyarzun Maria Paz , Pavez Jorge 
Published: February 2020

This research aims to study the incorporation and effective containment of gold nanostructures on a substrate electrode applied to electrochemical sensors for the detection of dopamine. gold nanoparticles (AuNPs) was synthesized using the protocol developed by Turkevich [1]. Additionally gold nanorods (AuNBs) were obtained using the method described by growth Nikoobakht [2]. These nanostructures have been incorporated into a metal substrate mediated self-assembled monolayers (SAMs) for a 4-mercaptopyridine (4MPy), which allows the confinement and effective communication of the nanostructure. Furthermore, to evaluate the anisotropic effect against dopamine response.
Chemical and morphological characterization system were used: X-ray photoelectron spectroscopy (XPS), the atomic force microscopy (AFM) (fig 1A), the scanning tunneling microscopy (STM) (fig 1B), and electron microscopy transmission (TEM). Additionally, for the functional characterization of the system, the cyclic voltammetry was used to determine: 1. The crystallographic orientation of the gold substrate; 2. The electrochemically active bare gold substrate and the nanostructures incorporated area, 3. quimidesorción the SAMs; 4. The electrochemical redox response of two probes K3Fe (CN)6 and Ru (NH)6Cl3 to evaluate the anisotropic effect.
Finally it was studied by voltammetric square wave detecting dopamine by preparing a calibration curve, which shows that as the concentration of neurotransmitter increases the signal, ie, the peak height ( Ip), it is proportional to the concentration, in both systems the same phenomenon occurs, however, for the device AuNBs formed with has a detection potential differing from the potential detection of a gold surfacer.
Acknowledgements: Proyectos Fondecyt Nº 1131062 y 1140192
references:
1.Kimling, J., M. Maier, B., Okenve, Kotaidis V., Boleta, H., Plech *A., Turkevich. (2006). new method for synthesis of gold nanoparticles. J phys Chem 110, 15700.
2.Nikoobakht, B., Mostafa, A. El-Sayed*. (2007). Preparation and Growth Mechanism of Gold Nanorods (NRs) Using Seed-Mediated Growth Method. Chem Mater 15, 1957.

Figure 1
Modeling and Simulation of Thermal Runaway in Cylindrical 18650 Lithium-Ion Batteries
Authors: Melcher Andreas Markus , Lei Boxia , Ziebert Carlos , Rohde Magnus , Seifert Hans Jürgen 
Published: February 2020

The thermal runaway of a single Li-ion battery (LIB) in larger battery package is the worst case scenario which must be avoided under all circumstances. In this work the electrochemical-thermal model for a LIB based on porous electrode theory is extended with contribution coming from exothermic side reactions to model the abuse mechanisms in Li-ion batteries with respect to the temperature which could lead to a thermal runaway. The electrochemical-thermal model is extended with several new contributions which occur in several temperature regimes. In detail the heat source in the corresponding heat equation is extended with the heat generated by various exothermic reactions, for example at the surface-electrolyte interface at temperatures in the interval T=[T1, T2], reactions between anode resp. cathode and the electrolyte between temperatures in the interval T=[T3, T4] and the destruction of the electrolyte above the temperature T>T5, where T1<T2 ≤T3<T4 ≤T5. These extensions will be modeled with a solid fuel or a constant fuel model as simplification coming from combustion theory. For this extended model simulations are performed for specified current profiles and exterior temperature profiles to simulate an oven trial and cell cycling. In the simulations a cylindrical 18650 LIB is investigated with a LiCoO2 cathode. The purpose of the simulations is to compute the temperature-field during the time evolution of a thermal runaway, therefore the cross section in horizontal and vertical direction are considered as well as the one-dimensional temperature profiles along these directions. Finally the time evolution of the overall mean cell temperature T is used to classify the different stages of a thermal runaway in a T-dT/dt-plot. The results will be compared with experimental ARC-measurements in pure oven experiments and cycling experiments.
The Redox Potential and Chemical Stability of Li7P3S11 Using VASP Calculation
Authors: Doh Chil-Hoon 
Published: February 2020

Study on Li7P3S11 material was carried out by ab initio calculation using the Vienna ab initio Simulation Package (VASP)[1]. Li7P3S11 was known as a super-ionic conductor (5.4 mS/cm at 25°C) to be a solid-electrolyte of all-solid-state lithium batteries. Two different crystal structure of Li7P3S11 were reported by Onodera (2010) and Tatsumisago (2007) with slight difference on atomic positions. Between total energies of VASP calculation on two structures, Tatsumisago’s structure had slightly more stable energy (Etotal –92.573 eV). Among Li7P3S11, Li3PS4, Li4P2S6 and Li4P2S7, the formation potential of Li7P3S11 was the highest value of 2.216 V(Li/Li+) to be the most stable material. Chemical reactivity of Li7P3S11 material toward moisture to be Li7P3O11 had the reaction energy of –0.34 eV. Li+ conduction of Li7P3S11 take place through vacancy and interstitial diffusion pathways. Xiong (2014) reported on the formation potential of Li7-1P3S11. Evaluated result of the formation potential of Li14-1P6S22 was also appeared similar to Xiong’s results. Formation potentials of Li14+1P6S22 were also evaluated for four different interstitial sites. Site(III) denoted at Xiong’s report had 0.643 V(Li/Li+) to be the most easy accommodation of Li+ ion. Patterns of the total density of states (TDOS) of Li14+xP6S22 (x=1,0,-1) were not so different and shown ~3.5 eV by the Hyed-Scuseria-Ernzerhof (HSE) hybrid functional and ~2.1 eV by GGA to be electronic insulator.
[1] Kresse,G.; Hafner, J. Phys. Rev. B, 47 (1993) 558; 49 (1994) 14251.

Figure 1
Modeling Co-Extruded Cathodes for High Energy Lithium-Ion Batteries
Authors: Cobb Corie Lynn 
Published: February 2020

Utilizing an existing macro-homogeneous porous electrode model developed by John Newman, this talk presents the potential energy density gains that can be realized in lithium-ion battery electrodes fabricated with co-extrusion (CoEx) technology. CoEx uses carefully engineered fluidic channels to cause multiple streams of dissimilar fluids to impart shape to one another. The result is a high-speed, continuous deposition process that can create fine linear structures much smaller than the smallest physical feature within the printhead. By eliminating the small channels necessary for conventional extrusion and injection processes, CoEx is able to deposit highly loaded and viscous pastes at high line speeds under reasonable operating pressures. The CoEx process is capable of direct deposition of features as small as 10 μm with aspect ratios of 5 or greater, and print speeds > 80 ft/min.
We conduct an analysis on two-dimensional cathode cross-sections in COMSOL and present the electrochemical performance results, including calculated volumetric energy capacity for Lithium Nickel Manganese Cobalt Oxide (NMC) co-extruded cathodes, in the presence of a lithium metal anode, polymer separator and ethylene carbonate–diethyl carbonate (EC:DEC) liquid electrolyte. The impact of structured electrodes on cell performance is investigated by varying the physical distribution of a fixed amount of cathode mass over a space of dimensions which can be fabricated by CoEx. By systematically varying the thickness and aspect ratio of the electrode structures, we present an optimal subset of geometries and design rules for co-extruded geometries. Modeling results demonstrate that NMC CoEx cathodes, on the order of 125-200 µm thick, can garner an improvement in material utilization and in turn capacity through the addition of fine width electrolyte channels or highly conductive electrode regions. We also present initial experimental results on CoEx NMC cathode structures.

The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000324.
A Combined First-Principles and Experimental Investigation of the Li7P3S11 Superionic Conductor
Authors: Chu Iek-Heng , Nguyen Han , Lin Yuh-Chieh , Wang Zhenbin , Xu Zihan , Hy Sunny , Deng Zhi , Meng Shirley Ying , Ong Shyue Ping 
Published: February 2020

Rechargeable all-solid-state lithium-ion batteries utilizing a fast lithium superionic conductor electrolyte (SCE) has the potential to revolutionize energy storage by providing an inherently safer, less flammable alternative to traditional organic electrolyte-based batteries. Synthesized from 70Li2S:30P2S5 glass-ceramic, the Li7P3S11 metastable crystal is a promising SCE that exhibits very high ionic conductivity of 17 mS/cm, comparable to those of liquid electrolytes. In this work, we present a combined computational and experimental study on this compound. We find that though Li7P3S11 is predicted unstable at zero temperature, it becomes stable at 630 K when vibrational entropy contributions are accounted for, in excellent agreement with experimental measurements. We will also report on the calculated surface energies and Wulff shape of the Li7P3S11 crystal. Finally, we demonstrate that ab initio molecular dynamics (AIMD) simulations predict Li7P3S11 to have a significantly higher room-temperature ionic conductivity than previously reported, suggesting that there is significant scope for the further optimization of this material.
(Invited) Swelling and Elastic Deformation of Lithium-Silicon Electrode Materials
Authors: Baker Daniel R , Verbrugge Mark W , Bower Allan F 
Published: February 2020

Lithium-battery electrodes made from silicon increase volume by a factor of four when charging from a de-lithiated to fully lithiated state, but by charging and discharging slowly enough, stresses can be reduced, which avoids stress damage to the electrode. We provide a mathematical description comprehending the relevant solid mechanics (i.e., stress and strain) and diffusion processes so as to describe highly expanding battery electrode materials and determine the maximum current at which lithium-silicon can be charged and avoid exceeding the material yield stress. An approximate metric for acceptable stress levels is that they are less than 1% of the elastic modulus. At these low stress levels, infinitesimal strain theory can be used for the computations. The rate of charge and discharge that keeps stress below this level depends on values for the elastic modulus, the Poisson ratio, the lithium diffusion coefficient, the particle size, the open-circuit potential of the material, and several other parameters whose values are generally concentration dependent. The derived formulas are analytic and straightforward to apply (e.g., they can be employed in conventional spreadsheet software) and can be used to assess potential new materials, design better electrodes, and improve operating strategies.
Example outputs from the mathematical model can be seen in the two figures below. The upper figure provides calculated results for the open-circuit potential, modulus, particle radius (left ordinate) and perturbation parameter (right ordinate) as a function of time (or average fraction of filled lithium sites y
0). During charge, the potential and the modulus (stiffness) decline monotonically, the radius increases monotonically, and the perturbation parameter is a complicated function of y
0. Histories of the radial, hydrostatic, and tangential stresses as a function of time (or average fraction of filled lithium sites y
0) and at radial positions r/a = 0, 0.5, and 1 are provided in the lower figure. Note that the abscissas are identical.

Figure 1
A Simulation Framework for Battery Safety Modeling
Authors: Marcicki James , Bartlett Alexander , Yang Xiao Guang , Mejia Valentina , Zhu Min , Chen Yijung , L'Eplattenier Pierre , Caldichoury Inaki 
Published: February 2020

Increased utilization of Lithium-ion batteries for a variety of applications is driving the need for advanced simulation tools that can predict the combined structural, electrical, electrochemical, and thermal response to abuse conditions. If such simulation tools are integrated into the product development process, the resultant data has the potential to inform decisions during development and create highly optimized designs.
Academic and national laboratory researchers have pioneered these models1-3, but there is currently no consensus on the required methods for multi-physics coupling or acceptable degree of homogenization. If coupling is present between the mechanical and electrical or thermal solvers, it is typically one-way and largely manually applied, which requires highly advanced users to implement due to mesh and element compatibility issues.
In order to initiate a much larger investigation into the abuse response of Li-ion cells, modules, and packs, a coupled structural, electrical, and thermal simulation framework has been developed within the commercially available LS-DYNA software. The finite element model leverages a three-dimensional mesh structure that fully resolves the unit cell components. Depending on the time scale of the mechanical crush, coupling with the mechanical solver can be one-way for impact loading conditions that occur in the sub-second time scale, or two-way for continuous crush in the tens to hundreds of seconds time scale. Measurements of the resistance between unit cell layers as a function of applied pressure are reported and used to parameterize the coupling between the structural, electrical, and thermal solvers. A spatially distributed equivalent circuit model predicts the electrical response with minimal computational complexity. The thermal model provides information to schedule the electrical model parameters, while simultaneously accepting irreversible and reversible sources of heat generation. The spatially distributed models of the electrical and thermal dynamics allow for the localization of current density and corresponding temperature response to provide the necessary tool structure for predicting the onset of thermal runaway.
Future work will focus on the structural material models and failure conditions required to quantitatively predict the battery crush response to a variety of loading conditions. Plans for additional multi-physics functionality within the simulation tool will also be highlighted.
References:

E. Sahraei, R. Hill, and T. Wierzbicki, J. Power Sources, 201, 307 – 321 (2012).

E. Sahraei, M. Kahn, J. Meier, and T. Wierzbicki, RSC Adv., 5, 80369 – 80380 (2015).

C. Zhang, S. Santhanagopalan, M. A. Sprague, and A. A. Pesaran, J. Power Sources, 290, 102 – 113 (2015).
Electrical Current Oscillations in Lower-Dimensional Battery Electrodes
Authors: Yamada Hidenori , Bandaru Prabhakar R 
Published: February 2020

In order to enhance the capacity of a charge storage device, nanostructures such as one-dimensional (1-D) carbon nanotubes (CNTs) have often been employed, much of the time with the effect of increasing the surface area exposed to electrolyte or enhancing the electrode inter-connections and reducing the electrical resistance. Previous work also demonstrated the need for new physics based on lower dimensional density of states (DoS), as would occur in CNTs or graphene [1]. Here, for nanostructured battery electrodes, we propose a new current-voltage (I-V) model based on 2D and 1D DoS, and compare with related experiments. The model is broadly based on Marcus-Hush-Chidsey (MHC) kinetics and is aimed to extend the utility of the MHC formulations, to a larger class of materials and situations. We employ an integral expression for current, which involves the DoS, the Fermi-Dirac function, and the Arrhenius rate law as the basis. Our model provides better agreement to measured chronopotentiometry data on Li-ion batteries with nanostructured organic polymer electrodes, compared to previous analysis. An interesting feature of our model is the prediction in one-dimensional nanostructures of electrical current oscillations in the I-V curve, corresponding to the gradual population (and de-population) of each successive sub-band, provided that the sub-band widths are comparable to the reorganization energy. We posit that the consideration of a variable/non-constant DOS in MHC electrokinetics may yield tests of dimensional character and concomitant contribution to electrochemical systems.
[1] H. Yamada and P. R. Bandaru, Appl. Phys. Lett. 102, 173113 (2013), ibid 104, 213901 (2014).
Fabrication and In Vivo Evaluation of Low-Invasive Patch Type Glucose Sensors
Authors: Yasuzawa Mikito , Li Jiang , Fuchiwaki Yusuke 
Published: February 2020

Continuous glucose monitoring system (CGMS) using implantable glucose sensor have provided significant benefit on the management of diabetic health care, since it can present not only the point of glucose degree but also its trend. Although the present glucose degree is same, rising and lowering phenomenon of blood glucose lead to an opposite treatment action. In addition, daily trend observation is useful for the evaluation and improvement of individual pharmacotherapy. However, since sensor device of CGM at a present day requires a length of 1 cm to be inserted in skin, development of a lower-invasive CGMS is expected for the improvement of diabetic patients’ quality of life.
In this study, a fine tapered needle shape glucose sensor, which has sensing region at the tip of a fine tapered electrode, was proposed. Since the sensing region is at the tip of tapered electrode, it only requires the sensor tip to be implanted in the tissue for glucose monitoring. In other words, it can be possible to perform as a patch type sensor, which impresses the user as a sticking sensor instead of a implanting sensor. Fine platinum-iridium alloy wire with a diameter of 0.17 mm was placed inside the tapered PEEK tube and glucose oxidase (GOx) was immobilized on the surface of platinum electrode by using the combination of electrodeposition and electropolymerization technique. Ag/AgCl film was prepared on the outer surface of PEEK tube in order to be employed as reference electrode together as counter electrode. Glucose sensor properties of the obtained GOx-immobilized electrode were evaluated by using in vitro and in vivo measurements. A patch type sensor with insert length of 1 mm was implanted in a rabbit. Clear sensor response corresponding to glucose concentration change was confirmed.

Figure 1
Fabrication of Smart Au/TiO2 Nanotubes/Si Based Schottky-Tunneling Diode Sensors for Electrochemical Detection of Biomarkers
Authors: Bhattacharyya Dhiman , Misra Mano , Mohanty Swomitra K. 
Published: February 2020

Rapid, point-of-care (POC) disease diagnostics presents several challenges including cost, detection time, equipment portability, and performance. Detection of volatile organic compounds (VOCs) based disease biomarkers from the breath provides a potential solution to the aforementioned problems. One such tuberculosis (TB) biomarker identified from breath is methyl nicotinate. In this regard, development of smart sensor systems can provide an economically feasible solution and pave the way for rapid disease diagnostics.
In this paper, we present the fabrication of a smart sensor developed by synthesis of self-organized TiO2 nanotube arrays formed by anodization of thin Ti film deposited on Si wafers by direct current (D.C.) magnetron sputtering. Site-specific interdigitated patterned growth of gold electrode was achieved using photolithography techniques. The gold interdigitated electrodes behave as the working electrode while platinum deposited on the back surface of the Si wafer acts as the back contact. Au on TiO2 presents a Schottky junction due to differences in their work function and can be overcome by light irradiation. On the other hand, an ultra-thin, inherent SiO2 layer on Si aids in tunneling electrons across the TiO2 – Si junction. Thus, Au/TiO2/SiO2/Si behaves as a Schottky tunneling diode junction that electronically couples a VOC oxidation catalyst (Au) to a photovoltaic absorber (Si).
A sweep of the bias voltage (-5V to 5V) and associated sensor response at room temperature upon exposure to both air and biomarker vapors (~1000 ppm) was carried out. From the current-voltage plot (I-V), the operating voltage was chosen overcoming the negative differential resistance such that the sensor current response to the biomarker vapor would be maximized under forward bias condition. The sensor current when exposed to the biomarker vapor was higher than that in air. All sensor measurements were carried out under illuminated conditions.
The variation in the output current of the sensor biased at the chosen operating voltage (~ 0.7V) at room temperature was observed for the range of 0.01 ppm to 1000 ppm biomarker concentration. The sensor demonstrated a strong response and the results suggest that the sensor is capable of detecting extremely small concentrations of the biomarker in the vapor phase. This smart sensor presents significant enhancement in sensor response over previously reported metal functionalized TiO2 nanotube array based sensing platform developed in our group for electrochemical detection of similar disease biomarkers.
Carbon Nanofiber Nanoelectrodes for Neural Stimulation and Chemical Detection: The Era of "Smart" Deep Brain Stimulation
Authors: Koehne Jessica E. , Marsh Michael , Bennet Kevin E , Andrews Russell , Lee Kendall H , Meyyappan M. 
Published: February 2020

A sensor platform based on vertically aligned carbon nanofibers (CNFs) has been developed. Their inherent nanometer scale, high conductivity, wide potential window, good biocompatibility and well-defined surface chemistry make them ideal candidates as biosensor electrodes. Here, we report two studies using vertically aligned CNF nanoelectrodes for biomedical applications. CNF arrays are investigated as neural stimulation and neurotransmitter recording electrodes for application in deep brain stimulation (DBS). Polypyrrole coated CNF nanoelectrodes have shown great promise as stimulating electrodes due to their large surface area, low impedance, biocompatibility and capacity for highly localized stimulation. CNFs embedded in SiO2 have been used as sensing electrodes for neurotransmitter detection. Our approach combines a multiplexed CNF electrode chip, developed at NASA Ames Research Center, with the Wireless Instantaneous Neurotransmitter Concentration Sensor (WINCS) system, developed at the Mayo Clinic. Preliminary results indicate that the CNF nanoelectrode arrays are easily integrated with WINCS for neurotransmitter detection in a multiplexed array format. In the future, combining CNF based stimulating and recording electrodes with WINCS may lay the foundation for an implantable “smart” therapeutic system that utilizes neurochemical feedback control while likely resulting in increased DBS application in various neuropsychiatric disorders. In total, our goal is to take advantage of the nanostructure of CNF arrays for biosensing studies requiring ultrahigh sensitivity, high-degree of miniaturization, and selective biofunctionalization.