bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling Thermal Decomposition of Metal Oxide Cathodes in Non-Aqueous Electrolytes for Prediction of Thermal Runaway in Lithium-Ion Batteries
Authors: Shurtz Randy C. , Hewson John
Published: February 2020

The magnitude and rate of heat release that leads to thermal runaway of lithium-ion batteries is highly dependent on the composition and material properties of the cathode material. This work considers the thermodynamic heat release with respect to calorimetry measurements for commercialized metal-oxide cathode materials in electrolytes consisting of LiPF6 in carbonate solvents. Kinetic forms are also developed for prediction of thermal runaway in single cells and cascading failure in groups of cells. This work builds on the examples of legacy models while drawing on more recent data to develop physics-based models with proper dependence on material properties. These models of cathode decomposition in electrolyte complement a recently published study on the thermal decomposition of lithiated graphite in electrolytes.

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525. SAND2019-4391 A
Lithium Ion Batteries and Next Generation Energy Storage Technology - Adoption to Aircraft and Aerospace
Authors: Brewer Roger Alan
Published: February 2020

Lithium ion batteries provide a high energy to weight ratio making the technology attractive for aircraft and aerospace applications. Introducing lithium ion battery technology, as with other types of battery chemistries, can prove challenging for a variety of reasons. As electrical load demands for aircraft increase controlling and harnessing high energy dense solutions will become more critical.

The presentation will begin with a basic introduction of lithium ion battery chemistry and evolve into a discussion on the role various aspects play in safely implementing lithium ion batteries on aircraft including the key design drivers and issues that influence system safety. The presentation will also cover key operational modes, applied to aircraft in general, that can drive risk and effect a prudent power system design (cell overheating, voltage “sag” below minimums at low temperatures, etc.) in the integration of battery technologies to an aircraft. Battery design features and attributes that relate to typical operating modes in an airborne platform will also be discussed in some detail.

The presentation will next evolve into a narrative on next generation energy storage technologies and supercapacitors (electric double layer devices) and their potential role in evolving airborne applications. Implementation of higher surge supportable energy storage designs, again driven by considerations at cold temperature conditions, will also be discussed, and of specific interest for Space applications. Energy and power density "road mapping targets" for evolving applications will be highlighted along with issues that influence nominal values including, but not limited to, operating temperature (cold and hot temperature extremes) typical of battery installations in harsher Aerospace environments. An illustration will be provided in the presentation of what the ideal aircraft battery looks like including the ability to float on an unregulated aircraft bus (without Batter Management Electronics) with large voltage swings, ripple content as well as other “nice to haves” (including higher packaged battery system Whrs and kilo-Watts per kilo gram than existing). A final summary will wrap up the discussion with an overview of the presentation material.
Insights from a Comprehensive Commercial Lithium Ion Battery Cycling and Aging Study
Authors: Ferreira Summer , Preger Yuliya , Fresquez Armando , Barkholtz Heather , Mier Frank Austin , Chalamala Babu R.
Published: February 2020

The single largest barrier to adoption of electrochemical storage in the grid is often stated to be the value of a battery over the life of the system. To ensure long-term system safety and reliability, batteries must be selected based on application specific requirements and performance characteristics. Our approach to addressing the uncertainty in the performance and cycle life of commercially viable lithium ion batteries for grid storage has been to design studies with multiple chemistries, and conduct long term life cycle evaluations with systematically varied cycling conditions. Namely, we initiated a large-scale, multi-year cycling study of commercial LiFePO4/LFP, LiNixCoyAl1-x-y­O2/NCA, and LiNixMnyCo1-x-yO2/NMC cells. This study looks at chemistry specific influences on efficiency and cycle life under variables that include discharge rate, depth of discharge (DoD) and temperature, and is complemented by a calendar aging study. The source of differences in aging behavior was investigated through electrochemical impedance spectroscopy and differential capacity analysis. We compare results to literature to identify the degree to which variations may be expected with manufacturer and version, as products can see manufacturing changes year to year. Understanding variations is critical for lifetime assessment and economic evaluation that is meaningful for installed systems. We further look at how these best-case scenario results from single cell studies may be used as a baseline in moving toward understanding aging in module and system configurations. The overarching goal is to begin to effectively understand laboratory cell studies in a context applicable to grid storage systems.

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
The Effects of Tunnel and Layer Openings in Energetic Aqueous Zinc Ion Storage in Manganese Dioxides
Authors: Ertell Ethan , Zec Zeljka , Poyraz Altug Suleyman
Published: February 2020

Manganese dioxides (MnO2s) exhibit rich and diverse crystallographic structures (polymorphs). MnO2 polymorphs comprise one-dimensional (1D) tunnels and two-dimensional (2D) layers which allow fast and highly reversible ion-exchange properties. MnO2s have widely been studied as cathodes in aqueous rechargeable batteries due to their large tunnel and layer openings and reversible 3+/4+ Mn redox couple. Here, we are reporting high temperature (240oC) hydrothermal syntheses of two tunnel-structured MnO2s with 0.46 nm x 0.46 nm and 0.46 nm x 0.92 nm dimensions and a layered MnO2 with an interlayer spacing of 0.46 nm. MnO2 materials are fully characterized using PXRD, SEM/EDX, TEM, and N2-sorption. Synthesized MnO2 materials are tested as cathodes in rechargeable zinc ion batteries (ZIB) in two electrode cells and using Zn metal anode. Cyclic voltammetry, rate capability, and galvanostatic cycling performances are evaluated in two different aqueous Zn2+ electrolytes (ZnSO4 and ZnTFSI) to disclose the mechanistic changes of reversible Zn2+ storage and the relationship between storage, tunnel and layer dimensions, and electrolyte. During the CV tests, all three materials showed similar redox potentials in ZnSO4, whereas in ZnTFSI, layered and 0.46 nm x 0.92nm tunnel sized MnO2s showed significantly different redox potentials along with an additional oxidation peak. These MnO2s also showed better capacity retention in ZnTFSI than in ZnSO4. These MnO2 materials have similar crystallite sizes and surface areas (25-55 m2/g), differing only in the dimensions of their openings (layer or tunnel sizes). This allows us to directly evaluate the effect of the structural openings and electrolyte in functional electrochemistry by minimizing the effects of other physicochemical properties.
(Invited) Electroless Deposition of Pb Monolayer - Prelude to Electroless Atomic Layer Deposition As Surface Selective, Surface Controlled, Self-Terminating Process
Authors: Brankovic Stanko
Published: February 2020

The presented experimental results including insitu scanning tunnelling microscopy (STM), electrochemical quartz microbalance (ECQCM) and open circuit potential (OCP) transient as well as our modelling and data analysis demonstrate the new phenomenon of the electroless (e-less) deposition of Pb monolayer (ML) on Pt(111), Ru(0001), Au(111) and Cu(111) substrates. The e-less Pb ML morphology and properties resemble its underpotentially deposited counterpart. The e-less Pb ML deposition, in its nature, represents the surface selective, surface, controlled self-terminating process. These attributes are consequence of the synergy between particular properties of the redox processes and substrates involved in the e-less Pb ML deposition. The e-less Pb ML deposition is enabling phenomenon for the two-step e-less atomic layer deposition (ALD) cycle where the e-less Pb ML serves as a reducing agent in the surface limiting redox replacement (SLRR)[1] reaction with noble metal ions, i.e. noble metal deposition. The full e-less ALD cycle results in an overall deposition of the controlled amount of noble metal which is the function of the areal density of deposited Pb ML and the stoichiometry of the SLRR reaction. The e-less ALD is highly selective to the metal substrates at which Pb forms an e-less ML providing an advantage when certain manufacturing and integration requirements are considered.
Electrochemistry Research in the Stickney Lab: A Brief Summary of Dr. John Stickney's Past and Present Research on GeTe
Authors: Sisk Peter W , Howell Pauline , Stickney John Lewellen
Published: February 2020

GeTe is a promising material for PRAM applications due to it’s two different crystal structures; crystalline and amorphous, which have very different resistance and optical properties. GeTe has demonstrated the ability to have switching speeds approaching 1ns, but the properties are dependent on stoichiometry, which can be difficult to control.1,2 While many GeTe films are formed using PVD or CVD, electrochemical methods offer a room temperature alternative with controlled stoichiometries.3 Using E-ALD, a deposition technique originating in the Stickney lab, alternating atomic layers of material can be electrochemically reduced onto the substrate creating smooth, epitaxial thin films. In the past, GeTe and GeSbTe films produced by this group have been Germanium rich due to the tendency of the chalcogenide, Tellurium, to reductively strip out of the film at the negative potentials needed to deposit Germanium. In this study, E-ALD is used to deposit the first atomic layers of GeTe onto a gold substrate.

References:

Physical Review B. 2006, 73, 045210.

Phys. Status Solidi B. 2012, 249, 10, 1939-1944.

Nanoscale Research Letters. 2015, 10, 432.
(Invited) Pd Shape-Controlled Nanoparticles Decorated with Promoter Metals for Electrochemical Nitrate Reduction
Authors: Lim Jeonghoon , Park Jinho , Lee Seung Woo , Hatzell Marta C.
Published: February 2020

Nitrate (NO3
-) is the world’s most widespread surface and ground water contaminant that causes adverse effects on human health such as methemoglobinemia (“blue baby syndrome”) and cancer. While most nitrate removal strategies occur through the use of ion exchange resins, these approaches are not sustainable as waste disposal of the brines remains a critical challenge. Electrocatalytic NO3
- remediation; however, is one emerging approach for nitrate removal which does not produce waste as NO3
- is converted directly to inert dinitrogen (N2) gas. The main challenge with electrocatalytic NO3
- reduction is the low activity and selectivity of the NO3
- to N2 because this conversion is a rate-determining step and results in undesirable products such as nitrite (NO2
-) and ammonium (NH4
+). To achieve an efficient activity and selectivity for the denitrification, we develop Pd shape-controlled nanoparticles and introduce secondary metals by using the underpotential deposition (UPD) method. The electrochemically deposited metals mainly promote the reduction of NO3
- to NO2
- and Pd facets catalyze the reduction of NO2
- to N2. Under the metal desorption area, we can control the surface coverage of metals by sweeping stopped at selected potentials. Conducting RRDE tests enabled the measurement of improved activity and selectivity of NO3
- to N2 using shape-controlled Pd that contain surface modifications (metal atoms). This work demonstrates that electrocatalytic nitrate reduction is an important approach to reduce environmental impacts associated with removing NO3
- from water.
At the Intersection of Photons and Electrons: A Perspective on Operando, in-Situ and Ex-Situ Synchorotron X-Ray Studies of Battery and Electrocatalysis Reactions
Authors: Alamgir Faisal M.
Published: February 2020

X-ray spectroscopies used under ex-situ, in-situ and operando conditions provide vital mechanistic information on charge transfer and structural re-organization processes in electrochemical materials. We will specifically look at how the core-hole techniques of near-edge and extended fine structure from x-ray absorption (XANES and EXAFS) can be used in the study of electrochemically active materials such as in batteries and fuel cells, particularly by tuning to resonances in both the soft and hard x-ray regimes.

First we will examine the role of oxygen in the charge compensation of LiMO2 compounds and the consequences of such for battery safety and for unprecedented changes to electrical/magnetic properties. The electronic and atomic structure local to oxygen was first examined indirectly using hard x-rays by operando resonant K-level measurements of M atoms in battery cathodes of working batteries. The results were then complemented by direct operando measurements at the K-edge of oxygen atoms in the cathode using soft x-rays. It will be demonstrated that the detailed electrochemical roadmap for the reaction mechanisms in LiMO2 cathodes could only be revealed by a combination of soft and hard x-ray based experiments. Next, we will look at the effects of dimension, strain and charge transfer on the electrochemical activity and durability of electrocatalysts for both low and high temperature fuel cells. Again, it will be demonstrated that a by fully utilizing XANES, EXAFS and complementary core-hole methods at both soft and hard x-ray regimes is necessary to reveal a detailed story of the reaction mechanisms in working electrocatalysts.
(Invited) Exploring the Mysteries in Electrochemistry with in Situ X-Ray Characterizations
Authors: Chen Hailong
Published: February 2020

In the past, the understanding of electrochemical reactions majorly relied on the monitoring and recording of the change of current and voltage, as well as the interpretation of the relations between them. In recent decades, a variety of spectroscopy methods have been used as complementary means to explore electrochemical reactions such as battery reactions, electrocatalysis reactions and electrolysis, etc. However, in most reported cases such characterizations were ex situ or postmortem. In situ or operando observations are in general more difficult as they require tremendous design and instrumentation efforts incorporating the electrochemical devices into the analytical testing platforms.

Since started in 2014, our group at the Woodruff School of Mechanical Engineering at Georgia Tech has been working on developing state-of-the-art X-ray based in situ tools for a variety of electrochemical reactions and devices. Lab X-ray diffractometer based setups were built to perform operando XRD examination on Li-ion and Na-ion batteries in charge-discharge cycling. Our recent research on design of high capacity cathode materials for sodium ion batteries will be reported and the phase transitions during the electrochemical intercalation/deintercalation of Na-ions were cleared observed and interpreted by the in-house operando XRD setup. Another example research based on synchrotron X-ray took the advantages of the high energy, high flux and high Q- and time-resolutions of the synchrotron facilities. In addition, research of in situ XRD for synthesis will also be presented, as the controlling and tuning of the materials is very important for materials used in electrochemical reactions.
(Invited) Chloride-Ion Concentration Flow Cells for Efficient Salinitygradient Energy Recovery
Authors: Zhu Xiuping , Tan Guangcai
Published: February 2020

Salinity gradient (SG) is a natural and renewable energy source, which naturally exists between river water and seawater and can also be created by engineering processes. Here, a novel chloride-ion (Cl−) concentration flow cell based on two symmetrical electrodes (BiCl3, CoCl2, VCl3 or BiOCl) separately by a cation-exchange membrane (CEM) was used as an efficient method to recover SG energy. Analysis from X-ray diffraction and X-ray photoelectron spectroscopy indicated that the concentration flow cell with metal chloride electrode (BiCl3, CoCl2 or VCl3) was based on Cl− extraction and insertion, and that of the BiOCl electrode was depended on Cl– intercalation and deintercalation. Besides, the Donna potential across the CEM was also employed for the SG energy harvest. The cell with BiOCl electrodes had the highest power density of 4.36 W m-2 with synthetic river water (1 g L-1 NaCl) and seawater (30 g L-1 NaCl), which was higher than those of most previous technologies for SG energy recovery. The higher power output could be attributed to the faster kinetics of Cl− intercalation/deintercalation on BiOCl electrodes with a layered structure compared to that of Cl- extraction/insertion on metal chloride electrodes. In addition, the results from cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge suggested that low charge transfer and ion diffusion resistances, and the high ion storage capacities of the BiOCl electrode also benefit its the higher power output.
(Invited) Template Free Method for Macroporous SnO2 Thin Film Sensors
Authors: Lionti Krystelle , Sundberg Linda , Fasoli Andrea , Sherwood Mark , Bozano Luisa
Published: February 2020

Transition metal oxides are attractive candidates for gas sensing thanks to their interesting semiconductive properties [1,2]. In particular, tin oxide (SnO2) is the most utilized n-type metal oxide semiconductor, as it typically provides high sensitivity to a large variety of gas analytes. In this study, we are using the versatility of solution-based approaches to prepare MOS materials at the nanoscale and to control critical film morphology parameters for gas sensing such as crystallinity, grain size, film thickness, as well as surface area (through porosity) – the focus of this paper. In the literature, methods of preparing porous SnO2 have been reported many times. However, they are either i) simple but yield SnO2 with small, hard to access pores (sol-gel), potentially non-contiguous films (nanoparticles packing), or ii) they are more complex and in turn more costly (use of porogen, electrochemical processes etc.). Here, we report on a simple, template-free, one-step process that, if deposited in the right conditions, inherently yields highly porous films with large pores (Fig. 1b). The morphology of the macropores was unanticipated with the pores being self-organized, and completely open to the surface. An important parameter to obtain these pores is to deposit the solution at an optimal aging time, as illustrated in Figure 1. Additionally, other factors such as solution concentration and pH, or the nature of the solvent can also impact the macropores formation. The role played by these factors will be discussed, and hypotheses on the macropores formation mechanism will be proposed. The presence of these macropores led to a two-fold increase in sensitivity in our gas sensing measurements (Fig. 1e, 1f) [3]. Altogether, these results suggest that solution-based processes are very powerful to prepare highly sensitive metal oxide gas sensors. The unique morphologies achieved could be highly advantageous in the context of an electronic nose.

References

K. Lionti et.al., TechConnect Briefs 2017, Chap. 7, p.219

A. Fasoli et.al., IEEE International Symposium on Olfaction and Electronic Nose 2017, p.978

K. Lionti et al., 2017, US10020199B1.

Figure 1
Design of a High Signal to Noise Balanced Platinum Thermal Conductivity Detector
Authors: Lotfi Ardalan , Hesketh Peter J. , Navaei Milad
Published: February 2020

Thermal Conductivity Detector (TCD) is one of the universal gas sensors which often is used in the Gas Chromatography (GC) systems. The principle behind TCD sensor is joule heating. TCD sensor heats the surrounding gas which results in change of thermal-physical properties of the sensor. The focus of this work is to improve the Signal to Noise Ratio (SNR) of the Thermal Conductivity Detector (TCD) by the separating the heating and sensing elements of the sensor. Although the TCD sensor has several advantages over chemical sensors: short response time, no base-line drift, and high corrosion resistance, the shortcoming of this sensor is the limit of detection (LOD) [1-3].

The conventional TCD sensor uses a single layer of thin film for both heating and sensing and even though it simplifies the fabrication process, degrades the TCD SNR. Here we propose a new design in which a thin layer of Atomic Layer Deposition (ALD) of Al2O3 is sandwiched between two layers of platinum film. In order to enhance the performance of the TCD at the operating temperature of 700˚ K [1, 4], the heating layer of the sensor needs to be thick enough to be able to pass a sufficiently high current. On the contrary, for the sensing layer to be sensitive to the change of temperature, it needs to be thin enough to have a high resistance value. In this study a lumped model was used to study the High SNR (HSNR) balanced TCD design which revealed that the sensing layer can follow the TCD heater’s temperature with a delay less than 0.3 ns while the HSNR balanced TCD’s response time is 6 µs. Therefore, by comparing the delay time between the two layers, and the response time of the sensor, it can be concluded that the sensing layer resistance represents the real-time temperature of the TCD. The sensor design schematic has been represented in Figure 1. The new design has a higher precision and accuracy which enhances the Limit of Detection (LOD) of the TCD sensor. This was achieved by separating the sensing and heating elements.

Lotfi, A., et al., Ultimate Sensitivity of Physical Sensor for Ammonia Gas Detection Exploiting Full Differential 3-Omega Technique. ECS Transactions, 2017. 80(10): p. 1571-1578.

Mahdavifar, A., et al., Simulation and Fabrication of an Ultra-Low Power Miniature Microbridge Thermal Conductivity Gas Sensor. Journal of The Electrochemical Society, 2014. 161(4): p. B55-B61.

Kommandur, S., et al., A microbridge heater for low power gas sensing based on the 3-Omega technique. Sensors and Actuators A: Physical, 2015. 233: p. 231-238.

Lotfi, A., M. Navaei, and P.J. Hesketh, A Platinum Cantilever-Based TCD for 3-Omega Sensing of Gas Mixtures. ECS Transactions, 2018. 86(16): p. 79-86.

Figure 1
Characterization of Electrochemical Proximity Assay of Platelet-Derived Growth Factor Using SPR/Fluorescence Spectroelectrochemistry
Authors: Zhou Lang , Chin Bryan A. , Simonian Aleksandr L.
Published: February 2020

As a potential biomarker, Platelet-Derived Growth Factor (PDGF) has been directly implicated with vascular disorders and malignant diseases such as cancers, glioblastomas and sarcomas. To realise sensitive and reliable detection of PDGF, Electrochemical Proximity Assay (ECPA) was employed. ECPA is an extremely flexible and sensitive strategy for protein recognition. In our previous work, a SPR/Fluorescence Spectroelectrochemical System (SFSS) was developed, integrating Surface Plasmon Resonance (SPR), Surface Plasmon Fluorescence and electrochemical spectroscopy. SFSS is able to enhance the power of surface characterization techniques, through cross-validation and compensation among all three techniques. Here, we took advantage of SFSS to explore on the ECPA of PDGF-BB. Through proper tags, we are able to recognise the signals from different components, observe the real-time binding dynamics of components occurring on biosensor interface, and estimate their surface coverages. SFSS has helped us deepen our understanding for ECPA into an unprecedented level, and improve its sensitivity and reliability on the detection of PDGF-BB.
Graphene-Enhanced Spectro-Electrochemistry on Boron-Doped Diamond Waveguides
Authors: Mizaikoff Boris
Published: February 2020

With an increasing usage of engineered nanoparticles, a considerable amount of nanoparticles is inevitably released into the environment. This circumstance raises increasing environmental pollution and human health concerns. To mitigate their negative impacts, it is essential to understand the transport, transformation, and ultimate fates of these species within the environment. Among the most important parameters is their interaction with dissolved organic matters (DOM), which may significantly affect the surface properties and aggregation behavior of engineered nanoparticles. Consequently, this affects not only their geochemical cycling, but also any potential environmental remediation strategy. Understanding the heterogeneity of nanoparticle-DOM interactions, and unravelling the mechanisms in molecular details, as well as the factors regulating such interactions calls for effective analytical tools.

Here, we present the development of advanced infrared attenuated total reflection (IR-ATR) sensing technologies for environmental analysis with specific focus on elucidating DOM-nanoparticle interactions in aquatic environments. The interaction dynamics of DOM with nanoparticles will be studied via thin-film diamond ATR waveguides combined with tunable quantum cascade laser and signal-enhancing graphene and graphene oxide surface structures (a.k.a. surface enhanced infrared absorption (SEIRA) spectroscopy) enabling unprecedently sensitive detection of DOM-nanoparticle interactions via molecular spectroscopy. Doping the diamond waveguide with boron (BDD) establishes an IR-transparent electrode material facilitating simultaneous electrochemical studies. Based on these orthogonal IR-spectroscopic and electrochemcial data sets derived from the same sample it is anticipated that DOM-nanoparticle interactions may be elucidated in yet unprecedented detail.
(Invited) A New Approach to Multifunctional Piezoelectric Thin Films for Flexible Device Applications
Authors: Kim Seung-Hyun , Won Sung Sik , Kawahara Masami , Koo Chang Young , Kingon Angus I
Published: February 2020

The objective of this research is to demonstrate the novel concept of enhancing the sensing capability and the long-term reliability of thin film piezoelectric devices via a low cost and simple MEMS-less processed flexible structure with our unique ultra-thin conductive metal foil substrate. The flexible thin metal foil substrate can act as a substrate and electrode without any process temperature limitation up to 750 oC. Piezoelectric films (PZT-based and environmentally friendly lead (Pb)-free KNN-based systems) constructed on ultra-thin flexible substrate enhance the piezoelectric performance because of the contributions resulting from the biaxial strain imposed by the substrate. These films show further improved output voltage and sensing capacity due to increased flexure of the device in comparison with piezoelectric devices integrated with more rigid substrates. Moreover, this flexible piezoelectric structure has a high degree of freedom with no shape limitation and is easy to laminate on any substrates including PCBs if necessary. In this research, we also suggest the key solutions for solving the current degradation mechanisms such as depolarization, temperature, voltage, and stress limitations, and other aging effects by systematic investigation from materials to structure designs. The prediction and the solution for degradation mechanism and failure mode will be explained in simple and clear terms. Our experimental results for piezoelectric materials and flexible devices propose to achieve the robust piezoelectric sensors and actuators that overcome the limitations of current state-of-the-art devices. Our suggested concept is envisioned as a commercially viable structure since the devices can be constructed by simple and mass-producible process.
3D Printable Edible Actuator
Authors: Rahman Julkarnyne M. Habibur , Yoshida Kazunari , Khosla Ajit , Kawakami Masaru , Furukawa Hidemitsu
Published: February 2020

Agar, Konjac glucomannan, Carrageenan are all used for making food gels. Agar gel has high gelling and melting point, Konjac glucomannan acts as thickener and a gelation enhancer in food-related application whereas Carrageenan is also produced from seaweed also has high strength and melting point. In this study, we tried combination of these gels and check their properties whether it is suitable for soft robotics or not. The conductivity of these mixtures is also studied. Our laboratory developed food 3D printer is used for printing these combinations to check its 3D printability. This type of edible gel and its electronics can be used to make edible actuator that will eventually lead the way of using it in biomedical and soft-robotics field.
Controlling Magnetic Properties in Bulk Ferromagnetic Metals By Electrochemical Charging and Discharging of Hydrogen Atoms
Authors: Ye Xinglong , Kruk Robert , Hahn Horst
Published: February 2020

Controlling magnetic properties of materials with external voltages has attracted much interest owing to its promising applications in various areas like actuation. However, the voltage effect in metals is usually restricted to few atomic layers as well as too small for real use due to strong electric field screening. Here, for the first time, we show that bulk magnetic properties of ferromagnetic metal can be tuned significantly through charging and discharging of hydrogen atoms. We manipulated the coercivity of micrometer-sized SmCo5 grains by a fraction of tesla with a voltage of only around 1 V. Employing this approach, voltage-assisted magnetization reversal is realized at room temperature. Through both experiments and simulation, we found that the huge voltage effect originates from the significant change of magnetocrystaline anisotropy in surface regions of SmCo5 grains due to hydrogen insertion and removal, which modifies the nucleation field during magnetization reversal. This work opens up a route for overcoming the screening length and has implication, for example, for using SmCo5 in sensors and actuators.
(Invited) Droplet Microfluidic Devices for Chemical Sensing Application; 1) Paper Digital Microfluidics and 2) Modular Microfluidics
Authors: Lee Jinkee
Published: February 2020

In this presentation, I want to share my recent research works about microfluidics chemical sensors. There are two topics; 1) Paper Digital Microfluidics and 2) Modular Microfluidics. First, the double-sided electrohydrodynamic jet printing of circuitry using silver nanowires (AgNWs) and dispensing of high viscosity silver nanoparticles (AgNPs) is demonstrated in the fabrication of an array of electrodes (3D circuitry) on a single sheet of paper. The penetration of AgNW ink through the paper’s thickness by capillary imbibition allows for multilayer electrical access to connect the individual electrodes. This makes it an automated and efficient choice as the functional area of the device is conserved and the surface of the paper is preserved. This allows for two-dimensional droplet manipulation on a paper-based digital microfluidics (PBDMF) platform. Compared to printed circuit board technology, paper-based electronics offer a range of desirable properties: they are light weight, portable, economical, flexible, biodegradable, and the materials are abundantly available. The fabricated PBDMF chip is demonstrated to be a low-cost, fully reconfigurable, and disposable point-of-care diagnostic platform for the environmental sensing of pesticide using organophosphorus hydrolase enzyme through colorimetric detection via smartphone. Second, we designed a modular microfluidic system for generating droplets using a three-dimensional (3D) printer. This system was manufactured as a modular system with multipurpose droplet generation flexibility. We fabricated various microfluidic modules with different functions, such as droplet generation, mixing, and electrical field generation. We demonstrate flexibility of this system by generating various types of emulsion droplets by changing the combination of modules. Moreover, the generated emulsion droplets showed electrodydrodynamic phenomena, such as the shape deformation, coalescence, breakup, and others, which can be applied to material synthesis, chemical sensing and reaction, bioassay and other applications. This modular microfluidic system is suitable to achieve various purpose as desired by the end user.
Development of Touch Sensor Using Ion Gel
Authors: Hara Yuta , Yoshida Kazunari , Ahmed Kumkum , Khosla Ajit , Kawakami Masaru , Furukawa Hidemitsu
Published: February 2020

The polymer gel is composed of polymeric chains which are crosslinked in a three-dimensional (3D) network structure and liquid which is widely applied to tissue engineering, medical treatment, and solid state electrochemical devices. The gel contains a large amount of water inside the three-dimensional network structure. The human body is also mostly composed of water, hence, the percentage of water in human body is relatively high similar to hydrogel. However, water contained in the gel evaporates in the air atmosphere.

Among various kind of gel, ion gel possessing ionic liquid is beneficial for applications since ionic liquids are liquid salts at room temperature and have useful properties such as non-volatility, non-inflammability, electrochemical stability, thermal stability and high ionic conductivity. In this study, we investigated the piezoelectric properties of ion gels to apply them for touch and pressure sensors in soft-matter robotics.

In this study, the used ion gel was made utilizing thiol-ene reaction and was composed of thiol monomer. The thiol-ene reaction is hardly influenced by the surrounding environment, hence, we can easily make ion gel. In addition, it is possible to form any objects using a photopolymerization initiator and a 3D printer. The aim of this research is to develop a tactile sensor using ion gel having non-volatility, non-flammability, thermal stability, high conductivity and softness close to humans.

The sensor is composed of ion gel and silicone rubber. It was made by injecting an ion gel into silicone rubber. The changes of impedance is measured by the change of shape of the ion gel due to the pressure. The sensor was tested with a press tester and an LCR meter for pressure sensing. It shows 521 kPa in maximum pressure sensing.

Currently, we are working on three-dimensional modeling of the sensor by using an ion gel and an insulating gel instead of using a mold. The technique shown in this study is expected to be applied to soft robot and robot hand.
Development of Fatigue Life Prediction Technology of Hydrogels
Authors: Iijima Tetsuro , Murasawa Go , Kawakami Masaru , Furukawa Hidemitsu
Published: February 2020

Various high-strength gels having strength of several Mega pascal have been developed, one after another by devising the internal structure of the gels. They have attracted attention as a new material. High-strength double network gel (DN gel) is a gel consisting of a hard 1st network and a soft 2nd network and have excellent properties such as super low friction, flexibility and biocompatibility. Particle double network gel (P-DN gel) consisting of powdered 1st network and 2nd network is a high strength gel capable of 3D free form fabrication by using a 3D gel printer. Utilizing these advantages, there are expectations for soft robot materials and mechanical materials. It is also important to grasp the amount of deformation of the gel and how much fatigued it is when the gel material is industrially used. Specifically, by attaching a fatigue monitoring device to a soft robot, it is possible to predict the optimum time to replace the parts. When it is used for mechanical materials, we need to judge on the necessity of emergency treatment. It will be considered to lead to comfortable use of things.In this research, we aimed to develop a fatigue monitoring device using hydrogels with reference to the internal structure and destruction phenomenon of P-DN gel. P-DN gels of various compositions were prepared and mechanical tests and evaluation of internal structure by dynamic light scattering were carried out to investigate the physical properties of these gels. As a result, the P-DN gel using super absorbent polymer (SAP) as the 1st gel showed the most suitable physical properties for use as a fatigue monitoring device.
(Invited) Design of Nanomaterial-Based Electrochemical Sensors for Environmental and Biological Applications
Authors: Chen Aicheng , Manikandan Venkatesh , Liu Zhonggang , Ahmed Syed
Published: February 2020

Electrochemical sensing strategies have spurred intense scientific interest owing to having the advantages of instrumental simplicity, rapid response, high sensitivity, cost-effectiveness, and portability. Nanomaterials and nanotechnology have facilitated the development of high-performance electrochemical sensors and biosensors with unique functionalities and processes for enhanced medical and environmental applications. Recently, my research team has designed and fabricated a variety of functional nanomaterials and nanocomposites. In this talk, the synthesis of advanced gold, metal oxides and graphene-based nanomaterials as well as their promising applications in electrochemical sensing will be presented. The electrochemical detection of biomarkers (e.g. nitric oxide), food additives (e.g. nitrite, sulfite, caffeic acid) and pollutants (e.g. mercury) will be discussed. The significant roles of nanomaterials in the development of high-performance electrochemical sensors will be highlighted.
Electrochemical Detection of Micro-RNAs As Potential Cancer Biomarker
Authors: Asadi Hamid , Ramasamy Ramaraja P.
Published: February 2020

MicroRNAs (miRNAs) are single-stranded RNA transcripts, typically of 19–23 nucleotides in length. Recently, miRNAs have been identified as important biomarkers that hold promise in early cancer diagnosis. Accumulative evidences have proved that abnormal expression of miRNAs is closely related with the occurrence, diagnosis and treatment of cancer [1]. Conventional methods of miRNA detection have some intrinsic drawbacks including the need for tedious and complex procedures, requirement of large amount of samples, highly skilled experts and high-end equipment. To address these shortcomings as well as to provide multiplexing capability, different types of electrochemical cancer biosensors have been developed. Electrochemical biosensors have been widely paid attention due to their merits including high sensitivity, specificity, low-cost, and multiplexing [2]. Herein, a label-free and sensitive biosensor was developed for miRNA-21 detection at femtomolar concentrations. A glassy carbon electrode (GCE) was first modified with carbon nanotube (CNT) which serves as platform for immobilization of probe DNA as well as providing higher surface area. Capture DNA probes were immobilized onto the surface of CNT modified electrode using an established molecular tethering method [3,4]. Electrochemical analyses confirmed the surface modification, immobilization, and hybridization between probe DNA and the target miRNA. Besides, different variables such as probe concentration and hybridization time were investigated and optimized to find the optimal experimental conditions for miRNA detection. The obtained results demonstrated that the proposed biosensor exhibits excellent analytical properties including high sensitivity, low detection limit, selectivity, and reproducibility for miRNA detection.

References

Lan H, Lu H, Wang X, Jin H (2015) MicroRNAs as potential biomarkers in cancer: opportunities and challenges. BioMed research international 2015

Kilic T, Erdem A, Ozsoz M, Carrara S (2018) MicroRNA biosensors: Opportunities and challenges among conventional and commercially available techniques. Biosensors and Bioelectronics 99:525-546

Ramasamy RP, Luckarift HR, Ivnitski DM, Atanassov PB, Johnson GR (2010) High electrocatalytic activity of tethered multicopper oxidase–carbon nanotube conjugates. Chemical Communications 46 (33):6045-6047

Zhou Y, Fang Y, Ramasamy RP (2019) Non-covalent functionalization of carbon nanotubes for electrochemical biosensor development. Sensors 19 (2):392
Wide Linear Range Detecting Non-Enzymatic Glucose Sensor Based on Cu-CuO Nanoparticles Decorated TiO2nanotubes
Authors: Zhou Zhiru , Zhou H. Susan
Published: February 2020

We successfully fabricated Cu-CuO/TNT electrode by coating the Cu-CuO nanoparticles onto TiO2 nanotube arrays surface through electrochemical deposition method, which is easy to operate and fast procedure. After the electrochemical deposition, Cu-CuO nanoparticles with a diameter of ~200nm were well dispersed onto TNT surface, which then given a smooth interaction surface and a 3D nanostructure with high uniformity. The as prepared Cu-CuO/TNT electrode was then used for non-enzymatic in vitro detection of glucose in sodium hydroxide (NaOH) solution. The non-enzymatic glucose sensor exhibits great analytical performance with wide linear range between 0.2-90mM, high sensitivity of 234 μA mM-1cm-2and low limit of detection of 0.019. Other than that, it also shows great selectivity toward glucose in presence of other interference species such as ascorbic acid(AA), dopamine(DA), uric acid(UA), lactose, sucrose, and fructose.

The wide linear range between 0.2-90mM of the sensor is really potential to be used for clinical and biopharmaceutical application. For diabetic patient, blood glucose concentrations can increase up to 40mM after glucose intake. For biopharmaceutical industry, glucose concentration can increase up to 80mM in the cell culture bioreactor. Current sensing platform described in a large part of scientific publication have little if no chance for application as their linear range is often outside the physiological range. In light of this information, the proposed non-enzymatic glucose sensor can be used for continuous monitoring of glucose in most applications.

Figure 1
Highly Sensitive and Selective Gas Sensors Using p-Type Oxide Nanoparticles Decorated ZnO Nanowire Network Sensors
Authors: Na Chan Woong , Kim Yonghwan , Myung Yoon
Published: February 2020

Metal oxide nanowire network structures are promising chemoresistive materials with a highly sensitive response, good stability and fast response due to their large surface area and gas accessible networked structures. In general, highly crystalline oxides nanowire (NW) networks were prepared by a thermal evaporation process. Those have lots of advantages for the detection of volatile organic compounds (VOCs) and environmental pollution gases. Especially, n-type oxide NWs such as SnO2, ZnO, and In2O3, and Ga2O3 are widely investigated due to their easy synthetization and high gas response. In other to enhance gas response of n-type oxides NWs, doping or loading of noble metals of Pt , Pd, Ag or p-type oxide semiconductor of CuO , Co3O4, NiO, and MnO2. In this study, we investigated for the detection using p-type metal oxide nanoparticles decorated ZnO NWs. Consequently, the surface modification of oxide NWs via various methods provides new approach to accomplish the selective detection of a specific gas, and after further researches, this approach could provide a new strategy in the field of gas sensors.
Micro- and Nanoelectrodes: Fabrication, Characterization and Application. the Detection of Silver and ROS/Rns in Biological Buffer
Authors: Sidambaram Prabhakar , Colleran John
Published: February 2020

The electrochemical determination of low concentrations of silver, and the short-lived highly reactive oxygen and nitrogen species (ROS/RNS), requires reliable, reproducible measurements with sensitive analytical methods. In this work, gold, platinum and platinum black micro and nanoelectrodes were fabricated. Characterisation revealed flat disk-shaped working areas of 20 - 25 µm (micro) and 1 - 10 nm (nano) in diameter, derived from steady-state limiting currents and validated using FE-SEM.[1] Reported studies on silver detection have been carried out under a myriad of conditions but, to date, electrochemical determination of silver in biological buffers and media has not been successful.[2] Ultra-low concentrations of silver (1 nM – 80 nM) were determined, by anodic stripping voltammetry (ASV) with Ag/AgBr as a reference electrode, using micro- and nanoelectrodes of platinum and gold in chloride-free phosphate buffer (PB, pH 7.4). Laser pulled electrodes exhibit highly reproducible stripping voltammetry data for the determination of silver and returned linear calibration curves. A low detection limit of 1.3 pM in this medium provides the ability to explore silver and silver-based bioinorganic drug uptake by tumour and microbial cells. [3]

This study also includes the fabrication of Pt/Pt-black nanoelectrodes for the detection of ROS/RNS in chloride-free PB (pH 7.4). These data should help with the identification and quantitation of cellular ROS/RNS release. In particular, monitoring oxidative stress, as a cellular response on exposure to bioinorganic drugs, should help to elucidate the interaction pathway of bioinorganic anti-cancer drugs. We envisage that electrochemical speciation studies will help to elucidate the mechanism of action and cellular uptake of bioinorganic silver-based anti-microbial and anti-cancer drugs in cell sustaining media for in vitro and, potentially, in vivo single cell analysis.

[1] Percival, S. J. et al., RSC Adv. 2014, 4 (21), 10491.

[2] Radulescu, M. C. et al., Sensors 2010, 10 (12), 11340.

[3] Prabhakar Sidambaram. et al., J. Electrochem. Soc. 2019, 166, 6, B532.