bluuebunny/crossref_metadata_2025 huggingface dataset:
Advanced Biocathode and Its Application in Battery
Authors: Zhang Pei
Published: February 2020

A novel microorganism of Bioechem proprietary, named P1, promotes high electron transport activity on cathode, shown as the highest cathodic current output than the other reported microorganisms. A biocathode, using P1 as catalyst, was tested in an electrochemical system and showed enhanced performance than abiotic cathode. The performance of the biocathode was further improved through the microbial-electrode surface modification by reducing total free energy of the system for better sorption of the bacteria cells on to the electrode; providing more bacteria sorption sites on surface of the electrode; And adjusting the dissolved oxygen concentration on bacteria-electrode interface for faster bacteria metabolic rate and electron transfer rate. With the enhanced properties of the biocathode, the microorganisms can promote the on site energy supply 10 times or more. The biocathode was also first time applied into a primary battery setup and showed promising capacity and durability compare to a same size battery setup using abiotic electrodes and traditional chemical electrolyte.
Simultaneous Determination of Amlodipine and Nebivolol at PANI-CeO2 Modified Carbon Paste Electrode
Authors: Jadon Nimsha
Published: February 2020

In the present study, simultaneous electrochemical determination of amlodipine and nebivolol was investigated by voltammetry based on PANI-CeO2 modified carbon paste electrode. The surface morphology and nature of the prepared PANI-CeO2 modified carbon paste electrode were characterized by electrochemical impedance spectroscopy (EIS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Voltammetric methods such as cyclic and squarewave voltammetry were used for the determination of amlodipine and nebivolol. Various parameters such as pH, scan rate etc. were optimized. After their optimization, a very low limit of detection and low limit of quantification were achieved with the modified carbon paste electrode. The fabricated electrode showed excellent reproducibility, repeatability and stability.

Keywords: Simultaneous Determination, Amlodipine, Nebivolol, Voltammetric technique.
Understanding Covalent and Noncovalent Functionalization of Carbon Nanotubes for Enzyme Electrocatalysis
Authors: Krishnan Sadagopan , Moulton James , Dharmaratne Asantha
Published: February 2020

In this work, our objective is to understand the influences of chemically functionalized carbon nanotubes (covalent) in combination with non-covalently functionalized for enzyme immobilization on a support graphite electrode. We hypothesize that enrichment of surface functionalities of carbon nanostructures allows high-density immobilization of bilirubin oxidase to electrocatalytically reduce oxygen to water along with good stability and large electrocatalytic currents. Although, several reports appear on separate covalent or non-covalent carbon nanotubes functionalization for enzyme immobilization, this study is the first of its kind that aims to obtain quantitative insights on the effect of synergistic combination of covalent plus noncovalent strategies for enzyme immobilization and electrocatalytic applications.
Iron Phosphide Nanoparticles As an Efficient Electrocatalyst for the Oxygen Evolution Reaction in Alkaline Solution
Authors: Umapathi Siddesh , Masud Jahangir , Ashokan Nikitaa , Nath Manashi
Published: February 2020

Splitting water to hydrogen and oxygen through hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is basis to feed the fuel cell. OER is a thermodynamically uphill process as it requires higher potential to form O2 molecule. The best known catalysts to split water with low overpotential are the oxides of Ir and Ru. As these catalysts are precious metals there has been intensive research to substitute them with earth-abundant resources. The new catalyst should fulfill the following: (i) the catalyst to split water has to use minimal energy (measured as applied voltage and referred to as overpotential); (ii) should comprise of earth abundant elements; (iii) should be stable; (iv) should be scalable.1 Transition metal oxides have been recently identified as high-efficiency catalysts for oxygen and/or hydrogen evolution reaction. Apart from the oxides there has been reports of sulfide, selenide and nitride based catalysts.2 Although transition metal phosphides has recently gathered attention as HER catalysts,3 very less metal phosphides have been reported as OER electrocatalyst. In this presentation, ultra-small iron phosphide nanoparticles as well nanoparticle composite with reduced graphene oxide (FeP-rGO) has been reported as efficient electrocatalysts for OER under alkaline conditions. FeP nanoparticles require an overpotential of 290 mV @ 10 mAcm-2. It is well known that rGO is a good conductor and a support material for the catalysts. Hence, mixing of FeP nanoparticles with rGO has improved the catalytic efficiency further by reducing the overpotential to 260 mV to achieve 10 mAcm-2 current density4. The FeP nanoparticles and FeP-rGO composite showed the lowest overpotential at 10 mA/cm2 that has observed among the pnictide making these the most-efficient phosphide based OER catalyst till date. The hybrid catalyst showed a low Tafel slope of 50.8 mV/dec. The stability of the catalyst was excellent with 4h of continuous oxygen evolution and the catalytic activity was retained with a similar overpotential @ 10 mAcm-2. The synthesis of hybrid catalysts, detailed characterization, and electrochemical studies including liner scan voltammetry (LSV), choronoamperometry will be discussed in detail.

References:

Bard, A. J.; Fox, M. A. Artificial photosynthesis solar splitting of water to hydrogen and oxygen. Acc. Chem. Res.
1995, 28, 141-145

Swesi, A. T.; Masud, J.; M. Nath. Nickel selenide as a high-efficiency catalyst for oxygen evolution reaction. Energy Environ. Sci.
2016, 9, 1771-1782.

 Popczun, E, J.; Read, C, G.; Roske, C, W.; Lewis, N, S.; Schaak, R, E. Highly Active Electrocatalysis of the Hydrogen Evolution Reaction by Cobalt Phosphide Nanoparticles. Angew. Chem. Int. Ed. 2014, 53, 5427 –5430.

Masud, J.; Umapathi, S.; Ashokaan, N.; Nath, M. Iron phosphide nanoparticles as an efficient electrocatalyst for the OER in alkaline solution. J. Mater. Chem. A, 2016,4, 9750-9754.

Figure 1
Enhanced Photoelectrocatalytic Activity in Ni-TiO2 Nanocomposites Fabricated By Pulse Potential Deposition
Authors: Mohajeri Soha
Published: February 2020

The Ni-TiO2 single layer nanocomposites were fabricated on copper substrates by the pulse plating (PP) and pulse reverse plating (PRP) techniques. Morphological studies conducted by field emission scanning electron microscopy (FESEM) revealed that pulse potentials and durations affected the microstructure of coatings. The chemical composition of coatings was studied by energy dispersive X-ray system (EDX) and it was found that by the prolongation of current-off durations in PP and anodic cycles in PRP, deposits containing 11.58 wt.% and 13.16 wt.% TiO2 were produced, respectively. The influence of heat treatment temperature on the phase structure of Ni-TiO2 nanocomposites was investigated using X-ray diffraction and it was demonstrated that the anatase to rutile transformation occurred at temperatures higher than 450°C. The hydrophilicity of Ni-TiO2 coatings was evaluated by monitoring the change of water contact angle under the UV illumination. It was observed that the nanocomposite prepared by PRP exhibited the maximum hydrophilicity after 3 hours of heat treatment at 450°C, for which the contact angel prior to UV irradiation was 78.96° and after 1h of UV irradiation it reduced to 13.65°. Surface hydroxyl groups density which account for the photo-induced hydrophilicity of the Ni-TiO2 coating was defined by X-ray photoelectron spectroscopy (XPS), before and after 1h of UV illumination. The results indicated that under the optimized condition, for the coatings prepared by PP and PRP, 12.6% and 15.3% increases were detected in the density of hydroxyl groups. To evaluate the effect of pulse plating parameters on the photocatalytic activity of the Ni-TiO2 coatings prepared by PP and PRP, photo-degradation experiments of methyl orange aqueous solution were carried out under the UV light. The results indicated that TiO2 content, irradiation duration and sintering temperature affected the photocatalytic efficiency of the coatings, and the optimized PP and PRP deposited coatings were capable of disintegrating the methyl orange up to 76.21% and 51.89% after 1 hours of UV illumination. The photoelectrocatalytic degradation of methyl orange by Ni-TiO2 coatings was studied and the effect of different applied potentials was determined. The amounts of methyl orange degraded by the PP and PRP deposited composites under the anodic potential of 600 mV along with 1 hours of simultaneous UV illumination were 75.30% and 89.61%, respectively.
(Keynote) Investigation the Effect of CO2 Absorption in Anion Exchange Membrane By Electrical Conductivity and NMR
Authors: Peng Jing , Roy Asa Logan , Elgammal Ramez Ahmed , Zawodzinski Thomas A.
Published: February 2020

The anion exchange membrane (AEM) has attracted considerable attention in the application of fuel cell technology. Compared with proton exchange membrane fuel cells, AEM fuel cells (AEMFCs) have advantages in cost, catalyst stability, efficiency and system size1. However, one challenge in the application of AEMFCs is the absorption of CO2 from the cathode air supply, which forms carbonate and bicarbonate species and reduces the ionic conductivity of membrane.

In this study, to better understand the effect induced by CO2 on AEM performance, the ion transport mechanism was investigated by using electrical conductivity and Nuclear Magnetic Resonance (NMR) techniques. A typical commercial anion exchange membrane Tokuyama A201 has been used for all experiments. OH- form membranes are prepared by soaking in low concentration (10-4 M) KOH solution. CO3
2- and HCO3
- form membranes are used after soaking in 1M K2CO3 or KHCO3 solution. Both electrical conductivity and NMR experiments have been performed on a series of OH- form, CO3
2- and HCO3
- form samples with different water contents from 20 °C to 80 °C. Figure 1 shows the electrical conductivity of HCO3
- form A201 at different relative humility as a function of temperature, which displays an increasing trend as the relative humility and temperature increase. Also note the low values of conductivity relative to that expected from a hydroxyl ion conductor. This is in accord with previous reports that indicate a significant decrease in conductivity upon uptake of CO2 into hydroxide-form membranes. 1H and 13C pulse-field-gradient NMR are used to characterize the speciation and diffusion coefficient D(NMR)
of water, CO3
2- and HCO3
- respectively. Difference in ionic conductivity and diffusion coefficient of each species in the membrane between three different forms can be observed. The estimated diffusion coefficient D(σ) from ionic conductivity obtained by using Nernst-Einstein equation is sometimes different from that measured by NMR. The comparison between D(NMR)
and D(σ) provides valuable information on ionic transport mechanism 2. Obtaining dynamic information on the behavior of CO2– derived species in the membrane will allow modeling to the distribution of such species in the membrane.

Acknowledgement.

We gretefully acknowledge the support of this work by the Office of Naval Research. We also appreciate the assistance of Tokuyama Soda in providing A201 membrane samples.

Reference:

1. X. M. Ren, S. C. Price, A. C. Jackson, N. Pomerantz and F. L. Beyer, Acs Appl Mater Inter, 6, 13330 (2014).

2. S. Ochi, O. Kamishima, J. Mizusaki and J. Kawamura, Solid State Ionics, 180, 580 (2009).

Figure 1
Controlled Ion Flow through Polymeric Anion Exchange Membranes
Authors: Pantelis Demetra M , Experton Juliette , Martin Charles R
Published: February 2020

Ion-selective polymeric membranes are integrated in electrodes for measuring concentrations of specific ions. The Nernst equation (Eq. 1) allows the ion activity of an unknown sample, a
out, to be calculated from activity of a known internal reference solution, a
in, and the potential across the membrane, E
m­.

(Equation 1)

R, T, z and F are the gas constant, temperature, charge of the analyte ion and Faraday’s constant, respectively.

While this logarithmic form of the Nernst equation has practical applications in analytical chemistry, the equation can also be written in the exponential form (Eq. 2).

(Equation 2)

This suggests an alternative application where a potential E
app drives ions across the membrane until the ratio of activities satisfies Equation 2. In drug delivery, for example, this provides a method to quantitatively transport a specific drug through a membrane. The delivery rate scales with the current applied across the membrane and dissipates when an equilibrium state is reached. At this point, the activity ratio provides a membrane potential, E
m, equal and opposite to the applied potential, E
app.

We have developed a device to monitor ion flow through a quaternary ammonium gel polystyrene membrane. Applying a potential across this anion exchange membrane resulted in the quantitative delivery of nitrate ions until the activities verified Equation 2. This suggests that dosage-controlled and selective drug delivery can be obtained using this membrane.

Figure 1
Mediator Effects on Solid-State Mediator Doped Polymer Electrolyte Membrane
Authors: Qiao Xiaoyao , Wang Yuchen , Zhang Chen , Zhou Xiangyang
Published: February 2020

Electrolyte and separator are two vital components in supercapacitors. High safety is one of the major advantages of polymer electrolyte, which means, even in extreme environment or during faulty, polymer electrolyte will not release any harmful gas or liquid. Mediators are a pair of compounds which can reciprocal transform by losing and gaining electrons. Thus, doping mediators in polymer electrolyte will improve the electronic conductivity. Use of the mediator doped electrolytes in the electrode matrix will benefit the transport process in supercapacitors. However, these electrolytes should not be used in the separators. Polyvinylidene fluoride (PVDF) and lithium trifluoromethanesulfonate (LiTFS) was selected as polymer electrolyte. One mediator couple are potassium ferrocyanide (K3Fe(CN)6) and potassium ferricyanide (K4Fe(CN)6). Another couple are iodine (I2) and sodium iodide (NaI). Conductivity of the membranes were measured with an device as shown in Figure 1. Results of electronic conductivity versus the concentration of mediators are given in Figure 2 and results of ionic conductivity versus the concentration of mediators are given in Figure 3. Electronic conductivity of membranes is enhanced from 10-7 S/cm level to 10-4 S/cm level by increasing the concentration of mediators from 0% to 5%. In the I2/NaI mediator doped membrane the electronic conductivity continuously increase with increasing the concentration above 5%. However, in the K3Fe(CN)6/ K4Fe(CN)6. doped membrane the electronic conductivity is a constant above 5%. Ionic conductivity of membranes is stayed on 10-2 S/cm level. The authors use the electron exchange mechanism and site percolation theory to explain the phenomenon.

Figure 1
Partial Battery Abuse Tests to Determine Battery Stability with Advanced Diagnostics
Authors: Torres-Castro Loraine , Lamb Joshua , Steele Leigh Anna M , Dufek Eric J. , Walker Lee K. , Orendorff Christopher J.
Published: February 2020

Traditional monitoring of electrochemical cells and batteries has been limited to observation of voltage and temperature of the cell or cells. While this monitoring can be very robust, there are limits to how predictive voltage and temperature behavior can be prior to a thermal runaway event. Ultimately, voltage and temperature changes are often lagging indicators or symptoms of battery failure, and by the time a noticeable change is detected it is too late to arrest cell failure with intervention or maintenance. Further, instantaneous voltage and temperature monitoring are often inadequate to determine the state of a battery at rest, particularly if the battery has been previously subjected to an abusive condition. Knowledge of the level of stability of a damaged battery would allow for both safer and more efficient handling of the abused battery.

This work examines the application of Electrochemical Impedance Spectroscopy (EIS) and Differential Capacity calculations (dQ/dV) as a tool for determining the state of stability (SOS) of an electrochemical cell or battery. The cells for this study were subjected to thermal and electrical abuse coupled with EIS monitoring at differing levels of battery abuse. This aims to not only provide a deeper understanding of how abused cells and batteries fail, but also form the technical basis of a tool that could ultimately be used to interrogate cells of an unknown stability and even monitor active cells for early signs of damage or failure. Fast impedance monitoring hardware previously developed at Idaho National Laboratory is used to provide not only monitoring after an abusive battery test but also look for changes in the cell while abusive conditions are applied. Differential capacity calculations are explored both after tests and during moderate levels of overcharge to explore any observable changes that may be monitored during charge and discharge operations. These markers could then be potentially applied to cross-examine batteries of an unknown stability as well as provide the basis for an active diagnostic method as part of a battery management system.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
Improving Battery Safety in Electric Vehicles By Monitoring Cooling Loop Temperature
Authors: Kazim Ali Hussain , Cola Baratunde
Published: February 2020

As automotive industry continues its embrace of high capacity Li-ion batteries, increasing safety monitoring measures are needed. The use of Li-ion battery in electric vehicles presents itself far more strenuous conditions than other applications such as cell phones, cameras, computers and other stationary applications. Not only the power requirements for electric vehicles are high but also the operating environment is much more uncertain due to temperature variability, vibration, high rates of charge and discharge. To dissipate heat away from batteries, cooling loop of water is used. To protect a battery bank from failure, effective thermal management is absolutely essential. To this end, we have developed a temperature monitoring method which supplement existing function of cooling with that of temperature monitoring. We have achieved this by introducing aqueous based redox couple potassium ferri/ferro cyanide in water and using graphite electrodes in the path of flowing electrolyte. The ions reduce/oxidize based on temperature and produce voltage proportional to temperature difference. As a result, we are able to obtain temperature profile of the entire cooling loop and provide additional information to battery management system for reliable operation.
Thermal Management of High Power Lithium Ion Battery Using Heat Pipe and Phase Change Material (PCM)
Authors: Jiang Zhiyuan , Qu Zhiguo
Published: February 2020

Thermal management system is critical for the electric vehicles and hybrid electric vehicles. This is due to the narrow operating temperature range for lithium ion batteries to achieve a good balance between performance and life. In this study, a novel thermal management strategy was proposed using heat pipe and PCM. The real battery heat release rate was measured by the accelerating rate calorimeter (ARC). Different packing methods of PCM and heat pipe were modeled using COMSOL multi-physics software. What is more, the thermal management efficiency of a battery pack using heat pipe and PCM coupling method was investigated. The battery pack was cooled by forced air convection. The effects of cooling section arrangement and inlet air velocity were obtained. The results show that the heat pipe and PCM coupled method was confirmed feasible and effective for fast charging lithium ion battery packs. For the heat pipe and PCM coupling module, the battery-heat pipe-PCM structure is the best placement for the thermal management. The battery temperature can be controlled under 313.23K at a 5.44W/cell heat release rate. The influence of the PCM thickness is more obvious at lower hear transfer rate at heat pipe cooling section. When the heat transfer rate reaches 300W/m2, increasing the PCM thickness leads to little decreasing of battery temperature. As to the battery pack, the increase of the inlet wind speed decreases the battery temperature. Moreover, the staggered arrangement of cooling section is proved to surpass the in-line arrangement.
Modeling Thermochemical Sources for a Broader Range of Materials and Conditions
Authors: Shurtz Randy C. , Hewson John
Published: February 2020

The past two decades have seen the development and implementation of models from calorimetry data that are useful for predicting the onset of thermal runaway in a single Li-Ion cell. This work looks toward further capabilities that can be extracted from calorimetry measurements. These include enabling heat release predictions that allow cell-to-cell propagation of thermal runaway; this requires more comprehensive models that include the effects of additional processes that occur after the onset of thermal runaway. Some of these additional processes are identified from calorimetry data and incorporated into models. The updated models are used to show how all of the identified high-temperature processes contribute to the total heat and gas generated during thermal runaway of Li-Ion cells. The implications for propagation scenarios are discussed.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

SAND NO. 2016-12692 C
Addressing Lithium-Ion Battery Reliability: A Survey of Electrochemical Behavior
Authors: Barkholtz Heather Marie , Fresquez Armando , Chalamala Babu , Ferreira Summer
Published: February 2020

Over the last three decades, lithium-ion batteries (LIBs) have emerged as premier electrochemical energy storage devices. Their widespread application includes cell phones, laptop computers, hybrid electric vehicles, etc. Today, this technology is applied to grid-level energy storage, supporting renewable energy integration into existing power grid infrastructure. To support increasing demand for long-term, large-scale LIB systems; a deeper understanding of commercial LIB safety and reliability is required. Despite thousands of published articles detailing development of LIB components, comparative studies of electrochemical performance as a function of application environments and conditions are scarce. Specifically, parameters such as: cycle stability, capacity, rate capability, cost, and safety implications must be defined as a function of reasonable operating temperatures. Herein, a survey of the electrochemical performance of several commercially available lithium-ion 18650 cells is reported. These studies describe the electrochemical response to temperatures and discharge currents within manufacturer specifications. Electrochemical impedance spectroscopy was used in conjunction with charge/discharge testing to help identify the mode of capacity fade under specific conditions. Several common phenomena occur within these systems, which are reviewed and discussed with a focus on their advantages and disadvantages.

Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND NO. SAND2016-12467 A
(Invited) Alternative Battery Failure Initiation Methods
Authors: Lamb Joshua , Steele Leigh Anna M , Orendorff Christopher J.
Published: February 2020

Propagating battery failure, where the energetic failure of a single cell leads to a cascading thermal runaway of other cells within a battery system, is of increasing concern as battery systems become larger and include greater numbers of cells. However, testing cell to cell propagation requires a method for initiating or simulating single cell runaway while adding a minimum of excess energy into the system. Traditionally single cell failure is initiated with standard battery abuse tests, such as overcharge, thermal ramp and nail penetration tests. However, nail penetration tests can be difficult to perform in fully developed battery systems while overcharge and thermal ramp add a significant amount of excess energy into the battery system. Recent work at Sandia has looked at non-traditional thermal runaway triggers that can be applied to off-the-shelf cells. Heat generation from a single cell was determined through accelerating rate calorimetry (ARC) and used to determine the total flux needed from high power quartz lamps to simulate the thermal runaway of a nearby cell. This was then used to initiate single cells with radiative heating. Single cells were also initiated using a fiber coupled laser to create a localized failure on a cell. This was evaluated for multiple laser energy levels and cell orientations, and coupled with CT evaluation of the point of failure.

Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
Modeling Thermal Runaway in Li-Ion Packs As a Function of Scale and Heat Source
Authors: Shurtz Randy C. , Hewson John
Published: February 2020

As deployment of large-scale Li-Ion battery modules is contemplated, there is a need to understand the propensity for thermal runaway in individual cells and the large-scale thermal failure at the module level. Sources of thermal energy that can lead to runaway include short circuits (internal or external), exothermic processes from overcharge of imbalanced cells, the external environment, and other factors. With battery modules consisting of hundreds or even thousands of cells, it will be necessary to design tolerance to local heat release, regardless of the source. This work presents a chemistry-independent framework for analyzing and modeling thermal runaway that will be demonstrated by applying it to multiple lithium-ion cell chemistries to also demonstrate the sensitivity to the cell chemistry. The combined effects of module scale and the thermal environment surrounding the battery are considered in detail.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

SAND NO. 2016-12691 C
Numerical Investigation of Thermal Runaway Propagation Induced By Internal Short Circuits in Li-Ion Cells
Authors: Li Qibo , Yang Chuanbo , Smith Kandler , Keyser Matthew , Pesaran Ahmad
Published: February 2020

It is known that potential safety risks of Li-ion battery limit their applications. Thermal abuse, which is induced by internal short circuit, is the most dangerous scenario among various safety risks. Numerous studies of internal short circuit have been done by experimental approach. However, experimental methods cannot provide sufficient information to show the mechanism of thermal runaway propagation during internal shorting. Recently, a comprehensive three-dimensional safety model for Li-ion cell, which is based on a multiscale multi-dimensional (MSMD) battery modeling methodology, has been developed by energy storage group in NREL. This safety model, which includes three sub-models, provides a unique capability to investigate the effects of internal short circuit on thermal runaway propagation in a Li-ion battery. In term of sub-models, electrochemical model is used to simulate electrochemical reaction of Li-ion battery; internal short circuit model and thermal abuse model are used to predict the behavior of thermal runaway. In this study, three-dimensional simulations with internal short circuit have been done by applying the safety model. The numerical approach was validated by an experiment utilizing an internal short circuit device, and the results were analyzed in time domain and frequency domain. The mechanism of thermal runaway propagation was discussed, and the dominant parameters to lead thermal runaway were identified. The simulation results reveal the behavior of thermal runaway is affected by initial short volume and short resistance as well as electrical resistance of the electrodes.
Effect of Oxygen Partial Pressure on the Fabrication and Characterization of LaB6-Doped-NiOx Thin Films Produced By Magnetron Sputtering
Authors: Wang Mengying , Diao Xungang
Published: February 2020

Nickel oxide (NiOx) thin films doped with LaB6 were deposited and fabricated by direct current magnetron sputtering technique onto ITO glass substrates with various ratio of argon and oxygen. LaB6 target was just back the cathode and stacked on the nickel metal target on which six holes were drilled and punched to make the La3+ deposit on the substrate. The introduction and addition of La3+ are believed forming the defects, substituting the Ni2+ sites by the analysis of X-ray diffraction, scanning electron microscopy and atomic force microscopy. It obviously leads to the most roughness surface and large crystallite size of the thin films with the ratio of argon and oxygen at 45:5. Moreover, the electrochromic (EC) characteristics response for nonstoichiometric LaB6–doped-NiOx films show a strong dependence on crystallite size variations and surface morphology. Therefore, the as-deposited thin films above demonstrate the good optical contrast and excellent durability, especially the lifetime which can last more than 10000 s. The attempt of this work may be helpful for charactering the EC devices with doping NiOx thin films. We think it will be a big step for the smart windows in energy efficient buildings.

Key words: LaB6–doped-NiOx films, optical contrast, electrochromic (EC) characteristics

Figure 1
Multi-Color Electrochromism in Vanadium Oxide Thin Films
Authors: Song Giljoo , Mjejri Issam , Gaudon Manuel , Rougier Aline
Published: February 2020

Abstract

To date, numerous researchers have spent great efforts in searching for transition metal oxides with diverse properties. Vanadium oxide are a family of interesting materials with high catalytic, electrical, optical and magnetic properties and potential applications such as thermochromic smart windows, batteries and electrochromic devices[1-2]. In this study, vanadium oxide thin films were deposited by two techniques, namely, reactive RF magnetron sputtering and Doctor Blade leading to V2O5 films with a wide range of optical properties. RF sputtered films deposited in gas mixture of argon and oxygen at room temperature on ITO substrates crystallized in an orthorhombic structure when using a V metal target while they were amorphous from V2O5 target. Depending on the deposition conditions, the film morphology was layer or needle type. Orthorhombic V2O5 thin fims were prepared by Doctor Blade deposition on ITO substrate from V2O5 powder synthesized by polyol process[3-4]. Independently of the deposition technique, the electrochromic properties of vanadium oxide films showed multi steps electrochromism, namely yellow to green, green to blue, and blue to grey, in lithium based electrolyte. The optical transmittance characterized by UV-visible spectrophotometer showed a maximum difference of 40% at 550 nm for RF sputtered films while a contrast in reflectance of 20%, in the spectral region 550-700nm, was recorded for Doctor Blade films. The influence of lithium insertion/desinsertion in the structure and chemical state was investigated using GIXD and XPS analysis. The relationship between the film structure, morphology, thickness, correlated with their deposition conditions and the EC mechanism will be discussed. References

Cao Z and Wei B, V2O5/single-walled carbon nanotube hybrid mesoporous films as cathodes with high-rate capacities for recharge able lithium ion batteries, Nano Energy 2, 481 (2013).

Yaoming Sun et al., Anisotropic vanadium dioxide sculptured thin films with superior thermochromic properties, Scientific Reports, 3, 2756 (2013).

I. Mjejri, L. Manceriu, M. Gaudon, A. Rougier, F. Sediri, Solid State Ionics, 292 8-14 (2016).

I. Mjejri, A; Rougier, M. Gaudon, Inorganic Chemistry, Submitted.
Structure-Dependent Response Characteristics of Electrochromic Dye-Modified Transparent Conductive Oxide Porous Electrode
Authors: Watanabe Yuichi , Suemori Kouji , Kamata Toshihide
Published: February 2020

Fast-response electrochromic (EC) cell composed of EC dye-modified TiO2-nanoparticle-based transparent porous electrode was reported by R. Cinnsealach et al. (Sol. Energy Mater. Sol. Cells, 55, 215, 1998). From then, TiO2 porous electrodes modified with EC dyes have been regarded as a promising candidate for fast-response EC display (ECD) applications. Our research purpose is the realization of flexible fast-response ECD applications. However, TiO2 porous electrodes require high sintering temperature (>400 °C) to use as EC electrode because TiO2 has high resistivity. This high process temperature required by TiO2 porous electrode was an important obstacle for their application as transparent electrodes in plastic substrate-based flexible ECDs. To solve this problem, we substituted transparent conductive oxides (TCO) for TiO2 as the porous electrode material. TCO materials have high electrical conductivity than TiO2, so they have the potential to work as the EC electrode even if they are sintered at low temperature.

Previously, we reported that the porous electrodes consisting of indium tin oxide (ITO) nanoparticles exhibit good optical transparency and high electric conductivity. Moreover, EC response characteristics of EC-dye modified ITO porous electrode sintered at 150 °C was improved than that of conventional TiO2 porous electrode due to its high conductivity (AIP Adv., 6, 065121, 2016). Therefore, TCO porous electrodes have potential for application in porous electrode for flexible ultrafast-response ECDs. To achieve such applications, it is necessary to analyze the factors controlling the EC response speed in TCO porous electrodes.

In this study, we investigated the response characteristics of EC dye-modified ITO, antimony-doped tin oxide (ATO), and TiO2 porous electrodes. ITO and ATO porous films have low electric resistivity due to their high electric conductivity. As mentioned above, ITO porous electrode exhibited fast response. On the other hand, low-resistivity ATO porous electrode exhibited slower response than that of a conventional high-resistivity TiO2 porous electrode. This clearly indicates that the EC response speed of the ATO porous electrode is dependent on a factor other than the electric resistance of the porous film. From the structural comparisons, it is revealed that the pore size of the film consisting of small nanoparticles is one of the key factors controlling the EC response speed of porous electrode. The details about the effect of porous film structure on EC response characteristics will be discussed.
Boron-Doped Ultrananocrystalline Diamond Microelectrodes for Chronic Dopamine Monitoring
Authors: Dutta Gaurab , Chang An-Yi , Siddiqui Shabnam , Arumugam Prabhu
Published: February 2020

Understanding the role of neurochemicals in human brain function is challenging. Researchers have showed the importance of extracellular neurotransmitters (NTs) such as dopamine, glutamate, GABA, adenosine and serotonin in Epilepsy, Schizophrenia and Parkinson’s disease. Among these NTs, dopamine (DA) has significant impact on motor and cognitive functions. New age miniaturized prosthetic devices coupled with modern sensing and stimulation electrodes provide a unique opportunity to apply fast scan cyclic voltammetry (FSCV) for chronic DA monitoring with millisecond resolution in vivo. In addition to traditional carbon electrode materials such as glassy carbon and pyrolytic graphite, emerging carbon nanomaterials such as nanotubes, nanofibers and nanodiamonds have spurred immense interest due to their high signal sensitivity and adequate resistance to surface fouling in implant environments. Among carbon electrode materials, boron-doped diamond (BDD) has unique properties such as high thermal conductivity, chemical inertness, biocompatibility, high mechanical stability, and high corrosion and fouling resistance, which makes it an excellent electrode material. In this work, boron-doped ultrananocrystalline diamond (BDUNCD) with 3-5 nm diamond crystallites with wide electrochemical potential window, flexible surface chemistry, low capacitive background current and ultra-smooth conformal surface with minimal non-specific adsorption to biomolecules is used for chronic DA sensing in vitro. The current gold standard electrode for DA sensing is carbon fiber microelectrode (CFM) with ~5 – 10 μm diameters. But CFMs are susceptible to surface fouling and are limited mostly to acute studies (<4h). In this talk, we discuss the dimensional stability of BDUNCD microelectrodes during DA monitoring for ~8 million electrochemical cycles in PBS buffer solution. We developed a new protocol to study BDUNCD electrode fouling and conductive and nonconductive regions by depositing silver nanoparticles and mapping their growth and distribution. Custom-made microfluidics is used to precisely control the microenvironment around the BDUCND microelectrode array. The fouling rates in 100 µM DA solution is systematically studied at different electrochemical potential windows (-0.6 V to 1.2 V) at 60 Hz for up to 7 h. During high frequency FSCV cycling with high current density, severe oxidative fouling and passivation is observed. This results in ~56% fouling at ~1.4 million cycles, i.e. an overall monitoring time of 7 h. Finally, the effect of in situ electrochemical cleaning will be discussed.
An Electrochemical Ammonia Sensor on Paper Substrate
Authors: Sekhar Praveen K. , Kysar Jesse
Published: February 2020

In this article, a room temperature ammonia sensor on a paper substrate is reported. The electrochemical sensor is constructed using platinum electrodes and ionic liquid electrolyte. The amperometric staircase response shows discernible signal differentiation between each concentration of NH3 (5-25ppm). The rise time and fall time for the NH­3 sensor were found to be 8 s and 7s respectively. The authors believe such a fast responding NH3 sensor on a paper substrate has never been reported. The detection limit was deduced to be 1 ppm based on the sensitivity versus concentration plot. A 17% decrease in sensor response was observed over 30 days of testing. Implementing an antenna on the paper substrate co-located with the sensor for wireless operation is envisioned in future.
Portable High Surface Area TiO2 Nanotube Array Sensor for the Detection of Benzene at Room Temperature
Authors: Hegde Shruti , Mohanty Swomitra , Kelly Kerry E.
Published: February 2020

Benzene is one of the few known human carcinogens as identified by the International Agency for Research on Cancer. It is a common indoor and outdoor pollutant, with sources ranging from cigarette smoke to traffic. Hence, there is an increasing need to detect low concentrations of benzene. Metal-oxide based nano-sensors, with their simple sensing mechanisms make for a good choice. Thin films based on titanium dioxide (TiO2) have previously been shown to respond to benzene (1), however these sensors are run at high temperatures (160-200°C), require a complex setup for operation, and have low surface area for sensing. This paper presents the development of TiO2 nanotube based sensor array (Figure 1) that has high surface area, is highly sensitive, and operates at room temperature using portable and simple instrumentation. TiO2 nanotubes were synthesized through anodization in electrolytic solution of ammonium fluoride (NH4F)-ethylene glycol (EG) and oxygen annealed for up to 500°C. The response of the synthesized hollow nanotubes was studied at room temperature for different concentrations of benzene vapor (100-500ppm). The response of the sensor coupons to benzene vapor was measured using an amperometric technique. The results showed an increase in current that was directly proportional to the concentration of benzene in the sample which indicates a quantitative nature of the sensor (Figure 2). The sensor was placed in a portable system which can be deployed to potential contamination sites for real-time monitoring applications. Results on sensing mechanism, stability of the sensor over time, sensor reusability, and detection limit will be presented.

(1) Mabrook M., Hawkins P. (2001) Sensors and Actuators, B: Chemical
75, 197-202.

Figure 1
Movement Intention Prediction By Superficial Magnetic and Pressure Sensor
Authors: Plaza Mauricio , Cifuentes Mauricio
Published: February 2020

This paper presents a discussion about the implementation of superficial magnetic sensor and pressure sensor to find patterns and parameters in order to predicting the intention of movement for people with musculoskeletal system problem in lower limbs.

The information is obtained through reading position and movement by magnetic and pressure sensor installed in different parts of the body. The advantage of this sensor is the reference of the position of the every part of the body. Using the sensor in some parts of the body is possible to calculate the muscle contraction for the prediction of intended movement.
Efficient Capture of Pathogens in Liquid Streams By Phage-Based Biomolecular Filtering
Authors: Du Songtao , Horikawa Shin , Chen I-Hsuan , Liu Yuzhe , Wikle Howard Clyde , Suh Sang-Jin , Chin Bryan A
Published: February 2020

This paper presents a filtration method to capture, concentrate, and isolate small quantities of bacterial pathogens in large volumes of liquid streams. The filter used in this work is a multi-layered planar arrangement of phage-coated, strip-shaped magnetic particles (4 mm × 0.8 mm × 0.03 mm) through which a liquid of interest flows. These magnetic particles are held and arranged by a magnetic force produced from solenoid coils. This “phage filter” is designed to capture specific bacterial pathogens through phage-based biomolecular recognition and allow non-specific targets to pass. An advantage of the phage filter is to eliminate a common clogging issue, which often occurs in conventional bead filters. The phage filter consists of a support frame, solenoid coils coupled to the support frame, and a plurality of phage-coated magnetic particles. The support frame is fabricated from a soft magnetic material. The solenoid is configured to generate a defined magnetic field. The phage-coated magnetic particles, magnetically coupled to the support frame, are arranged in a planar array, positioned within the opening of the support frame. Each magnetic particle is fixed at one end and can swing freely at the other end, allowing large, non-specific debris to pass. ANSYS-Maxwell magnetic simulations were run to obtain the magnetic flux vectors and field strength around the filter with varying electric currents and numbers of, coil layers and turns. The results were compared to experimental results produced using iron powders and a gaussmeter, followed by the selection of the optimal filter design. Then, a series of experiments were conducted where liquid solutions containing different concentrations of Salmonella were passed through the filter, and the capture efficiency was calculated by plate counting. The biomolecular recognition filter can be combined with standard detection methods, such as qPCR, to detect and identify pathogens rapidly.
Flexible Hybrid Mouth-Guard-Based Electrochemical Biosensing
Authors: Schwartz David Eric , Mei Ping , Krusor Brent , Zhang Yong , Street Robert , Rivnay Jonathan , Mercier Patrick , Wang Joseph
Published: February 2020

PARC and UCSD are developing a flexible hybrid biosensor platform to enable continuous remote monitoring of bioanalyte concentrations in saliva. The electrochemical sensor system will be fabricated on a small, flexible plastic foil for mounting on a mouth guard, and enable continuous sensing of lactate, glucose, or other analytes. Chronoamperometry based on enzymatic oxidation of target species has been demonstrated to have high sensitivity and capability for quantification of analyte concentrations. Saliva is favorable for biosensing because of its accessibility and the correlation with blood concentrations of important analytes. The goal of the current work is to demonstrate a manufacturable, reliable sensor system. To this end, the electronics will be fully encapsulated and include wireless charging and readout, with easily removable and replaceable printed electrodes. Here, we will present an overview of the system and discuss current progress.