bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combining Electrochemistry and Biology to Create a Suite of Portable Biosensors for Water Analysis
Authors: Mayall Robert Matthew 
Published: February 2020

Water analysis is a complex process requiring sample preparation, shipping, and analytical machinery. Often this process is removed from the individuals who require the test results. FREDsense Technologies is developing a platform sensor system for the fast and efficient analysis of water chemistry using biosensors. By combining biology and electrochemistry, microbes can be utilized to specifically measure a variety of different chemical compounds. FREDsense has demonstrated the efficacy of the platform through the development of an arsenic sensor (FRED-As) and FREDsense aims to commercialize and launch this product for near real-time arsenic analysis in the field.
The FRED system works through genetically engineering bacteria such that when they encounter a contaminant of interest they cleave a substrate in proportion to the target compound to produce a redox active species. This species then diffuses to a screen-printed carbon electrode surface to undergo a reversible oxidation detected either via cyclic or square wave voltammetry. This use of bacteria as an intermediary in the detection of compounds of interest creates a large signal amplification, as trace quantities of pollutants (low ppb) can be translated into the production of currents that are easily detectable on an inexpensive handheld potentiostat system (< $100).
To date, this system has been shown to respond reliably to single ppb levels of As (III) in under an hour in a laboratory setting, with field trials currently underway in multiple locations. This is coupled with an inexpensive and easy to manufacture potentiostat system running open-source software. This system is also expandable to detect other contaminants through the implementation of different genetic circuits, producing a selection of bacteria that can be chosen to monitor the varied needs of unique testing locations. Combined, this creates a powerful platform technology that can simplify the water analysis process for a variety of industries.
Sensitive Colorimetric Detection of Nitrite Ions Based on the Aggregation of Gold Nanoparticles
Authors: Kulkarni Aniruddha , Bird Victoria , Ziegler Kirk J 
Published: February 2020

Determination of nitrite both environmentally and in life processes has been of importance as its presence above a threshold causes detrimental effects. Hence, there is a need to develop new, simple and highly sensitive analytical assays. Nitrite detection has been achieved through various methods, including chemiluminescence, electrochemistry, and surface-enhanced Raman scattering which involve use of expensive equipments, tedious procedures and time consumption.
However, colorimetric assays can provide visual, on-site analysis, providing a simple and instantaneous detection method. In this work, a facile colorimetic assay has been proposed based on anti-aggregation of gold nanoparticles. Gold nanoparticles coated with aromatic amines react with nitrite ions that alter the aggregation state of the nanoparticles. The change to the aggregation state causes a shift in the local surface plasmon resonance bands, triggering a colorimetric response. An increase in the concentration of nitrite ions changes the color of the solution, which can be detected by the naked eye.
While many approaches have used thiol-based linkers, our use of disulphide cross-linkers, which bind more strongly to gold has increased the sensitivity of detection by an order of magnitude. Furthermore, the effect of this assay on synthetic urine has been explored to understand the effect of the presence of foreign ions on the detection of nitrite.

Keywords: Anti- aggregation, gold nanoparticles, surface plasmon, aromatic amines
Interactions of TiO2 Nanotubes with Contaminants of Emerging Concern for Applications in Point-of-Use Electrochemical Detection
Authors: Timmerman Ashley , Mohanty Swomitra K. , Carlson Krista 
Published: February 2020

The electrochemical detection of several pharmaceuticals and personal care products (PPCPs) in water was performed using titanium dioxide nanotube-based (Ti-NT) arrays. Sensing was performed with various pharmaceuticals in water from natural sources, achieving ppb detection limits. Low bias voltages (-1.2 V to +1.2 V) were selected for operation and correlates to sensor performance. Bias voltage was determined by cyclic voltammetry in order to record maximum oxidation and reduction peaks for the specific metal and chemical of interest. The Ti-NT arrays were decorated with various metal nanoparticles to increase the specificity and sensitivity of the sensor. Metals were chosen based on Density Functional Theory methods to calculate which metals are most likely to bind with the chemical of interest. For example, Ti-NTs functionalized with zinc nanoparticles were able to detect ppb levels of ibuprofen, while no detection occurred with the blank Ti-NTs.

Figure 1
The Benefit of an Integrative, Multiscale (Molecular- to Meso-Scale) Perspective for the Investigation of Energy Storage Materials
Authors: Marschilok Amy C , Takeuchi Kenneth J , Takeuchi Esther S 
Published: February 2020

Overcoming the difference between the usable output of any energy storage systems and its theoretical energy content remains a critical challenge. The inefficiency typically results in the production of waste heat (q) rather than useful work (w). Minimization of inefficiency can be approached through optimization at the macro level, where bulk parameters are identified and varied. One approach to analyze multivariate systems is through optimization, often involving statistical methods such as design of experiments. This is an effective tool when the needed information regarding the parameters affecting the system is known. However, the diversity and intricacies of new and modified battery materials inherently reduce the probability of optimization experiments resulting in marketable products because the detailed operation mechanisms are unknown. Further, optimization will likely not yield insight into the complexities of electric energy storage systems, especially when considering any heterogeneity of ion and electron flux at the numerous interfaces over several scale lengths within a battery. This would require multiple characterization approaches used in concert, to assemble information gathered at the local or atomic level and link it to mesoscale characterization and finally system level performance. Thus, the ability to control and ultimately predict the behavior of complex systems demands not just parameterization at the bulk scale, but rather specific experimentation and understanding over multiple length scales within the same battery system, from the molecular- to the meso-scale through understanding the associated basic science. This presentation will examine insights and implications from multiscale investigations of energy storage related materials.
A Sulfide Solid Electrolyte Surface Layer Formed Via Electrolyte Additives Enables Stable Plating of Li Metal
Authors: Pang Quan , Nazar Linda F 
Published: February 2020

Li metal batteries promise the next-generation rechargeable batteries for electric vehicles applications due to the highest specific capacity (3840 mA h g-1) and lowest reduction potential (−3.04 V vs. S.H.E.) of Li among all alkali and alkaline earth metals. However, a non-uniform solid electrolyte interphase (SEI) layer formed via parasite reactions of Li with the electrolytes leads to locally site-specific Li deposition, i.e., dendritic plating.1 Dynamic breaking and forming of this layer, in turn, leads to the accumulative loss of Li, build-up of the SEI and consumption of the electrolyte causing cell failure. Upon prolonged cycling, penetration of dendrites through the separator causes hazardous cell short-circuits. Modified electrolytes including concentrated electrolytes,2 LiF additive3 and artificial SEI layer4 have shown promise in suppressing dendrites.
In this presentation, we will demonstrate an in-vivo formed sulfide-based ionic conductive layer — realized by using a low concentration complexed electrolyte additive — that not only generates a kinetically favorable interface, but also reduces the corrosive reactions of the electrolyte with Li. Upon Li plating, the high ionic conductivity of the solid electrolyte layer allows the Li+flux to be evenly distributed over the conductive surface. Furthermore, even at extremely high current densities when incipient dendritic Li start to form, the reservoir additives in the electrolyte facilitate local formation of the conductive layer.
Upon resting at OCV, the Li|Li symmetric cell in the presence of the electrolyte additive shows much lower interfacial charge transfer resistance than a cell with a “blank” electrolyte (20 vs. 320 Ω cm-2). Furthermore, the impedance is stable over 2 days of rest, in contrast with significantly increasing impedance exhibited by the blank cell. Greatly improved long-term cycling of the symmetric cells is observed. The cell with additive exhibits extremely stable voltage evolution over 400 hours, whereas the blank electrolyte cell experiences voltage fluctuation followed by short-circuit after 270 hours (Figure 1a). Notably, stable cycling of Li|Li symmetric cells over 2500 hours at 1 mA cm-2 with 1 mA h cm-2 capacity was achieved using 100 mM additive (Figure 1b), and a significant decrease in polymerized solvent is observed compared to a cell with no additive. In a full Li metal cell using Li4Ti5O12 as the positive electrode, the cell with the electrolyte additive exhibits very stable capacity retention (88%) over 400 cycles. Reference

1. Y. S. Cohen, Y. Cohen, D. Aurbach, J. Phys. Chem. B, 2000, 104, 12282-12291.
2. J. Qian, W. A. Henderson, W. Xu, P. Bhattacharya, M. Engelhard, O. Borodin, J.-G. Zhang, Nat. Commun., 2015, 6, 6362.
3. Y. Lu, Z. Tu, L. A. Archer, Nat. Mater., 2014, 13, 961–969.
4. G. Zheng, S. W. Lee, Z. Liang, H.-W. Lee, K. Yan, H. Yao, H. Wang, W. Li, S. Chu, Y. Cui, Nat. Nanotech., 2014, 9, 618–623.

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Electrochemical Studies of Ru+4O2 Reactions with Lithium at Low Voltages
Authors: Yang Yiqun , Williams Jere A. , Arnold Corey L , Douglas Lacey D , Meda Lamartine 
Published: February 2020

Nanostructured pyramidal shape ruthenium oxide (Ru+4O2) was studied electrochemically using cyclic voltammetry (CV) and cyclic charge-discharge (CCD) experiments. The experiments were performed at five different cut-off voltages (4.0 to 1.5, 1.0, 0.80, 0.4, and 0.1 V) versus Li/Li+. CCD experiments performed from 4.0 to 1.5 V and 4.0 to 1.0 V showed a plateau at approximately 2.1 V that corresponds to 100 and 350 mAh g-1, respectively, with no significant formation of solid electrolyte interface (SEI). Insertion and de-insertion of lithium ions in the crystalline lattice of Ru+4O2 were determined to be the dominant mechanism. CV experiments performed in the same voltage range showed a reduction and an oxidation peak at 2.1 and 2.5 V, respectively, that corroborated the CCD experiments. When the cut off voltage was set below 0.80 V, the CV showed two peak currents at ~1.0 V (Ru0/Li2O) and ~0.6 V (SEI) during the first forward potential sweep. The SEI disappeared during the second cycle and beyond. On the other hand, during the reverse potential sweep two peak currents are observed at ~1.2 V and ~2.7 V. The latter represents the oxidation of Ru0 to Ru+4 and the peak at 1.2 V is assigned to the decomposition of the SEI. The CCD experiment revealed a total capacity of approximately 1200 mAh g-1 (~6 Li+ per mol of Ru+4O2), which was determined in the voltage range from 4.0 to 0.1 V. However, the expected capacity is 806 mAh g-1 (4 Li+ per mol of Ru+4O2) as described by the conversion reaction of lithium with Ru+4O2 (Ru+4O2 + 4Li++4e- <--->Ru0 + 2Li2O). Therefore, there is an excess capacity of ~600 mAh g-1. To understand the source of the excess capacity, CCD experiments were performed in the range of 2.0 to 0.1 V vs. Li/Li+ which revealed that the material is behaving as a capacitor. CV experiments performed in the same voltage range supported the CCD experiments. The calculated storage capacity in this range is only 90 mAh g-1. This value is too small to explain the amount of excess capacity observed in this material. The most possible scenario for the excess capacity is pseudo-capacitive and interfacial storage.
Properties of Lithium Phosphorus Oxynitride Films Prepared By Metalorganic Chemical Vapor Deposition Method
Authors: Fujibayashi Takashi , Iwabuchi Katsuhiko , Yoshii Naoki 
Published: February 2020

3D-structured thin-film batteries draw attention to applications like IoT, wearable, and medical devices because of their having non-flammability, electrochemical stability, and flexibility; furthermore, their capacity density can be enhanced by designing the structure, e.g. the aspect ratio (AR) of trench and pillar structures. For realizing 3D-structured batteries with high-capacity density, the step coverage for high AR-patterned structures is a crucial process parameter. In the case of conventional physical vapor deposition (PVD) method, the coverage is not conformal enough to deposit onto a high AR-patterned surface. On the other hand, chemical vapor deposition (CVD) method is attractive to deposit much more conformal films than PVD. In this study, properties of lithium phosphorus oxynitride (LiPON), which is a promising thin-film electrolyte material due to high-chemical stability and nontoxicity, films deposited using metalorganic (MO) CVD are investigated in detail. In this experiment, utilized precursors were lithium tert-butoxide, tris(dimethylamino)phosphine, O2, and NH3. Chemical composition and microstructure of prepared films were evaluated by various analytical methods such as XPS, RBS/NRA, Raman spectroscopy, and XRD. In addition, electrochemical properties of the film were evaluated by AC impedance (Nyquist plot) and cyclic voltammetry methods. Using this MOCVD system, Li4.1PO4.2N0.7 film with 7.5 nm of crystallite size and 5.0 nm/min of deposition rate shows 5.9x10-6 S/cm at 200 nm and 3.3x10-6 S/cm at 50 nm of ionic conductivity, and an excellent step coverage on a patterned substrate is also shown by SEM and EDX (Fig. 1). These results demonstrate the LiPON film deposited by MOCVD would be successfully available for 3D-structured thin-film batteries.

Figure 1
Engineered Current Collector Interface for High Energy Density Li-Ion Batteries
Authors: Ventrapragada Lakshman K , Podila Ramakrishna , Rao Apparao M 
Published: February 2020

Li-ion rechargeable batteries (LIBs) are the most promising candidates for use in electric and hybrid electric vehicles (EVs and HEVs) due to their high operating voltage and superior energy density compared to other conventional batteries such as the Ni-metal hydride battery. To enable cost-effective and long-lasting EVs, DoE estimates that the performance of present battery systems must be improved by at least four times without increasing the cost. LiFePO4 (LFP) emerged as a competitive cathode material for next-generation LIBs due to its remarkable stability and non-toxicity but they suffer from low electrical conductivity. While the addition of carbon improves the in-plane electrical conductivity, it fails to provide a conducting interface between the LFP/C/binder film and the current collector. This interfacial resistance at the current collector and active material interface (CCAMI) is critical for achieving high power density and rate capability but is often neglected. We addressed this issue by engineering the CCAMI with carbon nanotubes (CNTs). Previously, we demonstrated two roll-to-roll binder-free processes for coating Al foils with CNTS: (i) a CVD-based process for directly growing vertically aligned CNTs (VACNTs) on bare kitchen-grade Al foils [1], and (ii) a spray-coating process for coating industrial-grade Al foils with randomly oriented CNTs [2]. The above mentioned processes eliminate the need for a binder and thereby reduce both the dead weight of the inactive material and the CCAMI resistance. Specifically, we found that the VACNTs- or randomly oriented CNTs-coated Al foils obtained via our roll-to-roll processes enhance the areal (/gravimetric) capacity of LFP by >65% (/>50%) at low C-rates (<2 C), and by >85% (>70%) at high C-rates (>2 C). Moreover, the improved CCAMI resulted in gravimetric energy densities up to 360 Wh/kg and power densities up to 200 W/kg with much higher power capability (increased charge capacity at high discharge rates). Thus, this study describes an attractive approach for improved CCAMI, which is scalable and compatible with existing industrial protocols for coating LFP and takes us many steps closer to the commercial deployment of LIBs in HEVs and EVs.
[1] M. R. Arcila-Velez et al., Nano Energy. 8 (2014) 9–16. doi:10.1016/j.nanoen.2014.05.004.
[2] M. Karakaya et al., Appl. Phys. Lett. 105 (2014). doi:10.1063/1.4905153.
Composite Tin Dioxide-Titanium Dioxide Nanostructured Thin Film Electrodes As Lithium-Ion Anodes
Authors: Kacica Clayton Thomas , Wang Louis S. , Chadha Tandeep Singh , Biswas Pratim 
Published: February 2020

An aerosol-chemical vapor deposition technique (ACVD) was utilized in order to deposit highly oriented, one-dimensional nanostructured metal-oxide thin films. Film morphology was controlled using various system parameters in order to obtained the desired columnar morphology. Tin dioxide (SnO2) was chosen as an electrode material due to its high theoretical charge capacity (790 mA-h-g-1), and titanium dioxide (TiO2) was chosen for its remarkable stability and low volume change during charging. The columnar morphology is particularly well suited to SnO2 as the space between the columns allows for accommodation of the large volume expansion the material experiences during charging. Electrodes of SnO2 columnar nanostructures were first synthesized using ACVD by depositing the structures directly on to the current collector. Depositing directly onto the current collector eliminates the need for binding agents and conductive additives during battery fabrication. Then a layer of TiO2 was deposited on the surface of the SnO2 columns using atomic layer deposition. A variety of column heights, ranging from 500 nm to 2 um, and TiO2 layer thickness, ranging from no TiO2 to a 100 nm layer, were synthesized and their electrochemical properties investigated. For all electrochemical characterization experiments, Swagelok-type coin cells were fabricated using lithium foil as a counter electrode and 1M LiPF6 in 50/50 (v/v) EC/DEC as an electrolyte. Optimal electrochemical performance was observed in electrodes with a height of 800 nm and a 15 nm layer of TiO2. A rate capability test was performed to determine how the capacity of the electrodes changed at charging rates ranging from 100-2000 mA-g-1. A stable capacity of 410 mA-h-g-1 was obtained at a charge rate 1000 mA-g-1; rapid capacity fade was observed at higher rates. Galvanostatic charge-discharge was performed for each cell for 100 cycles or until failure at a charge rate of 400 mA-g-1, corresponding approximately to a charge rate of C/2. For the optimal electrode an initial irreversible capacity of 1164 mA-h-g-1 was observed as well as a stable capacity of 530 mA-h-g-1 after 100 cycles. This demonstrates a low cost synthesis of high performance anodes which provides an alternative to conventional electrode synthesis.
Ordered and Disordered Hybrid Tunnel Structured Manganese Oxides for Na-Ion Batteries
Authors: Byles Bryan , Pomerantseva Ekaterina 
Published: February 2020

Through modification of previously developed hydrothermal techniques, we synthesize two tunnel structured manganese oxides with novel hybrid tunnel configurations and investigate their behavior in Na-ion batteries. Tunnel manganese oxides represent a promising class of materials for Na-ion batteries due to their low cost, low toxicity, and high electrochemical activity. The two materials studied in this work contain unique combinations of structural tunnels composed of varying amounts of MnO6 octahedra surrounding stabilizing Na+ ions, resulting in numerous different tunnel dimensions within individual nanostructures. Through cross-sectional TEM analysis, the ordered phase was found to consist of a systematic combination of 2x2, 2x3, and 2x4 octahedra tunnels. The disordered phase, on the other hand, was found to consist of a more random and nonuniform distribution of not only 2xn (n=2, 3, 4, 5, 6) tunnels, but also larger 3x3 octahedra tunnels. Moreover, although both materials were synthesized with a nanowire morphology, the disordered phase is found to be composed of nanowires with smaller diameter.
We investigate these two materials as cathodes for Na-ion batteries and find that upon first discharge, the ordered phase exhibits a capacity nearly 300 mAh g-1, while the disordered phase exhibits a capacity of just below 200 mAh g-1. Upon further cycling, however, the disordered phase maintains a greater amount of its initial capacity, indicating that although the better defined tunnel structure may be advantageous for greater initial ion intercalation capacity, the disordered phase shows a greater degree of electrochemical stability. The rate performance of these two materials is discussed in relationship to the different diffusion pathways present in the materials, as well as the structural stability of the two phases upon repeated ions insertion and deinsertion. The performance of these materials is also compared to tunnel manganese oxides with pure tunnel configurations, and the advantage of having such a hybrid tunnel configuration is also emphasized. This work highlights the performance of two similar novel cathode materials for Na-ion batteries, as well as the relationship between the degree of structural order in manganese oxides and their electrochemical behavior in Na-ion batteries.
Hybrid Cathode of LiFePO4 and Activated Carbon Prepared with a Porous Al Current Collector and Its Battery Performance
Authors: Tsuda Takashi , Gunji Takao , Tanabe Toyokazu , Kaneko Shingo , Ohsaka Takeo , Soma Naohiko , Itagaki Kaoru , Matsumoto Futoshi 
Published: February 2020

In order to improve both energy and power densities while durability of the battery is maintained, a layer of LiFePO4 layer which has characteristic of high energy density is formed on one side of the Al current collector and a layer of activated carbon which has characteristic of high power density were formed on the other side of the Al current. The full cell is constructed with hybrid cathode and graphite anode (Fig. 1). When high current densities are used in the discharging process of the full cell, the discharging reaction occurs mainly at the part of activated carbon in the hybrid cathode. After discharging, Li ions which are doped in the activated carbon move to the LiFePO4 layer (energy transfer from activated carbon to LiFePO4 electrode) until the electrode potentials of the activated carbon and LiFePO4 layers are equal. Therefore, the hybrid cathode can combine both high power and energy densities.
Fig. 1 schematic drawing of a full cell of hybrid cathode/graphite anode.

Figure 1