bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infrared Spectroscopic Study of the Thermal Stability of Alkyl Carbonate Electrolytes
Authors: Porter Jason Morgan , Saqib Najmus 
Published: February 2020

Decomposition of ethylene carbonate (EC) in lithium ion batteries leads to battery swelling, off-gassing, and thermal runaway. Ethylene carbonate decomposes electrochemically by reduction at the anode or chemically in the bulk electrolyte at elevated temperature. The formation of a solid electrolyte interface (SEI) on the anode limits electrochemical decomposition so long as the SEI remains intact. While neat ethylene carbonate is thermally stable at temperatures exceeding 150°C, EC-based electrolytes containing lithium hexafluorophosphate (LiPF6) salt are known to chemically react at temperatures as low as 50°C. Decomposition rate has been shown to increase with higher salt content, indicating a salt-catalyzed thermal decomposition mechanism. Trace contaminants, especially moisture, have also been shown to strongly effect electrolyte thermal stability. Thus, small impurities in the manufacture of battery components can have dramatic effect on electrolyte stability and battery aging.
Electrolyte decomposition mechanisms have been studied extensively. Differential scanning calorimetry (DSC) and accelerated rate calorimetry (ARC) can identify temperatures of reactions, kinetic parameters, and heat release rates. Decomposition mechanisms and reaction products are also identified indirectly by ex situ electrolyte and off-gas analysis. Despite numerous studies, much remains unknown about decomposition chemistry in lithium ion batteries, especially the role of trace impurities on stability. Further, little is known about electrolyte decomposition mechanisms in batteries, as few operando electrolyte diagnostics exist.
In this work, the chemical stability of EC at elevated temperature is studied using infrared spectroscopy. Electrolyte samples are heated on an attenuated total reflection (ATR) spectrometer stage using both liquid samples and in operating half and full cell batteries. Liquid samples were prepared in an argon glove box with varying concentrations of LiPF6 salt, H2O, and in CO2 gas environments (to simulate cathode off-gassing). Accurate temperature readings up to 150°C were made using infrared thermometry. Operando spectroscopic measurements of electrolyte stability in graphite half cells, lithium cobalt oxide (LiCoO2) half cells, and lithium ion full cells were also collected. Reaction rates and activation energies are also reported using time-resolved infrared spectroscopy.
(Invited) Thermal Runaway Propagation Resistance in Lithium-Ion Batteries
Authors: Srinivasan Rengaswamy , Thomas Michael E , Airola Marc B. , Carkhuff Bliss G , Frizzell-Makowski Linda J. , Alkandry Hicham , Reuster James G. , Oguz Hasan N. , Green Peter W , Demirev Plamen A , Currano Luke J. 
Published: February 2020

Thermal runaway (TR) is a commonly-known mode of failure in lithium-ion (Li-ion) cells. TR generates large amounts of heat and fire as well as toxic gases that are potentially destructive. A Li-ion battery consists of multiple cells in which TR from a single cell could propagate creating cascading failures across multiple cells, generating high-energy shrapnel and a large quantity of toxic and corrosive materials. TR propagating between cells in multi-cell batteries causes more destruction than TR in a single-cell battery, the most striking examples being electric vehicle batteries in which fires are typically much larger than fires in single-cell mobile phones.
Conventional understanding of TR propagation has been limited to the perception that heat generated from a cell under TR is carried to the adjacent cells: a.) predominantly by ejected high-temperature gases and solids; and b.) to a lesser degree by conduction through metallic parts within the battery such as cell interconnects. If the conventional understanding is correct, then removing/venting the high-temperature gases and solids ejected at the time of TR from the battery compartment will primarily prevent cell-to-cell TR propagation. In fact, although batteries have been designed with vents that provide opportunity for hot matter to exhaust away from the rest of the cells, they have not successfully prevented TR propagation. In other words, the conventional model used in describing TR propagation needs to be revised.
We recently observed by infrared spectroscopy that when a cell temperature rises, but before the start of TR, flammable organic compounds such as carbonate esters are ejected from the cell. This observation sheds new light on the thermal propagation processes in multi-cell Li-ion batteries. The ester is ejected as a gas through vent valves in the cell, and it condenses outside the cell which is evident in its absorption spectra. Although the ester can be highly flammable (similar to gasoline), it requires a spark to ignite and an oxidizer to burn. If either is missing, the ester is deposited on adjacent cells, either as a liquid or a mixture of liquid and trapped gas, and is not vented out of the battery housing. The condensation of esters on adjacent cells is supported both by experimental data and computational fluid dynamics models. When the cell goes into TR, both ignition spark and oxidizers are present, which ignites the ester. The ester starts burning on the surface of the adjacent cells, sending them also into TR. This finding ultimately has implications for innovative technical solutions aimed at preventing large multi-cell battery fires.
Inhibiting Thermal Runaway in Large Format Li-Ion Batteries
Authors: Torres Gabriel , Moganty Surya Sekhar 
Published: February 2020

NOHMs Technologies is developing novel safe solvent hybrid electrolytes for safe, high energy density, high voltage, and high-power lithium-ion batteries for mobility and consumer applications. Over the past 25 years there has been a proliferation in the use of lithium ion technology and with that ever-increasing market demand for higher energy density cells – demand primarily met by advancements in the cathode and anode. This proliferation has come with the increased rise of safety concerns. There have been high profile incidents of what is known as thermal runaway across a wide variety of applications ranging from consumer electronics to electric vehicles.
It is well understood that thermal runaway occurs when the self-heating rate in the cell exceeds the heat dissipation out of the cell. This self-heating is the product of undesired side-reactions in the cell which are onset by abuse conditions such as excess heat, internal short circuits, etc. The key to inhibiting thermal runaway is to modify the cell such that the self-heating rate under abuse conditions is significantly reduced. Reducing the self-heating rate is important when considering battery packs that consist of many cells as is the case in electric vehicles, so that if one cell fails in a pack the thermal runaway does not propagate to adjacent cells. Given that market trends are moving away from low energy electrodes, our approach therefore is to modify the electrolyte system to reduce the overall cell self-heating rate. This is a tunable, drop-in solution to addressing the need for improving battery safety.
The incorporation of NOHMs novel safe solvents into the electrolyte formulation is shown to impact the abuse tolerance of cells on both the material level, i.e. the electrolyte-electrode interaction and on the cell level. The presented electrolyte systems demonstrate reduced overall energy and peak heat flow in the exotherm profiles of high-nickel cathode materials as well as lithiated graphite via differential scanning calorimetry (DSC). With this approach, we demonstrate significantly lower self-heating rates in an accelerating rate calorimeter (ARC) heat-wait-seek test on 30 Ah and above high-nickel cathode lithium ion cells. Combined with good rate capability and cycle life NOHMs’ novel safe solvents present an improvement in battery safety without compromising battery performance. This approach carries significance in not just safer individual cells but also in safer overall battery packs.
Early Warning of Thermal Runaway for Lithium-Ion Battery Based on Multi-Sensor Detection
Authors: Pan Yue , Feng Xuning , Lu Languang , Ouyang Minggao 
Published: February 2020

The expansion of the electric vehicle market, giving credit to the technical breakthroughs in the energy density and cycle life of lithium-ion batteries, is beyond our expectations. However, the lithium-ion batteries with high energy density still suffers from safety problems, such as thermal runaway. Thermal runaway always occurs with fire and explosion, which threatens human lives and properties. It is essential to make early warning before the triggering of battery thermal runaway happens.
In this study, an online fault-diagnosis algorithm that can be used for the early warning of thermal runaway is proposed based on joint information measured by multiple sensors. A set of sensors, including voltage, temperature, flammable gas and pressure, are used to monitor the direct and indirect features of thermal runaway. Figure 1 shows the scheme of the proposed fault-diagnosis algorithm, including five steps that explain how this algorithm makes decision of warning. Step I is for data collection, while the data are acquired from the thermal runaway tests. Step II is for data screening. The average temperature, average voltage, maximum temperature and minimum voltage are obtained for further data processing. Step III is for the difference calculation. The voltage difference and temperature difference are calculated. Step IV is called the fault level transformation. The continuous deviations and the continuous signals of gas sensor and pressure sensor are transformed into discretized fault levels. Step V is for the fault judgement. The overall fault level is calculated by merging all the fault levels. The thermal runaway can be captured by setting proper threshold to judge the overall fault level.
To confirm that the algorithm is capable of detecting thermal runaway before it develops into a severe hazard, thermal runaway tests on commercial 18650 cells were conducted. A customized transparent PMMA box, which has comparable volume of the module of Tesla Model S, is designed as the experimental vessel. Battery cells, which have the identical cell number of one Tesla module, are placed in the vessel. Thermal runaway is triggered by heating one of the cells. Sensors are placed in different locations of the vessel to find the optimal location. The test results validate the warning algorithm, and will be presented at the conference.
Acknowledgement: This research is supported by the National Natural Science Foundation of China under the Grant No. U1564205 and No.51706117, and funded by the Ministry of Science and Technology of China under the Grant No. 2016YFE0102200.
Figure 1. The scheme of the proposed fault diagnosis algorithm for TR warning.

Figure 1
Characterization of Double-Stranded DNA on Single-Walled Carbon Nanotubes (SWCNTs)
Authors: Wu Shang-Jung , Schuergers Nils , Lin Kun-Han , Gillen Alice Judith , Corminboeuf Clemence , Boghossian Ardemis Anoush 
Published: February 2020

DNA has been extensively studied due to its versatility as a dispersant of SWCNTs. The specificity and binding affinity of DNA to various analytes has been shown to be strongly sequence dependent. As a result, through modifications of the nucleotide sequence, the DNA conformation on the SWCNT surface can be tailored to suit specific needs for techniques such as single-molecule detection, in vivo imaging, and chirality separation. To date, the majority of research has focused on the interaction between single-stranded DNA and SWCNT surface, with less focus on the nature of the interaction between double-stranded DNA (dsDNA) and SWCNTs. As a result, the exact interaction mechanism governing this type of complex remains strongly debated and largely unknown.
In this study, we employ various biochemical methods to infer the conformation of dsDNA on the surface of SWCNTs. Our methods are based on imaging techniques for identifying DNA-modifying enzyme activity in the presence of dsDNA-SWCNT complexes. Our findings suggest that dsDNA can partially retain its native conformation on the SWCNT surface, and the degree of dsDNA accessibility is strongly sequence dependent. These findings offer new possibilities for SWCNT sensing applications that employ dsDNA, such as the optical detection of DNA-protein interactions.
(Invited) Single Luminescent Carbon Nanotubes Interrogate the Live Brain Extracellular Space at the Nanoscale
Authors: Cognet Laurent 
Published: February 2020

The extracellular space (ECS) of the brain represents up to a fifth of brain volume with an undisclosed complex miniaturized topology. While it has long been seen as a passive brain area, it however constitutes an important signaling region for the development, function and communication of neuronal and glial cells. Interestingly, we have identified luminescent single wall carbon nanotubes, as unique nanoreporters to probe the brain extracellular space. This comes from their unique morphological and near-infrared optical properties, which are now well established but also provide a rich platform for improvements. We used super-localization imaging and single particle tracking of luminescent carbon nanotubes to interrogate the local ECS architecture in live brain tissue at the nanoscale[1-3]. In particular, the interplay between the nanotube geometry and the extracellular space local environment allows extracting information about the ECS local viscosity [1, 4]. In this presentation our recent results about the specific ECS properties near identified brain structures [5] (e.g synapses) and in neurodegenerative disease animal models [6] will also be presented.

References

[1] Godin et al Nat. Nanotechnol. 12 (2017) 238-243.
[2] Gao, et al, Nanomaterials 7, 11, (2017) 393.
[3] Danné et al ACS Photonics, 5, 2, (2018) 359-364
[4] Danné et al in preparation
[5] Paviolo et al in preparation
[6] Soria et al in preparation
(Invited) Biological Multiphoton Imaging Techniques for Tracking Non-Fluorescent Carbon Nanomaterials
Authors: Corr Stuart James , Kakadiaris Eugenia , McDOWELL Meredith , Lewis Eric , Sonka Theresa , Anderson Andrew , Marti Angel , Wilson Lon J. 
Published: February 2020

Multiphoton Microscopy (MPM) has enabled an unprecedented level of dynamic exploration within living cells and organisms. The physical principle behind this imaging technique involves the use of near-infrared femtosecond lasers to excite optical processes in fluorescent molecules using two or more photons1. The use of long wavelengths (700 nm – 1000 nm) enables deep tissue penetration (up to 1000 μm) without inducing harmful biological effects. Previous studies include the examination of membrane potentials on the single-molecule scale2, the non-invasive observation of embryo development3, and the simultaneous multiplane imaging of calcium transportation in transgenic mice4. An excellent review of this field can be found in the literature5.
Herein we demonstrate a novel multiphoton-based technique for imaging negligible-to-non-fluorescent
carbon-based nanomaterials such as C60 fullerenes, single-walled carbon nanotubes, and graphene, which usually can only be imaged by conjugation of specific fluorescent tracers thereby altering their inherent dynamics within biological systems. More specifically, we demonstrate optical and photoluminescent activity in water-soluble C60-serinol, highly enriched (95 %) metallic and semiconducting single-walled carbon nanotubes, and graphene. This multiphoton imaging technique was also applied to in vitro and in vivo animal model studies. Various concentrations of the above-mentioned nanomaterials were given to human pancreatic ductal adenocarcinoma (Panc-1) and hepatocellular carcinoma (Heb3B) cancer cell lines, as well as normal, healthy pancreatic ductal epithelial cells (HPDE). In all cases, imaging of these nanomaterials was possible using the MP imaging technique even though the nanomaterials exhibit weak, almost zero inherent fluorescent properties. We also examined the ability to image these nanomaterials, real-time, in vivo, using mice with orthotopic 4T1 breast tumors. Finally, we also include a range of spectroscopy data to examine the specific optical characteristics of the carbon nanomaterials.

References

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Peleg, G.; Lewis, A.; Linial, M.; Loew, L. M. Proceedings of the National Academy of Sciences
1999, 96, (12), 6700-6704.

Chu, S.-W.; Chen, S.-Y.; Tsai, T.-H.; Liu, T.-M.; Lin, C.-Y.; Tsai, H.-J.; Sun, C.-K. Opt. Express
2003, 11, (23), 3093-3099.

Cheng, A.; Goncalves, J. T.; Golshani, P.; Arisaka, K.; Portera-Cailliau, C. Nat Meth
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Hoover, E. E.; Squier, J. A. Nat Photon
2013, 7, (2), 93-101.
Brightening of Long, Polymer-Wrapped Carbon Nanotubes By Large Scale sp3
Functionalization
Authors: Berger Felix Julian , Lüttgens Jan Matthias , Zaumseil Jana 
Published: February 2020

Networks of long, polymer-sorted semiconducting single-walled carbon nanotubes (SWNTs) show excellent transport of both electrons and holes and are thus perfectly suited for electrically-driven light emission in the near-infrared (NIR) [1,2]. So far, their application in near-infrared light-emitting devices has been hampered by their low photoluminescence quantum yield (PLQY) and strong self-absorption owing to their small Stokes shift. In recent years, the controlled introduction of a low density of sp3
defects as exciton trapping sites was shown to lead to red-shifted emission with longer exciton lifetimes and improved PLQYs. However, due to the polarity of the employed diazonium salt reagent, this approach was limited to aqueous dispersions of SWNTs with often short tube lengths and the undesired presence of stabilizers. Here, we present a novel route to sp3
functionalization with diazonium salts in organic, non-halogenated solvents, thereby making it compatible with polymer-wrapped long SWNTs produced by shear force mixing. As a result of the low density of exciton quenching sites on shear mixed SWNTs [3], the excitons are efficiently channeled to the emissive defect sites, leading to absolute PLQYs of 4 % for functionalized (6,5) SWNT dispersions in toluene. This new method paves the way toward the large scale production of high-quality sp3
functionalized SWNTs and hence also thin films for optoelectronic devices with narrowband near-infrared emission.
[1] Rother et al., ACS Appl.
Mater. Interfaces
2016, 8, 5571-5579.
[2] Brohmann et al., J. Phys. Chem. C
2018, 122, 19886-19896.
[3] Graf et al., Carbon
2016, 105, 593-599.

Figure 1
Synthesis and Metrology for Large-Area Applications of Single-Wall Carbon Nanotube Forests
Authors: Meshot Eric , Park Sei Jin , Buchsbaum Steven , Wu Kuang Jen , Fornasiero Francesco 
Published: February 2020

Commercial applications of vertically aligned single-wall carbon nanotube (SWCNT) “forests” are on the horizon, with the emergence of their use in nanocomposite membranes,1 electronic interconnects, thermal interface materials, among other promising demonstrations. To realize these potential applications, we sought to not only design reproducible wafer-scale synthesis of high-density SWCNT forests but also to establish advanced metrology to enable quantitative, large-area mapping of several key forest characteristics. This detailed information will unlock better understanding of interdependent correlations among the characteristics and how these correlations inform SWCNT forest growth mechanisms toward enhanced synthetic control.
We performed low-pressure chemical vapor deposition (CVD) on 4-in. Si wafers in an AIXTRON® Black Magic cold-wall furnace. The combination of a low flux of carbon precursors with sub-nm Fe/Mo catalyst films on alumina-coated Si wafers maintained small-diameter SWCNTs (mean as small at 1.87 nm) with number densities up to 2.2 x1012 cm-2. Although removing Mo resulted in categorically larger CNT diameters and lower densities (< 0.9 x1012 cm-2), the mass conversion rate from C2H2 to SWCNT product was essentially constant (~1.2 x106 % g catalyst-1) for all catalyst compositions and CNT densities. These results corroborate the notion that hydrocarbon dissociation may be thermally driven without assistance from the catalyst under these conditions, and that the role of Mo was primarily a physical one in creating smaller, denser SWCNTs. Furthermore, we leveraged a suite of advanced characterization techniques to generate area maps across a 4-in wafer to visualize and evaluate the uniformity of various forest properties, including Raman microscopy (forest height, graphitization level, diameters), synchrotron X-ray scattering (mean diameter),2 and Rutherford backscattering spectroscopy (forest density). The uniformity and coupled correlations among different structural characteristics (e.g., diameter-density, rate-density) within a single wafer were consistent with those observed for multiple wafers grown by sequential runs (up to 5 in a day). This validates the reproducibility of our process and suggests that these correlations may be more universal phenomena.
Lastly, our developments in synthesis represent to our knowledge best-in-class co-optimization of small-diameter, high-density, and large-area SWCNT forest growth. We will briefly discuss growth benchmarks in context of membranes, electrochemical devices, and antireflective surfaces as examples.

Bui, N.; Meshot, E. R.; Kim, S.; Peña, J.; Gibson, P. W.; Wu, K. J.; Fornasiero, F. Advanced Materials
2016,
28 (28), 5871-5877.

Meshot, E.; Zwissler, D. W.; Bui, N.; Kuykendall, T. R.; Wang, C.; Hexemer, A.; Wu, K. J. J.; Fornasiero, F. ACS Nano
2017, 11 (6), 5405-5416.
The Impact of Exposed Surface Area on the Response of SWCNT Optical Sensors
Authors: Gillen Alice Judith , Siefman Daniel Jerome , Wu Shang-Jung , Bourmaud Claire , Lambert Benjamin Paul , Boghossian Ardemis Anoush 
Published: February 2020

Due to their distinct and advantageous fluorescence properties, semiconducting single-walled carbon nanotubes (SWCNTs) are being applied to a variety of optical sensing applications. Limitations in solubility and biocompatibility have been overcome by non-covalently functionalizing the surface of the SWCNT with wrappings using techniques that retain its inherent fluorescence. Though wrappings based on surfactants and single-stranded DNA (ssDNA) have been extensively studied for this purpose, they are limited by factors such as lack of selectivity and lower fluorescence quantum yield, respectively.
In this study, we take advantage of the higher fluorescence emission of surfactant-coated SWCNTs and focus on new approaches that can tune their selectivity as sensors. Through the concomitant monitoring of both the fluorescence intensity and wavelength position of emission peaks, we demonstrate the ability to increase the selectivity of sensors based on surfactant-suspended SWCNTs while retaining their higher fluorescence intensity. These results provide not only a promising avenue for rationally designing SWCNT sensors, but also insight on the mechanisms governing the selectivity of existing SWCNT-based optical sensors.