bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of an on-Demand Internal Short Circuit (NREL/NASA)
Authors: Keyser Matthew , Pesaran Ahmad , Darcy Eric 
Published: February 2020

NREL, in conjunction with NASA, has developed an internal short circuit (ISC) device that can be placed anywhere within the battery and may be used with both spirally wound and flat-plate cells. The internal short device is small compared to other shorting techniques being developed by industry and does not rely on mechanical pressure deforming the battery to activate the short as do most of the other “internal shorts” being developed. The battery can be used and cycled within normal operating conditions without activating the internal short device. This allows for the battery to be aged prior to activation of the internal short. Another unique feature of NREL’s internal short device is that the resistance of the short can be tuned to simulate a hard (more energetic) or soft (less energetic) short. Once the short is activated, the positive and negative components of the battery are internally connected within the cell and internal short circuit begins. NREL’s ISC can simulate all four types of shorts within a cell – collector to collector, collector to anode, collector to cathode and collector to collector.
NREL uses the internal short circuit device to better understand the failure modes of Li-ion cells and to validate NREL’s abuse models. The internal short produced by NREL’s device is consistent and is being developed as an analysis tool for battery manufacturers and other national laboratories as well as OEMs. This has broad-reaching applications as automakers bring electrified vehicles to market in larger
Over the past three years, NREL has implanted their ISC into cylindrical 18650 LiCoO2 cells to determine the effectiveness of a shutdown separator with regards to ISC type – in particular, we compared a collector to collector ISC versus a collector to aluminum ISC. NREL has also been using the ISC to determine the effectiveness of a non-flammable electrolyte in LiMnO4 pouch cells. During our presentation, we will update the battery community on the effectiveness of the ISC in understanding the behavior of these safety devices incorporated into these two cell types and chemistries. We will also show how the ISC can be used for propogation testing in modules and packs.
Measurement of Energy Distributed Between Cell Mass and Hot Ejecta during Thermal Runaway of Lithium Ion Cells at Varying State of Charge
Authors: Yayathi Sandeep , Doughty D. H. , Walker William Q. 
Published: February 2020

Thermal runaway propagation is a major concern in battery packs constructed with large numbers of small lithium ion cells. This is especially true for battery applications involving manned space flight.
This work by NASA presents a scientific study that evaluates the thermal energy release of these cells during thermal runaway. Specifically, these experiments compare, as function of state of charge, the energy retained in the cell mass versus energy released in ejected materials and hot gasses. In addition, this study evaluates the effect of state of charge on thermal stability, including onset of self-heating and thermal runaway temperature for three types of commercial cells.
Tests are conducted utilizing accelerating rate calorimeter (ARC) equipment using a heat wait seek heating algorithm combined with unique cell containment fixtures and properly placed thermal sensors to allow the aforementioned energy calculations. This work seeks to inform the development of thermal abuse models and aid the engineering design and development of non-propagating battery pack designs utilizing small lithium ion cells.
Low-Cost Synthetic Routes for Fabricating Tandem/Multi-Junction Photoelectrochemical Devices
Authors: Cheng Wei , Rassoolkhani Alan M , Mubeen Syed 
Published: February 2020

Using sunlight to convert widely available and inexpensive feed stocks such as water, CO2, and industrial wastes (including halogenides) reliably to fuels and value added chemicals, efficiently and cost-effectively, has been, and continues to be a major goal. Most such reactions require a minimum of 1eV or more photon energies. For example, the minimum free energy required to split water reversibly is 1.23 eV. However, kinetic limitations and other sources of inefficiencies (for example, water oxidation on photoanodes is kinetically sluggish, and CO2 reduction at photocathodes needs high overpotentials) make the practical energy needed to carry such reactions even considerably higher. A single-junction photosynthetic device would therefore need to base on a semiconductor with a band gap (Eg) > 2.5 eV for it to carry out water splitting or CO2 reduction, precluding the exploitation of a substantial portion of the solar spectrum. Using tandem/multi-junction photovoltaic architectures is an attractive strategy to overcome these limitations. Such strategies have been estimated to be capable of achieving ~18% solar-to-hydrogen conversion efficiencies. John Turner and his colleagues [1] demonstrated a solar-to-H2 conversion efficiency of 12.4% using multi-junction III-V semiconductors in 1990’s. However, the high cost and complexity associated with device fabrication using Si and III-V semiconductors to produce triple junction devices have impeded commercialization. Here, we report a novel and low-cost wet chemical synthesis route to fabricate a tandem junction PEC device through direct deposition of inexpensive and efficient metal oxide/sulfide based photoanodes on single junction Si solar cells which act as photocathodes. The above structures were able to generate sufficiently high cell voltages to drive valuable, and, at times, challenging photoelectrochemical processes sustainably.
Reference:

Khaselev, O. & Turner, J. A monolithic photovoltaic-photoelectrochemical device for hydrogen production via water splitting. Science (New York, N.Y.) 280, 425–7 (1998).
VOC Gas Sensors Fabricated with Graphene Oxide Composites for Food Safety and Quality
Authors: Park Hyejin , Lee Eunji , Chung Yoonsung , Lee Seokhee , KIM Dong-Joo 
Published: February 2020

For food market, off-odors or flavors have become more than a quality issue with the increased awareness of food safety problems. This awareness to solve the safety problems, off-odor detection in foods, packaging materials, and their interactions involving scalping or other flavor system modification have been attracted. One of suggested methods is to use an electronic nose consisting of a gas sensor array to detect the volatile organic compounds (VOCs), released from foods as a byproduct of everyday physiological processes. Monitoring of the specific VOCs by a gas sensor can provide the information on both crop and field conditions. The array structure of gas sensors can enhance selectivity for in-situ detection [1, 2].
In this study, an array of sensors is investigated by employing graphene oxide and nanostructured metal oxide based on SnO2. Their composite films on a series of electrodes are prepared to create a high density of sensing array in a small size chip. A composition gradient sensing layers can produce unique gas response patterns. Figure 1 shows surface morphology of compositionally gradient tin oxides (1:6 ratio of GO to SnO2) and structure property confirmed by XRD result. The results on the growth of nanostructured films using solution process and vacuum process are presented. Figure 2 also shows sensing properties of the composites to formaldehyde gas at room temperature. The combinatorial structure enhances the sensing properties of devices in terms of sensitivity, selectivity and response rate. Additionally, such a sensor can meet the proposed idea, in-situ detection, and also the requirements for low-cost and high-volume production as well as high gas analytical performance.
This research was partially supported by a grant from a Strategic Research Project (2013-0132) funded by the Korea Institute of Construction Technology, and Auburn University IGP.

[1] A. D. Wilson and M. Baietto. Sensors. 2009, 9:5099-5148.

[2] K. Arshak, E. Moore, G. M. Lyons, J. Harris, and S. Clifford. Sensor Review. 2004, 24(2):181-198.

Figure 1
Manipulation of Nanoscale 3 Dimensional Architecture: Graphitic Carbon/Nickel Core-Shell Structured Nanoparticles Dispersed on Carbon Black Support
Authors: Na Hyunwoong , Oh JI-Won , Cho Yong Soo , Choi Hanshin 
Published: February 2020

Graphitic carbon and nickel core-shell structured nanoparticle was designed as a high surface area carbon with enhanced crystallinity and it was achieved by facile synthetic route. Nickel nanoparticle was directly deposited on mechanically agitating carbon black nanoparticle. After that, Ni/C was heated at high temperature and then cooled to room temperature. As a result, graphitic carbon layer covered Ni nanoparticles dispersed on carbon nanoparticle was obtained. In the suggested synthetic route, Ni acted as carbon transporter from support carbon black to surface graphite and also catalyst for graphitic layer on Ni surface by dissolution-precipitation reaction. Morphological evolution from the carbon black nanoparticle to graphitic carbon and nickel core-shell nanoparticle was shown. In addition, phase change of cored nickel nanoparticle and thickness of newly precipitated graphitic carbon layer were investigated. This study was focused on the validation for the particle design and however, it could be deduced that morphology and crystallinity of GC/Ni core-shell nanoparticle are manipulated by Ni content and heat treatment temperature.
Formulation of Ionic Liquid Electrolyte to Expand the Voltage Window of Supercapacitors
Authors: Van Aken Katherine L , Beidaghi Majid , Gogotsi Yury 
Published: February 2020

While their high-power performance exceeds that of batteries, supercapacitors lack the energy density capability for some energy storage applications. Since the energy density of the device is proportional to the square of operating potential window (OPW), an effective way to increase the energy density of the device is by increasing the potential window. Ionic liquid electrolytes are beneficial for this reason since they can theoretically operate at up to 6 V, though experimentally, this value is between 3-4 V depending on the properties of electrode materials. By employing a novel electrochemical technique to analyze symmetric supercapacitors of carbon electrodes and ionic liquid electrolytes, we have found one of the possible reasons for smaller OPWs of ionic liquids in practical applications.1 We observed that for a symmetric device with electrodes equal in size and weight, the different properties of cations and anions in the electrolyte results in an asymmetric performance of the two similar electrodes. By performing a systematic study with ionic liquid electrolytes and model electrode materials, we show that a symmetric behavior of the electrodes can be achieved by formulating an ionic liquid mixture containing different cations and anions. In our model electrochemical device, onion like carbon (OLC) was used to fabricate the device electrodes and two ionic liquids, EMI-TFSI and EMI-BF4, and their mixtures were used as electrolytes. This electrolyte mixing results in an extended OPW of the device and a higher energy density.
1. Van Aken, K. L., Beidaghi, M. & Gogotsi, Y. Formulation of Ionic-Liquid Electrolyte to Expand the Voltage Window of Supercapacitors. Angew. Chemie
127, 4888–4891 (2015).
Activated Graphene-Derived Porous Carbon with Exceptional Gas Adsorption Properties
Authors: Ganesan Aswathi , Shaijumon Manikoth M 
Published: February 2020

Designing nanoporous materials with high surface area, large porosity, superior structural stability and amenability to various processing conditions, is important to meet the commercial demands of large-scale reversible gas storage systems.[1, 2] Carbonaceous porous materials are particularly interesting in this respect, due to its fascinating properties, which include high surface area, high amenability to pore structure modification and surface functionalization, relative ease of regeneration, high thermal stability etc.[3,4] Here, we demonstrate a simple approach to synthesize a highly porous activated graphene- derived carbon (a-GDC), with ultra-high surface area (~ 3240 m2g-1) and enhanced porosity characteristics, from thermally exfoliated graphite oxide (TEGO), through an efficient and finely controlled KOH chemical activation process. Various experimental techniques including Fourier Transform-Infrared spectroscopy, High resolution Transmission Electron Microscopy and Pore size analyser are employed to characterize the materials. Detailed studies on the gas adsorption behaviour of a-GDCs have been performed at different temperatures and pressures using a volumetric gas analyser. Highly interconnected network of micro and mesopores present in a-GDC acts as active sites for adsorption of different gas molecules and outstanding gas uptake values of 21.1 mmolg-1 (298 K, 20 bar), 11.3 mmolg-1 (298 K, 35 bar) and 3.8 wt% (77 K, 10 bar) are obtained respectively for CO2, CH4 and H2, superior to several of the other high surface area nanoporous carbon materials reported so far.[5,6] A comprehensive comparison on the gas adsorption potential of a-GDCs with the existing previous reports on similar and other porous materials (MOFs, COFs etc ) is also presented. In addition, good kinetics of adsorption/desorption and moderate values of heat of adsorption obtained for the a-GDC samples are particularly interesting, while its large scale commercial applications are considered. The results will draw considerable attention towards developing such materials from other cheap and easily available carbon precursors, for more effective greenhouse gas capture and gas storage applications

References

R. E. Morris and P. S. Wheatley, Angew. Chem. Int. Ed., 2008, 47, 4966-4981.

A. Stein, Adv. Mater., 2003, 15, 763-775.

J. Lee, J. Kim and T. Hyeon, Adv. Mater., 2006, 18, 2073-2094.

H. Marsh and F. Rodriquez-Reinoso, Activated carbon, Elsevier, Amsterdam, 2006

S. Himeno, T. Komatsu and S. Fujita, J. Chem. Eng. Data, 2005, 50, 369-376.

G. Srinivas, J. Burress and T. Yildirim, Energy Environ. Sci., 2012, 5, 6453-6459.

Figure 1
Anion Conductive Multiblock Copolymers with Long Side Chains for AEM Fuel Cells
Authors: Liu Lisha , Ahlfield John M. , Kohl Paul A 
Published: February 2020

Anion Exchange Membrane (AEM) fuel cells are a possible route to overcoming fundamental issues with acid-based fuel cells. The issues include the high cost of platinum catalysts, complex water transport, and sluggish electrochemical reactions, etc. However, the performance of AEM fuel cells is not as good as that of Proton Exchange Membrane (PEM) fuel cells because of the limitations of current anion exchange membranes, such as low ionic conductivity, poor stability at high pH, and high water uptake.
A series of novel multiblock copoly(arylene ether)s with long side chains were synthesized for AEM fuel cells. The multiblock copolymers were synthesized by polycondensation of separately-prepared hydroxyl-terminated oligomers with fluoro-terminated oligomers. The resulting multiblock structure, in which one block is hydrophilic and one block is hydrophobic, was designed to ensure a nanophase-separated morphology. Multiblock copolymers with different block lengths and ion exchange capacities (IEC) were synthesized to maximize ion conductivity and explore the relationship between chemical structures and properties in anion exchange membranes. Furthermore, copolymers with long side chains exhibited higher stability in high pH environment than their counterparts without long side chains. The degradation mechanism was also studied for the long side chain block copolymers.
Financial support from US Office of the Deputy Assistant Secretary of the Army for Defense Exports and Cooperation (DASA-DE&C) is gratefully acknowledged.
A New Silica-Based Anode Using Three-Dimensional Nanostructured Copper As a Current Collector for Lithium Ion Batteries
Authors: Ara Ryota , Arai Susumu 
Published: February 2020

Introduction

Lithium ion batteries are widely used high energy density rechargeable energy storage devices, but there is great demand for batteries with higher energy densities. Consequently, new electrodes (or active materials) with improved capacities have been developed to replace current electrodes. Silicon and silica are promising candidates to replace the conventional graphite anode since their theoretical capacities (4200 mAhg-1 and 1965 mAhg-1, respectively 1)) are high compared to that of graphite (372 mAhg-1). Unfortunately, these active materials exhibit low cyclability due to degradation and separation of the silicon and silica from the current collector, caused by volumetric changes during alloying/de-alloying with lithium ions. Nanosized active materials have been examined as a means of mitigating this effect, and a three-dimensional (3D) network current collector has also been investigated to enhance the cyclability of lithium ion batteries using a silicon-based anode2). We previously reported a new and simple method of fabricating a 3D nanostructured copper layer by electrodeposition3).
Herein, we propose 3D nanostructured copper as a current collector using silica nanoparticles as the anode material for lithium ion batteries

Experimental

The composition of the 3D nanostructured copper plating bath was 0.85 M CuSO4{0.55 M H2SO4+3´10-4M polyacrylic acid (M.W. 5000). Electrodeposition was carried out under galvanostatic conditions at 25°C. A pure copper plate and a phosphorous copper plate were used as the cathode and anode, respectively. Silica nanoparticles were synthesized by the sol-gel method. 3D nanostructured copper was immersed into a solution of ethanol and tetraethyl orthosilicate. Ammonia water was added to this solution and silica nanoparticles were fabricated on/in the 3D nanostructured copper layer.
Electrochemical studies of the fabricated anode were carried out with coin cells assembled in an Ar-filled glove box. Each coin cell consisted of lithium foil as the counter and reference electrode and the fabricated anode as the working electrode. The electrolyte was 1 M LiPF6 in ethylene carbonate (EC) and diethyl carbonate (DEC) (1:1 vol%). Cycling tests were performed between 0 - 3 V (vs. Li/Li+) at a constant temperature of 25°C.

Results and Discussion

Figure 1 presents a cross-sectional SEM image of the fabricated anode and clearly shows uniform 200-300 nm diameter silica nanoparticles inside the 3D nanostructured copper layer.
Charge-discharge without conductive additive and binder was confirmed. The electrochemical performance of the anode will be discussed in detail at the meeting.

References

1)Young-Kuk Kim*, Jong-Woo Moon, Jung-Goo Lee, Youn-Kyung Baek, Seong-Hyun Hong, Journal of Power Sources, 272(2014) 689-695
2)Y. Liu, K. Huang, Y. Fan, Q. Zhang, F. Sun, T. Gao, L. Yang, J. Zhong, Electrochimica Acta, 88(2013) 766.
3) S. Arai, T. Kitamura, ECS Electrochemistry Letters,
3(5) (2014) D7.

Figure 1
Durability Study of Double Perovskite Cathode Materials for Intermediate Temperature-Solid Oxide Fuel Cells
Authors: Yang Ja-Yoon , Park Jun-Young 
Published: February 2020

Solid oxide fuel cells (SOFCs) are the electrochemical power generation devices that convert chemical energy into electrical energy directly, providing several advantages of fuel flexibility, low pollutant emission, environmental friendliness, high power density, and high efficiency. Recently, the long-term durability has been major concerns for making commercialization of SOFC systems. One of methods to mitigate these issues is to decrease the high operation temperature to the low or intermediate temperature through the use of advanced electrolytes and electrodes. Lower operating temperature is possibly able to enhance stability and economic feasibility of SOFCs. In this work, hence, we investigate the durability of Ni-cermet anode-supported neodymium-doped ceria (Nd0.1Ce0.9O2-δ, NDC) electrolyte cells at the practical SOFC operating condition of 650 oC. In addition, double perovskite structure-based materials are considered as the candidate cathode materials, due to their high electrochemical properties with the excellent stability, and compared to that of single perovskite structured cathode materials.

References

Lowering the temperature of solid oxide fuel cells, E. D. Wachsman, and K. T. Lee, Science
,
334, 935 (2011).

Fundamental mechanisms limiting solid oxide fuel cell durability, H. Yokokawa, H. Tu, B. Iwanschitz and A. Mai, J. Power sources, 182, 400 (2008).

Durability test of SOFC cathodes, M. J. Jørgensen, P. Holtappels and C. C. Appel, Applied Electrochemistry, 30, 411 (2000).

Keywords:
solid oxide fuel cells, cathode, double perovskite structure, durability, ceria.
Electrospun Porous Nanorod Perovskite Oxide/Ionic Conductor Composite As an Electrochemical Catalyst for Water Splitting
Authors: So In-Seop , Park Jun-Young 
Published: February 2020

As the global energy demand increases rapidly, developments of cost-effective and highly active catalysts are of prime importance for the energy conversion and storage device in the pursuit of sustainable energy, such as the water splitting cells, rechargeable metal–air batteries, and regenerative fuel cells. In these electrochemical energy devices, the oxygen evolution reaction (OER) shows the considerable overpotential owing to the slow kinetics of OER, similar to the sluggish oxygen reduction reaction (ORR) in fuel cells. Noble metal-based catalysts such as RuO2 and IrO2 are still used, but the scarcity and high cost of the noble metal-based catalysts limit their wide application. In order to develop highly active, durable, and low-cost OER catalysts, the perovskite structure -based catalysts have been considered because of their highly electrocatalytic activity for the OER. Further, The core/shell-fiber-structure OER catalystswere prepared by the advanced electrospinning and Pechini process. The electrospinning process has various advantages, such as the fast, simple, the direct use of inorganic particles as precursors, to fabricate the inorganic core/shell fibers. Hence, in this work, perovskite structure -based catalysts with the morphology of core/shell-fibers are fabricated for highly effective OER catalysts and characterized by various physicochemical and electrochemical tools.

References

[1] J.A. Turner, Science 305 (2004) 972-974.
[2] A. Fujishima, K. Honda, Nature 238 (1972) 37–38.
[3] R. Cao, J.-S. Lee, M. Liu, J. Cho, Adv. Energy Mater. 2 (2012) 816–829.
[4] S. Park, Y. Shao, J. Liu, Y. Wang, Energy Environ. Sci. 5 (2012) 9331-9344.
[5] Y. Jiao, Y. Zheng, M. Jaroniec, S.Z. Qiao, Chem. Soc. Rev. 44 (2015) 2060-2086.
[6] H. Dau, C. Limberg, T. Reier, M. Risch, S. Roggan, P. Strasser, ChemCatChem, 2 (2010) 724-761.

Keywords:
electrochemical catalysts, electrospinning, Pechini method, Perovskite-based catalyst, Water splitting cells, Oxygen evolution reaction.