bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Operando Electrochemical High-Temperature X-Ray Diffraction Study of Ni-Ce0.9 Gd0.1O2-δ Redox Properties
Authors: Korjus Ove , Aruväli Jaan , Kirsimäe Kalle , Kivi Indrek , Nurk Gunnar 
Published: February 2020

Typical anode materials for solid oxide fuel cells (SOFC) are Ni-cermets, either Ni/yttria stabilized zirconia (Ni-YSZ) or Ni/gadolinia doped ceria (Ni-GDC) [1]. In the case of Ni-cermet materials before the anode is ready for work NiO is reduced to Ni. During reduction process the solid phase volume of an anode decreases approximately 40%. Due to either system malfunction or contamination, air (oxygen) might diffuse into anode compartment, which causes Ni reoxidation to NiO. During this process the solid phase volume of an anode increases 66% [1,2]. Reoxidation of Ni might take place if after cell operation fuel gas flow is stopped in order to decrease fuel cell upkeep costs [3]. Reoxidation of Ni might also occur if electric load for the cell is too high and oxide ion flux through the membrane creates too oxidative environment at Ni catalyst.
In order to understand the dynamics of redox processes and to design the Ni-GDC electrodes with optimal microstructure the information related to simultaneous structural and electrochemical changes during SOFC operation would be very useful. In this work a novel approach for simultaneous monitoring of electrochemical (EC) properties and crystallographic structure in operating SOFC i.e. in operando SOFC EC-XRD measurement cell has been proposed and applied to understand the redox dynamics in Ni-GDC anode.
The impact of polarization on structure of Ce0.9 Gd0.1O2-d (GDC) in Ni-GDC cermet anode as well as impact of NiO ⇌ Ni redox cycles on the size and structure of Ni particles and electrical contact between particles has been studied with the in house developed in operando EC-HTXRD cell. Changes in the lattice parameters of Ni and GDC as well as electrochemical properties of Pt|Ni-GDC|ScCeSZ|GDC|LSC were monitored as a function of temperature (T), electrode polarization (E) and oxygen partial pressure (pO2). Influence of temperature, pO2 and polarization on GDC lattice parameters was observed. O2- current through the membrane lead to decrease of unit cell volume of GDC lattice. The observed change in lattice parameter upon polarization change from open circuit voltage (OCV) (depending on temperature, about 1.1 V) to 0.9V (potential of 3-electrode setup) was equal to 50 degree temperature change.
[1] A. Faes, A. Hessler-Wyser, A. Zryd, J. Van Herle, A review of RedOx cycling of solid oxide fuel cells anode, Membranes (Basel). 2 (2012) 585–664. doi:10.3390/membranes2030585.
[2] T. Klemenso̸, C. Chung, P.H. Larsen, M. Mogensen, The Mechanism Behind Redox Instability of Anodes in High-Temperature SOFCs, J. Electrochem. Soc. 152 (2005) A2186. doi:10.1149/1.2048228.
[3] D. Waldbillig, A. Wood, D.G. Ivey, Thermal analysis of the cyclic reduction and oxidation behaviour of SOFC anodes, Solid State Ionics. 176 (2005) 847–859. doi:10.1016/j.ssi.2004.12.002.

Figure 1
Synthesis of Ru-doped Double Perovskite Anode for SOFC
Authors: Monteiro Natalia K , Candido Gabriel Alves Silva , Fonseca Fabio C. 
Published: February 2020

One of the great current needs for anode material in solid oxide fuel cells is to combine in one redox-resistant compound an efficient multifunctionality, that is, that the same material must exhibit both good catalytic activity and mixed ionic-electronic conductivity. Such a material should ideally be active towards different fuels allowing fuel-flex SOFCs capable to operate using the most convenient fuel available in various situations. Ceramics with perovskite structure are, from this point of view, are promising candidates. Different compounds such as (La,Sr)(Mn,Cr)O and SrMoMgO have been investigated, but more efficient anodes are still required. In this study, the Pr0.5Ba0.5MnO3 was used as the precursor phase of the double perovskite PrBaMn2O5+δ (PBMO), obtained at reducing conditions. The transport and catalytic properties were studied in the pristine compound and in Ru-doped samples Pr0.5Ba0.5Mn1-xRuxO3 (Ru-PBMO). Ru substitution at the B-site is expected to enhance the catalytic properties of the ceramic toward ethanol or methane fuels. Ceramic powders were synthesized by the polymeric precursor method and characterized by thermogravimetric analyses, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrical properties of sintered samples were evaluated by dc 4-probe technique, in the 25 - 800 °C temperature range in both air and reducing conditions. The TG/DTA and XRD data show mass loss stabilization and crystalline phase formation occurring at ~800 °C. The evolution of the XRD pattern upon calcining temperature indicated the formation of single phase of Ru-PBMO samples at ~1100 °C. The initial results suggest that PBMO and PBMO-Ru compounds are promising SOFC anodes.
A Dual Functional Solid Oxide Fuel Cell for Power Generation and Energy Storage
Authors: Zhang Cuijuan , Huang Kevin 
Published: February 2020

Large-scale, cost-effective energy storage is highly desirable for balancing utility grid and renewable energy production. However, commercial scale demonstration of grid energy storage is generally lacking. Recently, we demonstrated a new bifunctional fuel-cell/battery hybrid system suited for stationary grid-scale energy storage. The new system is comprised of a reversible SOFC as the electrical charger/discharger and a redox-active metal/metal-oxide chemical bed as the energy store. During operation, the cathode of the system is constantly open to air, whereas the anode configuration defines the functionality of the system: power generation when the anode chamber is open to a fuel, and energy storage when the anode chamber is closed next to a neighboring metal/metal-oxide chemical bed.
The presentation highlights recent progress in performance evaluation and computational analysis of the fuel-cell/battery hybrid. These highlights include cycling performance in a temperature range of 500-600 oC and computational analysis of performance limiting factors. Strategies to achieve efficient and reversible hybrid system for simultaneous power generation and energy storage are proposed.
Failure Statistics for Commercial Lithium Ion Batteries
Authors: Harris Stephen J 
Published: February 2020

There are relatively few publications that assess capacity decline in enough commercial cells to quantify
cell-to-cell variation, but those that do show a surprisingly wide variability. Capacity curves cross each
other often, a challenge for efforts to measure the state of health and predict the remaining useful life
(RUL) of individual cells. We analyze capacity fade statistics for 24 commercial pouch cells, providing an
estimate for the time to 5% failure. Our data indicate that RUL predictions based on remaining capacity or
internal resistance are accurate only once the cells have already sorted themselves into “better” and
“worse” ones. Analysis of our failure data, using maximum likelihood techniques, provide uniformly good
fits for a variety of definitions of failure with normal and with 2- and 3-parameter Weibull probability
density functions, but we argue against using a 3-parameter Weibull function for our data. pdf fitting
parameters appear to converge after about 15 failures, although business objectives should ultimately
determine whether data from a given number of batteries provides sufficient confidence to end lifecycle
testing. Increased efforts to make batteries with more consistent lifetimes should lead to improvements
in battery cost and safety.
Advances and Application of Conformal Mesoscale Modeling to Battery Electrodes
Authors: Roberts Scott A. , Trembacki Bradley L. , Ferraro Mark E. , Mistry Aashutosh N , Brunini Victor E. , Mukherjee Partha P. , Noble David R. 
Published: February 2020

Advances in x-ray computed tomography (XCT) with sub-micron resolution and millimeters of field-of-view have enabled imaging of battery electrodes in sufficient detail to elucidate the mesostructure of the percolated particle network. Most often the secondary conductive binder phase is not visible using XCT and its structure can only be observed using electron-based techniques (e.g. scanning electron microscopy), which typically have a field-of-view too small for meaningful reconstructions. This secondary phase, however, is thought to be critically important for understanding electrode performance at the mesoscale.
We have developed a computational approach to creating computable three-dimensional (3D) mesoscale representations of the active material (particle), conductive binder, and electrolyte/void phases. This approach is built upon the Conformal Decomposition Finite Element Method (CDFEM) and combines 3D XCT image data for the active material phase and a novel “binder bridge” placement algorithm for the conductive binder. This approach enables the calculation of effective transport properties, such as electrical and ionic conductivity and mechanical moduli, that can be upscaled to macroscale battery simulations. Coupled electrochemical and mechanical simulations can also be performed to predict (dis)charge performance and degradation mechanisms of the electrode.
In this work, we discuss the computational requirements, in terms of mesh resolution and domain size, to reasonably minimize computational errors. We also compare our “binder bridge” approach to other approaches in the literature, including a popular stochastic representation. The effect of nano-porosity within the conductive binder phase is explored. As part of this comparison, we explore the differences between smooth and voxelated particle representations along with differences between finite element and finite volume methods. Finally, we discuss upscaling of some of these effective properties into functional forms that can be implemented in macroscale battery simulation platforms.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
Effect of Graphene Oxide on Electrochemical Behavior of MnO2/GO Supercapacitor
Authors: Singhal Rahul , Fagnoni Justin T. 
Published: February 2020

Supercapacitors have received a lot of attention due to their high-power performance, long cycle life low maintenance, and for applications in hybrid electric vehicles, portable electronic devices, and power back-up devices [1-3]. Various researchers studied MnO2 cathode materials for application in electrochemical capacitors, because of its low cost and natural abundance [2, 3]. However, MnO2 has limited electrochemical performance because of its poor conductivity and low surface area. To improve the electrochemical performances of MnO2, we have synthesized MnO2/graphene oxide (GO) nanocomposite with varying concentration of GO (0.4 mg/ml and 0.8 mg/ml).
GO/MnO2 nanocomposite was synthesized by adding KMnO4 in a solution of water and ethanol (3:1), containing desired amount of GO. The brown precipitates were obtained after a continuous stirring for 1 hr. The precipitate was washed and dried to obtain the GO/MnO2 nanocomposites. The electrodes were prepared by spreading a slurry of GO/MnO2 powder, carbon black, PTFE binder (80:15:5 weight ratio) onto Ni mesh. The electrochemical characterizations were carried out in an aqueous solution of 1M Na2SO4. The charge discharge studies were carried out between 100 mA/g to 5A/g current range. The discharge capacities were found to be 230 F/g and 105 F/g at a current of 100 mA/g and 5A/g, respectively for 20mg GO. The detailed results will be presented at the 233rd Electrochemical Society Meeting.

References:

P. Iamprasertkun, A. Krittayavathananon, A. Seubsai, N. Chanlek, P. Kidkhunthod, W. Sangthong, S. Maensiri, R. Yimnirun, S. Nilmoung, P. Pannopard, S. Ittisanronnachai, K. Kongpatpanich, J. Limtrakul, M. Sawangphruk, Sci. Rep. 6, 37560; doi: 10.1038/srep37560 (2016).

M. Toupin, T. Brousse, D. Be´langer, Chem. Mater.16 3184 (2004).

Y. Zhang, G. Li, Y. Lv, L. Wang, A. Zhang, Y. Song, B. Huang, International J. Hydrogen Energy 36 11760 (2011).

Figure 1
Synthesis and Transfer of High-Quality Graphene Grown on Al2O3(0001)/Pt(111) Template Wafers
Authors: Verguts Ken , Coroa Joao , Peters Lisanne , Wu Cheng Han , Huyghebaert Cedric , Brems Steven , De Gendt Stefan 
Published: February 2020

Today, CMOS compatible routes to grow and transfer large graphene sheets are still missing. Chemical vapor deposition (CVD) is the main synthesis technique yielding high-quality wafer-scale graphene. Platinum is expected to be an excellent catalyst to grow monolayer, large scale and high-quality graphene. Moreover, electrochemical graphene transfer methods are demonstrated, which facilitate the reusability of this expensive Pt template.
A process window is studied to grow graphene on platinum foils. The influence of growth temperature and time as well as the methane to hydrogen ratio is optimized. Moreover CO2 can be used as a graphene defect etching gas to replace hydrogen, resulting in successful graphene syntheses conditions.
It is shown that the polycrystalline nature of the Pt foil makes it extremely difficult to grow a uniform monolayer graphene sheet. It is also demonstrated that a smooth Pt(111) thin film on sapphire (Rrms = 0.2 nm) decreases the amount of graphene nucleation centres and thus strongly reduce the graphene multilayer areas. Therefore, a Pt(111) thin film appears ideally suited to grow millimetre-sized graphene islands in reasonable time frame (< 1 hour growth time).
To promote graphene delamination from the platinum growth template, it is of prime importance that an interfacial water (IFW) layer is formed. This IFW layer serves as a pathway for charged ions to intercalate between graphene and its CVD growth substrate. It is demonstrated that only a selection of ions succeed in intercalating and thus in a successful graphene delamination. The ions that are able to intercalate are electro-active outside the electrochemical window of the used solvent.

Figure 1
Charges, Defects and Interfaces in Two-Dimensional Materials and Devices
Authors: Liu Yuanyue 
Published: February 2020

Two-dimensional semiconductors show great promise for next-generation electronics and optoelectronics, yet they still face significant challenges to realize their potential. Here I will discuss our recent theoretical/computational studies on the charges carriers, defects and interfaces in two-dimensional materials and devices. Specifically, I will show (i) how to estimate the electron/hole mobility with reasonable accuracy; (ii) the role of defects and how to passivate the harmful ones [1,2]; and (ii) how to lower the metal-semiconductor resistance [3,4].
[1] Y. Liu, P. Stradins, S. Wei, Angew. Chem. Int. Ed. 2015, DOI: 10.1002/anie.201508828
[2] Y. Liu, H. Xiao, W. A. Goddard III, Nano Lett. 2016, 16, 3335
[3] Y. Liu, P. Stradins, S. Wei, Science Advances 2016, 2, e1600069
[4] Y. Liu, H. Xiao, W. A. Goddard III, JACS, 2016, 138, 15853
(Invited) Theory and Device Concepts of Novel Electronic, Optoelectronic, and Topological 2D Materials
Authors: Qian Xiaofeng 
Published: February 2020

2D materials provide extraordinary materials platform with many interesting physical properties distinct from their bulk counterpart and offer unprecedented opportunities for ultrathin electronic and optical applications. Here I will present our recent theoretical works on novel 2D multiferroics and 2D topological materials as well as a few device concepts. First, I will highlight our discoveries on 2D topological materials including binary and ternary transition metal dichalcogenides etc. Our works show that electric field, elastic strain, and van der Waals stacking can be utilized to introduce topological phase transition [1,2]. In particular, the electric field induced topological phase transition offers a possibility for realizing topological field effect transistor, which will be fundamentally different from conventional transistors. In the second example, I will introduce the discovery of 2D multiferroics in semiconducting group IV monochalcogenide monolayers [3]. These 2D materials exhibit giant spontaneous ferroelastic lattice strain and ferroelectric polarization. Both are strongly coupled, accompanied with large anisotropic 2D excitonic responses and nonlinear optical responses [4]. Our theoretical findings indicate that these multiferroic 2D materials possess low domain wall energy and migration barrier, suggesting great opportunities for multifunctional opto-electronic-mechanical devices such as 2D ferroelectric and ferroelastic memory and 2D ferroelectric excitonic photovoltaics. Finally, relevant experimental progresses as well as some critical challenges and opportunities in 2D materials and their nanostructures will be discussed.
1. Xiaofeng Qian, Junwei Liu, Liang Fu, and Ju Li. Quantum spin Hall effect in two-dimensional transition metal dichalcogenides.
Science
346, 1344-1347 (2014).
2. Junwei Liu, Hua Wang, Chen Fang, Liang Fu, and Xiaofeng Qian. van der Waals Stacking-Induced Topological Phase Transition in Layered Ternary Transition Metal Chalcogenides.
Nano Letters
17, 467-475 (2017).
3. Hua Wang and Xiaofeng Qian. Two-dimensional multiferroics in monolayer group IV monochalcogenides.
2D Materials
4, 015042 (2017).
4. Hua Wang and Xiaofeng Qian. Giant Optical Second Harmonic Generation in Two-Dimensional Multiferroics.
Nano Letters
17, 5027-5034 (2017).
(Invited) Colloidal Pb-Free Perovskite Nanocrystals for Optoelectronic Energy Applications
Authors: Nag Angshuman 
Published: February 2020

Pb-halide perovskites exhibit defect-tolerant behaviour resulting into efficient optoelectronic properties. We have worked on various aspects of material design, optical and optoelectronic properties of colloidal cesium lead halide perovskite nanocrystals.1-5 The key aspects that make Pb-halides an unique class of optoelectronic materials are: (i) Pb2+ exhibit stable nS2 electronic configuration in the outermost orbital, (ii) small effective masses of charge carriers because of 3-D structural network of [PbBr6]4- octahedra with Pb-Br-Pb bond angles close 180o, and (iii) strong spin-orbit splitting of Pb 6p states (conduction band minimum).
From last couple of years, we have started searching for colloidal Pb-free metal halide nanocrystals that can exhibit the combination of these three properties.6-7 In this talk, I will discuss about our experiences on Pb-free metal halide nanocrystals. The Pb-free materials that will be discussed are colloidal thallium halide (TlX), cesium antimony halide (M3Sb2X9; M = Cs and Rb), and cesium bismuth halide (Cs3Bi2X9) nanocrystals, where X signifies halides. Intrinsic issues regarding material design and photophysical properties relevant for optoelectronic applications will be discussed.
References:
1. Swarnkar, A; Chulliyil, R.; Ravi, V. K.; Irfanullah, M.; Chowdhury, A.; Nag A. Angew. Chem.
Int. Ed.
2015, 53, 15424.
2. Yettapu, G. R.; Talukdar, D.; Sarkar, S.; Swarnkar, A.; Nag, A.; Ghosh, P.; Mandal, P. Nano
Lett.
2016, 16, 4838.
3. Ravi, V. K.; Markad, G. B.; Nag, A. ACS Energy Lett.
2016, 1, 665.
4. Mir, W. J.; Jagadeeswarara, M.; Das, S.; Nag, A. ACS Energy Lett., 2017, 2, 537.
5. Sarkar, S.; Ravi, V. K.; Banerjee, S.; Yettapu, G. R.; Markad, G. B.; Nag, A.; Mandal, P. Nano
Lett., 2017, 16, 5402.
6. Swarnkar, A.; Ravi, V. K.; Nag, A. ACS Energy Lett., 2017, 2, 1089.
7. Mir, W. J; A. Warankar, A.; Acharya, A.; Mandal, P.; Nag, A. Chem. Sci.
2017
, 8, 4602.
8. Pal, J.; Manna, S.; Mondal, A.; Das, S.; Adarsh, K. V.; Nag, A. Angew. Chem.
Int. Ed.
2017, 56, 14187.
(Invited) Near Infrared Plasmon-Induced Charge Separation in Heterostructured Nanoparticles
Authors: Teranishi Toshiharu 
Published: February 2020

The structure of nanomaterial determines their individual properties and assembled structures they can form [1,2]. Highly efficient photoenergy conversion in heterostructured nanoparticle (NP) assemblies requires the formation of epitaxial heterointerfaces and band alignment engineering. This requirement has led to attention being given to recent advances and prospects in the charge separation properties of both type-II semiconductor/semiconductor NPs [3-6] and plasmon/semiconductor NPs [7,8]. Special attention has been given to plasmonic semiconductor/semiconductor combinations [7,8], where the near infrared plasmon-induced carriers in the plasmonic semiconductor phase are injected into the conduction band of another semiconductor phase.
[1] Wu, H.-L.; Sato, R.; Yamaguchi, A.; Kimura, M.; Haruta, M.; Kurata, H.; Teranishi, T. Science
2016, 351, 1306.
[2] Kanehara, M.; Arakawa, H.; Honda, T.; Saruyama, M.; Teranishi, T. Chem. Eur. J.
2012, 18, 9230.
[3] Saruyama, M.; So, Y.-G.; Kimoto, K.; Taguchi, S.; Kanemitsu, Y.; Teranishi, T. J. Am. Chem. Soc.
2011, 133, 17598.
[4] Sakamoto, M.; Inoue, K.; Saruyama, M.; So, Y.-G.; Kimoto, K.; Okano, M.; Kanemitsu, Y.; Teranishi, T. Chem. Sci.
2014, 5, 3831.
[5] Teranishi, T.; Samamoto, M. J. Phys. Chem. Lett.
2013, 4, 2867. (Perspective)
[6] Sakamoto, M.; Inoue, K.; Okano, M.; Saruyama, M.; Kim, S.; So, Y.-G.; Kimoto, K.; Kanemitsu, Y.; Teranishi, T. Nanoscale
2016, 8, 9517.
[7] Lian, Z.; Sakamoto, M.; Matsunaga, H.; Vequizo, J. J. M.; Yamakata, A.; Haruta, M.; Kurata, H.; Teranishi, T., under revision.
[8] Sakamoto, M.; Kimura, M.; Kawawaki, T.; Matsunaga, H.; Ranasinghe, C. S. K.; Yamakata, A.; Matsuzaki, H.; Furube, A.; Teranishi, T., submitted.
(Invited) Light on EuOx Nanostrutured Films
Authors: Mariscal Antonio , Serna Rosalia 
Published: February 2020

Europium monoxide (EuO) is a well-known ferromagnetic semiconductor with single crystal band-gap similar to Si (1.12 eV) and is compatible with the actual semiconductor technology, and suited for the development of integrated spintronics components. However, very little is known of the optical properties of this notable material in thin film configuration, and especially nanostructured. Only very recently some evidence on possible quantum confinement in EuO nanostructures has been reported [1]. In part, this is because EuO high quality films and nanostructures are very difficult to obtain and preserve. Indeed the only data available on its dielectric function are for single crystal EuO and dates from the 70’s from reflectance measurements.
Recently we have been able to prepare high quality textured nanocrystalline EuOx films by pulsed laser deposition in vacuum at room temperature through a reduction process. Because the EuO films rapidly oxidize under exposure to ambient, we have encapsulated them with a 10 nm thick Al2O3 layer. This has allowed us to preserve the EuOx nanostructures and to study both their linear optical and luminescent properties. In this contribution, we will show the optical dielectric function of thin nanocrystalline EuOx films in the NUV-VIS-NIR, using spectroscopic ellipsometry measurements with perfect Kramers-Kronig consistency. The results show how tweaking the EuOx composition and nanostructure modifies its dielectric function, and therefore it enables the control of the excitonic response modifying the band-gap of the films. We will show the photoluminescent emission of these films, and discuss its excitonic or ionic (Eu2+) origin. We believe that the knowledge of the optical properties of this unique material will open a new route for the integration with commercial semiconductors (Si, GaAs, GaN) for novel spintronics and photonics combined devices.
[1] G.M. Prinz, T. Gerber, A. Lorke, M. Müller, Quantum confinement in EuO heterostructures, Appl. Phys. Lett. 109 (2016). doi:10.1063/1.4966223.