bluuebunny/crossref_metadata_2025_split huggingface dataset:
A DFT Study of CO2-H2 Co-Adsorption on Ni/YSZ(111) for Solid Oxide Fuel Cell Applications
Authors: Essadek Abdelaziz , Roldan Martinez Alberto , de Leeuw Nora 
Published: February 2020

Solid Oxide Fuel Cell (SOFC) devices convert chemical energy into electrical energy by oxidizing fuels such as hydrogen, natural gas, ethanol or hydrocarbon mixtures, which highlights the capability of SOFCs as candidates for applications in stationary power generation. The main species used as fuel in the SOFC are H2 and CO which are oxidized at the anode [1]. Instead of pure H2 or CO, H2/CO mixtures can be used leading to more complicated mechanisms since other processes such as the water-gas shift reaction (CO + H2O ↔ CO2 + H2) are involved.
Robust materials are needed for SOFC since the working temperature is approximately equal to 800˚C. For example, a suitable anode is Ni/YSZ (nickel – yttria stabilized zirconia) since it has a high catalytic activity, mechanical and chemical stability and compatibility with the electrolyte under working conditions [2]. It is well known that the performance of the Ni/YSZ cermet depends on the microstructure and the distribution of Ni and YSZ phases in the cermet [3]. Additionally, this performance depends on the key reactions occurring at the triple phase boundary where the gas phase, Ni particles and YSZ surface meet. Thus, it is relevant to understand, at the atomic scale, the structure of Ni/YSZ and its interaction with the gas phase, and in particular CO2 and H2.
To simulate the interaction of CO2 and H2 with Ni-YSZ, we have used electronic structure calculations based on the Density Functional Theory using the Vienna Ab-initio Simulation Package (VASP). We have studied the deposition of Nin (n=4-10) clusters on the YSZ(111) followed by the adsorption of molecules on the optimised Nin/YSZ(111) structures and calculated the geometric and electronic structure at the most stable adsorption site. We have also analysed the reaction path of the reverse water-gas shift reaction (CO2 + H2 ↔ CO + H2O) on three different Nin/YSZ(111) (n = 5, 6 and 10) interfaces, considering two possible pathways intermediates: hydrocarboxyl or formate.
Finally, we have observed that both CO2 and H2 prefer to adsorb on the Nin cluster rather than on the surface. On the metal cluster the CO2 molecule is activated and the H2 is dissociated upon adsorption, whereas charge is transferred from the cluster to the molecules. We have determined two intermediate states and three intermediate states for the carboxylic acid and formate intermediate pathway, respectively, on the three Nin/YSZ(111) (n = 5, 6 and 10) interfaces.

References

1. J. Hanna, W. Y. Lee, Y. Shi and A. F. Ghoniem, Prog. Energy Combust. Sci., 2014, 40, 74–111.
2. Kim, S. et al. Solid State Ionics, (2007),

178, 1304–1309.
3. Kim, S. et al. Solid State Ionics, (2006), 177, 931–938.
Molecular Dynamic Study of Gadolinium-Doped Ceria and Yttria Stabilized Zirconia Grain Boundaries
Authors: Aparicio Angles Xavier , de Leeuw Nora H. 
Published: February 2020

Gadolinium-doped ceria (GDC) and yttria-stabilised zirconia (YSZ) are very well known materials, used as components for solid-oxide fuel cells (SOFC). They both are very good electrolytes, and they have been vastly used in this sense. The main difference between GDC and YSZ when used as electrolytes is that GDC shows higher oxygen conduction at lower temperatures, leading to the possibility of developing intermediate temperatures SOFC (IT-SOFC). But their versatility allow us to use them also as anode materials, like YSZ, which in combination of nickel particles, is used to catalyse oxygen reduction. In addition, YSZ combined with nickel (Ni-YSZ) is also used as anode in SOFC, in combination with GDC as electrolyte.
In any case, the main role of both is related to oxygen migration, i.e. ionic conductivity. In GDC and YSZ oxygen migration undergoes via a vacancy hopping mechanism. Vacancy mobility depends on several aspects, like the association energy with respect to the dopants, dopants concentration, or temperature, whose effects are very well studied. Grain boundaries (GBs) are also known to have an important impact in conductivity, despite that little is known about their influence. From an experimental point of view, results suggests that the presence of these GBs
offers faster migration channels. On the other hand, dopants tend to segregate to GBs, thus trapping oxygen vacancies and reducing the ionic conductivity of the materials. To clearly understand the role of GBs in the oxygen conductivity, it is necessary to study the system at the atomic level. One of the main issues, however, is that the model must include all the chemical and structural complexity inherent to GBs, which force us to generate very large models.
In this work, and based on interatomic potential and molecular dynamic techniques, we present a strategy based on the work of Sayle et al. (2007) referred as Amorphisation and Recrystallization (A&R). With this methodology, consisting on melting and recrystallizing the system at high pressures, we are able to obtain accurate models that allow us to describe realistic GBs including dislocations and translocations. After generating different models, we have performed a series of molecular dynamic simulations in order to see the effect of the temperature in the structure,
ionic mobility and also oxygen diffusion and therefore its conductivity. Results seem to indicate that indeed, the presence of the grain boundaries are beneficial for the enhancement of the oxygen diffusion in the system.
Mesoscale Modeling of Lithium-Ion Battery Electrodes: Computational Requirements and the Role of Polymeric Binders
Authors: Roberts Scott A. , Trembacki Bradley L. , Mendoza Hector , Long Kevin N. , Brunini Victor E. , Grillet Anne M. 
Published: February 2020

In recent years, advances in the imaging and computational representation of lithium-ion battery electrodes have made it possible to perform electrochemical and mechanical simulations on reconstructed electrode microstructures. These simulation capabilities hold great potential for informing electrode design and manufacturing processes by providing insight into the effects of material choices and manufacturing conditions on the microstructure. Mesoscale simulations are also used to investigate the performance of the battery, including the elucidation of capacity fade mechanisms.
Realistic mesoscale simulations, however, are not without their challenges. Significant domain sizes containing a large number of active particles are necessary to obtain a representative volume, and significant mesh resolution must be used to capture the details of the complex particle shapes. Additionally, the complex particle shapes can lead to poorly formed mesh elements leading to difficult numerical solutions. In this talk we address how these issues affect the ability to robustly perform simulations.
Many electrode images are also unable to resolve the polymeric binder. The location and properties of this binder are suspected to have a strong effect on battery performance. Coupled electrochemical-mechanical simulations are performed with both approximate and reconstructed binder representations. We use these simulations to elucidate the effect of binder location on electrode performance.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
Computer Modelling Studies of Lithium Transport in Nanoporous and Bulk Beta-MnO2
Authors: Ngoepe Phuti Esrom , Sayle Thi X T , Sayle Dean C 
Published: February 2020

Nanostructured manganese dioxides (MnO2) are among the promising materials for high-capacity lithium-ion batteries [1], lithium air batteries [2] and supercapacitors [3], that can be used in electric vehicles and other consumer electronics. Simulated amorphisation recrystallisation method has been successfully used to nucleate and crystallise bulk [4] and nanoporous β-MnO2 [5]. In the current study we demonstrate that nanostructuring of MnO2 results in the exposure of a variety of surfaces to be exposed at the (internal) pores because of the high curvature of the material; the low energy MnO2(101) surface does not dominate the morphology. This nanostructuring facilitates a wide variation of entrance sites into the 1x1 tunnels in contrast to the parent bulk material. In particular, the activation energy associated with Li intercalation/deintercallation into the (101) surface of the bulk material is calculated to be 0.6eV. On the other hand, for the mesoporous material we calculate the activation energy for Li transport and deintercallation to be 0.4eV.
1] B.X. Li, G.X. Rong, Y. Xie, L.F. Huang and C.Q. Feng, Inorg. Chem. 2006, 45, 6404.
[2] A. Débart, A.J. Paterson, J. Bao and P.G. Bruce, Angew. Chem., Int. Ed. 2008, 47, 4521.
[3] W. Wei, X. Cui, W. Chen and D.G. Ivey, Chem. Soc. Rev. 2011, 40, 1697
[4] T.X.T. Sayle, C.R.A. Catlow, R.R. Maphanga, P.E. Ngoepe and D.C. Sayle, J. Crystal Growth, 294,118-129, 2006.
[5] T.X.T. Sayle, R.R. Maphanga, P.E. Ngoepe and D.C. Sayle, J. American Chem. Soc., 131, 6161-6173, 2009.
(Invited) Comparative First Principles Studies of Hybrid Li-Ion/Li-Oxygen Battery Materials
Authors: Li Liang , Kinaci Alper , Chan Maria K. Y. 
Published: February 2020

In the Center for Electrochemical Energy Science (CEES) Energy Frontier Research Center, we are investigating a new class of energy storage materials – hybrid Li-ion/Li-oxygen materials – that combine transition metal and oxygen redox chemistries to deliver high energy storage capacity [1, 2, 3]. The electrochemical reactions, structural and electronic structure evolution of these materials are complex, requiring a combination of in-depth characterization and first principles modeling. In this talk, we will report on a comparison study of several examples of hybrid Li-ion/Li-oxygen materials using density functional theory calculations. We will discuss the structural and electronic structure reasons for differences in reaction pathways and competition between transition metal vs oxygen redox chemistries. Insight towards selecting and designing promising hybrid battery materials gleaned from the comparison will be discussed.
[1] L. Trahey, C. S. Johnson, J. T. Vaughey, S.-H. Kang, L. J. Hardwick, S. A. Freunberger, P. G. Bruce, M. M. Thackeray, “Activated Lithium-Metal-Oxides as Catalytic Electrodes for Li-O2 Cells,” Electrochemical and Solid-State Letters, 2011, 14, A64.
[2] M. M. Thackeray, M. K. Y. Chan, L. Trahey, S. Kirklin, and C. Wolverton, “Vision for Designing High-Energy, Hybrid Li Ion/Li–O2 Cells,” Journal of Physical Chemistry Letters, 2013, 4, 3607.
[3] Z. Yang, L. Trahey, Y. Ren, M. K. Y. Chan, C. Lin, J. Okasinski, and M. M. Thackeray, “In-Situ High-Energy Synchrotron X-ray Diffraction Studies and First Principles Modeling of α-MnO2 Electrodes in Li-O2 and Li-ion Coin Cells,” Journal of Materials Chemistry A, 2015, 3, 7389.
Modeling of Thermal Runaway-Induced Li-Ion Battery Failure Integrating Multiphysics and Multiscale Approaches As Well As Ageing Interaction
Authors: Abada Sara , Petit Martin , Lecocq Amandine , Huet François , Sauvant-Moynot Valérie , Marlair Guy 
Published: February 2020

Li-ion batteries are currently the preferred solution to store electrical energy. However, their safety is still a challenging issue. Since we are more and more moving from rechargeable battery packs working with water-based electrolytes to more powerful or more energy containing ones utilizing non aqueous electrolytes, risk profiles have changed abruptly from uncontrolled release of hydrogen during charging (e.g. in lead acid or Nickel Metal hydride type of batteries) to the so called and much more safety challenging thermal runaway process. Indeed, thermal runaway has been identified as the major concern in terms of Li-ion battery safety issues on its full value chain inducing significant thermal and chemical threats [1]. The phenomenon entails a cascade of stages initiated at material level and may be induced by various abuse conditions (abnormal disorders of thermal, mechanical or electrical nature). Progress in understanding this complex phenomenon, so far essentially achieved by experimentations at material and cell levels have opened the door to safer battery design or better safety management through various modeling techniques [2].
This paper deals with an innovative approach in such a contribution which consists in the development and validation of a physical and accurate model of Li-ion batteries electro-thermal behavior nearby thermal runaway conditions which includes sub-models reflecting ageing effect interaction. Therefore, enlarged application is targeted for such a model, depending on validation domain, since it is capable of analyzing the risk of failure induced by thermal runaway for applications to safety management expanded to new and aged batteries, or for safe “second life” use of Li-ion batteries.
The presentation will describe the overall methodology considered (see fig.1), provide the set of electrochemical-thermal sub-models used, describe the experimental plans based on three series of Li-ion cells (see fig. 2) developed for i) adjusting requested thermal parameters in the sub-models and ii) for validation purposes and eventually present results obtained so far.
<Fig.1>
<Fig.2>

References

[1] P. Ribière, S. Grugeon, M. Morcrette, S. Boyanov, S. Laruelle, G. Marlair, Energy Environ. Sci. 5 (2012) 5271.

[2] Sara Abada, Martin Petit, Amandine Lecocq2, Guy Marlair, François Huet, Valérie Sauvant-Moynot,
J. Power Sources, (2015),
in press, http://dx.doi.org/10.1016/j.powersour.2015.11.100

Figure 1
Etching Studies of BCN Thin Films
Authors: Prakash Adithya , Sundaram Kalpathy B 
Published: February 2020

The ever increasing advancements in semiconductor technology and continuous scaling of CMOS devices mandate the need for new dielectric materials with low-k values. The interconnect delay can be reduced not only by the resistance of the conductor but also by decreasing the capacitance of dielectric layer. Also cross-talk is a major issue faced by semiconductor industry due to high value of k of the inter-dielectric layer (IDL) in a multilevel wiring scheme in Si ultra large scale integrated circuit (ULSI) devices. Recently it has been found that Boron Nitride (BN) films can achieve low-k values around and hardness comparable to diamond [1][2]. BN is hygroscopic in nature. In this respect carbon can be added to the BN structure to produce Boron Carbon Nitride (BCN) films as the possible substitute for BN. The minimum dielectric constant achieved by plasma assisted chemical vapor deposition for a BCN thin film was reported to be 1.9. [2] The BCN films are also instrumental in suppressing the Cu migration [3]. The Young’s modulus of BCN films are reported well above 20 GPa making it one of the suitable options for low-k materials [4].
In the present work, BCN films were deposited by dual target sputtering of boron carbide (BC) target (DC), boron nitride (BN) target (RF) in nitrogen ambient with argon. The films were deposited under various N­2/Ar gas flow ratios and temperature. BCN is etched using an etchant that consists of 16 parts of Phosphoric acid (H3PO4), 1 part of Nitric acid (HNO3), 1 part of Acetic acid (CH3COOH), 20 parts of DI water. Various plots of etch rates with respect to deposition parameters and Arrhenius plots are studied.
REFERENCES
[1] Jun Liu, Kian Ping Loh, Ming Lin, Yong Lim Foo, Wei De Wang, and Dong Zhi Ch, Journal of Applied Physics, 96 (2004) 6679.
[2] Riedel R., Advanced Materials, 4 (1992) 759.
[3] M. K Mazumder, R. Moriyama, D. Watanabe, C. Kimura, H. Aoki, and T. Sugino: Jpn. J. Appl. Phys. 46 (2007) 2006.
[4] C. Morant, D. Caceres, J. M. Sanz, and E. Elizalde: Diamond Relat. Mater. 16 (2007) 1441.
Organic Thin-Film Transistors Based on Asymmetric Chrysene Derivatives
Authors: Murata Shuhei , Otsuki HIroyuki , Okamoto Kazuo , Kunugi Yoshihito 
Published: February 2020

Organic field-effect transistors (OFETs) have received significant attention because of the potential use in flexible and/or disposable portable electronic devices. The charge carrier mobility is strongly influenced by the organic semiconductor layer. But, it has been still lower than the charge carrier mobility for inorganic MOS FETs. Therefore, great efforts have been made toward the development of various semiconducting small molecules and polymers. Among these, fused π-conjugated semiconductors such as acene, thienoacene, and thienothiophene based compounds are promising materials for high-performance OFETs.
In this study we investigated the characterization of thin-film OFETs based on newly developed compound,asymmetric chrysene derivatives which regard phenyl chrysene as the main structure (Fig. 1). It is expected that the large and planar chrysene core would provide intermolecular interactions to achieve high charge carrier mobilities, and asymmetric molecular structure are promising for improvement of solubility.
Thin-films are fabricated by spin-coat and vapor deposition method on a n-doped Si wafer with a 220 nm thermally grown SiO2. The spin-coated films (50 nm thick) were fabricated by 0.4 wt% toluene solution at 2000 rpm for 30 sec. The vapor deposited films were deposited on insulating SiO2 layer was treated with a thin-film (ca. 30 nm) of a polymer insulator such as polystyrene (PS) or CYTOP (Asahi Glass Co.). Molecular packing and orientation was characterized by atomic force microscope (AFM), and X-ray diffractions　(XRDs) analysis. The electrical properties of the OFET devices were measured by using an Agilent 4155C semiconductor parameter analyzer under vacuum at room temperature.
The solution processed asymmetric chrysene based transistors showed typical p-channel FET characteristics. The field-effect carrier mobility of the device was determined to be 5.9×10-4cm2V-1s-1 and on/off ratio of 105 for P-28CR-6. The vaper deposited P-28CR-n based OFET shows also typical p-channel FET characteristics and their mobilities are strongly correlated with the applied polymer insulator, and the best field-effect mobility (3.1 cm2V-1s-1 and on/off ratio of 104) was obtained for the CYTOP-covered device. As shown in Fig. 2(b) carrier mobility is correlated by the length of alkyl chain for P-28CR-n. According to XRD analysis, orientation angle of chrysene core of P-28CR-n to the substrate is also correlated to the alkyl chain length of P-28CR-n. Interestingly, the field-effect mobility shows a similar trend to the orientation angle of the chrysene core for the alkyl chain length.

Figure 1
Rapid Determination of Diffusion Coefficients Utilizing Electrochemical Time of Diffusion (ETOD)
Authors: Moldenhauer Jonathan C , Paul David W 
Published: February 2020

The electrochemical time of diffusion (ETOD) experiment (formerly called electrochemical time of flight (ETOF)) is a generate/detect experiment that is performed on electrode arrays(1-5) . This method has been utilized to determine diffusion coefficients of electrochemically generated analytes, by measuring the time over which an analyte travels a given distance. Here we show an alternate analysis for ETOD data from what is typically found in the literature. We rearrange the equation from d=K√(D*tmc) where d is the distance, K is a geometric constant determined by the array, D is the diffusion coefficient of the analyte, and tmc is the time of maximum collection on the chronoamperometric curve(2) to √tmc=d/(K√D). This rearrangement allows for a “calibration curve” to be developed for an electrode array at a single distance with multiple analytes, each with a different and known diffusion coefficient, instead of using only a single analyte measuring tmc
at electrodes of multiple distances from a generator. This decreases the number of experiments that need to be performed to determine an unknown diffusion coefficient. This method also has all the advantages of more traditional ETOD/ETOF experiments in that it greatly simplifies the determination of diffusion coefficients as the concentration of the analyte, the area of the electrode, the viscosity of the solution, and the electron transfer kinetics can remain unknown. Here we show that diffusion coefficients determined by ETOD are comparable to those found in the literature, and that diffusion coefficients of probe molecules thickened by ethylene glycol are in reasonable agreement to those estimated using the Stokes-Einstein equation. Diffusion coefficients for ferricyanide, ferrocyanide, ruthenium(III) hexamine and dopamine were found within 5% of those from the literature, while the diffusion coefficients for the same probes through thickened solutions fell within 16% of the values predicted using the Stokes-Einstein Equation. With the consensus in the community being that the Stokes-Einstein equation can provide predicted diffusion coefficients within 35% of actual observed values (6), it can be considered that our method can provide diffusion coefficients that are reasonable for the previously unknown diffusion coefficients.
References
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2. C. Amatore, C. Sella and L. Thouin, J. Electroanal. Chem., 593, 194 (2006).
3. K. Slowinska, M. J. Johnson, M. Wittek, G. Moller and M. Majda, Proc. - Electrochem. Soc., 2001-18, 130 (2001).
4. D. Ky, C. K. Liu, C. Marumoto, L. Castaneda and K. Slowinska, J. Controlled Release, 112, 214 (2006).
5. F. Liu, G. Kolesov and B. A. Parkinson, J. Electrochem. Soc., 161, H3015 (2014).
6. H. A. Kooijman, Ind. Eng. Chem. Res., 41, 3326 (2002).