bluuebunny/crossref_metadata_2025_split huggingface dataset:
Center for Mesoscale Transport Properties: Molecular to Mesoscale (m2m)
Authors: Takeuchi Esther S 
Published: February 2020

The mission of the m2m EFRC is to understand and to ultimately control transport properties in complex battery systems with respect to multiple length scales, from molecular to mesoscale (m
2
m); to minimize heat and maximize work of electrical energy storage devices.
In the context of energy storage the focus is on battery polarization (i.e. thermodynamic voltage - loaded voltage) under use conditions. The determination of the factors that contribute to and control polarization at the material, electrode, and cell level will be explored under the program. The organization of the center has been developed to facilitate investigation of the processes taking place over multiple length scales. Additionally, as electroactive materials in the battery system are in complex environments, including multiple solid as well as liquid interfaces, the behavior of the materials in complex environments will be probed in detail. Lastly, the impact of time and extended electrochemical activity (electron and ion flux) on the material and energy storage system behavior will be determined.
The efforts of the Center are unified through the investigation of model materials where the initial focus includes examples of 1D, 2D and densely packed materials. Understanding the function of model materials from the atomic scale to the mesoscale to the systems level will reveal insight into the phenomena that control battery behavior, establishing the paradigms by which to explore and control other storage systems. Examples of the research results from the Center will be described.
Computational Studies of Lithium Manganese and Nickel-Manganese Oxide Spinel Surfaces
Authors: Iddir Hakim , Lau Kah Chun , Curtiss Larry 
Published: February 2020

LiMn2O4 is ideal as a high-capacity Li-ion battery cathode material by virtue of its low toxicity, low cost, and the high natural abundance of Mn. However, this material suffers from Mn dissolution problem that not only induces capacity fade, but can also poison the anode. Several approaches have been devised to mitigate Mn dissolution, including doping, coatings, and even particle shape control. Previous studies have shown that the electrochemical performance and cycling stability of these materials depend not only on the composition, but on the particle morphology as well. Simulations of the structure of low index surfaces of the spinel-structured LiMn2O4 and its derivatives, such as the high voltage LiNi0.5Mn1.5O4 spinel have been performed within the GGA+U approximation, and ab-initio molecular dynamics. New insights resulting from this work, including interactions with electrolytes, will be presented.
This work was supported as part of the Center for Electrochemical Energy Science, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.
Hybrid Li-Ion/Li-Oxygen Battery Materials
Authors: Chan Maria K. Y. , Kinaci Alper , Yang Zhenzhen , Zhan Chun , Lin Chi-Kai , Maroni Victor A. , Trahey Lynn , Yao Zhenpeng , Wu Jinsong , Castro Fernando , Li Qianqian , Dravid Vinayak , Wolverton Chris , Johnson Christopher , Lu Jun , Amine Khalil , Thackeray Michael M. 
Published: February 2020

In the Center for Electrochemical Energy Science (CEES) EFRC, we are investigating a new class of energy storage materials – hybrid Li-ion/Li-oxygen materials – that combine lithium ion and lithium oxygen capacity to deliver high energy storage capacity [1,2]. In this talk, we will discuss our synthesis, characterization, and first principles modeling efforts of these hybrid Li-ion/Li-oxygen materials, in an attempt to understand their electrochemical performance and reaction mechanisms. We will report on the in-situ observations of structural changes during electrochemical cycling, and accompanying first principles studies, in prototypical hybrid materials, Li5FeO4 and αMnO2 [3]. We will present results of high throughput computational searches for new hybrid materials [4]. Challenges and future prospects of hybrid materials will also 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.
[4] S. Kirklin, M. K. Y. Chan, L. Trahey, M. M. Thackeray, C Wolverton, “High-throughput screening of high-capacity electrodes for hybrid Li-ion-Li-O2 cells,” Physical Chemistry Chemical Physics, 2014, 16, 22073.

Figure 1
Surface Segregation Phenomena in La0.6Sr0.4Co0.2Fe0.8O3-δ Subjected to Mechanical Stress
Authors: Araki Wakako , Tanii Wataru , Arai Yoshio 
Published: February 2020

The present study reports on the surface segregation phenomena in La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) subjected to mechanical stress. LSCF samples with mirror-polished surfaces were annealed under uniaxial compression and also four-point bending to investigate the effects of the compressive and tensile stresses on the surface segregation. The annealing was performed at up to 1173 K under up to 100 MPa of mechanical stress. The surface segregaion was examined by using SEM, EDX, and micro-Raman spectroscopy. The Sr-rich phase segregates on the surface, especially where specific surface area is large. The size of the segregated particles increases with increasing annealing time, whereas their number reveals no clear dependence. The number of the segregated particles is fewer, whilst the particle size is larger for the sample annealed under the uniaxial compression, compared to the one annealed without compression. There is a significant difference in the segregation phenomena between the tensile and compressive surfaces annealed under the bending. The effects of the stress distribution as well as the porous structure on the segregation are also demonstrated. In addition to the segregaion, high-temperature creep deformation due to Sr diffusion and grain boundary sliding is observed. Based on the above results, the mechanism for the Sr surface segregation in LSCF under mechanical stress is discussed, considering Sr diffusion under microscopic and macroscopic stress fields. The surface reactivity of LSCF under mechanical stress is briefly discussed.
Analysis of Performance Limiting Factors in Solid-Oxide Iron-Air Redox Battery Operated with Different Redox Couples
Authors: Jin Xinfang , Zhao Xuan , White Ralph E. , Huang Kevin 
Published: February 2020

A new bi-functional fuel-cell/battery hybrid system has recently been developed in the presenter’s group for power generation and 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 storage. During operation, the cathode of the system is constantly open to air, whereas the anode configuration defines the true functionality of the system: power generation when the anode chamber is open to a flowing fuel, and energy storage when the anode chamber is closed next to a neighboring multivalent metal/metal-oxide chemical bed.
The presentation highlights recent progress in computational analysis of physics and chemistry governing the performance of the fuel-cell/battery hybrid. These highlights include the identification of performance limiting factors, analysis of heat flow balance and proposal of strategies to achieve energy efficient hybrid system for simultaneous power generation and energy storage.
Changes in SOFC Cathode Crystallographic Structure Induced by Temperature, Potential and Oxygen Partial Pressure Studied Using in-Situ HT-XRD
Authors: Kivi Indrek , Aruväli Jaan , Kirsimäe Kalle , Heinsaar Alar , Nurk Gunnar , Lust Enn 
Published: February 2020

Reversible changes in the lattice parameters of SOFC cathode were observed depending on the temperature (T), electrode potential (E) and oxygen partial pressure (p
O2) applied. At fixed T and p
O2, the cathode potential noticeably influences the unit cell volume, thus, the oxygen stoichiometry and concentration of vacancies.
The stabilization time of the XRD peak was in minute scale similarly with the plateau time on chronoculonometric curves. Relaxation time of the changes in crystal dimensions are correlated with electrochemical measurement data. The electrode structure (porosity) has strong influence to the shift time of XRD peak.
There was registered only slight influence of oxygen partial pressure and potential to the crystallographic parameters of LSM (La0.6Sr0.4MnO3
−
δ). At the same time for LSC (La0.6Sr0.4CoO3
−
δ) and GSC (Gd0.6Sr0.4CoO3
−
δ) the crystallographic unit cell volume was a function of electrode polarization and oxygen partial pressure. There is no remarkable vacancy formation detectable with HT-XRD in LSM cathode lattice caused by electrode polarizations applied.
Thermochemical crystallographic expansivity study of LSM, LSC and GSC cathodes with in situ HT-XRD method gives valuable experimental data about the crystallographic changes caused by changes in operating parameters like cell potential, temperature, and oxygen partial pressure in cathode compartment and therefore helps to understand thermomechanical and degradation behavior as a function of different conditions applied for SOFC cathode.

Figure 1
High Durability Electrodeposition Painting for SOFC Metal Interconnector
Authors: Inoue Shuichi , Nonaka Hidemasa , Saito Tadashi , Yoda Masakazu , Nakao Tadayuki , Takuwa Yuya 
Published: February 2020

Osaka Gas Co., Ltd. has been developing electrodeposition painting method for SOFC metal interconnector coating since 2010. Although the general electrodeposition painting was mainly consisted of resin with small amount of ceramics as a pigment, we have successfully increased the amount of ceramics in the coating and this method was adopted to SOFC metal interconnector coating. Generally, SOFC interconnector had the complex structure with the gas flow path. This method had the advantage of coating thickness uniformity regardless of the interconnector structure and mass productivity.
We have investigated to enhance the durability of the SOFC interconnector with this method.In addition, we aimed to reduce the cost of the metal interconnector by using the normal stainless steel, not stainless steel specially designed for the SOFC component.
The composition of Co-Mn spinel-type oxide widely used in this field was selected as the coating ceramics.
As is often the case with interconnector, the protective coating needed to be partially coated. The wet coating method like electrodeposition painting needed to be fired after coating to remove the resin and sinter the spinel-type oxide.
From the standpoint of processing cost, it was desirable to be fired in air, but non coated area was severely oxidized and Cr2O3 layer showing high ASR was formed on the surface of the stainless steel.
In order to prevent the oxidation of non-coated area and sinter the spinel powder enough, two steps of firing have been normally taken: the resin was removed in air first, then the Co-Mn spinel powder was sintered in the reduction atmosphere. This process cost tends to be high due to changing atmosphere.
However, our electrodeposition painting method did not need to be fired in two steps because its resin was acrylate resin which was removed completely even in the reduction atmosphere.
Cross section images of the post anneal coating showed the dense structure and the uniform layer thickness.
ASR test over 10,000hr showed excellent durability at the both of the continuous condition and thermal cycle condition.
The Cr diffusion from the stainless steel was also evaluated, it showed the high prevention of Cr diffusion.
The variability of coating weight were quite small, it was concluded that this electrodeposition painting method is suitable for mass production.
Manufacture of Solid Oxide Fuel Cells Using Electroless Co-Deposition: A Review of Work Carried out at Edinburgh Napier University
Authors: Davidson Alan , Wilson Callum , Shearer Neil 
Published: February 2020

This paper reviews work carried out at Edinburgh Napier University on the manufacture of anodes and cathodes for solid oxide fuel cells (SOFCs) using electroless co-deposition of nickel and ceramic powders. Most of the work has been focused on anodes where the co-deposition of nickel and yttria stabilised zirconia (YSZ) negates the need for traditional manufacturing methods such as screen printing and removes the need for expensive and time consuming high temperature consolidation of the ceramic part of the composite.
Work has also been carried out manufacturing cathodes by electroless co-deposition replacing YSZ with lanthanum strontium manganite and lanthanum nickel ferrite. Anodes and cathodes of both planar and tubular designs of SOFCs have been successfully manufactured using this technique and process variables have included ceramic particle size, bath pH, ceramic loading, the inclusion of pore-formers and tubular orientation in the electroless bath.
Testing of the electrodes included impedance analysis, long term degradation testing at 850oC for 500 and 1000-hours, high temperature electrical conductivity measurements, scanning electron microscopy and energy dispersive X-ray analysis.
The cost benefits of the electroless co-deposition process compared with other conventional processes are also discussed.
Boundary Observation and Contrast Tuning of Ni/YSZ Anode by TEM and FIB-SEM
Authors: Liu Shu-Sheng , Matsumura Syo , Koyama Michihisa 
Published: February 2020

The most widely used anode material in SOFC is Ni/yttria stabilized zirconia (Ni/YSZ). Its microstructure depends on the fabrication techniques, and determines its performance. Electron microscopy is often adopted to characterize the microstructure in wide scales. In this report, we focus on the microstructure observation of conventional Ni/YSZ anodes in two open issues: atomic structure of boundary by transmission electron microscopy (TEM) and phase contrast tuning by focused ion beam-scanning electron microscopy (FIB-SEM).
It is well-known that Ni/YSZ interface and Ni/YSZ/pore triple-phase boundary (TPB) play important roles in the stability and reaction activity of Ni/YSZ anodes. However, most of the microstructure researches related to interface and TPB lie in micro- or nano-scales. In atomic scale, few reports on the interfaces of conventional Ni/YSZ anode can be found. Moreover, there is no experimental study on the real atomic structures of TPB. So, high-resolution transmission electron microscopy (HRTEM) and scanning TEM (STEM) were adopted to observe the atomic structures at the interfaces and TPBs. Before observation, the pores of the porous electrode were infiltrated by low viscosity epoxy resin under vacuum, so that they could be easily distinguished in a microscopy and the bulk cell could be readily handled. The specimen for TEM was lifted out in a focused ion beam-scanning electron microscopy (FIB-SEM). After observation, high-index contact surfaces (e.g. Ni(15 13 1)/YSZ(4 4 10)) were found between Ni and YSZ. At TPB, YSZ(200) was found to be the contact surface while Ni(111) shows an included angle of ~13° with YSZ(200).
3D reconstruction is becoming popular with the help of several techniques, such as FIB-SEM and TEM. In case of FIB-SEM, many of previous works showed indistinct contrast among different phases, which will make the analysis difficult and the results distorted in some extent. Herein, we used a high-resolution machine (HITACHI MI4000L) and tuned many conditions to improve the contrast. The related mechanism will be discussed. For Ni/YSZ anode, distinct contrast was obtained among Ni, YSZ and pore (actually resin) by using InLens detector. The three phases could be automatically segmented by Avizo software. Then the 3D microstructure is reconstructed.
Architectured Interfaces and Electrochemical Modelling in an Anode Supported SOFC
Authors: Geagea Maya , Ouyang Jian , Chi Bo , Delloro Francesco , Chesnaud Anthony , Ringuedé Armelle , Cassir Michel , Thorel Alain 
Published: February 2020

The route for the increase in SOFC performances is many-fold: i/ in the low current density domain, through the enhancement of the catalytic properties of the electrodes, i.e. via a higher Triple Phase Boundary (TPB) density, hence a higher exchange current and a lower activation overpotential, ii/ in the ohmic loss region, through lower resistance, i.e. via thickness reduction, materials with a higher conductivity, iii/ in the high current density region, via the optimization of the electrodes microstructure, i.e. the control of the porosity, of the tortuosity and percolation of phases. Taking ideas from the batteries community, where the conceptual design of electrodes is much more mature, the present work proposes to explore how the corrugation of electrode/electrolyte interfaces impacts the performances.
This approach was applied to the anode/electrolyte interface of a SOFC based on standard compositions, YSZ (or YDC) for the electrolyte, and YSZ (or YDC) + nickel for the anode. The corrugation of surfaces was obtained through the patterning of this interface with different geometries (flat, pyramids, shallow and deep ellipsoids) at the 10-100 µm scale by cold pressing, templating or serigraphy. Thin electrolyte layers have been deposited on top of these architectures by Atomic Layer Deposition (ALD). In parallel, an electrochemical model was carried out and implemented by considering masses and charges conservation, gas transport and electrochemical reaction kinetics throughout the interface in FEM (finite element method) with COMSOL Multiphysics. The results showed a 25 % increase in the total current density for a certain ellipsoid geometry.
Electrochemical Performance of Plasma Sprayed Metal Supported Planar Solid Oxide Fuel Cells
Authors: Gupta Mohit , Weber André , Markocsan Nicolaie , Gindrat Malko 
Published: February 2020

High material and production costs are key barriers to the widespread commercialization of solid oxide fuel cells (SOFCs). Thermal spray techniques are a low cost alternative for the production of SOFCs. The objective of this work was to fabricate single cells by thermal spraying and to evaluate the impact of electrolytes and anodes, differing in terms of thickness, composition and microstructure, on the cell performance.
In this work, the anode layer was deposited on a planar ferritic steel support with in-plane dimensions 50 mm X 50 mm, thickness of 550 µm and 35-40% porosity by atmospheric plasma spraying (APS). The anode material consisted of nickel, yttria stabilized zirconia (YSZ) and a pore former. The anode layer thickness was around 60 µm. The electrolyte layer was deposited by a low pressure plasma spray technique called plasma spray-thin film (PS-TF) which can produce dense coatings at high deposition rates. The electrolyte material consisted of 3YSZ and 8YSZ consisting of different powder morphologies such as fused and crushed and agglomerated and sintered. In order to ensure sufficient gas tightness, electrolytes thicknesses of 50-90 µm were deposited. The cathode layer was screen-printed and sintered in-situ during the start-up of the electrochemical tests. The cathode material was La0.58Sr0.4Co0.2Fe0.8O3-δ (LSCF). It must be noted that no diffusion barrier layer was deposited between the YSZ electrolyte and the LSCF cathode which will affect the performance and stability of the cells. The electrochemical tests were performed in a temperature range of 600-800°C at atmospheric pressure under various gas compositions of H2, H2O and N2 on the anode side and of O2 and N2 on the cathode side while keeping the total gas flow constant. Current-voltage characteristics and impedance spectra were measured.
Porous anodes and dense electrolytes were achieved in all cases. The measured open cell voltage indicated acceptable electrolyte gas tightness. Power density of produced cells at an operating voltage of 0.7 V were measured as high as 600 mW/cm2. In this work, the impact of spray parameters and applied layer thicknesses on the gas tightness of the electrolyte and the area specific resistance of the cell will be discussed.

Keywords: plasma spraying, solid oxide fuel cells, electrochemical characterization, impedance spectroscopy
Characterization of Cracks and their Effects on the Effective Transport Pathways in Ni-YSZ Anodes after Reoxidation Using X-Ray Nanotomography
Authors: Nakajo Arata , Kiss Andrew M. , Cocco Alex P. , Harris William M. , DeGostin M. B. , Greco Fabio , Nelson George J. , Peracchio Aldo A. , Cassenti Brice N. , Deriy Alex , Wang Steve , Chen-Wiegart Yuchen , Wang Jun , Van herle Jan , Chiu Wilson K. S. 
Published: February 2020

Reduction-oxidation (redox) cycling of Ni-based electrodes for solid oxide fuel/electrolysis cell irreversibly alters their microstructure and can cause the fracture of the electrolyte. Non-destructive 3-D imaging techniques enable tracking the microstructural changes that occur during the cycling [1]. Despite the recent advances, the understanding of how local 3-D geometrical features in the heterogeneous electrode material contribute to the material degradation remains incomplete.
Absorption contrast X-ray nanotomography (XNT) of a same Ni(O)-yttria-stabilized zirconia (YSZ) sample was performed at the NiO K-edge white-line peak (8348 eV), before and after exposure to air at 800°C during 45 minutes. A complimentary XNT at 8376 eV confirmed a degree of oxidation in the range of 98%. The morphology of the Ni(O) phase was as expected completely different after re-oxidation. The spatial resolution in the range of 20 nm [2] further enabled the detection of cracks in the brittle YSZ phase. 3-D local curvature measurements were first performed to identify and characterize the crack initiation sites. Then, the capabilities of simple fracture mechanics models combined with curvature measurements were tested in the view of rapidly pinpointing the locations vulnerable to redox cycling. Finally, the detrimental effects of the cracks on the effective 3-D transport pathways in the Ni-YSZ anode under polarization was investigated using a skeleton-based discrete representation of the imaged volume and an analytical electrochemical fin model [3]. Topological properties, effective ionic conductivity and polarization resistance were calculated before and after oxidation. For the latter estimate, the effect of cracked YSZ network was considered first alone; that of the spatial re-distribution of triple-phase boundaries induced by re-oxidation will be included in the future.
[1] A. M. Kiss, W. M. Harris, S. Wang, J. Vila-Comamala, A. Deriy and W. K. S. Chiu, Applied Physics Letters 102 (2013) 053902.
[2] J. Vila-Comamala, Y. Pan, J. J. Lombardo, W. M. Harris, W. K. S. Chiu, C. David, Y. Wang, J. Synchrotron Rad. 19 (2012), 705–709.
[3] G. J. Nelson, A. Nakajo, B. N. Cassenti, M. B. DeGostin, K. R. Bagshaw, A A. Peracchio, G. Xiao, S. Wang, F. Chen, W. K. S. Chiu, Journal of Power Sources 246 (2014) 322-334.