bluuebunny/crossref_metadata_2025_split huggingface dataset:
Examination of Gadolinium Doped Ceria Mixed with Yttrium Stabilized Zirconia Mixed Ionic Electronic Conducting Solid Electrolytes for Use As Reversible High Temperature Cells
Authors: Dale Olivia R. , Virkar Anil , Simpson Michael 
Published: July 2021

Reversible cells can be used as solid oxide fuel cells (SOFC) and solid oxide electrolyzer cells (SOEC). The solid electrolytes used for such cells frequently have pure ionic conduction with insignificant electronic conduction. A previous study (Virkar and Tao, 2015) has shown that cells made of ceria doped yttrium stabilized zirconia (YSZ), a mixed ionic electronic conducting (MIEC) material, can be made to operate at the same efficiency level and with superior stability compared to a pure ionic conductor, like pure YSZ. This work is a continuation of that study, examining the use of gadolinium doped ceria (GDC) mixed with YSZ. The MIEC cell, 8mol%GDC+YSZ, will be further tested and designed to consume fuel or water vapor, generate power or hydrogen, and release heat at the same rate as the pure ionic conducting cell, YSZ, when operating in SOFC or SOEC mode. Future testing will also determine if the GDC MIEC cell can match or exceed the durability of the ceria doped YSZ.
The electrolyte layer, made of either pure 8YSZ or 8YSZ doped with 8mol%GDC, was die pressed and sintered at 1400oC (2oC/min) for five hours. On one side of the electrolyte, the anode interlayer is mixed with isopropyl alcohol and painted on the electrolyte's surface. The anode interlayer is composed of 50wt% NiO and 50wt% 8YSZ. The cell was heated to 950oC (2oC/min) for one hour. The anode functional layer, 70wt% NiO and 30wt% 8YSZ, was painted on top of the anode interlayer. The sample was then again heated to 950oC (2oC/min) for one hour to burn off any organic compounds. A cathode interlayer was then painted on the other side of the electrolyte layer. The cathode interlayer was also painted on and consists of 50wt% lanthanum strontium manganite (LSM) and 50wt% YSZ. The cell is heated to 1200oC (2oC/min) for two hours. Finally, a pure LSM layer is painted on top as the cathode current collector material and heated to 1100oC (2oC/min) for one hour to ensure good porosity. The cells were then sealed by compression-loading at the edges using glass-mica seals.
Results of tests will be reported for both SOEC and SOFC modes at 800oC. Data to be reported include open-circuit voltage, area-specific resistance, corresponding ionic currents based on an applied voltage, and long-term durability of the two cells in both SOFC and SOEC modes.
Influence of the Ti Content on the Electrochemical Performance and Surface Properties of (La0.6Sr0.4)0.99Co1−
xTixO3−

δ
Oxygen Electrode
Authors: Heinsaar Alar , Kivi Indrek , Moeller Prit , Kooser Kuno , Käämbre Tanel , Aruväli Jaan , Lust Enn , Nurk Gunnar 
Published: July 2021

Mixed ionic and electronic conducting (MIEC) oxides are being used as solid oxide fuel cell (SOFC) electrode materials [1, 2]. La1−
xSrxCoO3−

δ
(LSC) oxygen electrode has perovskite-type (ABO3) structure. The properties of these materials are determined by chemical composition, crystallographic structure and oxidation state of B-site elements. These electrode materials have good catalytic activity towards oxygen reduction reaction and oxide ion oxidation, but they have limited durability if carbon dioxide or humidity are presented in the electrode gas compartment. It is important to increase the long-term durability of these electrode materials at natural gas conditions, i.e. in gas from the external environment with micro-concentrations of impurities like water and carbon dioxide [3, 4, 5].
The SOFC oxygen electrode powders with different stoichiometry ((La0.6Sr0.4)0.99Co1−
xTixO3−

δ
, x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were prepared by using the thermal combustion method [6]. X-ray diffraction (XRD) analysis was used to characterize the crystallographic structure of the synthesized powders. Symmetrical cells for Electrochemical Impedance Spectroscopy (EIS), Focused Ion Beam Time of Flight Secondary Ions Mass Spectrometry (FIB-TOF-SIMS) and X-Ray Photoelectron Spectroscopy (XPS) were made using synthesized powders. Prepared symmetrical cells were characterized at different temperatures, potentials, gas compositions i.e. conditions.
Systematic impedance analysis showed that materials with bigger cation (Ti4+), doped into the LSC B-site, increase the material long-term stability against impurities like carbon dioxide and water. As a result of the work, the optimal amount of dopant (Ti4+) was found, which increased the stability of the material in the environment with impurities.
[1] C. Singhal, K. Kendall (Eds.), High-Temperature Solid Oxide Fuel Cells: Fundamentals, Design and Applications, Elsevier, Oxford, (2003).
[2] Weber, E. Ivers-Tiffée, J. Power Sources 127, 273 (2004).
[3] Kivi, J. Aruväli, K. Kiresimäe, A. Heinsaar, G. Nurk, E. Lust, J. Electrochemical Society, 160, F1022 (2013).
[4] Kivi, J. Aruväli, K. Kirsimäe, P. Möller, A. Heinsaar, G. Nurk, E. Lust, J. Solid State Electrochem, 21, 361 (2017).
[5] P. Jiang, Int J. Hydrogen Energy, 44, 7448 (2019).
[6] P. Bansal, Z. Zhong, J. Power Sources, 158, 148 (2006).
Simulation and Analysis of Thermal Stress and Sintering Warpage of Planar Solid Oxide Fuel Cells
Authors: Lang Shaocheng , Zhang Jihao , Wu Mingtao , Zheng Jianmin , Zhao Xin , Xiao Liusheng , Sun Zaihong , Han Minfang , Yuan Jinliang 
Published: July 2021

Solid oxide fuel cell (SOFC) is one of the new energy conversion technologies producing electricity and heat from fuel and oxidant through an electrochemical reaction. The high operating temperature has many advantages including high efficiency, flexible fuel adaptability and low emissions. However, it has also some drawbacks, e.g., thermal expansion mismatches among the involved materials, particularly when the temperature reaches around 1400 oC during the sintering process, which may cause non-uniform distribution of thermal stress and even further deformation and warpage observed in the cell manufacturing steps.
A three-dimensional CFD (computational fluid dynamics) simulation model is developed to study the thermal stress distributed in the sintered function layers of the anode-supported planar SOFC unit cells (10×10 cm2) using a finite element method. Five layers are included, i.e., cathode and its separation layer (GDC/LSCF, 70 µm), anode support and active layers (Ni/YSZ, 550µm), and electrolyte layer (YSZ, 30 µm) between them. In terms of the thermal stress and deformation, the predicted results are presented and discussed for the sintered unit cells with different angels located around the four cornels.
It is found that the maximum thermal stress occurs at the interface between the electrode and electrolyte; the magnitude and distribution of thermal stress at the interfaces are closely related to the material thermal properties; the maximum deformation about 13 mm in the thickness direction is predicted for the 90-angel shaped cornels at the sintering temperature 1400 oC, which is bigger than that for the case with the circular shaped cornels; the deformation magnitude depends not only on the maximum thermal stress, but also the difference between the maximum and minimum thermal stress. The findings and predicted results may be applied for optimization of design and sintering conditions for SOFC unit cells.
Acknowledgements
This work is supported by the National Key Research and Development Project of China (2018YFB1502204, 2018YFB1502203, 2018YFB1502205), the Ningbo major special projects of the Plan “Science and Technology Innovation 2025” (2018B10048).

Figure 1
Computational Predictions of Upscaling Solid Oxide Electrochemical Reactor Performances By Pillared Electrolyte | Electrode Interfaces
Authors: Jang Inyoung , Alexander John , Kawale Shrikant , Kelsall Geoff 
Published: July 2021

Increasing densities of electrode | electrolyte interfacial areas (and triple phase boundaries) of solid oxide fuel cells or electrolyzers (solid oxide electrochemical reactors, SOERs) offers one means of increasing performance, reproducibility and potentially decreasing cost. Three-dimensional (3D) structuring of those interfaces can be achieved by 3D printing, but modelling is required to optimize geometries. Using kinetic parameter values from the literature, COMSOL finite element software was used to predict effects of YSZ electrolyte (c.f. electrode) pillar geometries on SOER performance, relative to planar YSZ electrolytes. The modified geometries are based on yttria-stabilized zirconia (YSZ) electrolyte pillars on top of < 10 mm thick planar YSZ electrolyte, thereby increasing interfacial to geometric area ratios. Electrolyte layers have been inkjet printed on Ni(O)-YSZ substrate negative electrode precursors and porous lanthanum strontium manganite (LSM) positive electrode have been printed over the YSZ, after sequential sintering producing complete SOERs: H2O-H2 | Ni(O)-YSZ | YSZ-YSZ pillars | YSZ-LSM | LSM | O2.
Results will be reported showing that despite interfacial electrode | electrolyte areas being up scaled by factors of 10-100 - depending on pillar diameter (5-50 mm) and height (15-150 mm) - current densities were predicted to increase by only 70-100% due to increased current path length along the pillars, which increases ohmic potential loss relative to the faradaic impedance. Hence, predictions of enhancement depend strongly on the kinetic parameters of the electrode material.
Accelerating Aging Test on Solid Oxide Cell Interconnects
Authors: Daviran Samaneh , Poitel Stéphane , Montinaro Dario , Walter Christian , Herbrig Kai , Ouweltjes Janpieter , Van herle Jan 
Published: July 2021

The degradation of metal interconnects (ICs) is one of the main lifetime limiting issues in Solid Oxide Cells (SOCs). Chromium oxide thermally grows on the substrate surface that causes ohmic loss and its vapors poison the oxygen electrode reaction (OER). Mn-based spinels are presently among the materials of choice to protect ICs to prevent Cr diffusion.
As the target lifetime is around 40000h, it is of interest to design accelerated ageing tests, under harsher than nominal operating conditions, to simulate the long-time ageing behavior at nominal conditions.
In this study, the performance of IC coatings was investigated with accelerated ex-situ corrosion ageing tests, in which the operating condition of the air-side interconnect was simulated. Temperature and humidity were selected as test variable parameters. Area Specific Resistance (ASR) and Cr depletion/migration were studied for the stressed conditions. Tests were carried out on stainless steel substrate with Mn-Cu-Oxide and Mn-Co-Oxide as protective coatings.
Ageing tests over 1000h at different temperatures (750-950°C) and humidity (above 15%RH) were run while monitoring the ASR of the samples. Fig. 1 shows the ASR results for the samples run at different temperatures and in dry condition. Based on Fig. 1a-e, it is observed that the ASR trends remain constant during the test time. Although 916°C is well above nominal operating temperature, the ASR showed constant value within a reasonable range. At a test temperature 950°C (Fig. 1f), the ASR behavior of samples containing Co-Mn Oxide protective coating is the same found for lower temperatures; however, a sharp ASR increase in Mn-Cu Oxide coated samples can be observed. Applying humidity to high-temperature conditions also may help to accelerate the test, and its results will be presented. SEM/EDX post-test characterization provides information on the scale morphology and helps to understand the different behaviors at different stressed conditions.
Keywords: SOC; interconnect; protective coating; ageing test; accelerating test; Cr diffusion; ASR;

Figure 1
Praseodymium Manganate-Based Perovskites as Anode Materials for Fuel-Assisted Solid Oxide Electrolysis Cells
Authors: Yaremchenko Aleksey , Boiba Dziyana , Patrakeev Mikhail , Arias Serrano Blanca I. 
Published: July 2021

Long-term degradation remains the main issue for the viability of solid oxide electrolysis cell (SOEC) technology as a practical hydrogen production system. The major specific degradation mechanism in SOECs relates to delamination phenomena at or near electrolyte/anode interface. The principle of so-called fuel-assisted electrolysis is to supply the carbon-containing species which can react with oxygen at the anode side thus bringing down the oxygen chemical potential at the electrolyte/anode interface and improving its stability. The present work is aimed at the characterization of PrMnO3-based perovskites for potential application as anodes in solid oxide fuel-assisted electrolysis cells.
Pr0.6-x
A0.4MnO3
±δ (A = Sr, Ca; x = 0 and 0.05) were synthesized by glycine-nitrate combustion technique. The characterization included XRD, SEM/EDS, XPS, dilatometry and thermogravimetry, measurements of electrical properties and oxygen nonstoichiometry. XRD analysis confirmed the formation of solid solutions with orthorhombic perovskite structure. The oxides exhibit negligible variations of oxygen content under oxidizing conditions, while reducing p(O2) below 10-4 atm results in oxygen losses from the lattice and reduction of Mn cations. The low-p(O2) stability boundary of the perovskite phase at 800°C corresponds to ~10-17-10-16 atm; the stability domain is wider for Ca-substituted compositions and narrows with introduction of A-site vacancies. Dilatometric studies confirmed a good thermomechanical compatibility with common solid electrolytes. The electrical conductivity of Pr0.6-x
A0.4MnO3
±δ ceramics is p-type electronic and decreases with reducing p(O2), but still exceeds 40-50 S/cm under anticipated oxygen electrode operation conditions. The electrochemical performance of Pr0.6-x
A0.4MnO3
±δ electrodes was evaluated in contact with yttria-stabilized zirconia solid electrolyte as function of relevant parameters (fabrication conditions, with and without buffer layers, with praseodymia or ceria-based additives).
Additive Manufacturing of Large Area SOC with Advanced Features
Authors: Lira Maritta , Kostretsova Natalia , Bernadet Lucile , Morata Alex , Torrell Marc , Tarancón Albert 
Published: July 2021

The incorporation of electrochemical-based energy devices such as Solid Oxide Cells (SOC) to the renewable energy sector in the frame of a modern energy generation strategy could be beneficial, taking into account the opportunity to store renewable energy overproduction as hydrogen (SOEC operation mode) as well as to use, subsequently, this hydrogen as a fuel for energy generation in the same device (SOFC operation mode).
Nowadays, the common-used SOC manufacturing approaches, in most cases, meet the limits originated by the capabilities of the techniques to produce the ceramic components with more complicated geometries, in respect to planar or tubular shapes. To overcome these constrains, the additive manufacturing (AM), commonly referred as 3D Printing, could be applied for the production of the SOC-based devices with enhanced features.
The use of AM allows a high degree of design freedom and opens a wide field for fabrication of functional ceramics with high resolution of herarchical geometries, optimized through computational elements by CAD design and stereolithographic (SLA)ceramic printing. At the same time the AM, specifically the SLA in this work, allows the simplification of the whole SOC manufacturing process making it tunable in geometry and size opening a new trend for fabrication of large area SOC with enhanced features in terms of active area or other functionalities. In a more effective way in terms of time, cost and waste material reduction.
The enhancement of the performance of the SOC device has been proved due to the increase of the active area by the production of complex shaped electrolytes using the 3D Printing process. To demonstrate,its scalability, large area 3YSZ electrolytes (~60-70 cm2) with the advanced geometries were fabricated by stereolithography three-dimensional printer, to be implemented as an electrolyte-supported cell using YSZ composites with lanthanum strontium manganite (LSM) as a cathode and nickel composites as an anode, i.e. Ni-YSZ/3YSZ/LSM-YSZ.
Physical and Electrochemical Characterization of La0.25Sr0.25Ca0.40Ti0.95Ni0.05-xSnxO3–δ (x=0...0.05) Reversible Solid Oxide Cell Fuel Electrode
Authors: Maide Martin , Moeller Prit , Aruväli Jaan , Lust Enn , Nurk Gunnar 
Published: July 2021

Redox stability and sulfur- or carbon tolerance of solid oxide fuel cell electrodes are deeply defined by the chemical composition of the materials 1-3. Therefore, much effort is invested in finding more chemically stable and electrochemically active materials. Generally, mixed ionic electronic conductor (MIEC) fuel electrodes offer better stability at the expense of lower electrocatalytic activity towards H2 and CO oxidation, whereas, exsolution of catalytically active nanoparticles may help increase the latter 4. Recently, excellent electrocatalytic performance has been demonstrated for lanthanum and calcium doped strontium titanate based MIEC materials in fuel cell and electrolysis modes 5,6.
In this study, chemical stability and electrochemical performance of tin and nickel co-doped strontium titanate MIEC electrode materials (La0.25Sr0.25CaxTi0.9Ni0.50-ySnyO3–δ) were studied. Preliminary characterization included chemical stability studies followed by electrochemical characterization of most stable materials.
All studied fuel electrode materials were synthesized using standard nitrate combustion method. All the single cells were prepared using commercially available 250 μm thick Zr0.89Sc0.10Ce0.01O2-
d (10Sc1CeSZ, Kerafol) electrolyte support and La0.6Sr0.4CoO3-
δ
(LSC) oxygen electrode. Fuel and oxygen electrodes were sintered for 5 hours at 950°C and 900°C, respectively. Scanning electron microscopy, X-ray diffraction, FIB-TOF-SIMS and ICP-MS methods were used to characterize materials. Electrochemical characterization was carried out at temperature range from 700 to 850 °C in various H2O, CO2, H2 and Ar inlet concentrations.
The chemical stability was greatly influenced by the A-site deficiency and B-site composition of the material as confirmed by comparing the FIB-TOF-SIMS data of as-synthesized and 100 hours reduced fuel electrode materials. Furthermore, as expected, a variation in Ni and Sn content resulted in large variations in studied single cell’s performances. Finally, the stability to the sulphur impurities in fuel electrode gas was investigated for some studied materials.
References:

S. Tao, J. T. S. Irvine, J. Electrochem. Soc., 151, A252-A259 (2004).

S.-E. Yoon, J.-Y. Ahn, B.-K. Kim, and J.-S. Park, Int. J. Hydrogen Energy, 40, 13558 (2015).

Q. X. Fu, F. Tietz, Fuel Cells, 8, 283 (2008)

G. Kim, S. Lee, J. Shin, G. Corre, J. T. S. Irvine, J. Vohs, R. J. Gorte, Electrochem. Solid State Lett., 12, B48 (2009).

A. Yaqub, N. K. Janjua, C. Savaniu, J. T.S. Irvine, Int. J. Hydrogen Energy, 40, 760 (2012).

A. D. Aljaberi and J. T. S. Irvine, J. Mater. Chem. A, 1, 5868–5874 (2013).
Thermal Residual Stress and Failure Probability of Functionally Grade Ni-YSZ Anode of Solid Oxide Fuel Cells Using a Finite Element Analysis
Authors: Zhang Xi , Yan Zilin , Zhou Yexin , Zhong Zheng 
Published: July 2021

Due to the differences of thermal expansion coefficient between the components in the solid oxide fuel cells (SOFCs), there is a large residual thermal stress in the fabrication process of the cell. In this study, the functionally graded (FG) Ni-YSZ anode design was introduced between Ni-YSZ support and YSZ electrolyte to mitigate the thermal residual stress in SOFC. In the current FG anode design, composition of Ni and YSZ was varied according the function of
φ
(Ni) =
k
(
t
/
H
)

n

, where
k
is a constant which is equal to the volume fraction of Ni in Ni-YSZ anode support layer,
t
is the distance to the electrolyte,
H
is the thickness of the FG anode layer and
n
is the exponential factor. In the numerical model, the FG anode layer was evenly divided into
m
sublayers. The porosity was set to a constant value of 0.3 and uniformly distributed in the anode. The residual stress of the anode was modeled as the thermal stress when the anode was cooled from the reduction temperature of 1200 oC to room temperature of 20 oC. Residual thermal stress was calculated by finite element method (FEM) using the commercial ANSYS package. Failure probability of functionally graded SOFC was evaluated using the classic Weibull probability model.
The effects of sublayer number
m

=

(1, 2, 3, 4), exponential factor
n

=

(0.25, 0.5, ..., 4.0) and gradient layer thickness
H

=

(20, 30, 40 μm) on the stress and failure probability of functionally graded SOFC are discussed. The calculation results show that the FG anode layer can obviously reduce the stress, and effectively decrease the stress concentration between electrode and electrolyte. The failure probability can be reduced by two orders of magnitude at most as compared with the conventional SOFC. Under the same exponential factor
n
, appropriately increasing the number of sublayers
m
can reduce the stress of the gradient layer. The sublayers number
m

=
2 is a suitable value. With the increase of the thickness of the gradient layer, the anode failure probability increases. The research provides a reference for further optimizing the stress in SOFC.
Synthesis of Borate Doped La10Ge6O27: Confirming the Presence of a Secondary Conducting Pathway
Authors: Thomas Samuel W , James Matthew Samuel , Stockham Mark P , Deakin Joshua , Jarvis Abbey , Slater Peter R. 
Published: July 2021

Lanthanum silicate/germanate apatite materials have attracted significant interest as Solid Oxide Fuel Cell electrolytes due to their high oxide ionic conductivity at lower temperatures (500-800 ⁰C). In these structures, oxide ion conduction is due to interstitial pathways associated with the high oxygen excess within the structures. Therefore, cation doped La8+xA2-x(M6-xBxO4)O2+x/2 (A = Ca, Sr, Ba; M = Si and Ge; B = Mg, Ga, Al, Zn, B) have been reported to increase oxide ion conductivity via the introduction of excess oxide ions.[1-3]

Whilst apatite silicate has higher conductivities at lower temperatures due to lower activation energies, apatite germanates can achieve higher oxygen excess and therefore higher conductivities at elevated temperatures. However, in increasing oxygen content there is a change in symmetry from hexagonal to triclinic leading to a subsequent reduction in conductivity.[4] Previous studies have shown the issue may be overcome by the incorporation of Y doping e.g La8Y2GeO6O27 which leads to stabilisation of the higher conducting hexagonal phase.[5]

Herein, we demonstrate the successful incorporation of borate into La10-xYxGeO6O27 and show that it also stabilises the higher conducting hexagonal form. We show that B can be doped into both the Ge site and the oxide ion channels. Interestingly, the conductivity of samples with borate in the channels (which would be expected to block channel oxide ion conductivity along the c direction) is still reasonably high, which supports suggestions that there is significant conduction perpendicular to the channels in these apatite germanates.
[1] A Orera and P R Slater, Chem. Mater 2010 22 675-690
[2] P M Panchmatia, A Orera, G J Rees, M E Smith, J. V. Hanna, P. R. Slater and M. S. Islam, Angew. Chem. Int. Ed, 2011 50 9328-9333
[3] E Kendrick, M S Islam and P R Slater, J. Mater. Chem 2007 17 3104-3111.
[4] M S Chambers, P Chater, I R Evans and J S Evans, Inorg. Chem., 2019 58(21)14853-14862,
[5] A Najib, J. E. H. Sansom, J. R. Tolchard, P. R. Slater and M. S. Islam, Dalton Trans., vol. 19, pp. 3106-3109, 2004.