bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Enhancing Phase Stability and CO2 Tolerance of Ba0.5Sr0.5Co0.8Fe0.2O3-δ
Authors: Ivers-Tiffée Ellen , Almar Laura , Szász Julian , Meffert Matthias , Störmer Heike , Gerthsen Dagmar 
Published: February 2020

High-temperature devices such as solid oxide fuel cells (SOFCs) and oxygen transport membranes (OTMs) require materials with high chemical, microstructural stability as well as high catalytic activity towards the oxygen reduction reaction. In its cubic phase the mixed ionic-electronic conductor Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) presents outstanding oxygen transport properties and exceedingly low cathode resistance [1]. However, the application in OTMs has been hampered by its degrading oxygen permeability in the relevant temperature range (600 – 800 °C). It was shown by our group [2], that the multivalent Co-cation prefers within this temperature range a higher valence which destabilizes the cubic structure favoring the hexagonal phase formation.
Various doping strategies with transition metals like, e.g., Y have shown beneficial effects with respect to stabilizing the cubic BSCF phase and preservation of the oxygen conductivity [3,4]. In this direction the effect of B-site partial substitution with Y, Ti or Nb has been studied thoroughly by our group using scanning electron microscopy (SEM) and analytical (scanning) transmission electron microscopy ((S)TEM) combined with energy dispersive X-ray spectroscopy (EDXS).
In addition, the oxygen reduction reaction of pure and doped BSCF electrodes is investigated in oxygen-nitrogen mixtures (pO2 = 0.02 to 0.4 atm) as well as in CO2-atmospheres (0.1…1 vol. % CO2) using symmetrical SOFC cells with Ce0.9Gd0.1O2-δ (CGO) as electrolyte from 600 to 800 °C. Characterization by electrochemical impedance spectroscopy (EIS) combined with the distribution of relaxation times (DRT) reveals an enhanced tolerance of doped BSCF cathodes, in particular Y-doped, towards the adsorption-desorption of CO2 molecules. Channeling enhanced microanalysis (ALCHEMI) investigations on Y-doped BSCF demonstrate the coexistence of Y ions on both cation lattice sites with up to 55 % of the Y-ions located on the unintended A-lattice site [5,6].
Overall this study shows that enhancing the phase stability and the CO2 tolerance of BSCF by a rational substitution of the B-site is plausible while the high performance and its excellent oxygen transport properties are kept.

References:

[1] Z. Shao, S.M. Haile. Nature, 431 (2004) 170-173.
[2] P. Müller, M. Meffert, H. Störmer, D. Gerthsen. Microsc. Microanal., 19 (2013) 1595-1605.
[3] P. Haworth, S. Smart, J. Glasscock, J.C. Diniz da Costa. Sep. Purif. Technol., 94 (2012) 16-22.
[4] M. Meffert, L-S Unger, L. Grünewald, H. Störmer, S. F. Wagner, E. Ivers-Tiffée, D. Gerthsen. J. Mater. Sci., 52 (2017) 2705-2719.
[5] J. C. H. Spence and J. Taftø. J. Microsc., 130 (1983) 147-154.
[6] M. Meffert, H. Störmer, D. Gerthsen. Microsc. Microanal., 22 (2016) 113-121.
(Invited) Modeling Transport Processes in Perovskite-Based Mixed Ionic-Electronic Conducting Membranes
Authors: Kee Robert J. , Zhu Huayang 
Published: February 2020

Although many mixed ionic-electronic conductors (MIEC) share crystallographically similar doped perovskite structures, wide ranges of particular materials offer a diverse range of practically useful applications. Broadly speaking, the MIEC materials may be dominantly oxygen-ion conductors or proton conductors. The present paper is primarily concerned with transport processes that are relevant for membrane applications. Such applications include fuel cells, electrolyzers, gas separations, membrane reactors, and electrochemical compressors. The presentation uses illustrative examples.
In practice gases must react at the membrane surfaces to incorporate or release ions or other charge-carrying defects. The mobile charge carrying defects can include oxygen vacancies, protons, and a variety of small polarons. The defect transport may be represented in terms of Nernst-Planck fluxes. An internal electrostatic-potential field must be developed maintain charge-neutrality within the membrane. The Nernst-Planck flux depends on gradients of defect concentrations, electrostatic potential, and hydrostatic stress.
Depending on the material and the application, the membrane may be polarized by applying an electric potential from an external circuit. Ideally, for most membrane applications, the defect transport is entirely ionic. However, electronic defects (typically small polarons) can effectively result in electrical “leakage” that frustrates polarization. Applications such fuel cells, electrolyzers, and electrochemical compressors require membrane polarization. Depending on the material’s effective electrical conductivity polarization may not be practical.
Local defect concentrations cause crystal-lattice-scale strain, which results in macroscopic stress through the membrane and its mechanical support structure. Such chemo-mechanical coupling can cause membrane distortion and potentially damaging high stresses.
Modeling membrane performance requires incorporating the Nernst-Planck fluxes into conservation equations. The rate of change in defect concentrations is balanced by the divergence of the Nernst-Planck fluxes. The local electrostatic fields may be determined in the context of a Poisson equation that effectively produces local electroneutrality. The resulting nonlinear, coupled, system of partial differential equations, generally called the Nernst-Planck-Poisson equations, may be solved computationally.
(Invited) Advances in Proton Ceramic Fuel Cells, Steam Electrolyzers, and Dehydrogenation Reactors Based on Materials and Process Optimizations
Authors: Norby Truls 
Published: February 2020

Proton-conducting ceramics such as Y-doped BaZrO3-based perovskites form basis for hydrogen-fueled proton ceramic fuel cells (PCFCs) and proton ceramic electrolyzers (PCEs) for steam. Like the PCFC benefits from running undiluted hydrogen with superior fuel utilization without circulation, the PCEs produce directly dry hydrogen at the balanced total pressure of the electrolyzer while oxygen is diluted to lower pressure with the feed of steam, lowering the hazard of pressurized oxygen. The use of waste or renewable heat to generate and superheat the steam allows operation at high electrical efficiencies.
Operation at high steam pressures reduces p-type electronic conduction at the steam+oxygen electrode and the use of novel mixed proton-electron conducting double perovskites lowers the overpotential and hence p-type electronic conductivity further, altogether yielding acceptable faradayic efficiencies of the electrolyzer.
The presence of protons and significant protonic conduction in certain double perovskites in combination with their high electronic conductivity can be rationalized by recent results of studies of their structure and defect chemistry.
Proton-conducting ceramics also offer unique opportunities for dehydrogenation of hydrocarbons including natural gas along different schemes and for different products, as suggested by Iwahara three decades ago. With materials and reactor design optimizations as well as process adaptions we now see emerging demonstrations of such use of proton-conducting ceramics.
(Invited) Data-Driven Materials Design for Compounds with Improved Mg Intercalation Mobility
Authors: Liu Miao , Rong Ziqin , Zimmermann Nils , Haranczyk Maciej , Ceder Gerbrand , Persson Kristin A 
Published: February 2020

The increasing demand of solid-state energy storage requires improved technologies, such as Mg-ion batteries, to address safety and cost concers as well as the energy density limitations of state-of-the-art Li-ion battery technology, however, the realization of Mg-ion batteries hinges on the discovery of host materials that possess sufficiently high voltage, large energy capacity, and, most importantly, adequate mobility of the Mg2+ to ensure the viable intercalation cycling. To date, there has only been a limited number of examples demonstrating the feasibility of rechargeable Mg-ion batteries, motivating the current investigation to search over more broad chemical spaces for attainable multivalent (Mg2+, Ca2+, Zn2+) intercalation cathode candidates. In this presentation, we show our detailed work, based on the robust automated high-throughput density functional calculations and the high-quality theoretical data from Materials Project, to systematically evaluate the electrochemical performance as well as the intercalating mobility of multivalent cation over several hundreds of host compounds. We also demonstrate our in-house theoretical approaches (e.g., diffusion path topology analysis) that have been designed and practiced to quantitatively estimate the multivalent cation mobility. Our study suggests that the matching between the intercalant site preference to the diffusion path topology of the host structure plays a decisive role to control mobility more than any other factor.[1] Our “in silico” design and evaluation have found several promising Mg-ion cathode materials that possess improved Mg mobility (migration activation energy lower than 600meV) [2,3], and some of them have been confirmed by experimental research teams recently [4]. The results demonstrate that the data-driven computational materials design is a realistic tool to the successful discover and optimize new materials for energy-dense multivalent batteries.
The work is entirely supported by the Department of Energy as part of the Joint Center for Energy Storage Research (JCESR).

[1] Z. Rong, R. Malik, P. Canepa, G. Gautam, M. Liu, A. Jain, K. Persson and G. Ceder, Materials Design Rules for Multi-Valent Ion Mobility in Intercalation Structures, Chem. Mat. 2015, 27, 6016.

[2] M. Liu, Z. Rong, R. Malik, P. Canepa, A. Jain, G. Ceder and K. Persson, Spinel compounds as multivalent battery cathodes: a systematic evaluation based on ab initiocalculations, Energy Environ. Sci. 2015, 8, 964.

[3] M. Liu, A. Jain, Z. Rong, X. Qu, P. Canepa, M. Ralik, G. Ceder and K. Persson, Evaluation of sulfur spinel compounds for multivalent battery cathode applications, Energy Environmental Science, Energy Environ. Sci. 2016, 9, 3201.

[4] X. Sun, P. Bonnick, V. Duffort, M. Liu, Z. Rong, K. Persson, G. Ceder and L.F. Nazar, A High Capacity Thiospinel Cathode for Mg Batteries, Energy Environmental Science, Energy Environ. Sci. 2016, 9, 2273.
Mitigation of Chromium Poisoning Effects in SOFCs By Cathode Compositional Modifications and Interconnect Coatings
Authors: Gong Yiwen , Zhu Yuexing , Sun Zhihao , Basu Soumendra Nath , Pal Uday Bhanu , Gopalan Srikanth 
Published: February 2020

Solid oxide fuel cells (SOFCs) address critical needs in the energy infrastructure due to their high efficiency, low emisssions and noiseless operation. The intermediate temperature SOFCs(IT-SOFCs) enable the use of metallic interconnect instead of traditional ceramic interconnect. However, chromium poisoning due to transport from metallic interconnect and BOP components is deleterious to cell performance.
To prevent the chromium poisoning, either a new cathode material with a high tolerance of chromium poisoning needs to be deployed, or a protective coating with a high electrical conductivity needs to applied to the interconnect.
In this study, electrolyte-supported baseline half-cell with 8mol% YSZ as the electrolyte and (La0.8Sr0.2)0.95MnO3-δ as the working and counter electrode was fabricated. Its electrochemical characteristics were tested in dry air and 50 mA/cm2 cathodic current in the present of bare chromia-forming interconnect, and an interconnect with a protective coating. Further, to investigate the effect of alternate electrode compositions, new electrodes, e.g. Cr- doped LSM, were employed as the working electrode instead of LSM in the baseline cell, and tested under same conditions.
Long Term Testing of Solid Oxide Electrolysis Cells under Co-Electrolysis Conditions
Authors: Rao Megha , Sun Xiufu , Hagen Anke 
Published: February 2020

The increasing use of renewables for energy production brings about challenges, for instance, regarding the storage of electricity. Highly efficient solid oxide electrolysis cells (SOECs) can become an attractive solution for converting excess electricity into hydrocarbons (Power-to-Gas). The use of electricity to produce synthetic methane, especially, is considered as a part of the energy transition due to available infrastructure for storage and distribution.
In this contribution, state-of-the-art (SoA) SOECs consisting of a Nickel-Yttria Stabilized Zirconia (Ni-YSZ) fuel electrode, YSZ electrolyte and a mixed ionic electronic conductor (MIEC) Lanthanum Strontium Cobalt Ferrite-Gadolinium doped Ceria (LSCF-GDC) oxygen electrode were tested under co-electrolysis (H2O+CO2) conditions where the ultimate goal is to produce methane. The SOEC durability tests are traditionally carried out in galvanostatic mode due to the straightforward test control and data interpretation. In this mode, the cell voltages change due to degradation and reach values that are either above or below the thermoneutral voltage which lead to either endothermic or exothermic processes lowering the cell efficiency. However, from a SOEC system point of view, operating the SOEC at thermoneutral voltage (i.e. potentiostatic) is attractive yielding a more efficient system with a comparatively easier heat management. The aim in this study was to compare the SOEC durability under co-electrolysis conditions between galvanostatic and potentiostatic mode. Specifically, the cell was operated at 0.75 A/cm2 (galvanostatic) and at 1.2 V (potentiostatic) at 750 oC for 1000 hours and 500 hours respectively. A detailed electrochemical and microstructure analysis for the two testing regimes will be presented. The degradation mechanisms associated with individual electrode performance will be comprehensively discussed.
Dynamic and Impure Perovskite Structured Metal Oxide Surfaces
Authors: Hansen Karin Vels , Norrman Kion , Traulsen Marie Lund , Mogensen Mogens Bjerg 
Published: February 2020

During recent years a lot of results on segregation of metal oxide components to the surfaces of perovskite electrodes for solid oxide cells (SOC) have been published. The electrodes are typically of the families (La1-xSrx)sMO3, M = Mn, Fe, Co, Ni with 0 < x < 1, and s is the so-called A/B ratio, usually 0.9 < s < 1.1. M may in principle be a mixture of all four metals, and the mentioned transition metals are only examples. Especially SrO segregations have been reported, but other of the components of the perovskite may also segregate to the surface as well as impurities in the raw materials. Finally, impurities from the reactant gases may adsorb to the surface of such electrodes (1 - 5).
However, it has been suggested that e.g. the SrO segregation is due to the vacuum based ex situ analytical tools such as low energy ion scattering (LEIS), x-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS). In general, the literature results are quite scattered, so the issue is still open for discussion.
The aim of this paper is to settle this discussion. First a brief summary of some main literature results are given, and next some results of our own on studies on popular commercial perovskite materials are presented and discussed. The methods used are Raman spectroscopy and XRD, which are not vacuum techniques, and ToF-SIMS and XPS, which are vacuum techniques.
The conclusion is that usually a perovskite surface will be covered with segregated material of as well components like SrO as impurities in the perovskite starting material. Furthermore, the available evidences point to the perovskite surfaces being very dynamic with relatively fast changes that are visible within periods of few hours with developments continuing for hundreds of hours.
Acknowledgement
We acknowledge financial support from Energinet.dk through the ForskEL programme Solid Oxide Fuel Cells for the Renewable Energy Transition contract no. 2014-1-12231, and by The Energy Technology Development and Demonstration Program (EUDP) at the Danish Energy Agency via project “Maturing SOEC”, contract no. 64015-0523.
References

K. Norrman, K.V. Hansen, T. Jacobsen, RSC Adv., 5, 87679 (2015).

F.S. Baumann, J. Fleig, M. Konuma, U. Starke, H.-U. Habermeier, J. Maier, J. Electrochem. Soc.,
152, A2074 (2005).

J. Druce, H. Tellez, M. Burriel et al., Energy Environ. Sci., 7, 3593 (2014)

Z. Cai, Y. Kuru, J. W. Han, Yan Chen, Bilge Yildiz, J. Am.
Chem. Soc.,
133, 17696 (2011).

K.V. Hansen, K. Norrman, T. Jacobsen, Y. Wu, M.B. Mogensen, J. Electrochem. Soc., 162, F1165 (2015).
Innovative Approach on Nano-Metal Particles of Electrodes for Solid Oxide Cells
Authors: Myung Jae-ha , Neagu Dragos , Irvine John T. S. 
Published: February 2020

Solid oxide cells (SOCs) are electrochemical systems capable of operating reversibly and therefore may serve as versatile energy converters. Electrolysis mode, electricity can be converted to fuels or other valuable chemicals, on the other hand, fuel cell mode converts efficiently fuel to electricity on demand. Due to their severe operating conditions, the ideal fuel electrode materials has not been found yet to accomplish of its requirements such as electronic and ionic conductivity, and catalytic activity with strong stability in redox condition, while several high performance air electrode materials -have been identified. For a long time, Ni-YSZ cermet has been regarded as the embodiment of this functional trinity. However, even though degradation associated with reversible operation can be mitigated, the cermet electrodes still suffered from agglomeration during redox condition. Recent electrode designs have been developed to microstructures consisting of a porous mixed ionic electronic conductor backbone decorated with metallic nanoparticles (typically Ni) by impregnation method. However, these are still hindered by the lack of cost and time-effective methods to produce both robustness and high-performance from their nanostructured electrodes. Here, a simpler alternative, will be introduced, exsolution whereby the catalytically active metal is substituted in the crystal lattice of the backbone in oxidizing conditions and exsolved on the surface as designed metal particles under reduction condition. Here we demonstrated a simple and highly effective in situ method for producing nanostructured electrodes capable of delivering high performances in both fuel cell and electrolysis mode. Both the nanostructures and corresponding electrochemical activity show no degradation over 150 hours of testing.
Primary and Sub-Primary Particle Level Lithium Ion Battery Diagnostics Using Chemical-Sensitive STEM Tomography, Aberration-Corrected Imaging and Eels
Authors: Lin Ruoqian , Hu Enyuan , Yu Xiqian , Yang Xiao-Qing , Xin Huolin L. 
Published: February 2020

The results of using newly developed chemical-sensitive scanning transmission electron microscopic (STEM) tomography, aberration-corrected imaging, and STEM-EELS to study structural changes of electrode materials for Li-ion battery will be reported. Some initial results regarding the structural irreversibility and chemical segregation of layer-layer compounds relating to their composition will be discussed as an example. Our results show that upon charge/discharge cycles, it is possible to use STEM tomography to three-dimensionally resolve the internal pore structure and its development with sub-nanometer resolution. This structural degradation is correlated with chemical segregation of the electrode materials at two drastically different length scale—single-digit nanometer and sub-micron length scales. Using our experimental results as a direct input for our high-throughput ab initio calculations, we are able to show that the solubility of transition metals in a specific solid phase can be used as an important parameter in predicting the structural reversibility of transition metal cathode materials.
Acknowledgements
This work was supported by the U.S. Department of Energy, the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies (BMR and VTO Battery500 projects) under Contract Number DE-AC02-98CH10886 This research used resources of the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704
Using Electrochemical Impedance Spectroscopy and Equivalent Circuit Modeling to Analyze Capacity Fade in Lithium-Ion Batteries Due to Pulse Charging
Authors: Rajagopalan Kannan Dhevathi Rajan , Butts Latarence J. , Weatherspoon Mark H. , Moss Pedro L. 
Published: February 2020

Battery life is a critical and challenging issue for battery development and applications. The capacity of lithium-ion batteries reduces during continuous discharge-charge cycling. This capacity fade or loss occurs due to different mechanisms which are associated with side reactions that occur in these batteries [1]. The objective of this work is to use electrochemical impedance spectroscopy (EIS) to study the effects of pulse charging on the capacity and cycling characteristics of lithium-ion cells and compare it with conventional charging method at constant current-constant voltage (CCCV). Implementing conventional charging and pulse charging at an average of 0.5C and 1C on 18650 Lithium Iron Phosphate batteries separately provides varied results in capacity after few cycles. Equivalent circuit models are extracted from the measured EIS data for both of the charging methods to provide detailed results on capacity and battery performance.

Reference:

[1] P. Arora, R. E. White, and M. Doyle, “Capacity Fade Mechanisms and Side Reactions in Lithium‐Ion Batteries,” J. Electrochem. Soc. , vol. 145, no. 10, pp. 3647–3667, Oct. 1998.

Figure 1
In Situ Observation of Lithium Dendrite Growth and SEI By Optical Microscopy and Raman Spectroscopy
Authors: Kuo Li-Ming , Lo Wen-Tse , Hwang Bing-Joe , Cheng Ju-Hsiang , Su Wei-Nien , Assegie Addisu Alemayehu 
Published: February 2020

Li metal negative electrode is expected for the next-generation Li battery electrode material due to its extremely high theoretical specific capacity (3,860 mAhg-1), low density (0.534 g cm-3) and the lowest negative electrochemical potential (-3.040 vs standard hydrogen electrode). However, the critical challenges of Li metal anodes (poor cycle life and safety) remain unsolved. This is attributed to electrolyte decomposition and the Li dendrite growth during electrochemical cycling.
In this study, we developed a transparent two-electrode cell to carry out an in situ observation of the Li dendrite growth on Cu surface. Galvanostatic plating and stripping cycle(s) are applied at same current density on each cell. Meanwhile, the Raman spectroscopy is employed to take a mapping image along with the grown lithium surface. The morphology evolution of the Li dendrite growth and nucleation mechanism is observed in different electrolytes and additives. The behavior of lithium dendrite and SEI were analyzed comparatively with 1M LiPF6 EC/ DEC (v: v=1:1), 1M LiTFSI, DME/DOL (v : v=1:1), and 1M LiClO4, PC electrolyte at the same current density. We have clearly observed that after a few cycles of platting and stripping lithium dendrite grew dramatically on Cu surface with carbonate electrolyte and the Cu surface still remained some lithium dendrite due to the dead lithium formation, which causes low Coulombic efficiency. In addition, Raman spectroscopy is used to probe SEI composition. The correlation of lithium growth and its surface composition are established in this work, which can help to further understand the mechanism of lithium growth.