bluuebunny/crossref_metadata_2025_split huggingface dataset:
Operando Raman Spectroscopy and Impedance Spectroscopy, a Powerful Combination to Better Understand Fuel Electrodes in Solid Oxide Cells
Authors: Drasbæk Daniel Bøgh , Welander Märtha , Traulsen Marie Lund , Sudireddy Bhaskar Reddy , Holtappels Peter , Walker Robert A. 
Published: December 2020

Solid oxide cells are based on an oxygen ion conducting ceramics and thus can be used to convert a large variety of fuels into electricity and vice versa. As solid oxide fuel cells, hydrocarbon fuels such as methane can be converted to electricity forming water and carbon dioxide. However, the reversed reaction the reduction of water and carbon dioxide to hydrogen and carbon monoxide (the so called syngas) is also of interest e.g. for the synthesis of high value fuels in subsequent methanation or Fischer-Tropsch reactions. The state-of-the-art electrode for both solid oxide fuel cells and electrolysis cells are so called Nickel cermet electrodes, which are prone to carbon formation due to the high amount of Ni (usually above 33vol%).
An alternative fuel electrode concept is based on an electronically conducting ceramic and using infiltrated metals as electrocatalytically active elements. This concept is versatile as it allows the use of various electrocatalysts, not limited to Ni. Based on a comparative study, Fe, Co in addition to Ni have been identified as promising electrocatalyst materials and have been investigated as regards their behavior in carbon containing gas atmospheres [1]. Raman spectroscopy in combination with impedance spectroscopy and especially during operation of the cell is a powerful tool to investigate electrodes in solid oxide cells [2,3].
In this study Raman spectroscopy has been applied either in-situ (at open circuit voltage) or operando (under load in fuel cell mode) to investigate carbon formation and electrochemical performance. The results show a clear decrease in carbon formation when Co was present in the electrode. In-situ experiments confirmed in general an electrode deactivation when carbon was built up, while operando studies revealed an electrode activation when carbon was observed. This latter effect is tentatively attributed to an improvement of the electrical contact within the ceramic electrode. The influence on the impedance as well the detailed impact of operation parameters will be discussed.
References:
[1] D.B Drasbæk et al. Electrochimica Acta 2019, 327, 135004.
[2] J. Kirtley et al., J. Phys. Chem. C 2013, 117, 49.
[3] D.B. Drasbæk et al., Fuel Cells 2019, 19, 484.
Recent Advancements in Solid Oxide Fuel Cell Electrolysis Technology at Nexceris, LLC
Authors: Dogdibegovic Emir , Kopechek David , Wallace Anila , Harasyn Pamela , Arkenberg Gene , Kidner Neil J. , Swartz Scott , Seabaugh Matthew Mark 
Published: December 2020

Increasing demand for long-term energy storage and reduced carbon emissions promotes solid oxide electrolysis cell (SOEC) technology. SOEC systems can achieve high hydrogen production rates with near 100 percent stack electrical efficiency while co-electrolysis of carbon dioxide and water leads to production of syngas. With over 25 years’ experience building and testing solid oxide fuel cell (SOFC) materials, components and stacks, Nexceris has a proven track-record of commercializing SOFC products to major OEMs. The established manufacturing platforms at Nexceris enable smooth expansion into SOEC applications.
In this talk, development of new SOEC electrode materials, stack components and stacks will be discussed. Over 50 down-selected air and fuel electrodes were electrochemically screened on 25 cm2 electrolyte-supported single cells and compared to baseline electrodes. Multiple electrode sets provided current density over -1.5 A/cm2 at 1.3 V and 800 °C with 75 percent steam/25% percent hydrogen fuel and air. The promising electrodes were implemented into short stacks with active cell area of 42 cm2. Stacks were operated continuously in SOEC mode at 1.3-1.4 V for ≥ 500 hours. The resulting short stack demonstrations show promising SOEC baseline performance and durability platform for future cell and stack development. Co-electrolysis and water electrolysis tests were also conducted and yielded comparable performance. Nexceris’ ChromLok coatings for bipolar plates were also integrated to stacks and tested under realistic conditions.
(Invited) Steam Electrolysis Using Proton-Conducting Perovskites: Prospects and Challenges
Authors: Matsumoto Hiroshige , Kwati Leonard , Fujisaki Takaya 
Published: December 2020

This paper demonstrates and discusses steam electrolysis performance using proton-conducting solid oxide materials with respect to the benefit and prospects as well as challenges toward the technical application for hydrogen production.
Water electrolysis will take an important role as the energy storage for the vast use of renewable energy. Steam electrolysis is characterized by high energy conversion efficiency compared to low temperature water electrolysis. However, the conventional technique is accompanied by high operation temperature because the ionic conduction in solids needs high temperature. As a mean to reduce the operation temperature, the proton conducting perovskite is thus a choice for the electrolyte since it works in intermediate-temperature regime. We have reported so far SrZr0.5Ce0.4Y0.1O3-δ (SZCY541) [1] and BaZr0.44Ce0.36Y0.2O3-δ (BZCY(54)8/92) [2] to be highly proton conducting and sufficiently stable in steam at the inter mediate temperatures. The latter exhibits the conductivity of 10-2 S/cm in moist hydrogen at 500°C and has been demonstrated as the electrolyte for steam electrolysis [3].
The most remarkable difference of proton conductors from other solid electrolytes is the mechanism for the generation of proton conducting charge carriers. It takes place as a result of hydration of oxide ion vacancies. One of the challenges for the material is the volumetric deformation accompanied by hydration/dehydration that possibly leads fatigue of the cell structure. Another is originated from the defect chemistry, that is the hydration is competing with oxygen incorporation to the oxide ion vacancy that result in the electronic hole formation in oxidative atmosphere. Electronic leakage, reduction of Fardaic efficiency, is originated from this hole conductivity intrinsically being in the materials. Mixed-conducting electrode materials are still under investigation by many researchers. Another issue is the inter-diffusion of transition metal species from the electrodes to the electrolyte causing the reduction of the proton conductivity. These challenges will be discussed for improving the reliability of the proton conductor steam electrolysis.
Acknowledgement
This work was supported by the Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), "energy carrier" (Funding agency: JST), the JSPS-NSF Partnerships for International Research and Education (PIRE), the JSPS Core-to-Core Program of Advanced Research Networks (Solid Oxide Interfaces for Faster Ion Transport), METI International joint research and development of innovative energy technology, JST SICORP, and World Premium International Research Center Initiative (WPI), MEXT Japan.
References
[1] Matsumoto et al., Pure Appl. Chem., 85, 427–435, 2013
[2] Leonard et al., Inter. J. Hydrogen Energy, 42, 3926-3937, 2017
[3] Leonard et al., J. Mat. Chem A, 6, 19113-19124, 2018
[4] Fujisaki et al., Solid State Ionics, 333, 1-8，2019
Effect of Elemental Substitution in (Ba,Sr)6RE2Co4O15−BaCe0.5Pr0.3Y0.2O3-δ for Cathodes of Proton-Conducting Ceramic Fuel Cells
Authors: Kunimoto Naoki , Muroyama Hiroki , Matsui Toshiaki , Eguchi Koichi 
Published: December 2020

Solid oxide fuel cells are promising energy conversion devices because of high efficiency and high fuel flexibility, but their high-operating temperature (700-900 ºC) causes problems such as fast degradation of components and long start-up/shut-down time. To overcome these problems, low- temperature operation is preferable. Proton-conducting ceramic fuel cells (PCFCs) are promising energy conversion devices for intermediate-temperature operation, especially below 600 ºC. This is because the activation energy of proton migration in proton-conducting oxides, such as rare earth-doped barium cerate, is lower than that of the oxide ion. At the current state, however, the performance of PCFCs is mainly limited by the cathode materials.
Recently, we have reported that the composite of Ba4Sr2Sm2Co4O15 (BSSC4224)–BaCe0.5Pr0.3Y0.2O3 (BCPY) showed higher activity below 600 ºC in 3% humidified synthetic air, as compared with high-performance cathodes reported1). In this composite, BSSC4224 mainly served as an active site for the dissociative absorption of oxygen.
In this study, then, the effect of the elemental substitution, especially the Ba/Sr ratio and rare-earth elements, in (Ba,Sr)6
RE
2Co4O15, on the ASR was studied. Symmetric cells consisting of the BaCe0.8Y0.2O3 (BCY) disk electrolyte and Ba5SrRE
2Co4O15 (RE =Nd, La, Eu, Sm, Pr, and Gd), Ba4Sr2Gd2Co4O15 or Ba5SrGd2Co4O15 (BSGC5124)–BCPY electrodes were fabricated. The electrode performance was measured in 3% humidified synthetic air (21% O2–79% N2) at 450–700 ºC by impedance spectroscopy.
In impedance analysis, BSGC5124 had the lowest ASR below 550 ºC among Ba5SrRE
2Co4O15 electrodes. Then, the composite of BSGC5124–BCPY was prepared and its performance was compared with that of BSSC4224–BCPY composite. We found that BSGC5124–BCPY has comparable area-specific resistance and activation energy to BSSC4224–BCPY although BSGC5124 itself had much lower area-specific resistance and activation energy than BSSC4224. Therefore, we concluded that the dissociative adsorption of oxygen on the BSGC5124 phase is not the rate limiting step for the oxygen reduction reaction in this composite system.
[1] T. Matsui, K. Manriki, K. Miyazaki, H. Muroyama, K. Eguchi, J. Mat
er. Chem. A, 6, 14188 (2018).
Electrode Degradation in Proton-Conducting Ceramic Electrochemical Devices
Authors: Hernandez Rodriguez Marcos , Hernandez Carolina Herradon , Le Long Quoc , Sullivan Neal P 
Published: December 2020

We present our efforts to identify, quantify, and mitigate sources of degradation in proton-conducting ceramic electrochemical devices. As described in another presentation, researchers at the Colorado School of Mines are currently scaling up proton-conducting ceramics into multi-cell stacks for both fuel-cell and electrolyzer applications. This integration of novel protonic-ceramic materials with stack packaging materials brings questions regarding materials compatibility and stack-level degradation. The lower operating temperature (500 – 600 ºC) of protonic-ceramic devices presents promise for reducing the driving forces behind several well-established degradation mechanisms found in more-prevalent oxygen-ion conducting ceramics. Nickel sintering in the anode support should decrease, as should chromia-scale growth and electrode poisoning from metallic interconnects. That said, other aspects of protonic ceramics could enhance degradation. For example, under fuel-cell operation, water vapor is formed at the cathode, increasing oxygen partial pressure and promoting chromia poisoning. Further, these degradation mechanisms are presented over thousands of hours of stack operation, often happening simultaneously, clouding our understanding.
In this presentation, we describe our efforts to identify and mitigate the key degradation mechanisms found in proton-conducting ceramic electrochemical devices and stacks. Through collaboration with the University of Bordeaux, we have developed unique device packaging and experimentation to enable careful measurement of electrochemical performance at electrode-electrolyte interfaces over thousands of hours of operation. As shown in the figure, a ~ 2-mm-thick BaCe0.4Zr0.4Y0.1Yb0.1O3-δ (BCZYYb4411) electrolyte is sandwiched between two identical BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY) air electrodes to form an electrolyte-supported symmetric cell. Fuel electrodes can also be studied. The cell is packaged, perhaps with metallic interconnects, within carefully designed alumina fixturing that maintains consistent electrical connections throughout the long testing periods. The assembly is sealed within a quartz reactor and placed within a furnace, and enables exploration of a wide range of operating conditions, gas compositions, and temperatures.
In this talk, we will present results focusing on degradation at the cathode-electrolyte interface. The effect of H2O concentration, and the role of metallic interconnects in cathode degradation will be presented.

Figure 1
Electrochemical Characterization of Pr(A)MnO3 Perovskites As Oxygen Electrodes for Solid Oxide Fuel-Assisted Electrolysis Cells
Authors: Yaremchenko Aleksey , Boiba Dziyana , Patrakeev Mikhail , Arias-Serrano Blanca I. 
Published: December 2020

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) powders were synthesized by glycine-nitrate combustion technique. The characterization included XRD, SEM/EDS, XPS, dilatometry and thermogravimetry, measurements of electrical properties, and determination of oxygen nonstoichiometry by coulometric titration. XRD analysis confirmed the formation of solid solutions with orthorhombic perovskite-like structure. Pr0.6-x
A0.4MnO3
±δ exhibit negligible variations of oxygen content with temperature and oxygen partial pressure under oxidizing conditions, while reducing p(O2) below 10-4 atm results in a progressive oxygen losses from the lattice and reduction of variable-valence cations. The low-p(O2) stability boundary of the perovskite phase at 800°C corresponds to ~10-17-3×10-16 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 oxygen chemical potentials anticipated for the oxygen electrode operation conditions at 800°C. The electrochemical performance of Pr0.6-x
A0.4MnO3
±δ porous electrode layers was evaluated in contact with yttria-stabilized zirconia solid electrolyte using symmetrical cell configuration as function of relevant parameters (electrode fabrication conditions, with and without ceria-based interface layers, modifications via impregnations by praseodymia or gadolinia-doped ceria).
Enhanced Long Term Durability of Metal-Supported Solid Oxide Electrolysis Cells By Advanced Coatings
Authors: Shen Fengyu , Hu Boxun , Tucker Mike C 
Published: December 2020

Metal-supported solid oxide electrolysis cells (MS-SOECs) with symmetric cell architecture were developed for high temperature electrolysis at Lawrence Berkeley National Laboratory (LBNL). The cell is comprised of a thin ceramic electrolyte and porous electrode backbones sandwiched between stainless steel metal supports. MS-SOECs offer a number of advantages over conventional all-ceramic SOECs due to their low-cost structural materials (e.g. stainless steel), mechanical ruggedness, excellent tolerance to redox cycling, and extremely fast start-up capability. The current density of MS-SOEC at 1.3 V and 50 vol% steam content is improved by optimizing microstructure of electrode backbone and procedure of catalyst infiltration. MS-SOEC with composite LSCF-SDC air electrode catalyst displays a degradation rate of 1.6%/100 h with current density of 0.33 A cm-2 at 700 °C in 1000 h test (Figure 1). Post-mortem analysis reveals that the degradation is caused by the primary modes of fuel electrode catalyst coarsening and Cr poisoning on air electrode catalyst, and secondary modes of metal support oxidation and local elemental accumulation of Ni. In an effort to suppress Cr migration thereby improving long term durability, advanced coatings, such as CoOx, NiFe2O4, (Co,Mn)3O4, etc., are applied to the cathode-side support by atomic layer deposition or electrodeposition. The impact of coating composition and deposition method will be reported.
Figure 1. Durability of the cell with LSCF-SDC air electrode catalysts at constant current of 0.33 A cm-2 and 700 °C, with 50 vol% H2-50 vol% H2O.

Figure 1
Ammonia As an Energy Vector
Authors: Soloveichik Grigorii L. 
Published: December 2020

The Advanced Research Projects Agency (ARPA-E) funds high risk, high reward transformational research to reduce energy related emissions, reduce imports of energy from foreign sources, improve energy efficiency across all economic sectors, and ensure US technological lead in advanced energy technologies, including electrochemical technologies for energy transformation and storage for distributed, grid scale and automotive applications.
Ammonia is produced at a scale of about 180 million tons per year and is easily stored and transported. Currently it is mostly used as a fertilizer and a feedstock for production of various chemicals. However, its physical properties, high energy density, the absence of carbon emissions, availability of feedstock (air and water), and well developed synthesis and infrastructure make ammonia almost ideal energy vector. Produced using renewable energy, it can be used for long duration energy storage and as a zero-emission transportation fuel as well as a hydrogen carrier. To address these technological challenges, ARPA-E launched the Renewable Electricity to Fuels through Utilization of Energy-dense Liquids (REFUEL) program. This program and, in part, OPEN program fund the development of transformational technologies for the conversion of intermittent renewable energy, water and air to energy-dense carbon neutral liquid fuels including ammonia and their conversion to hydrogen or back to electricity using fuel cells. All these directions will be covered in the presentation with emphasis on ammonia fuel cells.
Fuel cells provide the most efficient conversion of ammonia to electricity. Indirect fueling includes the intermediate ammonia cracking to hydrogen (Industrial process runs at 850oC but temperature could be substantially lower with advanced catalysts), which can be purified to PEM fuel cell grade. Direct fueling requires less capital expenses, and can be used with different types of fuel cells (SOFC, PCFC, AEMFC and molten carbonate fuel cells). Performance of direct ammonia fuel cells (DAFC) was demonstrated to be very close to the performance of the same cells fueled by hydrogen (with correction for the dilution). Issues of crossover (for polymer membranes), electrocatalyst stability (nitridation), cell architecture, and operation parameters will be discussed.
Recent advances in the development of novel DAFCs that is being funded by ARPA-E via REFUEL and OPEN 2018 programs will be presented. Comparison of DAFCs with combustion engines fueled by ammonia for energy applications will be given.
Unbiased Identification of Optimal Chemical Pathways in Electrochemical Reaction Cascades
Authors: Blau Samuel M , Dwaraknath Shyam , Spotte-Smith Evan Walter Clark , Persson Kristin A. 
Published: December 2020

Electrochemically-driven reaction cascades are responsible for solid-electrolyte-interphase (SEI) formation in metal-ion batteries and anolyte/catholyte degradation in flow batteries, critically controlling stability and lifetimes of energy storage systems. However, the reactive complexity and long timescales involved in such processes limit the insight that can be obtained experimentally or from atomistic simulations like classical or ab initio molecular dynamics. To avoid the limitations of atomistic dynamics, we aim to construct a chemical reaction network (CRN) which includes all possible species and reactions that may participate in SEI formation. Such a CRN could identify the collection of reaction pathways that control the growth of the SEI, a key step towards engineering functional electrochemical reactivity.
Utilizing our novel computational infrastructure that enables accurate and high-throughput simulations of electrochemically-relevant species, we performed over 20,000 density functional theory calculations in order to construct a CRN characterizing SEI formation, which includes more than 8,000 species and 100,000 reactions. To our knowledge, the resulting reaction network is over five times larger and includes substantially more complex chemistry than any previously reported CRN.
However, the size and complexity of our network necessitates a novel approach to identify optimal reaction paths. We therefore developed an improved graph representation of multi-reactant reactions such that optimized pathfinding algorithms can be applied to general reaction networks for the first time. This allowed us to identify the optimal chemical pathways involved in the formation of a key Li-ion SEI product in an automated and unbiased fashion. Our approach can be readily applied to modeling other critical reaction pathways in any electrochemical system, from redox flow batteries and fuel cells to electrocatalytic processes.
Multielectron Bifunctional Systems for Symmetric Nonaqueous Redox Flow Batteries
Authors: Porath Anthony , Cook Korey , Duda Addison , Dan Adina , Guarr Thomas F. , Hoekstra Elizabeth 
Published: December 2020

The introduction of renewable energy generation sources onto the electrical grid is critically dependent on the development of reliable, inexpensive energy storage technology. Redox flow batteries (RFBs) may offer a solution, but many issues remain. For example, aqueous systems are limited in cell voltage owing to the accessible potential window of water. While other electrochemically useful solvents could provide a larger window, their cost and durability have been problematic. Moreover, the need for an ion-exchange membrane to prevent crossover further increases cost and adds significant cell resistance, especially in nonaqueous systems.
We have previously reported the use of linked electron donor/acceptor D-L-A or D-L-A-L-D compounds (where L represents a simple alkyl or aryl linker) to allow the replacement of the expensive ion-exchange membrane with a simple porous separator. Such systems have at least three accessible stable redox states: the “parent” D-L-A state, an oxidized form D+-L-A (catholyte), and a reduced form D-L-A-
(anolyte).
Numerous systems of this type have now been prepared and characterized, yielding nominal cell potentials over 2 V, with promising stability. Several of these systems have the capability of undergoing a net 2e- oxidation as well as a net 2e- reduction, allowing for increased energy density. One such compound is shown below.
The electrochemical properties of several representative linked electron donor/acceptor materials will be described, including progress toward the development of a 4e- system having 9 (nine!) accessible stable redox states. Preliminary data from a prototype RFB device employing such compounds as active materials will also be presented.

Figure 1