bluuebunny/crossref_metadata_2025_split huggingface dataset:
About the Necessity to Consider Membrane Electrolyte Degradation Statistically
Authors: Dlugosch Thomas , Kirsch Sebastian , Friedrich K. Andreas 
Published: February 2020

One key factor for the commercialization of fuel cell vehicles is a sufficient membrane durability. In this context, car manufactures work on reliability accelerated stress test procedures (AST) to measure membrane lifetime. There have been many lifetime investigations for polymer electrolyte membrane fuel cells (PEMFCs) especially for the perfluorinated sulfonic acid (PFSA) membrane [1-3]. For comparison of membrane lifetimes, it is necessary to ensure reproducibility of the experimental lifetime data. However, in part of the literature lifetime of membranes was derived from few repetitions – if not none – of single cell experiments only [e.g. 3-5]. Random failures due to membrane production variations, cell assembly inaccuracies and statistical defects cannot be quantified without statistical analysis. Accordingly, some conclusions in literature might have been blurred due to insufficient repetition of measurements.
In this work, we stress the necessity to generate statistically relevant membrane degradation data. The development of the open circuit voltage (OCV) and the H2-crossover current (iH2) is shown in Figs. 1-2 for one specific AST and nine cells. It can be seen, that in the range of reproducibility lifetime can be 1000 or 20000 cycles. At the conference more evidence for the wide nature of the lifetime distribution will be presented. Accordingly, the distribution in voltage loss and hydrogen crossover development cannot be neglected if clear conclusions about membrane life shall be derived. Without a high number of repetitions the statistical significance is not assured. Some of the recent conclusions in literature about impact on membrane lifetime will be considered critically from this point of view.
References:

Zhang, et al., J. Power Sources 195 (2010) 1142–1148

Zhang, et al., J. Power Sources 205 (2012) 290– 300

Chandesris, et al., Int. J. Hydrog. Energy 42 (2017) 8139 – 8149

Zhang, et al., Int. J. Hydrog. Energy 39 (2014) 15989 - 15995

J. Parnian, et al., J. Membr. Sci. 556 (2018) 12-22

Figure 1
Iron-Nitrogen-Carbon (Fe-N-C) Active Sites Imaging By Scanning Transmission Electron Microscopy (STEM)
Authors: Asset Tristan , Kumar Kavita , Dai Sheng , Xu Mingjie , Yan Xingxu , Chen Yechuan , Li Xiaoyan , Pan Xiaoqing , Maillard Frederic , Dubau Laetitia , Atanassov Plamen 
Published: February 2020

Iron-nitrogen-carbon electrocatalysts (i.e. Fe-N-C) are of interest for the oxygen reduction reaction because they can solve the geological and economic constraints associated with the use of Pt-based electrocatalysts. However, the nature and the stability of their active sites is yet to be fully understood. The presence of nitrogen and atomically dispersed Fe is believed to result in the presence of various moieties, i.e. Fe-Nx, N-pyridinic, N-pyrrolic, etc. Such assumptions are based on the fitting of the N1s peak observed by X-ray photoelectron spectroscopy (XPS) 1,2 and, for the Fe-Nx moieties, extended X-ray absorption fine structure (EXAFS) 3. Imaging a non-model Fe-N-C electrocatalyst at an atomic scale could provide additional insights onto the exact structure of those moieties, and, in combination with electrochemical ageing, ease the assessment of their stability. Here, we discuss the multiplicity of actives sites in an Fe-N-C electrocatalyst synthesized by the sacrificial support method. We use a combination of XPS, EXAFS, scanning transmission electron micrographs (STEM) and electron energy loss elemental mapping (EELS – see Figure 1) to unveil the presence, additional to Fe-Nx, of other active sites, e.g. Fe-NxCy or nitrogen moieties. Then, we investigate the stability of said moieties (with a focus onto Fe-Nx) using a combination of step-cycles (10,000 cycles; 0.6 – 1.0 V vs. RHE, 3s – 3s, in Ar-saturated 0.1 M H2SO4, T = 80°C) and STEM (see Figure 1), showing that, in these experimental conditions and for this specific family of Fe-N-C electrocatalysts, the atomically dispersed Fe forms clusters – but not nanoparticles – during the ageing process.
(1) Artyushkova, K.; Serov, A.; Rojas-Carbonell, S.; Atanassov, P. J. Phys. Chem. C
2015, 119, 25917–25928. (2) Matanovic, I.; Artyushkova, K.; Strand, M. B.; Dzara, M. J.; Pylypenko, S.; Atanassov, P. J. Phys.
Chem. C
2016, 120 (29225–29232), 6–13. (3) Zitolo, A.; Goellner, V.; Armel, V.; Sougrati, M.; Mineva, T.; Stievano, L.; Fonda, E.; Jaouen, F. Nat.
Mater.
2015, 14 (September), 937–942.

Figure 1
P2G System Technology Development Aiming at Building a CO2-Free Hydrogen Society
Authors: Sakamoto Masaki , Izuhara Daisuke , Sotouchi Hiroko , Aoyagi Fukuo 
Published: February 2020

The government's "Basic Energy Plan" decided on April 11, 2014 has been decided to promote initiatives aimed at realizing "hydrogen society", a society that utilizes hydrogen in everyday life and industrial activities It was. Following this, the Ministry of Economy, Trade and Industry will formulate the "Hydrogen / Fuel Cell Strategy Roadmap" in June 2014 and aim to establish a CO2-free hydrogen supply system around the year 2040.
According to the Government's "Long-Term Energy Supply and Demand Outlook" published in July 2015, the renewable energy ratio to total electricity generation in FY 2030 is estimated to be 22 to 24%. On the other hand, renewable energy has large output fluctuations due to the influence of the natural environment, and geographically unevenly, there are concerns such as suspension of connection to the transmission and distribution electric power network. One solution to this problem would be the Power-to-Gas system utilizing the conversion using electric power from renewable energy into hydrogen. The obtained hydrogen can reduce CO2 emissions by replacing fossil fuels in heating sector.
At the Agency for Natural Resources and Energy, the report of the "CO2 Free Hydrogen Working Group" was compiled in March, In the report, technical issues such as low cost and high efficiency of various technologies including water electrolysis equipment, improvement of durability, improvement of utilization rate were taken as technical issues.
In this research, we demonstrate technological development from hydrogen production using renewable energy to transportation, storage and use in the real society, and establish the basic technology for practical application of "Power to Gas system".
The applicability of the water electrolyzer was confirmed by grasping the electrical characteristics of the water electrolyzer (the ability to absorb unstable power, responsiveness, etc.) from the data of the evaluation equipment. In addition, it was expected that 74% could be achieved with the year-round water electrolyzer system efficiency.
In the future business model using the 1.5 MW PEM type water electrolyzer, the MEA performance for achieving the required system efficiency of 80.5% is based on the voltage efficiency has already been achieved.
Assuming a system at the stage of practical use, we concluded that direct utilization for industrial use and utilization as a CO2-free fuel for the heat demand for industrial use are effective. In line with this conclusion, we have determined the specifications of a pure hydrogen boiler assumed as a hydrogen utilization device, by investigating the tolerance of fluctuations and the partial load operation in line with actual plant operation.

ACKNOWLEDGEMENT

This work was partially supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan.
Characterization of Cerium Dioxide Thin Films Prepared By Plasma-Enhanced Atomic Layer Deposition for Solid Oxide Fuel Cells
Authors: Jeong Wonyeop , Lee Sanghoon , Ryu Sangbong , Cho Gu Young , An Jihwan , Cha Suk Won 
Published: February 2020

Solid oxide fuel cells (SOFCs) are considered to be the next generation of energy conversion devices because of their environmental friendliness and high efficiency. Particularly due to its high operating temperature, it has high fuel flexibility and does not require water management. However, the high operating temperature that causes these advantages accelerates the degradation of fuel cell components, thereby reducing the durability and limiting the usable materials. Therefore, in recent years, a lot of research has been conducted to lower the operating temperature of the SOFCs.
One method of lowering the operating temperature of SOFCs is to apply an electrolyte having good ionic conductivity at low temperatures(400-600℃). Potential examples are doped ceria materials. One of the well-known ceria-based electrolytes is Gd-doped ceria (GDC), which exhibits ion conductivity 1-2 times higher than yttria stabilized zirconia, YSZ, which is the most commonly used electrolyte in SOFC. GDC has good ionic conductivity, but when exposed to a reducing environment, Ce4+ is reduced to Ce3+ and begins to have electronic conductivity, which causes a decrease of open circuit voltage (OCV). Therefore, in order to apply GDC as an electrolyte, an additional blocking layer must be added so that it is not exposed to the hydrogen environment of the anode. This additional layer increases not only the thickness of the electrolyte but also the interfacial resistance between the layers, thereby increasing the ohmic resistance. Therefore, the fabrication of GDCs with thinner and better surface properties is critical to improving the performance of low temperature SOFCs.
In this study, CeO2 thin film was fabricated using atomic layer deposition (ALD) as a preceding step for the fabrication of GDC thin films. Oxygen plasma was used to oxidize the precursor to widen the ALD window and to produce the highly crystalline CeO2. The growth rate of CeO2 was determined by controlling precursor and oxidizer exposure time, and the thickness of thin film per cycle was confirmed. The surface morphology was observed by scanning electron microscope (SEM), and dense and pinhole-free thin film surface was confirmed. In addition, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses were performed and the characteristic crystalline peaks and chemical compositions were compared with those of the thermal ALD CeO2 thin films.
(Invited) Solid State Batteries: Energy Density, Cycle- and Manufacturability
Authors: Soloveichik Grigorii L. 
Published: February 2020

Conventional Li-ion batteries (LIBs) are close to practical limits in energy density and cost. The major disadvantage of LIBs is the presence of a flammable electrolyte and a porous separator, which makes them hazardous and restrict the choice of electroactive materials. Solid state batteries (SSBs) could be potentially safer and more energy dense if dendrite-free Li anode is used. The Advanced Research Projects Agency (ARPA-E), which funds high risk, high reward transformational research to reduce energy related emissions, reduce imports of energy from foreign sources, improve energy efficiency, and ensure US technological lead in advanced energy technologies, focuses on the development and scale up of membrane component for solid state batteries as well as full cells with high energy density.
According the Integration and Optimization of Novel Ion-Conducting Solids (IONICS) program, a thin (≤20 μm) solid state (ceramic or polymer) electrolyte has to demonstrate ASR ≤5 Ohm-cm2 with high current density and movable areal capacity in Li metal cells. Several major risks for SSBs with Li metal anode have been identified: 1) low electrolyte conductivity, 2) incompatibility of solid membrane with Li metal, 3) anode volume change, 4) dendrite formation, and 5) non-uniform Li plating/segregation, and mitigation strategies will be examined. These issues are related mainly to cyclability, while the cell architecture (e.g. thickness, porosity, non-active materials) defines the energy density and affects its manufacturability, which remains mostly uncharted territory for solid state batteries.
Recent advances and trends in the development of novel approaches to materials for solid state batteries, their design and manufacturing of large format full solid electrolyte cells with different cathodes that is being funded by ARPA-E via RANGE, IONICS and OPEN 2018 programs will be discussed.
(Invited) Measurement of Polarization Resistance of LSM + YSZ Electrodes on YSZ Using AC and DC Methods
Authors: Virkar Anil 
Published: February 2020

Most of the measurements of electrode polarization are conducted using electrochemical impedance spectroscopy (EIS). The electrochemical devices, however, operate in a DC mode. Thus, frequency-dependent circuit elements (capacitances, constant phase elements, inductances) have no significance on the actual operating current and voltage of a device. The objective of the present work was to measure electrode polarization resistance using both EIS and DC technique and compare the results.
A solid cylinder of 8YSZ of diameter ~1.17 cm and length ~5.00 cm was made by powder pressing in an isostatic press using a polymer mold and sintering at 1600oC in air for 4 h. Platinum electrodes/probes were painted along the circumference at four places approximately 1.2 cm apart. The strip width was ~2 mm. The sample was fired at 900oC. LSM + YSZ electrodes were applied on the two circular end faces and fired at 1000oC for 2 h. Pt wires were attached to the four Pt electrodes. Gold mesh was adhered to the circular LSM + YSZ electrodes. The sample was secured in a ceramic fixture and placed in a tubular furnace. Measurements were conducted in O2-N2 gas mixtures containing 100%, 10%, 5% and 1% O2. For DC studies, a DC voltage was applied in the range of 0.05 V and 0.38 V across the sample. At each applied voltage, the corresponding current was measured and potentials at all four probes was measured. From the measured potentials and the current, the ionic resistance of the cylinder was determined, from which the ionic resistivity was determined. From the voltage measured between one of the end electrodes and a probe, the ionic resistance between the end electrode and the probe, and the net current density, overpotential at the electrode was determined. This was done as a function of current. Also, from these measurements, electrode polarization resistance was determined. For EIS studies, done only under no applied DC voltage, spectra were obtained between electrode-1 and probe-2 and between probe-2 and electrode-2. From these measurements, the polarization resistances of the two electrodes were determined separately. EIS spectra were also obtained across electrode-1 and electrode-2. The spectra across electrode-1 and probe-2 and across probe-2 and electrode-2 were summed point by point. These spectra were then compared with the spectra across the entire sample.
High Performance Reversible Solid Oxide Cells with Porous La0.6Sr0.4FeO3-Δ Oxygen Electrodes
Authors: Guan Chengzhi , Chen Kongfa , Zhou Jing , Wang Jian-Qiang , Zhou Xiao-Dong 
Published: February 2020

As a mixed electronic and ionic conductor (MIEC), (La,Sr)FeO3-δ has been extensively studied to replace manganite based materials as oxygen electrode of intermediate temperature (600-800oC) reversible solid oxide cells (RSOCs). However, compared to Sr doped LaCoO3 material, the electrochemical performance of cobalt-free (La,Sr)FeO3-δ needs to be improved to meet the requirements of commercial applications. Contrary to the conventional solid-state reaction and sol-gel method, molten salt synthesis (MSS) is a simple, versatile, and environmental-friendly approach to synthesize highly active perovskite catalysts with controllable compositions and morphologies. Especially, the corrosion effect of molten salts and the salt-removal process in MSS process have potential to manufacture particles with open porous topographic structure, resulting in large specific surface area. Therefore, it’s promising to use the MSS method to enhance the activity of cobalt-free (La,Sr)FeO3-δ.
In this study, the MSS method was employed to synthesize perovskite La0.6Sr0.4FeO3-δ (LSF) at 850oC as the oxygen electrode of a button solid oxide cell. In the material preparation procedure, moderate chloride composite was added in the reactants, forming a liquid environment to accelerate the reaction. At 800 °C, the button cell exhibits a peak power density of 1.73 Wcm-2 using pure H2 as fuel and reaches an electrolysis current density of 1.50 Acm-2 under 1.3 V in 50% CO2/50% H2, both of which are much better than the reference cell with a La0.6Sr0.4FeO3-δ electrode prepared by sol-gel method. The button cell also demonstrates a stable performance under a constant current density of 0.5 Acm-2 in SOFC mode for 200 hours. We also discussed the mechanism for the ultra-high electrochemical performance of La0.6Sr0.4FeO3-δ by charactering the difference between LSF powders synthesized by MSS method and sol-gel method. The results show that LSF using MSS powders possess a great plenty of pores in the grains. Meanwhile, the valance and the coordinator number of Fe atoms are reduced owing to the poor solubility of oxygen and the corrosion in the molten chlorides, leading to more oxygen vacancies. Therefore, we concluded that the combining effect of the microstructure and the enhanced amount of oxygen vacancies make the porous LSF electrode exhibits attractive electrochemical performance in both SOFC mode and SOEC mode.

Figure 1
(Invited) Mixed Protonic-Electronic Membrane Reactors; Converting Hydrocarbon Resources and CO2 to Fuels
Authors: Wachsman Eric D. 
Published: February 2020

Membrane reactor technology holds the promise to circumvent thermodynamic equilibrium limitations by in-situ removal of product species, resulting in improved chemical yields. Recent advances in mixed-conducting oxide-membrane technology present the possibility for a dramatic reduction in the cost of converting petroleum, coal and biomass derived feed stocks to hydrogen and other “value added” hydrocarbons. We have developed novel membrane reactor technology, based on high temperature proton conductors, that can convert a wide range of hydrocarbons to pure H2, and syngas for synthesis of liquid fuels and chemical feed stocks. By simultaneous H2permeation and catalysis, we have demonstrated the ability to increase water gas shift yields >70% over thermodynamic limitations. Similarly, we have demonstrated increases in steam reforming yields, and the ability to reform CH4with CO2.
More recently we have developed single-step gas to liquid reactors that convert natural gas to C2+products with high yields and no unwanted oxidation byproducts. The direct utilization of CH4and CO2to simultaneously produce C2+hydrocarbons (C2and aromatics) and syngas (CO and H2) on opposite sides of a mixed protonic-electronic conducting SrCe0.7Zr0.2Eu0.1O3-δmembrane reactor is demonstrated. On one side (interior) of the membrane reactor, direct non-oxidative methane conversion (DNMC) over an iron/silica catalyst produces C2+hydrocarbons and H2. On the other side (outer surface) of the membrane, permeated H2(driving the DNMC reaction) reacts with a CO2sweep gas to form CO and water via the reverse water gas shift (RWGS) reaction. This novel single H2-permeable membrane reactor simultaneously addresses both reduction of greenhouse gas (CO2 and CH4) emissions as well as production of value-added hydrocarbon products (C2+, CO, and H2) with in situ gas separation.
(Invited) Titanate-Based Electrodes for Solid Oxide Cells
Authors: Barnett Scott A , Zhang Shan-Lin , Zhu Tenglong , Lu Matthew Yunching , Mogni Liliana Veronica 
Published: February 2020

This talk describes solid oxide cell electrodes based on Sr(Ti0.3Fe0.7)O3 (STF). For oxygen electrodes, the substitution of a small amount of Co (up to 15%) for Fe substantially reduces polarization resistance, e.g., from 0.7 to 0.2 Wcm2in air at 600 oC.[1] The oxygen transport rate coefficients and polarization resistance RP
values are increased by a factor of ~ 3 times by Co substitution, and are generally much better than those for the widely used (La,Sr)(Co,Fe)O3 electrodes. Electrode and cell stability are markedly improved compared to LSCF cathodes. PrOxinfiltration into Co-substituted STF yields a substantial reduction in RP
, to values useful for low-temperature (<600 oC) solid oxide cells. For fuel electrodes, Sr(Ti0.3Fe0.7)O3 yields good performance at ≥ 800 oC and hydrogen-rich fuels, but the performance suffers at lower temperature and in depleted fuel due to slow H2 dissociative adsorption.[2] The substitution of 7% Ni for Fe in Sr deficient STF substantially reduces RP
under these conditions.[3] The Ni substitution results in the exsolution of Ni and Fe from the perovskite, yielding Ni-Fe nanoparticles that decorate the oxide electrode surfaces and promote hydrogen dissociative adsorption. Perovskite stoichiometry, which changes during exsolution, is found to play an important role in electrode performance; initially Sr-deficient anodes yield much lower RP
values. RP
values for Ni-substituted STF are comparable those of Ni-YSZ anodes.

References：
[1] S.-L. Zhang, H. Wang, M.Y. Lu, A.-P. Zhang, L.V. Mogni, Q. Liu, C.-X. Li, C.-J. Li, S.A. Barnett, Energy & Environmental Science (2018, DOI: 10.1039/C8EE00449H).
[2] T. Zhu, D.E. Fowler, K.R. Poeppelmeier, M. Han, S.A. Barnett, Journal of The Electrochemical Society
163 (2016) (8) F952.
[3] T. Zhu, H.E. Troiani, L.V. Mogni, M. Han, S.A. Barnett, Joule (2018) 10.1016/j.joule.2018.02.006.
High-Temperature Membrane for Water Removal in in-Situ Process
Authors: Lee Tae Hyun , Dorris Stephene E , Ma Beihai , Balachandran Uthamalingam 
Published: February 2020

Water is a main by-product of many chemical processes, such as the production of hydrocarbons from synthesis gas, condensation reactions, and oxidative dehydrogenation. In most cases, water must be removed before or during product purification. Current water removal technologies, including direct condensation, azeotropic distillation, and vacuum or reactive distillation, are energy intensive. We are investigating use of in-situ water removal membranes to circumvent the energy-intensive conventional approaches for separating water at low temperatures and pressures. The water removal membranes would provide a continuous flux of water at constant temperature and pressure while avoiding the energy-consuming steps of conventional separation methods. Large energy losses associated with water removal could be avoided, and process efficiency significantly improved.
Water is undesirable as a primary by-product at the reaction site because it could lower the reaction rate by decreasing the catalyst activity. Removal of water at the reaction site, therefore, can prevent catalyst deactivation, and it also can increase the reaction yield by shifting the equilibrium conversion to the desired products. Because the existing polymer-based membrane technologies have a temperature limitation, we are developing ceramic membranes for separating steam under process conditions over a wide temperature range (200-900ºC). Preliminary results of the steam permeation rate measurement with dense ceramic membranes made of ionic conductor will be presented in this talk.