Acknowledges Financial Support Research Articles

(Invited) Design of Ceramic Fuel Electrode for Solid Oxide Cells for Direct Oxidation of Hydrocarbon Fuels and for Direct CO2 Electrolysis

Large scale consumption of fossil fuels has led to the rapid increase in the atmospheric CO2 concentration, resulting in very adverse environmental concerns and frequent natural disasters. There is a grand challenge to improve conversion efficiency of fossil fuels and mitigate CO2 emmissions for terrestial applications. To enable long-term manned space exploration, there are critical needs in recycling CO2 to oxygen for life support and in situ generation of propellants using CO2 feedstock for ascent vehicles. Solid oxide cells (SOCs) have a great promise for energy conversion and storage for both terrestrial applications and space explorations. In the fuel cell mode, SOCs can convert chemical energy to electrical energy with high efficiency and fuel flexibility. In the electrolysis mode, SOCs can efficiently utilize CO2 as feedstock for chemical synthesis. The conventional Ni-based fuel electrode is vulnerable to deactivation by carbon build-up (coking) from direct oxidation of hydrocarbon fuels or for direct electrolysis of CO2, and suffers volume instability on redox cycling. This talk will report novel heterogeneous functional materials as SOC fuel electrodes that possess a combined property of good coking resistance and redox cyclability, enabling SOCs to be operated on hydrocarbon fuels for electricity generation in the fuel cell mode and for direct CO2 electrolysis for fuel synthesis in the electrolysis mode.The general philosophy to design novel SOC fuel electrodes is to develop ceramic materials that are redox-stable, possess mixed ionic and electronic mixed conductivity, and have catalytic activities for fuel oxidation and CO2 splitting reaction. Different types of ceramic fuel electrode materials have been explored and characterized as SOC fuel electrodes. The phase formation, redox-stability, electrical conductivity, electrochemical performance, and tolerance to coking and redox-cycling have been systematically evaluated. By judicious design of ceramic-based heterogeneous functional materials, high performance redox-flexible ceramic fuel electrodes can be achieved for direct oxidation of hydrocarbon fuels and for direct CO2 electrolysis. Acknowledgements Financial support from the U.S. Department of Energy (DE-EE0009427), National Science Foundation (DMR–1832809) and NASA EPSCoR (Grant # 80NSSC20M0233) is greatly appreciated.

Designing High Entropy Amorphous Oxides for Li-Battery Electrolytes

Amorphous Li-oxides such as LiPON and amorphous Li garnet are considered as promising solid-state electrolytes for use in hybrid or all-solid-state oxide- and sulfide-based batteries as separators or protective layers.1-3 These materials possess several appealing characteristics, such as their intrinsic grain-boundary-free nature and relatively low manufacturing temperature (ranging from room temperature to 600 °C), which facilitates co-synthesis with Co-substituted or even Co-free cathodes that are unstable at standard electrolyte sintering temperatures. Alternatively, they can be applied as protective coatings toward Li anodes and other Li-free anode concepts, bridging the electrochemical stability voltage gap with liquid electrolytes or catholytes and preventing uneven interfacial reactions. The amorphous Li-oxides can be classified based on their structural entropy, i.e., the number and types of local bonding units (LBUs). As of today, ‘low entropy’ amorphous LiPON with only one type of LBU achieves the highest cycle number and battery lifetime.4 ‘High entropy’ amorphous Li-ion conductors, such as Li perovskites or Li garnets, exhibit an unusually high number of LBUs. local ordering and the Li-ion dynamics remain poorly understood, in part owing to the difficulty in characterizing their disordered states. This study employed a novel synthesis protocol to stabilize amorphous Al-doped Li garnets, representing so far the highest number of LBUs (≥ 4) in an amorphous Li-ion conductor.5 We resolved their phase evolution and local structures by a combination of spectroscopy, microscopy, and calorimetry techniques. A much wider (<680 °C) but processing-friendly temperature range was identified to stabilize various amorphous phases with edge- and face-sharing Zr, La, and Li LBUs that do not conform to the formation rules for Zachariasen’s glasses. These amorphous Li-ion conductors reveal an unusual setting in which Li and Zr act as network formers and La acts as a network modifier, with the highest Li-dynamics observed for smaller Li–O and Zr–O coordination among the amorphous phases. Our insight provides fundamental guidelines for the phase, local structure, and Li-transport modulation for amorphous Li garnets and pave the way for their integration in next-generation solid-state or hybrid battery designs with enhanced safety and lifetime. Acknowledgments Y.Z. acknowledges financial support provided by the MIT Energy Initiative fellowship offered by ExxonMobil. This research was supported by Samsung Electronics. This research was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which was supported by the National Science Foundation under NSF award no. 1541959. CNS is a part of Harvard University. This research used resources of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, and was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357, and the Canadian Light Source and its funding partners.

Do women mind the non-GAAP? Board gender diversity and non-GAAP disclosure quality

We examine whether board gender diversity promotes high-quality non-GAAP disclosures. Specifically, we use two recently-developed measures that capture key characteristics of financial reporting quality, namely consistency and comparability in non-GAAP reporting. We find that gender-diverse boards are more effective at ensuring both consistency and comparability of non-GAAP earnings disclosures. Our results will help investors to understand the information communicated by non-GAAP reporting. They also will guide standard-setters and regulators as they determine standards and guidelines that lead to better outcomes for investors.

Real responses to anti-tax avoidance: Evidence from the UK Worldwide Debt Cap

We analyze how multinational firms reallocate real operations and debt across their affiliates in response to anti-tax avoidance policies. The UK introduced a worldwide debt cap in 2010, generating a quasi-natural experiment that limited interest deductibility for a group of multinational firms. We find that multinationals affected by the reform reduced the amount of debt held in the UK and increased debt held abroad. Affected multinationals reallocated a share of their real operations away from the UK. Our findings provide causal evidence for tax-motivated debt and real activity reallocation within multinationals and show how multinationals can circumvent tax avoidance regulations.11We would like to thank Jennifer Blouin, Steve Bond, Travis Chow, Mike Devereux, Jim Hines, Krzysztof Karbownik, James O’Donovan, Daniela Scur, Michael Stimmelmayr, Juan Carlos Suarez Serrato, Shiheng Wang, Bohui Zhang and three anonymous referees for their comments. Further thanks to the participants of National Tax Association conference, Utah Tax Invitational, China International Conference in Finance, Asia Meeting of Econometric Society, Ce2 workshop, Oxford University Centre for Business Taxation Summer Symposium, Fanhai International School of Finance at Fudan University seminar, Australian National University, International Institute of Public Finance Annual Congress and European Economic Association Congress for their helpful suggestions. Xing acknowledges financial support from National Natural Science Foundation of China (No. 71903125), Shanghai Pujiang Program (No. 16PJC056) and Shanghai Institute of International Finance and Economics. All omissions and errors are our own.

Charged quark stars in f(R,T) gravity* *JMZP acknowledges financial support from the PCI program of the Brazilian agency "Conselho Nacional de Desenvolvimento Científico e Tecnológico"–CNPq. T. Tangphati was supported by King Mongkut's University of Technology Thonburi's Post-doctoral Fellowship. A. Pradhan thanks IUCCA, Pune, India for providing facilities under associateship programmes

Recent advances in nuclear theory and new astrophysical observations have led to the need for specific theoretical models applicable to dense-matter physics phenomena. Quantum chromodynamics (QCD) predicts the existence of non-nucleonic degrees of freedom at high densities in neutron-star matter, such as quark matter. Within a confining quark matter model, which consists of homogeneous, neutral 3-flavor interacting quark matter with corrections, we examine the structure of compact stars composed of a charged perfect fluid in the context of gravity. The system of differential equations describing the structure of charged compact stars has been derived and numerically solved for a gravity model with . For simplicity, we assumed that the charge density is proportional to the energy density, namely, . It is demonstrated that the matter-geometry coupling constant β and charge parameter α affect the total gravitational mass and the radius of the star.

Open charm mesons and charmonia in magnetized strange hadronic matter * *A.J.C.S acknowledges the support towards this work from the Department of Science and Technology, Government of India, via an INSPIRE fellowship (INSPIRE Code IF170745). AM acknowledges financial support from Department of Science and Technology (DST), Government of India (CRG/2018/002226)

We investigate the in-medium masses of open charm mesons (D( , ), ( , ), ( , )) and charmonium states ( , , , , ) in strongly magnetized isospin asymmetric strange hadronic matter using a chiral effective model. In the presence of a magnetic field, the number and scalar densities of charged baryons have contributions from Landau energy levels. The mass modifications of open charm mesons result from their interactions with nucleons, hyperons, and the scalar fields (the non-strange field σ, strange field ζ, and isovector field δ) in the presence of a magnetic field. The mass modifications of the charmonium states result from the modification of gluon condensates in a medium simulated by the variation in the dilaton field (χ) in the chiral effective model. The effects of finite quark masses are also incorporated in the trace of the energy-momentum tensor in quantum chromodynamics to investigate the mass shifts of charmonium states. The in-medium masses of open charm mesons and charmonia are observed to decrease with an increase in baryon density. The charged , , , and mesons have additional positive mass shifts due to Landau quantization in the presence of a magnetic field. The effects of the strangeness fraction are observed to be more dominant for mesons compared with D mesons. The mass shifts of charmonia are observed to be larger in hyperonic media compared with nuclear media when the effect of the finite quark mass term is neglected. These medium mass modifications can have observable consequences on the production of the open charm mesons and charmonia in high-energy asymmetric heavy-ion collision experiments.

On-Site Inspecting Zombie Lending

“Zombie lending” remains a widespread practice by banks around the world. In this paper, we exploit a series of large-scale on-site inspections made on the credit portfolios of several Portuguese banks to investigate how these inspections affect banks’ future lending decisions. We find that an inspected bank becomes 20% less likely to refinance zombie firms, immediately spurring their default. Overall, banks seemingly reduce zombie lending because the incentives to hold these loans disappear once they are forced to recognize losses. This paper was accepted by Tomasz Piskorski, finance. Funding: D. Bonfim and G. Cerqueiro acknowledge financial support from Fundação para a Ciência e a Tecnologia [Grants PTDC/EGE-OGE/30314/2017 and UID/GES/00407/2013]. H. Degryse acknowledges financial support from Fonds Wetenschappelijk Onderzoek. S. Ongena acknowledges financial support from the Horizon 2020 European Research Council [Grant ERC ADG 2016 - GA 740272 lending]. Supplemental Material: The data files and online appendix are available at https://doi.org/10.1287/mnsc.2022.4452 .

Taxes in Non-GAAP Reporting: Evidence of Strategic Behavior in Selecting Tax Rates Applied to Exclusions

When reporting after-tax non–generally accepted accounting principles (GAAP) earnings, firms are required to adjust for the tax effects of exclusions. Since 2010, the Securities and Exchange Commission (SEC) has issued and updated compliance and disclosure interpretations (C&amp;DIs), which specifically require firms to disclose the tax effects of exclusions. We assemble a detailed, hand-collected data set of S&amp;P 1500 firms’ disclosures to provide the first large-sample evidence on the reporting of the tax effects of non-GAAP exclusions. We find three key results. First, echoing the SEC’s concern, a significant proportion of non-GAAP reporting firms do not follow the C&amp;DI guidelines (i.e., they do not disclose the tax effects of exclusions). Second, among firms that disclose the tax effects of exclusions, we find that managers strategically select the tax rates applied to exclusions to achieve after-tax earnings targets. Third, manager-reported non-GAAP earnings are less persistent for future operating earnings and cash flows relative to non-GAAP earnings calculated by applying various benchmark tax rates to exclusions. This evidence suggests that managers’ strategic behavior in selecting the tax rates applied to exclusions pollutes reported non-GAAP earnings and reduces their usefulness for predicting future performance. Overall, our results shed light on a specific channel through which firms use non-GAAP reporting to meet or beat earnings expectations. This paper was accepted by Brian Bushee, accounting. Funding: N. (X.) Chen appreciates financial support from the University of Houston. T. Shevlin acknowledges financial support from the Paul Merage School of Business at the University of California–Irvine. P.-C. Chiu acknowledges the financial support received from the Hong Kong Research Grant Council [Grant RGC14522716]. Supplemental Material: Data files and the online appendix are available at https://doi.org/10.1287/mnsc.2022.4433 .

Attention and Underreaction-Related Anomalies

Recent studies have proposed a large set of powerful anomaly-based factors in the stock market. This study examines the role of investor inattention in the corresponding anomalies underlying these factors and other underreaction-related anomalies. Using media coverage as a proxy for investor attention, we show that the anomalies underlying many recently proposed prominent factors are much more pronounced among firms with low media coverage in portfolio-formation periods. In addition, we find many other prominent anomalies that previous literature has attributed to underreaction also tend to perform much better among firms with low media coverage. The average Fama-French five-factor alpha spread of these anomalies is about 0.97% per month among firms with low news coverage and only 0.24% per month among firms with high news coverage. Moreover, most of the alpha spread comes from the short leg of the anomalies and from the firms that are more difficult to arbitrage. Overall, our evidence indicates that investor inattention at least partially drives many of the recently proposed factors. This paper was accepted by Haoxiang Zhu, finance. Funding: L. Tao received financial support from the National Natural Science Foundation of China [Grant 72171050], the Ministry of Education Project of Humanities and Social Sciences [Grant No. 17YJCZH161], and the University of International Business and Economics Fund for Distinguished Young Scholars [Grant No. 18JQ07]. J. Yu acknowledges financial support from the National Natural Science Foundation of China [Grant No. 71790591]. Supplemental Material: The online appendix and data are available at https://doi.org/10.1287/mnsc.2022.4332 .

Development of a clinical prediction model for perinatal deaths in low resource settings.

SummaryBackgroundMost pregnancy-related deaths in low and middle income countries occur around the time of birth and are avoidable with timely care. This study aimed to develop a prognostic model to identify women at risk of intrapartum-related perinatal deaths in low-resourced settings, by (1) external validation of an existing prediction model, and subsequently (2) development of a novel model.MethodsA prospective cohort study was conducted among pregnant women who presented consecutively for delivery at the maternity unit of Zanzibar's tertiary hospital, Mnazi Mmoja Hospital, the Republic of Tanzania between October 2017 and May 2018. Candidate predictors of perinatal deaths included maternal and foetal characteristics obtained from routine history and physical examination at the time of admission to the labour ward. The outcomes were intrapartum stillbirths and neonatal death before hospital discharge. An existing stillbirth prediction model with six predictors from Nigeria was applied to the Zanzibar cohort to assess its discrimination and calibration performance. Subsequently, a new prediction model was developed using multivariable logistic regression. Model performance was evaluated through internal validation and corrected for overfitting using bootstrapping methods.Findings5747 mother-baby pairs were analysed. The existing model showed poor discrimination performance (c-statistic 0·57). The new model included 15 clinical predictors and showed promising discriminative and calibration performance after internal validation (optimism adjusted c-statistic of 0·78, optimism adjusted calibration slope =0·94).InterpretationThe new model consisted of predictors easily obtained through history-taking and physical examination at the time of admission to the labour ward. It had good performance in predicting risk of perinatal death in women admitted in labour wards. Therefore, it has the potential to assist skilled birth attendance to triage women for appropriate management during labour. Before routine implementation, external validation and usefulness should be determined in future studies.FundingThe study received funding from Laerdal Foundation, Otto Kranendonk Fund and UMC Global Health Fellowship. TD acknowledges financial support from the Netherlands Organisation for Health Research and Development (grant 91617050).

Information Accessibility and Corporate Innovation

This study identifies information accessibility as a determinant of corporate innovation. Using the sudden termination of Google’s search services in China, we find a persistently large negative effect on the intensity and quality of innovation among firms relying on foreign knowledge. The results are stronger for firms in industries dominated by foreign technology, in regions with local web filters, and for firms with fewer alternative sources of foreign information. We also find that the affected firms cite fewer foreign patents and their innovation efficiency declines after Google’s exit. Overall, the results are consistent with the view that access to information is an important driver of technological progress. This paper was accepted by Kay Giesecke, finance. Funding: D. Kong acknowledges financial support from the National Natural Science Foundation of China [Grants 71802160, 71991473, and 71772178] and the Major Project of National Social Science Foundation of China [Grant 21ZDA010]. C. Lin acknowledges financial support from the National Natural Science Foundation of China [Grant 71790601]. L. Wei acknowledges financial support from the Research Grant Council of the Hong Kong Special Administrative Region, China [Project T35/710/20R]. J. Zhang acknowledges financial support fromthe PRC Ministry of Education Youth Project for Humanities and Social Science Research [Grant 18XJC630008]. Supplemental Material: The data files and online appendix are available at https://doi.org/10.1287/mnsc.2021.4224 .

A crucial phase in plants - it's a gas, gas, gas!

A crucial phase in plants - it's a gas, gas, gas!

Public Concern About Immigration and Customer Complaints Against Minority Financial Advisors

We examine the relation between public concern about immigration and customer complaints against minority financial advisors in the United States. We find that minority advisors are more likely to receive complaints in periods of high public concern about immigration than in other periods, relative to their white colleagues from the same firm, at the same office location, and at the same point in time. This result holds for both complaints with merit and dismissed complaints and is more pronounced in counties where residents likely hold stronger anti-immigration views. We also find that minority advisors are more likely to face regulatory actions or leave their firms after customer allegations in periods of high public concern about immigration than in other periods. Overall, our study provides descriptive evidence of a positive relation between public concern about immigration and customer dissatisfaction with minority advisors. This paper was accepted by Suraj Srinivasan, accounting. Funding: K. K. F. Law acknowledges financial support from a Nanyang Technological University’s Start-Up Grant. L. Zuo acknowledges financial support from the Cornell SC Johnson College of Business and fromUniversity of Toronto RogerMartin Award for Emerging Leaders. Supplemental Material: Code is available at https://doi.org/10.1287/mnsc.2021.4283 .

Demand Estimation Using Managerial Responses to Automated Price Recommendations

We provide a new framework to identify demand elasticities in markets where managers rely on algorithmic recommendations for price setting and apply it to a data set containing bookings for a sample of midsized hotels in Europe. Using nonbinding algorithmic price recommendations and observed delay in price adjustments by decision makers, we demonstrate that a control-function approach, combined with state-of-the-art model-selection techniques, can be used to isolate exogenous price variation and identify demand elasticities across hotel room types and over time. We confirm these elasticity estimates with a difference-in-differences approach that leverages the same delays in price adjustments by decision makers. However, the difference-in-differences estimates are more noisy and only yield consistent estimates if data are pooled across hotels. We then apply our control-function approach to two classic questions in the dynamic pricing literature: the evolution of price elasticity of demand over and the effects of a transitory price change on future demand due to the presence of strategic buyers. Finally, we discuss how our empirical framework can be applied directly to other decision-making situations in which recommendation systems are used. This paper was accepted by Omar Besbes, revenue management and market analytics. Funding: D. Garcia acknowledges financial support from the Austrian Science Fund [Single Project “Understanding Consumer Search” FWF-P 30922]. Supplemental Material: The online appendix and data are available at https://doi.org/10.1287/mnsc.2021.4261 .

PEFCs Using Metallic Ti and Sn Gas Diffusion Layers

Introduction Many types of carbon materials are used in PEFCs. Especially, gas diffusion layer (GDL), with a thickness of ca. 0.2 mm are made of relatively expensive carbon fibers. In general, metallic materials can be more electronically conductive than carbon black based materials, and thinner GDLs could be prepared using metals. Here in this study, we evaluate and compare several types of metallic materials to apply as GDLs. Using such alternative metallic GDLs, current-voltage (I-V) characteristics were measured and overvoltages were separated. The purpose of this study is to examine possibilities of metallic GDLs for PEFCs, by varying materials, thickness, porosity, and preparation conditions. Experimental We measured I-V characteristics of PEFCs using metallic GDLs. Four types of porous metallic sheets were used as GDLs, shown in Figures 1 to 3: (i) Ti fiber-based sheet (porosity: 70%; thickness: 200μm; Nikko Techno Ltd.), (ii) Ti fiber-based sheet with porous Sn layer, (iii) Ti punching metal sheet (sheet thickness: 12μm; hole diameter: 300μm; Fukuda Metal Foil & Powder Co., Ltd.), and (iv) Sn punching metal sheet (sheet thickness: 100μm; hole diameter: 300μm, Fukuda Metal Foil & Powder Co., Ltd.). Except for cathode-side GDLs, standard materials were used such as Pt/C electrocatalyst (Tanaka Kikinzoku Kogyo, TEC10E50E). Electrochemical impedance spectroscopy (EIS, Solartron 1255WB) was used to separate overvoltages in the electrochemical characterization. Results and discussion I-V characteristics of the cells with the cathode GDLs (i) to (iv) are shown in Figure 4. Decrease in cell performance was mainly caused by an increase in ohmic losses. Comparing these GDLs, Sn-based materials are generally more conductive than Ti-based materials to decrease ohmic losses, but concentration overvoltage can also be high when the GDLs (ii) and (iv) were used. Both contact and internal resistance were reduced when using the porous Ti punching metal sheet instead of the Ti fiber sheet. Further study is in progress to increase I-V characteristics of MEAs by optimizing materials selection and structure. Acknowledgement Financial support from New Energy and Industrial Technology Development Organization (NEDO) is gratefully acknowledged (Contract No. 20001214-0). References Larminie，A. Dicks，Fuel Cell Systems Explained, 2nd Edition, John Wiley & Sons, West Sussex, England, 2003.T．Kitahara，T．Konomi，H．Nakajima, and J．Shiraishi， Japan Soc. Mech. Engineers, B76 (761) 101 (2010), in Japanese.S．Matsumoto，M．Nagamine，Z．Noda，J．Matsuda，S．M．Lyth，A．Hayashi，and K．Sasaki，J ． Electrochem ．，165 (14)，1165 (2018).C．A．Reiser，L．Bregoli，T．W．Patterson，J．S．Yi，J．D．yang，M．L．Perry，and T．D．Jarvi，Electrochem . Solid-State Lett.，8 (6)，A273 (2005). Figure 1

PEFCs Using Metallic Ti and Sn Electrocatalyst Supports

Introduction Currently, Pt-based catalyst on carbon black support (Pt/C) is widely used as the electrocatalyst for polymer electrolyte fuel cells (PEFCs). Carbon black support has high electronic conductivity and high specific surface area for supporting highly-dispersed Pt catalyst nanoparticles. However, under cathode condition of PEFCs e.g. during start-stop cycles, carbon black support can be electrochemically oxidized, causing detachment and aggregation of Pt catalyst nanoparticles (1). In order to solve this issue, we are developing SnO2 and TiO2 supports, which are relatively stable even under cathode conditions, coated on carbon-based materials as the conductive backbone, exhibiting high durability (2, 3). However, as far as we use carbon materials, carbon corrosion problem may still be remained. Here in this study, porous metallic Ti and Sn sheets are applied as catalyst support. Such electrodes may exhibit high durability under PEFC cathode conditions due to the formation of stable TiO2 and SnO2 layers on the outermost surface of Ti and Sn metals. Furthermore, metallic sheets with porous structures also have a potential to act as gas diffusion layers (GDL). This study aims to prepare such electrodes integrating electrocatalysts with high conductivity and high durability. Experimental For preparing metallic Ti supported electrodes, porous Ti sintered sheets were used. First, the porous Ti sintered sheets were chemically etched in NaOHaq to increase their surface area. The etched Ti sheets were then heat-treated at 400 °C in 5%H2-N2. Pt catalyst nanoparticles were then decorated on the Ti sheets by the arc plasma deposition (APD) or the acac method (4). We also prepared Nb-doped Ti sheets to improve their electronic conductivity. For preparing metallic Sn supported electrodes, cellulose-based filter paper was used as a template. First, SnO2 sol was impregnated into the filter papers in vacuum, followed by heat treatment in oxidizing atmosphere to remove the cellulose-based templates. After that, porous metallic Sn sheets were obtained by reducing heat-treatment. The Pt catalyst nanoparticles were decorated on the porous Sn sheets by the acac method (4). Microstructures of the porous Pt/Ti and Pt/Sn sheets were observed by FE-SEM and STEM-EDS. Their electrochemical activities were measured in a half-cell setup in HClO4 electrolyte. Results and Discussion Figure 1 shows an FE-SEM image of the porous Ti sheet after the surface treatment by NaOHaq. The surface of the Ti sheets after the surface treatment has needle-like TiO2 nanostructures with a diameter of several nm, with high surface area. Figure 2 shows the linear sweep voltammograms by the half-cell tests for the Pt/Ti sheet electrodes. The Pt/Ti sheet electrode prepared by the acac method may have higher contact resistance than the Pt/Ti sheet electrode by the APD method. However, such contact resistance may be reduced by Nb-doping the Ti sheets. Figure 3 shows an FE-SEM image of the prepared Sn sheet for catalyst support. We could prepare metallic Sn sheets with porous structures derived from the filter paper template. However, optimization of heat-treatment conditions is further required. It is because the reduction of SnO2 is difficult if the heat-treatment temperature is too low, but Sn will be melted if the temperature is too high. Acknowledgement Financial support from New Energy and Industrial Technology Development Organization (NEDO) is gratefully acknowledged (Contract No. 20001214-0). References L. M. Roen, C. H. Pail, and T. D. Jarvi, Electrochem. Solid-State Lett., 7 (1), A19 (2004). S. Matsumoto, M. Nagamine, Z. Noda, J. Matsuda, S. M. Lyth, A. Hayashi, and K. Sasaki, J. Electrochem. Soc., 165 (14), 1165 (2018). Y. Nakazato, D. Kawachino, Z. Noda, J. Matsuda, A. Hayashi, and K. Sasaki, ECS Trans., 80 (8), 897 (2017).A. Hayashi, H. Notsu, K. Kijima, J. Miyamoto, and I. Yagi, Electrochim. Acta, 53 (21), 6117 (2008). Figure 1

Preparation of PEFC Electrocatalysts Using SnO2 Thin Layer Support

Pt/C is widely used as polymer electrolyte fuel cell (PEFC) electrocatalyst. However, under high potential at the cathode, Pt detachment and aggregation due to carbon corrosion can occur. Therefore, conventional Pt/C electrocatalysts have a difficulty in durability, for e.g. heavy-duty applications. Our research group has been preparing electrocatalysts with both high activity and high durability (1-3). However, their electrocatalytic activity has to be further improved. For this reason, we are further improving catalytic activity by alloying platinum with cobalt on such SnO2-based catalyst support. Cobalt is one of the relatively stable metals under the PEFC electrocatalyst condition, and PtxCoy alloy catalysts are known to be capable of exhibiting higher activity over Pt catalysts (4). In addition, the doping of SnO2 with 2 mol% Nb is expected to increase electronic conductivity of SnO2 (5,6). Experimental Sn0.98Nb0.02O2 thin layer was deposited on the GCB (denoted as Sn0.98Nb0.02O2/GCB) by the ammonia coprecipitation method. Pt(acac)2 and Co(acac)2 were applied to simultaneously impregnate Pt and Co to obtain Pt-Co alloy catalysts (acac method). The Pt : Co ratio was adjusted to prepare Pt3Co alloy to obtain Pt3Co/Sn0.98Nb0.02O2/GCB electrocatalyst. The preparation procedure is schematically described in Figure.1. Results and discussion In order to evaluate Pt and Co loadings, ICP analysis was performed. We then made half-cell tests to evaluate electrochemical activities of these electrocatalysts. Electrochemical surface area (ECSA) was measured by cyclic voltammetry (CV), and oxygen reduction reaction (ORR) activity was derived from kinetically controlled current density (ik ) in the rotating disk electrode (RDE) measurement. We prepared MEA (Membrane Electrode Assembly) using this electrocatalyst (Pt3Co/Sn0.98Nb0.02O2/GCB) on the cathode side. We then made full-cell tests to evaluate cell performance such as current-voltage characteristicsFrom the ICP results, we confirmed that we could impregnate both Pt and Co close to the designated ratio in the acac method. Microstructures and EDS maps are shown in Figure. 2, confirming that Pt and Co were uniformly supported on the SnO2 surface layer on GCB. Electrochemical results and detailed microstructural analysis will be reported and discussed. Acknowledgement Financial support from New Energy and Industrial Technology Development Organization (NEDO) is gratefully acknowledged (Contract No. 20001214-0). References S. Matsumoto, M. Nagamine, Z. Noda, J. Matsuda, S. M. Lyth, A. Hayashi, and K. Sasaki, J. Electrochem. Soc., 165 (14), F1164 (2018).Y. Nakazato, D. Kawachino, Z. Noda, J. Matsuda, S. M. Lyth, A. Hayashi, and K. Sasaki, J. Electrochem. Soc., 165 (14), F1154 (2018). T. Yoshizumi, M. Nagamine, Z. Noda, J. Matsuda, A. Hayashi, and K. Sasaki, ECS Trans., 92 (8), 479 (2019). T. Tada, Y. Yamamoto, K. Matsutani, K. Hayakawa, and T. Namai, ECS Trans., 16 (2), 215 (2008). F. Takasaki, S. Matsuie, Y. Takabatake, Z. Noda, A. Hayashi, Y. Shiratori, K. Ito, and K. Sasaki, J. Electrochem. Soc., 158, B1270 (2011). K. Sasaki, F. Takasaki, Z. Noda, S. Hayashi, Y. Shiratori, and K. Ito, ECS Trans., 33 (1), 473 (2010). Figure 1

High T c Superconductivity in Heavy Rare Earth HydridesSupported by the National Natural Science Foundation of China (Grant Nos. 12122405, 51632002, and 11974133), the Program for Changjiang Scholars and Innovative Research Team in Universities (Grant No. IRT 15R23). C.J.P. acknowledges financial support from the Engineering and Physical Sciences Research Council (Grant No. EP/P022596/1).

Sulfur and lanthanum hydrides under compression display superconducting states with high observed critical temperatures. It has been recently demonstrated that carbonaceous sulfur hydride displays room temperature superconductivity. However, this phenomenon has been observed only at very high pressure. Here, we theoretically search for superconductors with very high critical temperatures, but at much lower pressures. We describe two of such sodalite-type clathrate hydrides, YbH6 and LuH6. These hydrides are metastable and are predicted to superconduct with T c ∼ 145 K at 70 GPa and T c ∼ 273 K at 100 GPa, respectively. This striking result is a consequence of the strong interrelationship between the f states present at the Fermi level, structural stability, and the final T c value. For example, TmH6, with unfilled 4f orbitals, is stable at 50 GPa, but has a relatively low value of T c of 25 K. The YbH6 and LuH6 compounds, with their filled f-shells, exhibit prominent phonon “softening”, which leads to a strong electron-phonon coupling, and as a result, an increase in T c.

Model-Based Optimization of Solid Oxide Electrolysis Cells and Stacks for Power-to-Gas Applications

The temporarily fluctuating power supply produced by renewable energy sources (RES) forces the integration of energy storage technologies in our energy network at a massive scale, in order to make future scenarios of a sector-coupling and distributed clean energy supply feasible. Power-to-Methane (PtM) chemical storage concepts are very attractive in this regard, since the production of synthetic CH4 has the advantages of a high-energy density carrier that is easily transportable within the existing pipeline infrastructure and that is a feedstock for various applications in the form of compressed or liquefied natural gas (CNG/LNG). However, in all these scenarios, the levelized cost of the synthetic fuel is a major obstacle due the relatively inefficient conversion chain, i.e. energy losses associated with the fuel production plus consumption. Thermal integration of high-temperature (HT) steam electrolysis based on solid oxide electrolysis cells (SOECs) with the exothermic catalytic methanation is a very promising concept to boost the system’s efficiency by making use of the intrinsically favored thermodynamics and kinetics of HT-electrolysis for H2 generation. On stack level, electrical efficiencies (based on the lower heating value (LHV)) of 96% and specific energy consumptions of 3.3 kWh per Nm3 of H2 were reported for HT-steam electrolysis [1], whilst net system PtM efficiencies of ~80% could be demonstrated in a pilot project [2].Still, there exists the fundamental question on how to optimize the cell design and the operating conditions in terms of balancing area-specific power density, efficiency, degradation rates, and costs, i.e., how to use this synergy optimally in a future real-world application.Here, we use a detailed multi-physics and multi-scale SOEC simulation tool alongside initial and long-term experiments performed on commercial electrolyte- (ESC) and anode-supported cells (ASCs) to make further strikes towards this question. Firstly, a planar single cell model coupling 1D+1D gas transport and spatially-resolved charge transfer across the electrode thickness is calibrated based on polarization curves recorded at different temperatures (600-900 °C) and inlet compositions (80-95% H2O, balance H2). By accounting for realistic microstructural cell data acquired from Scanning Electron Microscopy (SEM), a nearly quantitative accordance with the experimental data could be achieved. Subsequently, by incorporating a 2D heat transport model, adiabatic simulations are performed to identify optimal operation conditions in a parametric study, which are used as a basis for the long-term degradation experiments. It is demonstrated how the selection of the cell design affects the selection of optimal operation points, and how the creation of reactant starvation zones within the cell can severely impact the electrical efficiency. A scale-up to the stack level is performed afterwards by applying a 3D stack model [3], which considers heat loss to the surroundings across a thermal insulation layer. This enables to realize system-oriented simulations with conditions experienced by the stack that are close to the real-world application. In this way, the implications of scaling-up on (i) the SOEC performance depending on the cell design, and (ii) the selection of optimal operation conditions from an electrolyzer point-of-view in the context of PtM are illustrated on the basis of industrially-scaled stacks. Acknowledgements Financial support by the federal ministry for economic affairs and energy (Bundesministerium für Wirtschaft und Energie, BMWi) under Grant Numbers 03EIV041D and 03EIV041E in the “MethFuel” group of the collaborative research project “MethQuest” is gratefully acknowledged.

Comparative Study of Carbon and Conducting Polymer-Based Hybrid Electrochemical Capacitors Using Potassium Iodide Redox Electrolyte

A key challenge for the existing electrochemical energy storage systems, enabling versatile and advanced applications in modern electronics, is related with the improvement of their performance in terms of gravimetric and volumetric energy and power, durability, safety and exploitation costs. However, neither batteries, nor electrochemical capacitors (ECs) technologies do not meet all these demands. Hence, the concept of hybrid capacitor has been developed allowing to combine the main advantages of batteries (high energy) and ECs (high power, long lifespan). Among various strategy of development of such hybrid devices is the incorporation of electrochemically active redox species in addition, or instead of a conventional double-layer supporting electrolyte. To date, it has been widely reported that the electron transitions between redox centres present in the electrolyte at various oxidation states result in the increased capacity and energy in comparison to the simple electrical double-layer-type systems. By the fact that these processes should be fast and highly reversible, the rate of charging/discharging remains on a level expected for high power systems.It is worth to emphasize that most of reported active electrolyte-based hybrid ECs rely on carbonaceous materials enabling low electrodes resistance, providing a well-developed surface area and a high number of active sites for the electrochemical reaction. In the present work, we propose an alternative electrode material based on a conducting polymer (poly(3,4-ethylenedioxythiophene (PEDOT)) to support the redox processes of the iodide-based active electrolyte. The performance evaluation is based on the comparison to the the system fabricated from the conventional high surface area activated carbon electrodes (AC). The structure, morphology and porosity of investigated materials are analysed with various physicochemical characterization methods (SEM, XRD, Raman, UV/Vis and N2 physisorption) and electroanalytical techniques. The electrochemical studies revealed that despite a low specific surface area of a PEDOT (S BET equal to 40 m2 g-1), the gravimetric cell capacitance is similar to obtained for AC-based cell (S BET=2600 m2 g-1). Interestingly, despite a lower potential window of PEDOT system (1.2 V vs. 1.5 V for the AC), the volumetric capacitance and energy is even higher due to the high packing density of PEDOT electrodes. A better capacitance/energy responses were also observed upon complete parameters normalization, i.e. including the mass of electrolyte present in the pores and void spaces of the electrodes. It should be noted that such approach, although of a great importance in a viewpoint of realistic industrial application, and is often neglected by the researchers.The performance of both systems is also discussed in terms of stability and the effect of continuous operation (under galvanostatic cycling or potentiostatic ageing) on the coulombic efficiency and the self-discharge rate, where the latter has been found to be significantly lower for PEDOT-type cell, with respect to the AC counterpart. The presence and the amount of undesired reaction by-products, i.e. iodates, is analysed ex-situ using electrochemical sensing methods. As a result, a mechanism of parasitic charge loss under open circuit, leading to self-discharge, is described and named as a “dual redox-shuttle effect”, mainly attributed to the reactions taking place at the negative electrode. Acknowledgement Financial support was provided by the National Centre for Research and Development (NCBR, Poland) under Techmatstrateg Grant no. 347431/14/NCBR/2018.