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ABSTRACTA novel design for a high temperature SOFC, based on lamellar electrode-electrolyte segments obtained by solidification of an oxidic eutectic melt on an electrolyte substrate is presented. Such “composite” electrodes contain NiO or MnO - 8Y-ZrO2 lamellae, which after reduction / oxidation yield electrode-electrolyte lamellae with 1–2 μm width and a vertical dimension of> 100 μm, depending upon the amount of eutectic melt solidified on a polycrystalline substrate. The nucleation of the eutectic on a polycrystalline substrate followed by a semi-directional crystallization of the two phases yields a gradient of 3-phase boundaries over the height of such an electrode, with the number of 3-phase boundaries increasing towards the substrate.

Abstract Recently, the oxygen potential dependence of the signal of a potentiometric CO 2 sensor, based on a cation conductor with carbonate as gas sensitive layer, has been interpreted as caused by electronic transference through the electrolyte. Though this interpretation is quite correct, the relationships on the basis of which the effect of electronic conductivity has been discussed are wrong and so are the conclusions on the electronic conduction parameter of the electrolyte material under consideration, i.e. of the lithium ion conductor Li 3 PO 4 + SiO 2 (5 mol%). In what follows, the questionable points will be corrected and the role of the electronic conductivity for the understanding of the behaviour of a CO 2 sensor will be re-examined.

Redox flow batteries are promising devices for large-scale stationary energy storage.

Tin (Sn), antimony (Sb), as well as their intermetallic compound SnSb are potential high‐capacity negative electrodes for lithium‐ or sodium‐ion batteries. Starting from bulk Sn and Sb, the effect of ball milling in sodium‐ion half cells with a diglyme‐based electrolyte is studied. Nonreactive ball milling of Sn, Sb, and carbon leads to intimately mixed but largely phase‐separated composites (Sn + Sb) with electrochemical sodiation behavior being the sum of the individual phases. Thereby, Sb shows an unusual and rapid capacity fade in the chosen electrolyte which is unexpected, considering the usually excellent compatibility of diglyme‐based electrolytes with negative electrodes. Reactive ball milling of Sn and Sb using a planetary ball mill leads to the phase‐pure intermetallic compound β‐SnSb. Compared with Sn + Sb, SnSb shows excellent performance with a specific capacity exceeding 400 mAh g−1 after 190 cycles and a high rate capability (around 400 mAh g−1 at 5 C). Hence, herein, Sb is largely inactive as a pure phase but active when bound in the β‐SnSb intermetallic compound. Using in situ electrochemical dilatometry, the “breathing” of the electrodes during charging/discharging is minimized by optimizing ball‐milling time, which improves cycle life.

As COVID-19 spreads worldwide, governments have been implementing a wide range of measures to contain it, from movement restrictions to economy-wide shutdowns. Understanding their impacts is essential to support better policies for countries still experiencing outbreaks or in case of emergence of subsequent pandemic waves. Here we show that the cumulative decline in electricity consumption within the 5 months following the stay-home orders ranges between 3% and 12% in the most affected EU countries and USA states, except Florida, which shows no significant impact. Italy, France, Spain, California, Austria, and New York have recovered baseline consumption by the end of July, whereas Great Britain and Germany remain below baseline levels. We also show that the relationship between measures stringency and daily decline in electricity consumption is nonlinear. These results illustrate the severity of the crisis across countries and can support further research on the effect of specific measures.

Abstract The modeling of fuel cells requires the coupling of fluid transport with electro-chemical reactions. There are two approaches commonly used. Firstly, the electrodes can be treated as two planes, where the potential gradient can be considered as being locally one-dimensional. In this case a two dimensional current density distribution is obtained. Secondly, the two electrode layers can be spatially resolved and the protonic and electronic potentials obtained by solving a pair of coupled Poisson equations. The latter approach requires much higher computational resources, because a higher spatial resolution is required and a large set of model parameters is required. On the other hand, much more detailed local information can be obtained by this method. The motivation for this study was to compare the results quantitively with detailed experimental data for a high temperature polymer electrolyte fuel cell with a geometric area of 200 cm2. Both model approaches show very good agreement with measured local current density distributions. The second model is able to provide a deeper insight into the current density variation through the membrane and catalyst layers and reveals points with local extremes. The present results are specific for high temperature polymer electrolyte fuel cells but the conclusions may readily be applied to the modeling of other high temperature fuel cell types.

Due to their high theoretical capacity, transition metal oxide compounds are promising electrode materials for lithium‐ion batteries. However, one drawback is associated with relevant capacity fluctuations during cycling, widely observed in the literature. Such strong capacity variation can result in practical problems when positive and negative electrode materials have to be matched in a full cell. Herein, the study of ZnMn2O4 (ZMO) in a nonconventional electrolyte based on 3‐cyanopropionic acid methyl ester (CPAME) solvent and LiPF6 salt is reported for the first time. Although ZMO in LiPF6/CPAME electrolyte displays a dramatic capacity decay during the first cycles, it shows promising cycling ability and a suppressed capacity fluctuation when vinylene carbonate (VC) is used as an additive to the CPAME‐based electrolyte. To understand the nature of the solid electrolyte interphase (SEI), the electrochemical study is correlated to ex situ X‐ray photoelectron spectroscopy (XPS).

This study examines the effects of oil supply and global demand shocks on the volatility of commodity prices in the metal and agricultural commodity markets using the SVAR model. The empirical evidence is based on real time daily closing international commodity prices covering the period 2 December 2019 to 1 October 2020. The findings are presented in cumulative impulse responses and variance decompositions. The former is utilized to examine the accumulated influence of structural shocks on the volatility of agricultural and metal commodities whereas the latter reflect the share of variation in the volatility of each commodity arising from each structural shock. Various patterns are provided on how metal and agricultural commodity prices have been influenced by the COVID-19 pandemic. Policy implications are discussed.