Analysis of microstructural effects in multi layer lithium ion battery cathodes

A possible way to increase the energy density in lithium-ion batteries, and, at the same time, reduce the production costs, is to use thicker electrodes. However, transport limitations can occur in thick electrodes, leading to a drawback in performance. A way to mitigate this problem is a more sophisticated microstructure of the electrode, using, e.g., structural gradients. This can, for instance, be achieved by multi-layer casting, i.e., casting and drying of a first layer, and then adding a second layer. An important question is how the interface between the two layers is shaped and how the corresponding microstructure influences the electrochemical performance. In the present paper, two different two-layer cathodes are analyzed and compared to single-layer cathodes of the same thickness. The analysis involved tomographic imaging, a statistical analysis of the 3D microstructure of the active material particle systems with a focus on the interface between the layers, and electrochemical characterization of the active material systems using experimental measurements as well as electrochemical simulations. The analysis showed that at the interface the connectivity of active material particles decreases, which results in higher electric resistivity. This effect is stronger if an intermediate calendering step is performed, i.e., the first layer is calendered before casting the second layer

Urban eddy covariance measurements reveal significant missing NOx emissions in Central Europe

Nitrogen oxide (NOx) pollution is emerging as a primary environmental concern across Europe. While some large European metropolitan areas are already in breach of EU safety limits for NO2, this phenomenon does not seem to be only restricted to large industrialized areas anymore. Many smaller scale populated agglomerations including their surrounding rural areas are seeing frequent NO2 concentration violations. The question of a quantitative understanding of different NOx emission sources is therefore of immanent relevance for climate and air chemistry models as well as air pollution management and health. Here we report simultaneous eddy covariance flux measurements of NOx, CO2, CO and non methane volatile organic compound tracers in a city that might be considered representative for Central Europe and the greater Alpine region. Our data show that NOx fluxes are largely at variance with modelled emission projections, suggesting an appreciable underestimation of the traffic related atmospheric NOx input in Europe, comparable to the weekend-weekday effect, which locally changes ozone production rates by 40%

Assessing a New Clue to How Much Carbon Plants Take Up

Current climate models disagree on how much carbon dioxide land ecosystems take up for photosynthesis. Tracking the stronger carbonyl sulfide signal could help

The pleistocene species pump past its prime:Evidence from European butterfly sister species

This is the final version. Available on open access from Wiley via the DOI in this recordData availability statement: Read data are available from the ENA at PRJEB43082. Sequence alignments for the COI barcode locus were obtained from the dataset DS-EUGENMAP (dx.doi.org/10.5883/DS-EUGENMAP) on BOLD at www.boldsystems.org and were originally produced by Dincӑ et al., (2021). The script used for calculating diversity and divergence is available at https://github.com/samebdon/orthodiver/blob/master/orthodiver.py.The Pleistocene glacial cycles had a profound impact on the ranges and genetic make-up of organisms. Whilst it is clear that the contact zones that have been described for many sister taxa are secondary and have formed during the last interglacial, it is unclear when the taxa involved began to diverge. Previous estimates based on small numbers of loci are unreliable given the stochasticity of genetic drift and the contrasting effects of incomplete lineage sorting and gene flow on gene divergence. Here we use genome-wide transcriptome data to estimate divergence for 18 sister species pairs of European butterflies showing either sympatric or contact zone distributions. We find that in most cases species divergence predates the mid-Pleistocene transition or even the entire Pleistocene period. We also show that although post divergence gene flow is restricted to contact zone pairs, they are not systematically younger than sympatric pairs. This suggests that contact zones are not limited to the initial stages of the speciation process, but can involve notably old taxa. Finally, we show that mitochondrial and nuclear divergence are only weakly correlated and mitochondrial divergence is higher for contact-zone pairs.Biotechnology & Biological Sciences Research Council (BBSRC)Natural Environment Research Council (NERC)European Union Horizon 202

Feasibility studies of the time-like proton electromagnetic form factor measurements with PANDA at FAIR

The possibility of measuring the proton electromagnetic form factors in the time-like region at FAIR with the \PANDA detector is discussed. Detailed simulations on signal efficiency for the annihilation of $\bar p +p$ into a lepton pair as well as for the most important background channels have been performed. It is shown that precision measurements of the differential cross section of the reaction $\bar p +p \to e^++ e^-$ can be obtained in a wide angular and kinematical range. The individual determination of the moduli of the electric and magnetic proton form factors will be possible up to a value of momentum transfer squared of $q^2\simeq 14$ (GeV/c)$^2$. The total $\bar p +p\to e^++e^-$ cross section will be measured up to $q^2\simeq 28$ (GeV/c)$^2$. The results obtained from simulated events are compared to the existing data. Sensitivity to the two photons exchange mechanism is also investigated.Comment: 12 pages, 4 tables, 8 figures Revised, added details on simulations, 4 tables, 9 figure

On the choice of the driving temperature for eddy-covariance carbon dioxide flux partitioning

Peer reviewe

Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR

Simulation results for future measurements of electromagnetic proton form factors at \PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel $\bar p p \to e^+ e^-$ is studied on the basis of two different but consistent procedures. The suppression of the main background channel, $\textit{i.e.}$ $\bar p p \to \pi^+ \pi^-$, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance

Gross Primary Productivity of Four European Ecosystems Constrained by Joint CO₂ and COS Flux Measurements

Gross primary productivity (GPP), the gross uptake of carbon dioxide (CO2) by plant photosynthesis, is the primary driver of the land carbon sink, which presently removes around one quarter of the anthropogenic CO2 emissions each year. GPP, however, cannot be measured directly and the resulting uncertainty undermines our ability to project the magnitude of the future land carbon sink. Carbonyl sulfide (COS) has been proposed as an independent proxy for GPP as it diffuses into leaves in a fashion very similar to CO2, but in contrast to the latter is generally not emitted. Here we use concurrent ecosystem-scale flux measurements of CO2 and COS at four European biomes for a joint constraint on CO2 flux partitioning. The resulting GPP estimates generally agree with classical approaches relying exclusively on CO2 fluxes, but indicate a systematic underestimation under low light conditions, demonstrating the importance of using multiple approaches for constraining present-day GPP