Auger- and X-ray Photoelectron Spectroscopy at Metallic Li Material: Chemical Shifts Related to Sample Preparation, Gas Atmosphere, and Ion and Electron Beam Effects

Li-based batteries are a key element in reaching a sustainable energy economy in the near future. The understanding of the very complex electrochemical processes is necessary for the optimization of their performance. X-ray photoelectron spectroscopy (XPS) is an accepted method used to improve understanding around the chemical processes at the electrode surfaces. Nevertheless, its application is limited because the surfaces under investigation are mostly rough and inhomogeneous. Local elemental analysis, such as Auger electron spectroscopy (AES), could assist XPS to gain more insight into the chemical processes at the surfaces. In this paper, some challenges in using electron spectroscopy are discussed, such as binding energy (BE) referencing for the quantitative study of chemical shifts, gas atmospheric influences, or beam damage (including both AE and XP spectroscopy). Carefully prepared and surface-modified metallic lithium material is used as model surface, considering that Li is the key element for most battery applications

XPS chemical state analysis of sputter depth profiling measurements for annealed TiAl-SiO2 and TiAl-W layer stacks

For the application of surface acoustic wave sensors at high temperatures, both a high-temperature stable piezoelectric substrate and a suitable metallization for the electrodes are needed. Our current attempt is to use TiAl thin films as metallization because this material is also known to be high temperature stable. In this study, Ti/Al multilayers and Ti-Al alloy layers were prepared in combination with an SiO2 cover layer or a W barrier layer at the interface to the substrate (thermally oxidized Si or Ca3TaGa3Si2O14) as an oxidation protection. To form the high-temperature stable γ-TiAl phase and to test the thermal stability of the layer systems, thermal treatments were done in vacuum at several temperatures. We used X-ray photoelectron spectroscopy (XPS) sputter depth-profiling to investigate the film composition and oxidation behavior. In this paper, we demonstrate how the semiautomatic peak fitting can help to extract beside the elemental information also the chemical information from the measured depth profiles. © 2020 The Authors. Surface and Interface Analysis published by John Wiley & Sons Lt

Context-based Normalization of Histological Stains using Deep Convolutional Features

While human observers are able to cope with variations in color and appearance of histological stains, digital pathology algorithms commonly require a well-normalized setting to achieve peak performance, especially when a limited amount of labeled data is available. This work provides a fully automated, end-to-end learning-based setup for normalizing histological stains, which considers the texture context of the tissue. We introduce Feature Aware Normalization, which extends the framework of batch normalization in combination with gating elements from Long Short-Term Memory units for normalization among different spatial regions of interest. By incorporating a pretrained deep neural network as a feature extractor steering a pixelwise processing pipeline, we achieve excellent normalization results and ensure a consistent representation of color and texture. The evaluation comprises a comparison of color histogram deviations, structural similarity and measures the color volume obtained by the different methods.Comment: In: 3rd Workshop on Deep Learning in Medical Image Analysis (DLMIA 2017

Jamming transitions in cancer

The traditional picture of tissues, where they are treated as liquids defined by properties such as surface tension or viscosity has been redefined during the last few decades by the more fundamental question: under which conditions do tissues display liquid-like or solid-like behaviour? As a result, basic concepts arising from the treatment of tissues as solid matter, such as cellular jamming and glassy tissues, have shifted into the current focus of biophysical research. Here, we review recent works examining the phase states of tissue with an emphasis on jamming transitions in cancer. When metastasis occurs, cells gain the ability to leave the primary tumour and infiltrate other parts of the body. Recent studies have shown that a linkage between an unjamming transition and tumour progression indeed exists, which could be of importance when designing surgery and treatment approaches for cancer patient

The Influence of the Composition of Ru100−xAlx (x = 50, 55, 60, 67) Thin Films on Their Thermal Stability

RuAl thin films possess a high potential as a high temperature stable metallization for surface acoustic wave devices. During the annealing process of the Ru-Al films, Al2O3 is formed at the surface of the films even under high vacuum conditions, so that the composition of a deposited Ru50Al50 film is shifted to a Ru-rich alloy. To compensate for this effect, the Al content is systematically increased during the deposition of the Ru-Al films. Three Al-rich alloys—Ru45Al55, Ru40Al60 and Ru33Al67—were analyzed concerning their behavior after high temperature treatment under high vacuum and air conditions in comparison to the initial Ru50Al50 sample. Although the films’ cross sections show a more homogeneous structure in the case of the Al-rich films, the RuAl phase formation is reduced with increasing Al content

Lifetime vs. rate capability: Understanding the role of FEC and VC in high-energy Li-ion batteries with nano-silicon anodes

Fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are the most frequently used electrolyte components to enhance the lifetime of anode materials in Li-ion batteries, but for silicon it is still ambiguous when FEC or VC is more beneficial. Herein, a nanostructured silicon/carbon anode derived from low-cost HSiCl3 is tailored by the rational choice of the electrolyte component, to obtain an anode material outperforming current complex silicon structures. We demonstrate highly reversible areal capacities of up to 5 mA h/cm2 at 4.4 mg/cm2 mass loading, a specific capacity of 1280 mA h/gElectrode, a capacity retention of 81% after 500 deep-discharge cycles versus lithium metal and successful full-cell tests with high-voltage cathodes meeting the requirements for real application. Electrochemical impedance spectroscopy and post-mortem investigation provide new insights in tailoring the interfacial properties of silicon-based anodes for high performance anode materials based on an alloying mechanism with large volume changes. The role of fluorine in the FEC-derived interfacial layer is discussed in comparison with the VC-derived layer and possible degradation mechanisms are proposed. We believe that this study gives a valuable understanding and provides new strategies on the facile use of additives for highly reversible silicon anodes in Li-ion batteries.Fil: Jaumann, Tony. Ifw Dresden; AlemaniaFil: Balach, Juan Manuel. Ifw Dresden; AlemaniaFil: Langklotz, Ulrike. Technische Universität Dresden; AlemaniaFil: Sauchuk, Viktar. Fraunhofer Institute for Ceramic Materials and Systems; AlemaniaFil: Fritsch, Marco. Fraunhofer Institute for Ceramic Materials and Systems; AlemaniaFil: Michaelis, Alexander. Technische Universität Dresden; AlemaniaFil: Teltevskij, Valerij. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Mikhailova, Daria. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Oswald, Steffen. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Klose, Markus. Leibniz Institute for Solid State and Materials Research; Alemania. Technische Universität Dresden; AlemaniaFil: Stephani, Guenter. Branch Lab Dresden. Fraunhofer Institute for Manufacturing Technology and Advanced Materials; ArgentinaFil: Hauser, Ralf. Branch Lab Dresden. Fraunhofer Institute for Manufacturing Technology and Advanced Materials; ArgentinaFil: Eckert, Jürgen. Technische Universität Dresden; Alemania. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Giebeler, Lars. Leibniz Institute for Solid State and Materials Research; Alemania. Technische Universität Dresden; Alemani

High-rate amorphous SnO2 nanomembrane anodes for Li-ion batteries with a long cycling life

Amorphous SnO2 nanomembranes as anodes for lithium ion batteries demonstrate a long cycling life of 1000 cycles at 1600 mA g−1 with a high reversible capacity of 854 mA h g−1 and high rate capability up to 40 A g−1. The superior performance is because of the structural features of the amorphous SnO2 nanomembranes. The nanoscale thickness provides considerably reduced diffusion paths for Li+. The amorphous structure can accommodate the strain of lithiation/delithiation, especially during the initial lithiation. More importantly, the mechanical feature of deformation can buffer the strain of repeated lithiation/delithiation, thus putting off pulverization. In addition, the two-dimensional transport pathways in between nanomembranes make the pseudo-capacitance more prominent. The encouraging results demonstrate the significant potential of nanomembranes for high power batteries

Electrodeposition of manganese layers from sustainable sulfate based electrolytes

Functional manganese-(Mn)-containing layers are becoming increasingly important in the fields of sacrificial corrosion protection, biodegradable medical devices or electrochemical energy conversion systems. Electrodeposition can be a low cost and time-efficient production route, but the very electronegative nature of Mn makes this reduction process quite challenging. In this paper, electrolytic potentiostatic deposition of metallic Mn layers from environmentally friendly aqueous manganese sulfate electrolytes with pH 3 is successfully demonstrated. A continuous electrolyte flow in the cathodic compartment of the electrochemical cell for controlling the pH value during deposition was found to be essential for achieving good layer qualities. Based on cyclic voltammetry analysis in combination with quartz crystal microbalance measurements a suitable deposition potential range was identified. The obtained electrodeposited layers were characterized by means of SEM, XRD, GD-OES and XPS. The shift of the deposition potential from − 2.4 VMSE to − 2.6 VMSE (deposition time 60 min) yields a thickness increase of the metallic α-Mn deposits from < 500 nm to ~ 2 μm. Only thin additional surface regions of Mn-oxides/-hydroxides were identified. The important role of (NH4)2SO4 as complex-forming electrolyte additive is discussed and an impact of the salt concentration on the deposit properties is revealed. This is a promising starting point for further Mn alloy deposition analysis