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Unravelling the Mechanism of Pulse Current Charging for Enhancing the Stability of Commercial LiNi0.5Mn0.3Co0.2O2 Graphite Lithium Ion Batteries
Get PDFThe key to advancing lithium ion battery LIB technology, particularly with respect to the optimization of cycling protocols, is to obtain comprehensive and in depth understanding of the dynamic electrochemical processes during battery operation. This work shows that pulse current PC charging substantially enhances the cycle stability of commercial LiNi 0.5 Mn0.3 Co 0.2 O2 NMC532 graphite LIBs. Electrochemical diagnosis unveils that pulsed current e amp; 64256;ectively mitigates the rise of battery impedance and minimizes the loss of electrode materials. Operando and ex situ Raman and X ray absorption spectroscopy reveal the chemical and structural changes of the negative and positive electrode materials during PC and constant current CC charging. Speci amp; 64257;cally, Li ions are more uniformly intercalated into graphite and the Ni element of NMC532 achieves a higher energy state with less Ni amp; 9472;O bond length variation under PC charging. Besides, PC charging suppresses the electrolyte decomposition and continuous thickening of the solid electrolyte interphase SEI layer on graphite anode. These amp; 64257;ndings o amp; 64256;er mechanistic insights into Li ion storage in graphite and NMC532 and, more importantly, the role of PC charging in enhancing the battery cycling stability, which will be bene amp; 64257;cial for advancing the cycling protocols for future LIBs and beyon
Benchmarking the reproducibility of all solid state battery cell performance
Get PDFThe interlaboratory comparability and reproducibility of all solid state battery cell cycling performance are poorly understood due to the lack of standardized set ups and assembly parameters. This study quantifies the extent of this variability by providing commercially sourced battery materials LiNi0.6Mn0.2Co0.2O2 for the positive electrode, Li6PS5Cl as the solid electrolyte and indium for the negative electrode to 21 research groups. Each group was asked to use their own cell assembly protocol but follow a specific electrochemical protocol. The results show large variability in assembly and electrochemical performance, including differences in processing pressures, pressing durations and In to Li ratios. Despite this, an initial open circuit voltage of 2.5 and 2.7 V vs Li Li is a good predictor of successful cycling for cells using these electroactive materials. We suggest a set of parameters for reporting all solid state battery cycling results and advocate for reporting data in triplicat
Ab Initio Simulation of Raman Fingerprints of Sulfur Carbon Copolymer Cathodes During Discharge of Li S Batteries
Get PDFSulfur carbon copolymers have emerged as promising alternatives for conventional crystalline sulfur cathodes for lithium sulfur batteries. Among these, sulfur n 1,3 diisopropenylbenzene S DIB copolymers, which present a 3D network of DIB molecules interconnected via sulfur chains, have particularly shown a good performance and, therefore, have been under intensive experimental and theoretical investigations. However, their structural complexity and flexibility have hindered a clear understanding of their structural evolution during redox reactions at an atomistic level. Here, by performing state of the art ab amp; 8197;initio molecular dynamics based Raman spectroscopy simulations, we investigate the spectral fingerprints of S DIB copolymers arising from local structures during consecutive reactions with lithium. We discuss in detail Raman spectral changes in particular frequency ranges which are common in S DIB copolymers having short sulfur chains and those consisting of longer ones. We also highlight those distinctive spectroscopic fingerprints specific to local S DIB structures containing only short or long sulfur chains. This distinction could serve to help distinguish between them experimentally during discharge. Our theoretically predicted results are in a good agreement with experimental Raman measurements on coin cells at different discharge stages. This work represents, for the first time, an attempt to compute Raman fingerprints of sulfur carbon copolymer cathodes during battery operation including quantum chemical and finite temperature effects, and provides a guideline for Raman spectral changes of arbitrary electrodes during discharg
Coherent Magnons with Giant Nonreciprocity at Nanoscale Wavelengths
Get PDFNonreciprocal wave propagation arises in systems with broken time reversal symmetry and is key to the functionality of devices, such as isolators or circulators, in microwave, photonic, and acoustic applications. In magnetic systems, collective wave excitations known as magnon quasiparticles have so far yielded moderate nonreciprocities, mainly observed by means of incoherent thermal magnon spectra, while their occurrence as coherent spin waves magnon ensembles with identical phase is yet to be demonstrated. Here, we report the direct observation of strongly nonreciprocal propagating coherent spin waves in a patterned element of a ferromagnetic bilayer stack with antiparallel magnetic orientations. We use time resolved scanning transmission X ray microscopy TR STXM to directly image the layer collective dynamics of spin waves with wavelengths ranging from 5 amp; 956;m down to 100 nm emergent at frequencies between 500 MHz and 5 GHz. The experimentally observed nonreciprocity factor of these counter propagating waves is greater than 10 with respect to both group velocities and specific wavelengths. Our experimental findings are supported by the results from an analytic theory, and their peculiarities are further discussed in terms of caustic spin wave focusin
Chemical and electronic structure of Cu2O, NiO, and Cu2O NiO combinatorial material libraries as hole transport material for halide perovskite solar cells
No full textAdmist the rising global temperatures and the rapid change of the overall climate, renewable energy technologies are of rising importance. Solar energy is one of the possible energy sources to harvest and significant progress has been made in this research field in recent decades. New types of materials, such as metal halide perovskite MHP , are a rising stars in the field of solar cell SC technologies. However, for each new material, its composition and properties must be measured, analyzed and understood, to guarantee a growth in efficiency and stability. One of these analysis methods is X ray photoelectron spectroscopy XPS , which allows the revelation of the surface composition of materials as well as their electronic and chemical properties. Unfortunately, XPS is known to be a relatively slow method, which limits its applicability its use for large data sets, such as combinatorial libraries. This work aims to establish XPS as a high throughput analysis method. This is done by introducing an integration analysis method, which can give a good estimation of the elemental composition on the fly during a measurement, even without the need of a large signal to noise ratio. This is done on a 72 72 mm2 CuxNi1 amp; 8722;xOy CuNiO compositional library, which is used to show how characterization and evaluation routines can be optimized to improve the throughput in XPS, especially for combinatorial studies. Furthermore, a new analysis script is introduced, which helps to analyze large XPS data sets, while using an active Shirley background SBG and linking the different material properties with each other. Another focus of this thesis is the investigation of interfaces between the combinatorial CuNiO library and two types of MHP materials MA0.16FA0.79Cs0.05Pb I0.84Br0.16 3 MAFACsPbIBr and FA0.85Cs0.15PbI3 FACsPbI . With the goal to find possible a relationships between the interface structure and stability of the perovskite. To this end, first bare binary metal oxide MO Cu2O and NiO are measured to gain basic knowledge for the scaled up analysis of the interface properties of the libraries. This also includes the change of i.e. oxidation states and other properties of plasma cleaned samples, which is a necessary step in the SC stack production. As a next step, different two libraries have been investigated. There, we show the effect of different plasma cleaning strengths on the elemental composition of these libraries and how the elemental gradient influences it. Finally, the knowledge gained is used when analyzing the effect of the underlying hole transport layer HTL properties on the halide perovskites, by using a thickness gradient orthogonal to the Cu Ni gradient. Here, we show that the in vacuum measured MAFACsPbIBr has the largest loss of organic component on the Cu rich side, which is not the case for the FACsPbI. For this type of perovskite, the plasma cleaning method Cu I amount is of greater importance, where we can show that the reduction of the Cu I is more important to generate a in vacuum stable perovskite. Additionally, we show the strong influence of the combination of X rays and vacuum on perovskite degradatio
MINERVA, a new x ray facility at the ALBA Synchrotron devoted to assemble and characterize the Silicon Pore Optics Mirror Modules for the NewATHENA mission
No full textThe ALBA Synchrotron Barcelona, Spain has built MINERVA a new X ray facility designed to support the development of the NewATHENA mission Advanced Telescope for High Energy Astrophysics , whose objective is to observe and study energetic objects in space accretion disk around black holes, large scale structure, etc... . MINERVA is dedicated to assemble stacks manufactured by cosine into mirror modules MM , building blocks of the NewATHENA optics. This new beamline is originally based on the X ray parallel beam facility XPBF 2.0 at the Physikalisch Technische Bundesanstalt PTB at BESSY II but also includes additional features on the scanning scheme to improve the characterization time of each MM produced. Interoperability between MINERVA and XPBF 2.0 is nonetheless preserved to boost the mass production of the MMs and characterize their performance. MINERVA is now in operation and has been funded by the European Space Agency ESA and the Spanish Ministry of Science and Innovatio
Zero residual stress determination of iridium carbon bilayer and multilayers coatings by utilizing chromium
No full textNewAthena New Advanced Telescope for High Energy Astrophysics has been endorsed by the European Space Agency in November 2023 and the mission is entering a pre industrialization phase prior to the foreseen adoption early 2027. A key aspect of the thin film coating development for the NewATHENA X ray optics, is to determine the adhesion efficiency and the residual stress limitation of the coatings on silicon substrates. To do so, we magnetron sputtered different layer thicknesses of chromium layers underneath iridium carbon bilayer and linear graded multilayer coatings. The samples were characterized using X ray Reflectometry XRR to derive the thickness and micro roughness. The residual stress was assessed by profilometry using a Dektak 150 stylus profilometer. The curvature of the samples before and after coating, along with the total film thickness derived from XRR, was used to evaluate the residual stres
Complementary techniques for the reliable characterisation of tissue samples A case study on pancreatic tumours analysed by means of X ray fluorescence analysis and IR spectroscopy
No full textAn improvement in the reliability and comparability of tissue characterization results is crucial for enabling further progress in cancer detection and the assessment of therapeutic effects. This can only be achieved by integrating quantitative methods into well established qualitative characterization routines. This case study presents a hybrid metrological approach for tissue characterisation including vibrational Fourier Transform InfraRed FTIR spectroscopy and traceable reference free X Ray Fluorescence analysis XRF . Through the combination of spatially resolved qualitative molecular information with quantitative elemental concentrations an all encompassing sample characterisation can be provided. The study was performed on tissue sections of syngeneic murine pancreatic ductal adenocarcinoma KPC KrasG12D ; Trp53R172H ; Pdx 1 Cre tumours ex vivo. Sections from healthy pancreatic tissues, sham exposed tumours and tumours subjected to low dose radiotherapy treatment 2 Gray and 6 Gray were analysed using both methods. Additional sample integrity studies using Near Edge X ray Absorption Fine Structure NEXAFS spectroscopy at the carbon and nitrogen K edges were performed to assess the effect of sample aging and XRF investigations on the samples. Results showed an increase in the concentrations of elemental biomarkers, including S, K and amide I structures in malignant pancreatic tissue compared to healthy pancreatic tissue. The exposure of tumours to 6 Gy radiation decreases the levels of these elements towards a phenotype seen in the healthy pancreas. A protocol for hybrid investigations is presented, with emphasis on the sample preparation, minimizing the impact of consecutive applied methods on their measurands, and ensuring the compatibility and reliability of achieved results. The study demonstrates the cancer recognition capabilities, and the sensitivity for low dosage radiotherapy treatment monitoring for each method individually and assesses the potential of combining molecular fingerprinting with non destructive quantitative elemental information for tissue sample characterizatio
