Reliable and traceable characterization of battery electrode materials is essential for standards and harmonized measurements in the growing lithium-ion battery sector. We report a coordinated interfacility study of commercial cathode NMC622, performed within the EURAMET projects OpMetBat and HyMetBat to evaluate reproducibility, uncertainty, and cross-method comparability. A single batch was analyzed using synchrotron X-ray diffraction, high-resolution neutron diffraction at two facilities, transition metal K-edge XANES/EXAFS, DFT-based electronic structure and spectral simulations, and electrochemical measurements. Neutron diffraction yields consistent lattice parameters and transition metal occupancies and enables traceable quantification of lithium content. Lithium loss from neutron refinement agrees with electrochemical charge extraction at low delithiation, whereas deviations at higher states of charge indicate parasitic faradaic processes. XANES and EXAFS confirm local coordination and oxidation states, while DFT reproduces spectral features. Operando impedance correlates with structural evolution and supports state-of-charge metrology. Together, these cross-facility results establish a robust metrological workflow for layered oxide cathode materials.

In this work, we present an end-station with two perpendicular high-efficiency soft x-ray spectrometers at the plane grating monochromator beamline in the Physikalisch-Technische Bundesanstalt laboratory at the electron storage ring BESSY II. It is designed for polarization-dependent x-ray emission spectroscopy and resonant inelastic x-ray scattering spectroscopy and covers the photon energy range from 80 to 1100 eV. Depending on the energy range to be monitored, either one of two spherical mirrors and either one of three variable line spacing gratings in each spectrometer is selected to provide optimal performance in terms of resolving power and detection yield. A calibration of the optical components and detection devices enables quantitative measurements and the possibility of the determination of x-ray fluorescence fundamental parameters in the soft x-ray range.

Valence change memristive devices based on tantalum-oxides (TaOx) exhibit excellent switching performance due to thermodynamics of the oxide phases, resulting in a robust switching mechanism, based on predominant movement of oxygen ions. The accurate physical details of how the conducting filaments form at a quantitative level remain only partially understood, largely because traditional characterization techniques only provide indirect, device-level insights into the complex nanoscale switching dynamics. In this work, we present a quantitative, reference free, non-destructive approach to investigating TaOx-based memristive devices using nano-X-ray fluorescence analysis with monochromatic synchrotron radiation in the soft X-ray regime. Several spots with different origins and compositions were observed, indicating the switching dynamics are more complex than supposed. Our approach enables direct spatially resolved probing of elemental distributions within the device, including those in the buried layers critical for the resistive switching.

While highly successful, density functional theory is known to have limitations owing to its neglect of many-body electron-electron interactions. This neglect leads to errors in the single-particle energies, leading to underestimated bandgaps and bandwidths as well as errors in band alignment at interfaces. Many-body perturbation theory, in the form of the GW self-energy correction, has been widely used to improve upon these shortcomings. Although less well studied, the same GW method is also able to predict the finite quasiparticle lifetime that is seen to cause anomalous broadening in the lowest-lying lines of valence emission spectra. Using near-edge x-ray absorption and emission, we probe the electronic structure of Li2CO3. Our measurements are compared to first-principles calculations, including GW self-energy corrections to the single-particle energies and excitonic effects from the Bethe-Salpeter equation.

We report on a comprehensive, international interlaboratory comparison of multiple thin film samples, including pure metals, stoichiometric oxides, multilayers consisting of three different metals, non-stoichiometric alloys, and a lithium-ion battery material based on nickel, manganese, and cobalt oxides. The thickness of the layers ranged from a few tens of nanometers to about one micrometer, depending on the type of thin film. The participants of the interlaboratory comparison analyzed the samples using X-ray fluorescence analysis and a relative standard deviation of the results ranging from about 3% to 17% was observed, with thicker alloy samples tending to perform worse. An extensive pre-characterization scheme was used in the form of different complementary analytical techniques such as X-ray reflectometry, time-of-flight secondary ion mass spectrometry, and X-ray tomography. Synchrotron-based reference-free X-ray fluorescence analysis measurements were used to determine physically traceable results. Using such a variety of independent methods ensured a robust overall validation approach. This corroborates that calibration samples for such thin films can be designed, produced, and qualified in a flexible and straightforward manner. These calibration samples can easily be integrated into process control for a variety of application fields, including X-ray fluorescence analysis and other techniques.

X-ray spectroscopy techniques are widely used in material science providing valuable insights into elemental composition, chemical state and structure Considering the impact of the used X-ray radiation on the sample is crucial to differentiate between beam induced effects and material properties, avoiding misinterpretation, and improving reliability of experimental results. Especially operando experiments of complex systems like batteries with a variety of chemical reactions under operation and degradation mechanisms profit from optimized nondestructive experimental parameters. We present a systematic investigation strategy to face the challenge of radiation damage, supported by a case study on selected solid-state electrolyte materials for lithium sulfur batteries. Using synchrotron radiation, Near Edge X-ray Absorption Fine Structure is applied to monitor dose-dependent, X-ray-induced changes. Based on calibrated instrumentation a quantitative correlation between chemical changes and induced doses allows to determine threshold equivalents that can be extrapolated to other experiments.

Lithium manganese nickel oxides are a prominent class of materials used for positively charged lithium-ion batteries. Three different archetype stoichiometries of lithium nickel manganese cobalt oxides (NMC) were studied with bulk-sensitive X-ray Raman and surface-sensitive soft X-ray absorption spectroscopy. We have conducted complementary operando battery X-ray experiments on the NMC622 electrode over one full charge and discharge cycle in a specifically designed operando battery cell. The ex situ NEXAFS spectra of the Ni L-edges show distinct differences in their multiplet characteristics depending on the cathode composition. The obtained operando X-ray Raman spectra show changes in the branching ratio of the Ni 2p spectra and confirms that the state of charge of the battery correlates with changes in the bulk of the electrode.

The degradation of batteries has very different causes depending on the material and operation modes. However, most of these causes are associated with changes in one or more interfaces, in particular through depositions and their potential chemical changes under operating conditions. Over the last decade operando investigations have therefore become increasingly state-of-the-art, elemental analysis of full cell systems, though, is still missing due to a lack of depth resolved methods. Using laboratory confocal micro-X-ray fluorescence spectroscopy the analysis of a Li-ion battery coin cell during 10600 cycles are presented. It is shown that the confocal setup enables to differentiate between the nickel-manganese-cobalt-oxide (NMC) cathode with high levels of transition metal concentration and a possible deposition of traces of Mn, Ni, Co in the underlying layers. This allows for spatially resolved insights in operando without changing the layer stack, nor electrode area. This paper is the first to demonstrate the non-destructive and quantitative elemental analysis of battery interfaces under operating conditions. This quantitative analysis is the prerequisite for the determination of absolute transport and conversion rates, without which the transition from empirical research to a focused development of batteries will not succeed.

As nanostructures in the semiconductor industry become smaller and more complex, non-destructive characterization methods capable of measuring buried domains become crucial. Grazing emission x-ray fluorescence (GEXRF) spectroscopy is a measurement technique capable of resolving nanometer-sized features of buried nanostructures while providing information about the sample's elemental distribution. In this work, a study was conducted to realistically assess the uncertainties of this method, considering correlations between geometric parameters. Furthermore, we showed strategies to effectively reduce the measurement time in GEXRF experiments by applying state-of-the-art single photon evaluation and machine learning denoising techniques for two-dimensional detectors. The study was performed on two different sample positions on a HfO2/TiO2nanograting, where the GEXRF method was able to resolve geometric differences between them. Based on a finite element method model of the nanograting, the expected fluorescence intensities can be simulated, from which the nanostructure's geometry can be reconstructed. The reconstructed geometric shapes show good agreement with atomic force microscope and transmission electron microscope measurements, highlighting the method's capability for investigating samples within the nanometer regime.

Self-assembled monolayers of 7-mercapto 4-methylcoumarin (MMC) on a flat gold surface were studied by Molecular Dynamics (MD) simulations, reference-free grazing incidence X-ray fluorescence (GIXRF) and X-ray photoemission spectroscopy (XPS), to determine the maximum monolayer density and to investigate the nature of the molecule/surface interface. In particular, the protonation state of the sulfur atom upon adsorption was analyzed, since some recent literature presented evidences for physisorbed thiols (preserving the S-H bond), unlike the common picture of chemisorbed thiyls (losing the hydrogen). MD with a specifically tailored force field was used to simulate either thiol or thiyl monolayers with increasing number of molecules, to determine the maximum dynamically stable densities. This result was refined by computing the monolayer chemical potential as a function of the density with the Bennet Acceptance Ratio method, based again on MD simulations. The monolayer density was measured with GIXRF, which provided a quantitative estimate of the number of sulfur atoms on top of flat gold surfaces embedded in a solution of MMC, to allow the formation of a dense monolayer. The sulfur core level binding energies in the same monolayers were measured by XPS, fitting the recorded spectra with the binding energies proposed in the literature for free or adsorbed thiols and thiyls, to get insight on the nature of the molecular species present in the layer.

Extreme broadening previously observed in certain N x-ray fluorescence lines excited near the N K edge in nitrates has been observed in the S L x-ray fluorescence in sodium sulfate, Na2SO4. It is explained as a large imaginary self-energy corresponding to an anomalously short lifetime of quasiparticles in one of the valence bands of these compounds. Our latest measurement and the corresponding many-body theory indicate that this is a general effect not specific to nitrates.

A methodology based on molecular dynamics simulations is presented to determine the chemical potential of thiol self-assembled monolayers on a gold surface. The thiol de-solvation and then the monolayer formation are described by thermodynamic integration with a gradual decoupling of one molecule from the environment, with the necessary corrections to account for standard state changes. The procedure is applied both to physisorbed undissociated thiol molecules and to chemisorbed dissociated thiyl radicals, considering in the latter case the possible chemical potential of the produced hydrogen. We considered monolayers formed by either 7-mercapto-4-methylcoumarin (MMC) or 3-mercapto-propanoic acid (MPA) on a flat gold surface: the free energy profiles with respect to the monolayer density are consistent with a transition from a very stable lying-down phase at low densities to a standing-up phase at higher densities, as expected. The maximum densities of thermodynamically stable monolayers are compared to experimental measures performed with reference-free grazing-incidence X-ray fluorescence (RF-GIXRF) on the same systems, finding a better agreement in the case of chemisorbed thiyl radicals.

This work aims to study the insertion of AlCl4- anion in the crystalline structure of oriented pyrolytic graphite (PG) at the point of view of the anion itself. The electronic and atomic structures of the anion at different intercalation stages are studied. In particular double-edge (bicolor) X-ray absorption spectroscopy at the Al and ClK-edges is carried out, highlighting a contraction of the anion bonding at the highest intercalation degree obtained electrochemically (stage 3), while the electronic population changes for both the edges upon cycle.

An 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 characterization.

Non-destructive reference-free grazing incidence X-ray fluorescence (RF-GIXRF) is proposed as a highly effective analytical technique for extracting molecular arrangement density in self-assembled monolayers. The establishment of surface density standards through RF-GIXRF impacts various applications, from calibrating laboratory XRF setups to expanding its applicability in materials science, particularly in surface coating scenarios with molecular assemblies. Accurate determination of coverage density is crucial for proper functionalization and interaction, such as in assessing the surface concentration of probes on plasmonic nanostructures. However, limited synchrotron radiation access hinders widespread use, prompting the need for molecular surface density standards, especially for benchmarking substrates for surface-enhanced Raman and infrared absorption spectroscopies (SERS and SEIRA) as well as associated surface-enhanced techniques. Using reproducible densities on gold ensures a solid evaluation of the number of molecules contributing to enhanced signals, facilitating comparability across substrates. The research discusses the importance of employing molecular surface density standards for advancing the field of surface-enhanced spectroscopies, encouraging collaborative efforts in protocol development and benchmarking in surface science.

Spatially resolved x-ray fluorescence (XRF) based analysis employing incident beam sizes in the low micrometer range (μXRF) is widely used to study lateral composition changes of various types of microstructured samples. However, up to now the quantitative analysis of such experimental datasets could only be realized employing adequate calibration or reference specimen. In this work, we extent the applicability of the so-called reference-free XRF approach to enable reference-freeμXRF analysis. Here, no calibration specimen are needed in order to derive a quantitative and position sensitive composition of the sample of interest. The necessary instrumental steps to realize reference-freeμXRF are explained and a validation of ref.-freeμXRF against ref.-free standard XRF is performed employing laterally homogeneous samples. Finally, an application example from semiconductor research is shown, where the lateral sample features require the usage of ref.-freeμXRF for quantitative analysis.

Microcalorimeter x-ray detectors offer the specific advantage of being high -resolution energy -dispersive detectors. Furthermore, they can be designed to cover almost any energy range, from soft x-rays to gamma rays. Many of the current energy values of L, M, and N x-ray lines in the soft x-ray range (below 1.2 keV) have not been established through a chain of calibration. Based on our experience, we propose here a method of measuring the energies of these lines that should establish peak positions to a few tenths of an electron volt. It would involve the calibration of a microcalorimeter detector with diagram line energy values determined by a grating x-ray spectrometer calibrated by a plane grating monochromator using synchrotron radiation. We present L -line spectra from Cu, Co, and Ni obtained with a microcalorimeter detector to demonstrate the feasibility of obtaining high -resolution spectra in the energy range below 1 keV.

The investigation of Co oxidation states in pristine LiNixMnyCo1-x-yO2 (NMC) cathodes (NMC111, NMC622, NMC811) has been a subject of ongoing debate, with conflicting findings in the literature. In this study, we present a novel and comprehensive approach to address and clarify this issue using a variety of high energy-resolution X-ray spectroscopy techniques. To shed light on the Co oxidation states in NMC cathodes, we employed independent measurements including X-ray absorption spectrometry in both soft and hard X-ray ranges, as well as resonant X-ray emission spectrometry in the soft X-ray range. The investigation centered on the transition metal (TM) K and L edges, providing a thorough exploration of the electronic structure transitions. The study identified minor shifts in Co oxidation states, and theoretical calculations quantified the ratio of Co atoms undergoing oxidation state changes, which were approximately 2.05% (NMC111 to NMC622) and 3.75% (NMC111 to NMC811). Independent measurements that targeted electronic structure transitions using K-edge and L-edge absorption and emission spectrometry were strategically combined to enhance the reliability of the results. The diverse methodological approach aimed to contribute to a comprehensive understanding of Co oxidation states in NMC cathodes. This study highlights the importance of combining complementary techniques to address intricate scientific debates effectively.

Since the discovery of Metal Assisted Chemical Etching (MACE) 1, the direct dependence of the resulting silicon nanostructures as extruded by the metal mask has led to several applications on large area, like photovoltaics2, Surface Enhanced Raman Scattering platforms 3, energy harvesting and thermo-electrics4. Coupling MACE with nanosphere lithography5 allowed the fabrication of silicon nanowire arrays with desired dimensions and functionalities over a large area. In this communication, an overview of some applications of porous silicon nanowires will be given with particular attention to the realization of porous nanowires, losing structural stiffness and gaining high flexibility, used for the development of gold-coated active substrates for surface-enhanced Raman spectroscopy (SERS) and for the development of thermoelectric devices where the thermal transport properties of single nanowires are of interest. Surface-enhanced Raman spectroscopy, discovered in 19746, is a promising analytical tool for detecting chemical and biological species at single molecule levels in liquid and gas phases. Its specificity and sensitivity have led to applications in electrochemistry, environmental analysis, and bio-sensing. Thanks to the development of electromagnetic and chemical theories to explain SERS, it is now widely accepted that the phenomenon is primarily attributed to electromagnetic field enhancement. The light enhancement is achieved through the excitation of localized surface plasmon resonances (LSPRs) in gaps, crevices, or sharp features of plasmonic materials, typically noble and coinage metals with nanoscale features. This process generates Raman hot spots due to the proximity of metal nanostructures separated by a few nanometers. In our work, we optimized the fabrication of gold-coated flexible porous silicon nanowires understanding the formation of the hot spots at the tip-to-tip sites of nanowires bundles7 and controlling the patterning over large area obtained by nanospheres self-assembly to correlate the nanospheres distribution in a monolayer to the final SERS substrates enhancement performances and homogeneity8. Moreover, we integrated the SERS measurements with the absolute quantification of the number of active molecules contributing to the SERS signal by means of reference-free synchrotron-based X-ray fluorescence measurements9. The progress in this work on SERS will be discussed. Furthermore, in the field of thermoelectric materials and devices, an accurate evaluation of the thermal and electrical conductivity of single nanowires is mandatory, so our efforts are addressed to the production and the advanced characterization of single porous silicon nanowires. MACE represents the most suitable method to produce long nanowires with desired diameter and aspect ratio (> 1:200) for single-wire electrical and thermal characterization10. Porous silicon nanowires of 100 nm of diameter obtained by MACE from highly doped substrates have been nanomanipulated, bonded and measured on a custom-designed MEMS platform 18, and the thermal conductivity resulted being of 0.8 W/MK, lower than thermal silicon dioxide values and almost two orders of magnitude less than crystalline bulk silicon. The thermal and electrical conductivity of the silicon nanowires can be modified by conformally coating the nanostructures with ALD-based deposition of ZnO. The STEM characterization of the structural properties of the coated single nanowires is discussed together with the thermal and electrical conductivity. Acknowledgements Part of this work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101007417, having benefited from the access provided by CEA LETI in Grenoble within the framework of the NFFA-Europe Pilot Transnational Access Activity, proposal [ID310]. Part of this work has been carried out at Nanofacility Piemonte, a laboratory supported by the ‘‘Compagnia di San Paolo’’ Foundation, and at QR Lab - Micro & Nanolaboratories, INRiM. References Li, X. & Bohn, P. W. Appl. Phys. Lett. 77, 2572–2574 (2000). Peng, K. Q. & Lee, S. T. Advanced Materials vol. 23 (2011). Qiu, T., Wu, X. L., Shen, J. C., Ha, P. C. T. & Chu, P. K. Nanotechnology 17, (2006). Dávila, D. et al. J. Micromechanics Microengineering 21, 104007 (2011). Huang, Z., Geyer, N., Werner, P., De Boor, J. & Gösele, U. Advanced Materials vol. 23 285–308 (2011). McQuillan, A. J. Notes Rec. R. Soc. Lond. 63, 105–109 (2009). Kara, S. A. et al. RSC Adv. 6, 93649–93659 (2016). Cara, E., Mandrile, L., Ferrarese Lupi, F., Giovannozzi, A.M., Dialameh, M., Portesi, C., Sparnacci, K., De Leo, N., Rossi, A.M. and Boarino, L., Sci. Rep, 8(1), 11305 (2018). Cara, E., Mandrile, L., Sacco, A., Giovannozzi, A.M., Rossi, A.M., Celegato, F., De Leo, N., Hönicke, P., Kayser, Y., Beckhoff, B. and Marchi, D., Journal of Materials Chemistry C, 8(46), 16513-16519 (2020). Ferrando-Villalba, P. et al. Sci. Rep. 8, (2018). Figure 1