TY - CONF A1 - Mrkwitschka, Paul T1 - Standardized Chemical Characterisation of Graphene Oxide Flakes by X-Ray Photoelectron Spectroscopy and Energy-Dispersive X-Ray Spectroscopy N2 - Reliable quantification of the chemical composition of graphene-related 2D materials as powders and liquid suspensions is a challenging task. Analytical methods such as XPS, ICP-MS, TGA and FTIR are recommended to be used in ongoing projects at standardisation bodies. The specific parameters to be measured are also defined, e.g. the oxygen-to-carbon (O/C) concentration ratio, the trace metal impurities, or the functional groups present [1]. In this contribution, for the first time, the results of a systematic study on the capability of SEM/EDS to reliably quantify the O/C ratio in a well-defined and well-characterized graphene oxide material [2] are presented. It is expected that the quantitative EDS analysis of light elements emitting characteristic X-ray lines below 1 keV to be provided with significantly larger measurement uncertainties than the analysis of elements with an atomic number of 11 (Na) or above [3]. The robustness of the SEM/EDS results obtained at various measurement conditions (various excitation energies) is tested by comparing the results to the established XPS analysis [4], which has been carried out on the same samples. A crucial step in sample preparation from liquid suspension with graphene oxides flakes onto a substrate for analysis with both XPS and EDS. It is demonstrated that if a closed and enough thick drop-cast deposited spot is succeeded to be deposited on a substrate, both surface-sensitive XPS analysis and bulk-characterising EDS result in very similar elemental composition of oxygen and carbon. Hence, theoretical, expected O/C atomic ratio values for pure graphene oxide of ~0.5 [1] are achieved (with both methods), see Figure 1. Further, the effect of untight deposited material enabling co-analysis of the (silicon) substrate, is evaluated for both methods, XPS and EDS. To note that all the EDS results in this study have been quantified standardless. The results of this study demonstrate the reliability of the reference measurement protocol for SEM/EDS to be introduced into ISO/DTS 23359, including the dedicated sample preparation, particularly for the cases when the concentration of the GO flakes in stock liquid suspension is low. Further, also the consideration of this GO material as one of the very few available as a commercial material on the market as the very first GO reference material with regard to its morphology as well as chemical composition. Both the standard measurement procedure and the candidate reference material will immensely contribute to characterise reliably the chemical composition of graphene-related 2D materials with SEM/EDS as one of the most widely used methods in analytical laboratories T2 - EMAS 2025 Workshop CY - Mataró, Spain DA - 11.05.2025 KW - Advanced Materials KW - Graphene KW - Chemical Quantification KW - EDX KW - XPS PY - 2025 AN - OPUS4-64082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pellegrino, F. A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg T1 - Unveiling Order in Graphene Oxide Synthesis Through A Design of Experiment and Chemometric Strategy Based on Tour’s Method N2 - Graphene oxide (GO), a derivative of graphene containing oxygen functional groups, shows significant potential for a wide range of applications due to its unique electrical, mechanical, and chemical properties. Traditional synthesis methods, such as Tour's method, often rely on trial-and-error, leading to variations in product quality and yield. To address these challenges, we applied Design of Experiments (DoE) to systematically investigate the effects of key synthesis parameters, including reaction temperature, reaction time, and oxidant concentration. We identified the most significant factors influencing GO characteristics using a Plackett-Burman design and chemometric analysis. Our results highlight that the oxidation level is the most critical factor, impacting outcomes observed through various characterization techniques, such as UV-Vis spectroscopy and X-Ray Diffraction. Principal Component Analysis (PCA) and Multiple Linear Regression (MLR) provided insights into the synthetic parameters most strongly affecting material properties. While some findings aligned with expectations, others were counterintuitive. For instance, oxidation temperature had a minimal effect on the final material characteristics and may not need to be prioritized in the synthesis process. On the other hand, stirring was found to enhance the homogeneity of the material and promote more uniform oxidation. This study demonstrates the effectiveness of DoE in the controlled production of graphene oxide, offering a reliable framework for manufacturing high-quality GO tailored to specific applications. By minimizing time and resource consumption, this approach is increasingly relevant in the context of materials science, which demands higher quality, safety and sustainability standards. T2 - Joint Regulatory Risk Assessors Summit – Advancing Safety & Sustainability Assessments of Advanced Materials CY - Paris, France DA - 19.06.2025 KW - Graphene oxide KW - Chemometry KW - UV-Vis KW - XRD KW - XPS KW - EDX PY - 2025 UR - https://macrame-project.eu/macrame-meetings-workshops/jointrras/#Agenda AN - OPUS4-63676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chemello, Giovanni T1 - Towards Reproducible Analysis Workflows for Reliable Structural and Chemical Composition of Industrial Graphene N2 - The scientific and technological interest in graphene has been growing more and more in the late years due to its outstanding properties and diverse promising applications. However, graphene implementation into the industrial market is still limited and many challenges are yet to be addressed before this material can become suitable for the large-scale production. One of the most crucial challenge to overcome is to develop reliable and reproducible ways to characterize the material properties which can heavily affect the product performance. In our study the chemical composition of nine different samples of industrial graphene, graphene oxide and functionalized graphene were investigated. The samples were analysed both in form of powder and pellets. A comparative characterisation of the chemical composition was performed through X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray Spectroscopy (EDX). XPS depth resolution is in the order of 10 nm, while for EDX the analysis was performed at two different energy levels, i.e. 5 keV and 15 keV, and thus varying the analysis depth from 200 nm to 2000 nm. The XPS measurement area is 300x700 µm² while the EDX measurement was performed by analysing a grid of 25 locations (5x5) of 150 x 150 ?m2 area, covering the whole pellet surface of 5 mm diameter and then calculating the mean of the elemental concentration. The results of the elemental concentration values from XPS and EDX analyses show a good agreement for all the elements presents in the samples, despite the different spatial resolutions of the two techniques. Therefore, the samples appear homogeneous both in the lateral and vertical directions. The results relative to powder and pellets samples do not differ in a significant way except for a slight increase in the carbon content regarding the pellet samples, probably due to a minor contamination effect introduced through pressing. Nevertheless, pellets samples appear to be quite representative for the material while being much more convenient in terms of handling and safety compared to nano-powders and providing a regular flat surface for EDX analysis. Finally, this approach correlating XPS and EDS represents a simple, fast and reliable way for characterizing the chemical composition and the homogeneity of industrial graphene. This study is part of the project Standardisation of structural and chemical properties of graphene (ISO-G-SCoPe) which has received funding from the EMPIR programme co-financed by the Participating States and from the European Union?s Horizon 2020 research and innovation programme under Grant agreement No. 19NRM04. T2 - SALSA Make and Measure... and Machines CY - Online meeting DA - 16.09.2021 KW - Graphene KW - XPS KW - EDX KW - Graphene functionalisation PY - 2021 UR - https://fakultaeten.hu-berlin.de/en/mnf/forschung_internationales/grs/salsa/SALSA_MM AN - OPUS4-53463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winckelmann, Alexander T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by glow-discharge optical emission spectroscopy N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs. T2 - Adlershofer Forschungsforum 2022 CY - Berlin, Germany DA - 11.11.2022 KW - Lithium Ion Batteries KW - GD-OES KW - FIB KW - SEM KW - EDX PY - 2022 AN - OPUS4-56246 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -