Reseach Project #1 (pdf)               Apply for Project #1

Improving the lifetime and safety of batteries requires advanced measurement techniques, such as electrochemical impedance spectroscopy (EIS). With EIS, the frequency response of a battery is measured in the so-called frequency domain, which can then be used for material characterization and state indication, such as State-of-Charge (SoC) and State-of-Health (SoH) [1]. EIS experiments are usually conducted with expensive laboratory equipment that is outside the budget of a battery management system for electric vehicles or stationary grid applications, not to mention electronic devices or other small-scale appliances. Furthermore, the typically long duration of experiments may limit the feasibility of using EIS for real-time diagnostics. An alternative approach is to conduct EIS experiments in the so-called time domain, which considerably relaxes the requirements on instrumentation and shortens experiment duration [2]. This approach brings real-time diagnostics within closer reach, making it more practical for application in dynamic, real-world conditions. While EIS experiments contain a wealth of information, overlapping signal contributions make it, however, challenging to separate the different processes (e.g., charge-transfer and diffusion) occurring within a battery. Factors such as varying battery sizes can amplify or diminish the impedance contributions of different processes. As a result, scaling effects, such as differences in size, provide an opportunity to disentangle overlapping contributions. Combining time-domain EIS with detailed insights into overlapping impedance processes offers, therefore, a promising step toward real-time battery state indication.

In this project, the influence of scaling effects of batteries is investigated as a variable parameter to help assigning the various impedance contributions with the help of a digital twin model of the battery. For this purpose, batteries of a particular geometry are built using a given selection of materials, yet with variations of the dimensions. These batteries are measured using both frequency-domain and time-domain EIS at IET-1 for a proper time-frequency-domain comparison. The digital twin, developed and parameterized jointly by IET-1 and ICE-1, can then be employed to distinguish between stationary and transient effects in the EIS response. In particular, both physics-based and data-driven models will be evaluated in the project. The influence of external factors (e.g., diverse current-load profiles) on SoC and SoH will be evaluated as well. Limitations of the standard laboratory equipment for time-domain measurements, both in terms of their response function and the lack of real-world noise (e.g., in automotive applications), will be addressed using a hardware-in-the-loop approach by ICE-1. In particular, by making use of a real-time simulator, the incremental prototyping approach [3] will be used to scale the digital twin models to levels not reachable with the physical system (e.g., to consider specific geometries, or external factors). A prospective additional use of test hardware that can be concurrently coupled to an actual battery as well as a digital twin is the further refinement of the digital twin model in a closed loop using design-of-experiments concepts.

This PhD project contains the following tasks:

• Assembling batteries of varying dimensions (e.g., geometries and number of layers) and characterize their cycling behavior.
• Analysis and comparison between time domain and frequency domain EIS experiments on the different batteries to improve state estimation. This includes the programming of experiment protocols on the test hardware.
• Develop a digital twin model of the assembled batteries. Compare physics-based and data-driven models, and refine their parametrization.
• Investigating the influence of load profiles and real-world measurement noise on the impedance response of batteries, both for frequency-domain and time-domain EIS. Evaluation of the influence of such external factors on state estimation.
• Couple the test hardware both to a real battery and, as a hardware-in-the-loop device, to a digital twin, following an incremental prototyping approach.
• Extrapolation of results towards applications for large-scale automotive and stationary batteries (e.g., voltage control and energy management systems).

Gantt chart of the PhD project, based on the above-mentioned tasks

[1] Orazem ME, Tribollet B. Electrochmical impedance spectroscopy. John Wiley and Sons; 2011 http://doi.org/10.1002/9780470381588

[2] A. Mertens, J. Granwehr, J. Electrochem. Soc. 163, H521 (2016). DOI:10.1149/2.0511607jes

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Research Project #2 (pdf)               Apply for Project #2

The European Union has set ambitious targets for renewable energy adoption, with solar photovoltaics (PV) playing a crucial role in achieving these goals [1, 2]. As of 2024, crystalline silicon (c-Si) technology dominates the PV market, but emerging technologies like perovskite/silicon tandems show promise for higher efficiencies and potentially lower costs [3]. The global PV supply chain is currently dominated by China, raising concerns about Europe's energy security and industrial competitiveness [4]. This PhD project aims to analyze the future landscape of PV technologies in Europe, focusing on the potential shift from c-Si to tandem devices and the implications for sustainability and supply chain resilience. The primary goal of this research is to develop different scenarios of PV technology landscape in Europe by 2050, considering technological advancements, economic and environmental factors. The project will employ a multi-faceted approach, including:

• Comprehensive literature review on PV technology development (c-Si, perovskite/silicon tandems etc.).
• Techno-economic analysis to project future costs and performance.
• Life Cycle Assessment (LCA) to compare environmental impacts of PV technologies of the future market (such as Global Warming Potential, Cumulative Energy Demand, Water Depletion, and Resource Depletion).
• Supply chain analysis to assess Europe's potential for achieving independence in PV manufacturing.

Additionally, this project will employ Multi-Criteria Decision Analysis (MCDA) to synthesize the diverse factors influencing PV technology in Europe. MCDA is a structured approach for evaluating complex decisions involving multiple, often conflicting criteria. MCDA will be used to integrate the results from techno-economic analysis, LCA, and supply chain analysis. This will enable a holistic evaluation of different PV technologies considering environmental impacts, economic viability, technological performance, and supply chain resilience simultaneously.

This PhD project will benefit from the complementary expertise of two institutes: Jülich Systems Analysis (ICE-2) and the Institute of Photovoltaics (IMD-3). ICE-2 brings extensive experience in environmental and economic assessment of energy technologies, including LCA, techno-economic analysis, and multi-criteria decision analysis. IMD-3 provides deep technical expertise in photovoltaic materials, devices and manufacturing processes. Their insights will be crucial for developing realistic technology scenarios and projecting future developments. By combining assessment capabilities with photovoltaics-specific knowledge, this project will deliver a well-rounded analysis of the transition pathways for photovoltaics in Europe and enable wholesome interdisciplinary supervision.

Work Packages:

WP1: Historical Analysis and Technology Overview (Months 1-6)

• Review the history of silicon solar cell technologies from R&D to commercialization
• Review different tandem device concepts, including perovskite/silicon and gather information on materials and production methods
• Assess the current state and future potential of multi-junction devices

WP2: System Description (Months 3-10)

• Define the system boundaries and the scope of the model, describing
• Describe the core parameters and technologies that are going to be analyzed

WP3: Life Cycle Assessment (Months 10-24)

• ConductLCA for c-Si and perovskite/silicon tandem technologies
• Analyze key impact categories (e.g., Global Warming Potential, Cumulative Energy Demand)
• Project future environmental impacts based on expected technological improvements

WP4: Techno-economic Analysis (Months 10-24)

• Develop cost models for c-Si and tandem technologies
• Project future cost reductions and efficiency improvements
• Analyze the economic competitiveness of different PV technologies in the European context

WP5: Supply Chain Analysis and European Independence (Months 24-36)

• Assesscurrent global PV supply chains and Europe's position
• Analyze potential process routes for upscaling PV production in Europe
• Evaluate the feasibility of establishing sustainable and independent PV supply chains in Europe
• MDCA of different cost and sustainability results  

WP6: Synthesis and Future Scenarios (Months 24-36)           

• Integrate findings from previous work packages
• Assess the potential role of Europe in the global PV market

Expected results:

1. Quantify the environmental impacts of different PV technologies throughout their life cycle, providing valuable data for policy-makers and industry stakeholders.
2. Develop predictive models for the techno-economic performance of c-Si and alternative PV technologies, considering factors such as efficiency improvements, manufacturing costs, and economies of scale.
3. Identify critical bottlenecks and opportunities in the European PV supply chain, proposing strategies for achieving greater independence and resilience.

The outcomes of this PhD research will not only advance the scientific understanding of next-generation PV technologies but also provide crucial insights for shaping Europe's energy future. By addressing the complex interplay between technological innovation, economic factors, and environmental sustainability, this project will contribute to the development of a robust, independent, and eco-friendly European PV industry.

[1]             IEA PVPS Report, „Trends in PV Applications 2023,“ IEA PVPS TCP, 2023.

[2]             International Energy Agency, „Special Report on Solar PV Global Supply Chains,“ IEA, 2022.

[3]             International Energy Agency, “Life Cycle Inventories and Life Cycle Assessments of Photovoltaic Systems”, IEA, 2020.

[4]             International Energy Agency, “Strategic PV Analysis and Outreach, Snapshot of Global PV Markets”, PVPS Task 1, 2024.

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Research Project #3 (pdf)               Apply for Project #3

As cities worldwide transition towards electrification and sustainable mobility, there is an urgent need to assess the environmental and public health benefits of these transformations. This PhD project aims to explore the impact of electric vehicles (EVs), public transit innovations, and shared mobility on air quality and urban ecosystems worldwide. The research will evaluate the potential of these solutions to transform urban transportation, reduce environmental degradation, and promote healthier cities. Specifically, the project examines how the shift toward a low-carbon and sustainable future in transportation affects environmental health and air quality.

The study will model future scenarios in both passenger and freight transportation, capturing trends such as electromobility (e.g., electric cars, buses, micromobility options like e-bikes and scooters) and new integrated mobility solutions, including autonomous vehicles, shared mobility, and advanced public transit [1]. These scenarios will be customized to reflect specific regional needs, offering insights into both domestic and international transportation contexts.

Based on these transport scenarios, future emission changes across traffic, marine, and aviation sectors will be considered. Given the rising electrification of transport, changes in the energy sector are anticipated and will be incorporated into emissions scenarios. These scenarios will serve as input for the global chemistry-climate model EMAC [2], enabling a comprehensive analysis of projected impacts on air quality. The aim is to understand how emissions changes, such as reductions in NO_x and VOCs from the transport sector alongside possible SO₂ increases from power plants, affect primary pollutants like ozone (O₃) and fine particulate matter (PM_2.5) components (e.g., organic aerosol, nitrate, ammonium, and sulfate). The air quality impacts of green transport initiatives will be assessed across a diverse set of global cities, representing varied climates, economies, and infrastructures, as classified by the intermediate-level regional breakdown of the IPCC Sixth Assessment Report Working Group III [3]. This approach seeks to identify best practices and scalable solutions suitable for different urban environments.

Expected air quality improvements from reduced vehicle emissions are anticipated to correlate with declines in respiratory illnesses and other health issues. The project will quantify these health benefits, specifically estimating the reduction in premature mortality linked to PM_2.5 and O₃ exposure [4]. Health impacts will be assessed by calculating the premature deaths from diseases such as chronic obstructive pulmonary disease (COPD), acute lower respiratory illness (ALRI), cerebrovascular disease (CEV), ischemic heart disease (IHD), and lung cancer (LC) related to PM_2.5 exposure, as well as COPD cases related to enhanced O₃ levels. These mortality reductions will provide a vital public health perspective supporting the adoption of green transportation.

Key Tasks in This PhD Project:

• Development of Transport Scenarios: Model future trends in passenger and freight transportation, informed by anticipated advances in mobility, on both regional and global scales.
• Quantification of Emission Changes: Assess the extent to which electrification and new mobility solutions can reduce urban pollutant emissions (e.g., NO_x, VOCs) compared to conventional transport, while also considering potential increases in emissions (e.g., SO₂) from power facilities due to increased electricity demand.
• Environmental and Air Quality Modeling: Use advanced modeling tools to simulate emissions and air quality improvements under different electrification and mobility scenarios in diverse urban environments.
• Health Impacts of Air Quality Improvements: Evaluate the long-term health benefits of air quality improvements, focusing on the relationship between reduced premature mortality and decreased traffic emissions.

This PhD project offers a unique chance to contribute to one of the most significant transitions of our time, expanding our understanding of how electrified and innovative mobility solutions can drive positive environmental and public health outcomes.

[1.] Kraus, S., T. Grube, and D. Stolten, Mobility Trends in Transport Sector Modeling. Future Transportation, 2022. 2(1): p. 184-215.

[2.] Karydis, V.A., et al., How alkaline compounds control atmospheric aerosol particle acidity. Atmospheric Chemistry and Physics, 2021. 21(19): p. 14983-15001.

[3.] IPCC, Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change 2022, Cambridge, UK and New York, NY, USA: Cambridge University Press.

[4.] Lelieveld, J., et al., The contribution of outdoor air pollution sources to premature mortality on a global scale. Nature, 2015. 525(7569): p. 367-371.

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Research Projec #4 (pdf)               Apply for Project #4

The Institute of Climate and Energy Systems, ICE-3 and ICE-4, explores the dynamics and chemistry of the atmosphere to improve the predictability of air pollution, climate and weather. We are seeking a PhD student, who will be jointly supervised by the 2 institutes ICE-3 and ICE-4, for an experimental project, which aims for improving our current knowledge of the chemical transformation of hydrocarbons emitted by trees. Hydrocarbons are chemically transformed by oxidants producing harmful air pollutants such as ozone and particles. The project will study the nocturnal oxidation of the most abundant hydrocarbon (isoprene) using the unique simulation chamber facilities at Forschungszentrum Jülich. These chambers allow the study of oxidation processes at atmospheric conditions necessary for a holistic understanding of the chemical mechanism, for which large uncertainties exist. The successful candidate will be responsible for carrying out and interpretating the experiments with the aim of quantifying previously unknown yields of oxidation products that constrain the chemical mechanism and determine the formation of secondary air pollutants.

Tasks of the PhD project are:

• Development of experimental methods for quantitative measurement of the oxidation products using state-of-the-art mass spectrometers and new calibration methods.  
• Planning and interpretation of experiments using chemical box modelling and coordination of the large number of research groups involved in the chamber experiments
• Operation, calibration and evaluation of mass spectrometers during the experiments
• Presentation of results in international conferences and publication in peer-reviewed journals

We offer:

• An exciting, interdisciplinary research environment in an international team
• Excellent scientific environment and cutting-edge technological and scientific facilities
• Opportunities to attend conferences abroad and visit internationally renowned scientific groups
• Excellent supervision due to a high supervisor - student ratio

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Research Project #5 (pdf)                Apply for Project #5

Germany should become climate neutral by 2045. The transport sector, which is responsible for a large portion of greenhouse gas emissions, plays a decisive role in the energy system transition (Energiewende). While emissions in other sectors are decreasing, greenhouse gas emissions in the transport sector are hardly changing at all. The share of alternative energy sources in the transport sector is low.

Power-to-fuel (PTF) technology is one way to increase the use of renewable energy from wind and hydropower in the transport sector [1, 2]. Studies from FZJ within the  Competence Center Virtual Institute – electricity to gas and heat  –  have shown that alternative fuels, such as biodiesel or alkylate gasoline, can not only help to reduce greenhouse gas emissions, but also, for example, nitrogen oxide emissions [3].

Electro-fuels or e-fuels, produced from hydrogen from renewable energy open the possibility of indirect electrification of the car fleet. Although less efficient than electric drives or fuel cells, e-fuels have a high energy density and can be used on existing infrastructure, so they will gain importance especially in applications where the use of batteries and fuel cells are complicated. The chemical composition of e-fuels, which consist of oxygen-containing molecules, causes different emissions than fossil fuels. Initial studies indicate that the use of e-fuels such as 1-octanol and oxymethylene ether (OME) produce less particulate matter and nitrogen oxides. Studies on their impact on future air quality are still lacking.

Within the framework of this project, the effects of e-fuels on local air quality will be investigated in four work packages.

• First, the emissions of vehicles operating with e-fuels are investigated under real driving conditions. For this purpose, the portable exhaust gas measurement system (PEMS) developed at IEK-8 [4] will be expanded to include analytics for particle measurement and NH₃, the concentration of which has been  increasing in inner cities [5]. The setup will be used to analyse particles and gaseous vehicle emissions of, e.g. NO, NO₂, CO, N₂O, CO₂ and volatile organic compounds (VOC) [3]. The speciated VOC concentrations will be measured with gas chromatography/mass spectrometry (GC/MS). Emission measurements at different speeds and accelerations allow the creation of emission matrices that make it possible to generate the emissions behaviours for different driving profiles. This harmonized emission profiles will be used to compare the emission behaviour with from e-fuels with those from fossil fuels.
• Secondly, the possible impact of e-fuels on pollutant emissions in North Rhine-Westphalia will be investigated. For this purpose, the driving condition-dependent emission parameters calculated from the emission measurements in the first work package will be used as input data for the road-resolved model developed at IET-4 [6]. This model is used to simulate the future significance of emissions from e-fuels under different scenarios.
• Using comparative box model studies, it was found that photooxidant formation depends quite significantly on the composition of the emitted exhaust gas mixtures, especially on the concentration ratio of the emitted NOx and VOC [4]. So, in a third step, the effects of the measured emissions on the local air chemistry will be investigated. For this purpose, the concentrations of volatile organic compounds in the exhaust gas will be analysed and their ability to produce ozone as a single substance or as a mixture of substances will be examined at its specific VOC/NOx ratio in the SAPHIR atmospheric simulation chamber at ICE‑3.
• The results of the work are presented at conferences and published in peer-reviewed journals.

The project combines experimental work with numerical simulations. Experimental skills, interest in air chemistry and knowledge of instrumental analysis are prerequisites for successful completion of the project.

[1]           Schemme, S., R.C. Samsun, R. Peters, and D. Stolten, Power-to-fuel as a key to sustainable transport systems – An analysis of diesel fuels produced from CO₂ and renewable electricity. Fuel, 2017. 205: p. 198-221.

[2]           Breuer, J.L., J. Scholten, J.C. Koj, F. Schorn, M. Fiebrandt, R.C. Samsun, R. Peters, An Overview of Promising Alternative Fuels for Road, Rail, Air, and Inland Waterway Transport in Germany. ENERGIES, 2022. 15(4).

[3]           Polinowski, V., R. Wegener, and D. Klemp, Luftchemische Bewertung alternativer Energieträger, in Bewertung des Einsatzes und der Auswirkungen alternativer Kraftstoffe für die Entwicklung der zukünftigen regionalen Infrastruktur - Abschlussbericht Kompetenzzentrum Virtuelles Institut – Strom zu Gas und Wärme. 2022, Virtuelles Institut - Strom zu Gas und Wärme. p. 250-311.

[4]           Polinowski, V., Aufbau und Einsatz eines on-board Messsystems zur Untersuchung der Abgaszusammensetzung von Fahrzeugen betrieben mit konventionellen und alternativen Kraftstoffen. 2023, RTWH Aachen (submitted).

[5]           Klemp, D., R. Wegener, R. Dubus, and U. Javed, Acquisition of temporally and spatially highly resolved data sets of relevant trace substances for model development and model evaluation purposes using a mobile measuring laboratory. Schriften des Forschungszentrums Jülich Reihe Energie & Umwelt / Energy & Environment. Vol. 497. 2020, Jülich: Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag. 110 S.

[6]           Breuer, J.L., R.C. Samsun, R. Peters, and D. Stolten, The impact of diesel vehicles on NOx and PM10 emissions from road transport in urban morphological zones: A case study in North Rhine-Westphalia, Germany. Science of The Total Environment, 2020. 727: p. 138583.

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Research Project #6 (pdf)               Apply for Project #6

The energy transition to a carbon-neutral economy requires new technologies for energy production, conversion, and storage. One of the key technologies is CO₂ conversion where renewable energy (wind, solar, etc.) can be chemically stored within CO₂-derived fuels and chemicals. Compared to biological, thermochemical, or photochemical methods, the electrochemical CO₂ conversion has significant advantages: controllable reaction rates, mild reaction conditions, high product selectivity, as well as modular and scalable electrolyzer design. One of the most urgent challenges in CO₂ electrocatalysis is the development of new catalytic materials. The catalyst is a crucial part of CO₂ electrolyzer not only because it accelerates the reaction rates but also because product selectivity (e.g., CO, HCOOH, C₂₊-products) and stability strongly depend on catalyst structure under reaction conditions (i.e., pH and electrochemical potentials).

Several classes of materials are known to be selective CO₂ conversion catalysts: some d-elements (e.g., Au, Ag, Ni, Co, and Cd) for CO, Sn for formate or formic acid, and Cu for multi-carbon C₂₊-derivatives. Most current catalyst materials have been studied in either neutral or alkaline conditions because of both structural stability and side reaction suppression (i.e., hydrogen evolution). However, non-acidic CO₂ electrolysis has a critical limitation of either bicarbonate cross-over through the electrolyte, salt precipitation at the catalyst layer, or limited ionic conductivity. Therefore, investigations on acidic CO₂ electrolyzers are demanded, in particular regarding catalytic materials that are both resistant to acidic chemical environment and selective to CO₂ conversion against hydrogen production.

Within the proposed PhD project, the successful candidate will conduct a comprehensive study on new Sn-based electrocatalytic material development for acidic CO₂ conversion reaction. The PhD candidate will work in three main areas: (1) material synthesis and characterization with various complementary methods, (2) performance test of electrocatalytic CO₂ conversion, and (3) detailed in-situ/operando studies of material structural evolution upon electrocatalytic processes. The aimed materials will be the complex Sn-based oxides with perovskite (ABO₃) and spinel (A₂BO₄) structures. Sn will be placed in B-site, which is well known to be active in the CO₂ electrochemical reduction process. The A-cations will be elements that can stabilize spinel or perovskite structure-types (e.g., Ba or Sr) and possibly enhance the electrocatalytic performance of the materials (e.g., Cu, Ni, Ag, Co, or Cd). The materials will be synthesized in the form of single element compounds as well as solid solution multi-cation phases.

The uniqueness of the proposed PhD project lies in the combination of classical methods (materials synthesis, structural and electrochemical studies) with the advanced synchrotron based in-situ/operando investigations of materials performance on the atomic scale. Successful candidate will closely work with researchers from two institutes (INE-1 as a main host, and INW-1 for in-situ/operando studies), gaining expertise in both above-mentioned research fields.            

The following will be the most important parts of the proposed PhD work:

• Synthesis of new Sn-containing materials with ASnO₃ and A₂SnO₄ compositions.
• Investigation of their atomic structures on long- and short-range with advanced structural methods (X-ray, neutron, NMR and EPR spectroscopy).
• Preliminary electrocatalytic testing of the performance and stability of the obtained materials in static and flow cells.
• In situ/operando investigation of materials evolution upon electrocatalytic CO₂ reduction using synchrotron methods (high energy X-ray wide and small angle scattering (XRD, WAXS, SAXS), extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES)).
• Overall analysis of new materials (based on the obtained data) as perspective candidates for industrial applications.

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Research Project #7 (pdf)               Apply for Project #7

Rechargeable batteries, as efficient and cost-effective energy storage devices, are one of the key technologies for the transformation to a sustainable energy supply. Worldwide, lithium-ion batteries dominate the market for stationary and automotive storage devices, but also for smaller portable devices, due to their high energy density. However, this technology cannot be realized without the use of resource-critical elements such as Li, Ni, Co and Cu. Many resource-critical elements used in today's lithium-ion batteries can be replaced by non-critical elements in Na-ion batteries, however at the expense of energy density. A possible new approach that has a realistic potential to increase the energy density of Na-based batteries are so called "anode-free" Na-metal batteries. “Anode-free” is a terminological simplification for a negative electrode (anode) that is formed during battery charging by the reduction of mobile ions to metal and its electrodeposition on the negative anodic current collector. Since the active anode material is not present in the discharged state, the weight and volume of the cell are reduced and the gravimetric and volumetric energy density of the battery is increased.

Anode-free batteries grapple with significant issues like dendrite formation and low cycle life due to uneven Na deposition and mechanical degradation. Alloying functional layers present an effective solution to these problems. By forming alloys with sodium, these layers promote uniform Na deposition and longer cycle life. The way these layers form alloys with Na, the specific phases they go through, and the speed of these changes (phase kinetics) can greatly affect the battery's lifespan. Therefore, conducting structural investigations into the alloying layers is crucial for optimizing nucleation functional layers. By studying the nature of the alloying phases and their transformations during battery operation, we can optimize the design of these layers to further enhance the performance and lifespan of anode-free batteries.

The structural characterization of such functional layers and interfaces is challenging and therefore this project employs state-of-the art surface-sensitive X-ray scattering techniques to investigate the correlation of the structure of the functional layers with its electrochemical properties: X-ray reflectivity (XRR) can access the thickness, density and roughness of the multilayer system, while measurements in grazing incidence (GI) geometry (below and around the critical incident angle of the X-rays) can achieve depth-resolved insight. The GI approach may be coupled with either small- and wide-angle scattering (SAXS/WAXS) to observe microstructural changes and the in-plane arrangement of Na as a function of e.g. electrochemical potential, while coupling with the pair distribution function (PDF) allows to determine interatomic distances and local disorder. We perform the scattering experiments both in the laboratory at FZJ and we travel to multi-day beamtimes at synchrotron sources, and techniques are chosen as required during the course of the project.

Combining the long-standing experience of your hosts, the IET-3 for energy materials design and the JCNS-3 for scattering techniques, will allow you to achieve new insights on anode-free Na batteries. Explicitly, the aim of the project is to understand the fundamental mechanism of Na homogenization through the functional layer and how nucleation sites can be regulated through alloying and electrochemical potential differences. While both, the “anode-free” concept and the advanced scattering techniques itself are at the forefront of their respective scientific fields, this project has the potential to significantly impact the developments of novel high energy dense Na-metal batteries.

Working packages

1. Preparation of thin films on aluminum to act as nucleation functional layers, with subsequent materials characterization (at IET-1)
2. Battery fabrication and electrochemical analysis to understand the electrochemical properties, as well as sample preparation for XRR and GI experiments (at IET-1, and input by JCNS-3)
3. XRR and GI measurements in the laboratory, as well as GI-PDF experiments at synchrotron sources (at JCNS
4. Visualization, analysis and interpretation of scattering data in correlation with electrochemical properties, e.g. with Python, Origin Pro (at JCNS-3 and close interaction with IET-1)
5. Publication of results in peer-reviewed scientific journals and presentation at conferences

The IET-1 and JCNS-3 can be reached within 10 minutes walking on the campus of FZJ, guaranteeing close and intense exchange during all project phases.

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Reseach Project #8 (pdf)               Apply for Project #8

The impact of climate change is becoming increasingly apparent. Consequently, there is a growing need to mitigate CO₂ emissions and develop efficient and sustainable CO₂ separation technologies. At IET-1, carbon nanofiber adsorbents have been developed that can be tailored for many gas separation applications,^[1] such as CO₂ separation from flue gas^[2] or from biogas^[3]. Besides a high surface area and straight forward synthesis, these fibers feature a narrow pore system with pore diameters in the range of single gas molecule, leading to a molecular sieving effect where gases are selectively adsorbed in the pores based on their size. Moreover, the pore size can be changed by the synthesis parameters and, thus, can be tailored to a specific gas separation problem. The fibers themselves are formed by electrospinning, a process that stretches a polymer solution into fibers in the nanometer range by applying a high voltage. So far, the carbon nanofibers have been produced based on synthetic and fossil-based polyacrylonitrile. However, for a sustainable alternative, it would be necessary to utilize a biomass-based material. Lignin, a biopolymer, appears to be a promising and sustainable alternative.

Lignin, the second most abundant biopolymer in plants after cellulose, is often generated as a waste product in various industries, such as paper production. At IBG-2, the innovative “OrganoCat”^[4] process has been developed for the efficient extraction of lignin from biomass. This lignin-first biorefinery approach isolates lignin under mild conditions, resulting in a less degraded product compared to other lignocellulose processing methods. The process achieves this by employing a biphasic, inert in situ extraction of the lignin during the reaction, enhancing its preservation. It has demonstrated robustness and versatility, effectively extracting lignin from a wide range of plant biomasses.^[5] Additionally, methods have been optimized to further fractionate and purify the extracted OrganoCat lignin through anti-solvent fractionation^[6] and CO₂-expansion of the solvent.^[7]

The electrospinning of lignin into nanofibers is a process that is seldom employed, due to the lower spinnability of lignin compared to synthetic polymers. In particular, the spinning of pure, additive-free lignin is rarely reported in literature. Depending on the origin, lignin can offer different properties as it can vary in its average chain length, monomer composition (S/G ratio) or functionalization. So far, it is unknown how these properties effect the spinning process.

The aim of this work is to identify suitable lignin properties for successful electrospinning, optimize the synthesis of lignin-based carbon nanofibers and characterize their gas adsorption and gas separation capabilities. This includes the following work packages:

-         Extraction of different lignins from biomasses via the OrganoCat process (at IBG-2)

-         Optimization of the electrospinning process to produce nanofibers from lignin (at IET-1)

-         Optimization of the thermal stabilization and carbonization of the lignin fibers to carbon nanofibers (at IET-1)

-         Characterization of the (carbon) nanofibers using imaging methods (electron microscopy) as well as analytical methods (elemental analysis and gas adsorption techniques etc.) (at IET-1)

-         Analysis of gas separation capabilities using various gas adsorption techniques (at IET-1)

Lignin extraction from diverse plant sources—such as hardwoods, grasses, and agricultural residues—yields lignins with distinct structural characteristics due to variations in plant cell wall composition. Hardwoods typically produce lignin rich in syringyl (S) units, grasses yield lignins with higher guaiacyl (G) units, and agricultural residues often contain mixed S, G, and p-hydroxyphenyl (H) units. By applying different lignin purification methods, specific fractions can be obtained that have narrower size distribution and impurities by e.g. sugars, acids, etc. These differences influence lignin's physical properties, reactivity, and potential performance in spinning. Analyzing extracted lignins from various plants involves characterizing functional groups, and monomer units (¹H-¹³C-HSQC-NMR), with ³¹P-NMR the free OH-groups can be quantified.

In order to spin lignin successfully, various parameters, such as the electrospinning parameters, the setup and the spinning solution can be examined and optimized. Besides a simple one-needle setup, more sophisticated multi-needle or coaxial needle-in-needle setups are available. With the optimized setup, the spinnability of the lignin samples prepared and analyzed at the IBG-2 can be tested in the electrospinning process to identify correlations between the morphology (fiber/non-fiber product, fiber diameter, spinning artefacts) and the properties of the lignin samples.

Following successful spinning of the lignin, the fibers have to be carbonized at high temperature (600 – 1200 °C) to obtain carbon nanofibers. In order to prevent melting of the lignin fibers, a thermal stabilization is usually performed. The influence of relevant parameters such as duration and heating rate on the morphology and composition of the fibers can be investigated as part of the work. Characterization of the fiber morphology after electrospinning, stabilization and carbonization can be done with imaging methods such as electron microscopy. Additionally, analytical methods such as elemental analysis, x-ray spectroscopy (XPS) or differential scanning calorimetry (DSC) can be used to determine the composition and melting behavior of the lignin.

Besides electrospinning, characterization of the gas adsorption properties will be a main focus of this work. For this purpose, standard methods such as nitrogen or argon adsorption can be used to determine the surface area as well as CO₂ adsorption to investigate the pore structure. A potential molecular sieving effect and its dependency on the synthesis parameters shall be investigated using these methods. Following the basic gas adsorption characteristics, in-depth analysis of the gas adsorption properties and gas separation capabilities for CO₂ can be performed. This includes the measurement of pure-gas adsorption isotherm of various relevant gases as well as analysis of their competitive adsorption in gas mixtures. For this, gravimetric methods as well as breakthrough analysis are available, which enable the investigation of adsorption kinetics in a setup close to application as well.

[1]      a) A. Kretzschmar, V. Selmert, H. Weinrich, H. Kungl, H. Tempel, R.-A. Eichel, ChemSusChem 2020, 13, 3180–3191; b) A. Kretzschmar, V. Selmert, H. Weinrich, H. Kungl, H. Tempel, R.‐A. Eichel, Chem. Eng. Technol. 2021, 44, 1168–1177; c) A. Kretzschmar, V. Selmert, H. Kungl, H. Tempel, R.-A. Eichel, Microporous Mesoporous Mater. 2022, 343, 112156;

[2]      V. Selmert, A. Kretzschmar, H. Weinrich, H. Tempel, H. Kungl, R.-A. Eichel, ChemSusChem 2022, 15, e202200761.

[3]      V. Selmert, A. Kretzschmar, H. Kungl, H. Tempel, R.-A. Eichel, Adsorption 2024, 30, 107–119.

[4]      a) P. M. Grande, J. Viell, N. Theyssen, W. Marquardt, P. Domínguez de María, W. Leitner, Green Chem. 2015, 17, 3533–3539; b) D. Weidener, H. Klose, W. Leitner, U. Schurr, B. Usadel, P. Domínguez de María, P. M. Grande, ChemSusChem 2018, 11, 2051–2056; c) D. Weidener, W. Leitner, P. Domínguez de María, H. Klose, P. M. Grande, ChemSusChem 2021, 14, 909–916; d) P. M. Grande, L. Schoofs, D. Weidener, W. Leitner, H. Klose, ChemSusChem 2024, e202401063;

[5]      a) D. Weidener, M. Dama, S. K. Dietrich, B. Ohrem, M. Pauly, W. Leitner, P. Domínguez de María, P. M. Grande, H. Klose, Biotechnology for biofuels 2020, 13, 155; b) L. Schoofs, B. Thiele, J. Tonn, T. Langletz, S. Herres-Pawlis, A. Jupke, P. M. Grande, H. Klose, Energy Fuels 2024, 38, 4192–4202;

[6]      D. Weidener, A. Holtz, H. Klose, A. Jupke, W. Leitner, P. M. Grande, Molecules 2020, 25.

[7]      D. Weidener, H. Klose, W. Graf von Westarp, A. Jupke, W. Leitner, P. Domínguez de María, P. M. Grande, Green Chem. 2021, 23, 6330–6336.

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Research Project #9 (pdf)               Apply for Project #9

The efficiency of perovskite/silicon tandem solar cells has already surpassed the theoretical limit of silicon solar cells, reaching 34.6%.^[1] In the pathway of efficiency development, much effort has been focused on the interface passivation between perovskite and electron transporting layer (ETL) C60 to suppress interfacial recombination, where different kinds of organic compounds have been applied.^[2] Among those passivation materials, the most used organic ammonium salts can coordinate with unsaturated Pb at the interfaces and thus supress defect-assisted recombination. In the meanwhile, due to the band offset between perovskite and C60, some organic passivators with dipole are applied to reduce the band offset by downward bending the energy band of perovskite, mitigating extraction loss. With these strategies, a wide-bandgap perovskite with high quasi fermi level splitting (QFLS) can be obtained, and the open-circuit voltage (V_OC) of complete device can be enhanced. However, these passivators offering high QFLS usually suffer from stability issues. Thus, apart from highly passivated surface, stability issues also need to be taken into consideration, which requires investigation on the passivation mechanisms and assessment about the possible effect on operation stability.

Moreover, the buried interface is also very crucial for tandem device fabricated from nanotextured wafer, since the recombination cross-section is enlarged compared to planar surface. Hence, for p-i-n structure, the passivated p-side contact is highly important for efficient hole extraction. In the meanwhile, the surface property of hole transporting layer (HTL) will also affect the growth of solution-fabricated perovskite on nanotextured wafer. A common issue is the surface wettability. Due to surface tension, a hydrophobic surface of HTL on nanotextured surface will lead to voids in the pyramid valley, which will be harmful to hole extraction. Thus, the passivated p-side contact with hydrophilic surface is needed for efficient hole extraction and mitigated recombination.

With all the problems described above, passivators based on organic ammonium salts need to be explored for n-side passivation and modification for hydrophilic surface needs to be investigated for p-side contact. For these purposes, the following tasks will be included in the PhD work:

• Investigation on the surface passivation mechanism for perovskite.
• Material development of passivators between perovskite/C60 interface for high V_OC and stability.
• Surface modification of p-type contact on nanotextured wafer for hydrophilic surface and efficient hole extraction.

[1]   NREL (2024). Best Research-Cell Efficiency Chart. https://www.nrel.gov/pv/cell-efficiency.html

[2]   Liu, J., He, Y., Ding, L. et al. Perovskite/silicon tandem solar cells with bilayer interface passivation. Nature (2024). https://doi.org/10.1038/s41586-024-07997-7.

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Research Project #10 (pdf)               Apply for Project #10

The transition to a sustainable energy infrastructure is essential to meet energy and environmental demands of future generations. Economically viable and technologically mature materials for energy storage and conversion are needed to enable this transition. Catalytic layers in electrolysis and fuel cells for the production and use of hydrogen utilize electrocatalytically active metal/metal-oxide nanoparticles that are stably anchored to oxide supports. The development of advanced catalyst materials therefore requires fundamental understanding of catalytic properties and reaction dynamics at supported nanoparticle catalysts. The role of the support in modifying the electronic structure and interfacial properties of nanoparticle-support systems is of foremost interest in this realm.

At the IET-3 we pursue research in theory and computation that complements experimental materials research on novel electrocatalysts. Crucial scientific challenges in this context are addressed with numerical atomistic modelling, either ab initio or molecular mechanics-based. These encompassprocesses that alter structural, mechanical and thermodynamic properties of solid materials, microscopic charge transfer, and degradation via catalyst dissolution or support corrosion. To assure reliability of the computational workflows we develop accurate and efficient computational methodologies and evaluate their feasibility by comparison with experimental data provided by our partners. Among them, the ER-C-1 applies ultra-high resolution scanning transmission electron microscopy to understand materials properties on the atomic level and thus provide valuable data for enhancing modelling techniques. In particular, in-situ electron microscopy techniques will be applied to study the atomic-scale dynamic behavior at elevated temperature with or without reactive gas environment of supported nanoparticles.

The primary aim of the proposed joint simulations and experimental project is to harness the world-class EXASCALE supercomputing and electron microscopy facilities of the research center to develop state-of-the-art modeling techniques that will enable enhanced understanding of the supported nanoparticle catalysts. The PhD student will develop and employ machine learning force fields in combination with electronmicroscopy techniques to perform studies of interfacial structure, structure-property relationships, and electrocatalytic processes in supported nanoparticle systems. The high-performance computing simulations will involve large systems of tens of thousands to millions of atoms and will allow for one-to-one comparison with real systems that they will be investigating using in-situ electron microscopy together with ER-C-1 colleagues. The PhD candidate will explore particle-support interactions and related thermodynamics of the process, as well as structure and dynamics at the interface of the particle-support system. The work will focus on metal and metal-oxide materials for energy-related applications, for example Ni/SrTiO₃, Ni/YSZ, Cu/ZnO, Pt/TiO₂, or Rh/CeO₂. The research project will expand on recent collaborations between the IET-1 and ER-C (10.26434/chemrxiv-2024-x665q-v2). Studies will be performed on world-class facilities at the Forschungszentrum Jülich with the JUPITER EXASCALE machine and the electron microscopy center as main resources.

The specific PhD project tasks are:

• to employ high-performance EXASCALE supercomputing resources for nanoscale simulations of electrocatalytic materials,
• to develop AI/ML force fields for use in computer-based simulations of nanoparticle-support systems comprising tens of thousands to millions of atoms and validate it against ab initio simulations on smaller scale models (up to a few hundreds of atoms),
• to apply the devised force fields to large-scale molecular dynamics simulations of the particle-level processes such as shape formation and degradation.
• to correlate the results of advanced simulations with experimentally-obtained electron microscopy data
• based on simulated and measured data to find descriptors of electrocatalytic activity and stability for supported nanoparticle catalysts
• to effectively collaborate with the internal and external partners.

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Reseach Project #11 (pdf)               Apply for Project #11

Background. Hydrogen plays a pivotal role as an energy carrier in the transition towards sustainable energy and industry ecosystems [1]. Physical storage of molecular hydrogen is challenging in either gas or liquid phase and requires specific materials or operating conditions with high associated costs [2]. On the other hand, liquid organic hydrogen carriers (LOHCs) store hydrogen via chemical bonding in an organic molecular structure, which provides both safe and economically feasible options for infrastructure compatibility [2,3]. During hydrogenation (or dehydrogenation) hydrogen molecules are incorporated into (or released from) LOHC molecules at a catalytic surface, using heat and pressure as thermodynamic driving forces. The typically required high temperatures (>300 °C) limit the overall energy efficiency of the chemical hydrogen storage process. A promising approach for enhancing the hydrogen turnover consists of modulating the reaction environment at the catalyst surface by applying an electrochemical potential. The envisioned non-faradaic electrochemical modification of catalytic activity can modify the LOHC molecule/catalyst interaction and induce structural dynamics at the solid–liquid interface that facilitate the release of hydrogen. However, electrochemical conditions at active catalytic surfaces must be carefully controlled to avoid irreversible decomposition of the LOHC molecules. While Faradaic electrochemical activation and direct LOHC fuel cells have been demonstrated in experiments [4,5,6], fundamental understanding of the physicochemical interactions between LOHC molecules and electrified catalyst surfaces, in particular under non-faradaic conditions, is still limited and systematic studies including theory and computation are required.

Goals. This project will develop a computational model of the interface between an electrified platinum catalyst surface and liquid organic hydrogen carrier (LOHC) molecules, such as benzyltoluene. Using computer simulations based on density functional theory (DFT), we will elucidate the mechanism as well as transition state and intermediate structures of LOHC molecules during hydrogenation and de-hydrogenation at the catalytic interface. Accounting for the electrochemical environment, the influence of interfacial polarization and electric fields on the chemical reactivity of adsorbed LOHC molecules will be characterized, and the potential window for stable operation will be estimated. The theoretical investigations of this Ph.D. project at the Institute of Energy Technologies: Theory and Computation of Energy Materials (IET-3)will be closely aligned with experimental studies conducted simultaneously at the Institute for a Sustainable Hydrogen Economy: Catalytic Interfaces for Chemical Hydrogen Storage (INW-1). Through combined theoretical and experimental assessment, we aim to achieve fundamental understanding of the electric modulation effect in catalytic LOHC (de)hydrogenation for chemical hydrogen storage and define conditions for optimal efficiency, selectivity, and durability of the process.

Computational methods. We hypothesize that polarizing the catalytic interface by applying an electrochemical potential can enhance the catalytic turnover during (de)hydrogenation of LOHC molecules [7]. Towards this end, we aim to understand the physicochemical principles underlying this effect. Quantum-chemical DFT simulations provide versatile means for studying reaction pathways and associated barriers for the hydrogenation and dehydrogenation of LOHC molecules at electrified solid–liquid interfaces. Concepts from chemical reactivity theory allow to rationalize the impact of electrochemical control and identify descriptors for interfacial LOHC reactivity [8]. Frontier orbital analysis is used to estimate the stability potential windows of LOHC molecules [9]. The simulation workflow will provide essential insights for the interpretation of experimental results and the design of optimized catalytic processes for hydrogen storage.

Tentative Work Plan. Within the collaboration between IET-3 and INW-1, the Ph.D. student to be hired for this project will first construct atomistic models of catalytic interfaces between a Pt surface and a liquid phase of LOHC molecules. The DFT framework will be calibrated to the thermodynamic properties of the LOHC system. They will then explore capabilities of this framework to describe the interfacial structures and transition states during LOHC (de)hydrogenation and, based thereon, gain insight into critical reaction steps and kinetic barriers. Following this, the influence of the electrochemical reaction environment will be included by grand-canonical DFT and solvation methods and the impact of interface polarization on the catalytic reaction barriers will be analyzed. The stability properties of LOHC molecules at the charged catalyst surface will be determined by computation of frontier orbitals and decomposition pathways. Subsequently, the results from DFT simulations will be used to construct kinetic rate models for the catalytic LOHC (de)hydrogenation on Pt as a function of external control variables. The Ph.D. student will actively engage in a close collaboration with experimentalists at INW-1 to validate and leverage results from simulation and modelling.

Outcomes. The Ph.D. project will deliver a simulation and modelling workflow to describe the processes of (de)hydrogenation of LOHC molecules at electrified catalytic interfaces. The project results will be disseminated through presentation at international conferences and publication in recognized scientific journals. The resultant understanding will set the theoretical foundation of utilizing electrochemical control for tuning molecular interactions at catalytic interfaces for hydrogen storage technologies.

[1] D. Guan et al. (2023) Energy Environ. Sci. 16, 4926-4943.

[2] P. M. Modisha et al. (2019) Energy Fuels 33, 2778-2796.

[3] P. Patrick et al. (2017) Acc. Chem. Res. 50, 74-85.

[4] J. Cho et al. (2023) J. Am. Chem. Soc. 145, 16951-16965.

[5] L. Fusek et al. (2024) J. Phys. Chem. Lett. 15, 2529-2536.

[6] M. D. Stankovic et al. (2024) ACS Energy Lett. 9, 4459-4464.

[7] C. G. Vayenas et al. (1988) J. Phys. Chem. 92, 5083-5085.

[8] A. K. Lautar et al. (2020) Phys. Chem. Chem. Phys. 22, 10569-10580.

[9] S. P. Ong et al. (2011) Chem. Mater. 23, 2979-2986.

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Reseach Project #12 (pdf)               Apply for Project #12

The transition to a sustainable energy infrastructure is essential to meet energy and environmental demands of future generations. In this regard, interest in materials arising and related to nuclear and hydrogen-based energy production have drawn considerable attention. At the same time, economically viable and technologically mature materials for energy generation, storage and conversion are needed to facilitate this ongoing transition. Mixed, multi-element materials, called also high entropy materials represent an intriguing relative recent innovation in material design due their often-enhanced properties they possess over conventional “low entropy” materials. Saliently, such materials are understood to occur both anthropogenically within spent nuclear fuel (SNF) in the form of mixed uranium oxides, metallic particles and “grey phase” oxide precipitates, whilst at the same time similar material derivatives are the subject of intense material science research and development due to their desirable societally relevant properties. Invariably the investigation of such materials is both experimentally and computationally challenging to their unique chemical and structural complexity. By applying a hybrid experimental-computational approach, experimental observations made against such materials on the lab scale can be readily benchmarked and understood with the computational support, allowing a positive feedback loop towards facilitated materials discovery.

The PhD project is a joint experimental-simulation venture between the Institute of Nuclear Waste Management (IFN-2) and Institute for Energy Technologies - Theory and Computation of Energy Materials (IET-3) at Forschungszentrum Juelich GmbH respectively which seeks to apply state-of-the-art synthesis, characterization and atomistic simulations techniques on high entropy oxides (HEOs) and alloys (HEAs) that are relevant to nuclear energy related materials and hydrogen conversion. The project will harness unique world-class EXASCALE supercomputing and radioactive handling facilities to develop unique and novel HEO and HEA compositions to enhance the understanding of such compounds in relevance to SNF and advanced functional materials including hydrogen production. The high-performance computing simulations based on machine learning interaction potentials will involve large systems of tens of thousands to millions of atoms and will allow for one-to-one comparison with real systems that the PhD candidate will be measuring together with INF-2 colleagues. He/she will explore HEO and HEA systems including those based on UO₂, 4d/5d transition metal alloy compositions and alkaline earth perovskites and mixed oxides. With support of the supervisors from the participating institutes, the PhD candidate will subsequently develop world leading expertise jointly in nuclear material handling, fabrication, characterization, atomistic simulations and computation analysis.

 IFN-2 focuses on researching materials and processes relevant to the safe management of radioactive waste and its eventual final disposal. The research at IFN-2 is multidisciplinary, although typically the core focus is nuclear related, the institute combines radio-, geo- and materials chemistry disciplines in addition to computation and simulation synergistically. Research at IFN-2 covers the complete post-operative nuclear reactor cycle, from the initial waste generation, such as the discharge of SNF from the reactor core to its eventual disposal in a geological repository, including research examining the long-term safety behaviour. IFN-2 research further supports unresolved issues prior to waste disposal but also supporting general nuclear safety for instance pre-disposal planning, and research on international safeguards for instance supporting the International Atomic Energy Agency (IAEA) among other organisations. Inevitably, many material types encountered in nuclear waste management bear pertinence beyond this field, such as complex oxides, high entropy alloys and materials for hydrogen evolution. As such, the institute pursues research that is not just nuclear relevant but also societally.  

 IET-3 pursues research in theory and computation that complements experimental materials research on novel electrocatalysts and battery materials. Crucial scientific challenges in this context are addressed with numerical atomistic modelling, either ab initio or molecular mechanics-based. These encompassprocesses that alter structural, mechanical and thermodynamic properties of solid materials, microscopic charge transfer, and degradation via catalyst dissolution or support corrosion. To assure reliability of the computational workflows we develop accurate and efficient computational methodologies and evaluate their feasibility by comparison with experimental data provided by our partners. Among them, partners at INF-2 apply state-of-the-art synthesis and characterization techniques, utilizing unique infrastructure available within the institute for production and analysis of a variety of nuclear technology-related materials, complex alloys and oxides. These methods provide high resolution and enhanced detail regarding material properties and characteristics, down to the atomic level, which subsequently provide valuable data for developing accurate modelling techniques.

The specific tasks are:

• To employ high-performance EXASCALE supercomputing resources for nanoscale simulations of energy materials,
• To develop AI/ML force fields for use in computer-based simulations of complex HEO systems
• The chemical synthesis of HEO and HEA materials relevant to spent nuclear fuel and hydrogen energy production.
• Materials characterization and analysis using techniques including high resolution X-ray diffraction and spectroscopy.
• To effectively collaborate with internal and external partners.
• Dissemination of scientific results in the form of scientific conferences and written publications.

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Research Project #13 (pdf)               Apply for Project #13

The International Atomic Energy Agency (IAEA) and its Network of Analytical Laboratories (NWAL) conduct analytical measurements on swipe samples taken during inspections at nuclear facilities to verify the absence of undeclared nuclear materials and activities. These efforts and the increasing number of samples to be analyzed require constant quality control measures. This can be achieved through the further development of highly sensitive analytical methods, which goes hand in hand with the development of tailor-made reference materials that must be specifically designed for their application, e.g. novel Th-doped uranium oxide reference microparticles for age determination applications.

In the safeguards laboratories of Forschungszentrum Jülich an aerosol-based process to produce well-defined microparticulate uranium oxide reference materials (cf. Figure) for mass spectrometric verification measurements has been implemented to support a sustainably robust quality control system of the IAEA for particle analysis in nuclear safeguards which includes analytical instrument calibration, method development and validation as well as their application in international interlaboratory exercises.[1-4] Finally, in 2020, the safeguards laboratories were officially qualified as the first member worldwide for the provision of microparticulate reference materials to the IAEA’s dedicated NWAL.

To support the IAEA’ NWAL with excellent expertise and precisely designed reference microparticles the HITEC fellowship is focused on the following working packages (WPs):

WP1: Synthesis of Th-doped uranium-oxide microparticles using the aerosol-based process established in the safeguards laboratories at FZJ as well as the development and evaluation of alternative wet-chemical synthesis routes, e.g. hydrothermal synthesis (in cooperation with ICSM).

WP2: Development of alternative wet-chemical routes for the production of undoped and Th-doped uranium oxide-based reference microparticles and subsequent comparison of the products with those produced by the already established aerosol-based process.

WP3: Structural and elemental/isotopic characterization of microparticles by state-of-the-art diffraction (XRD), spectroscopic (e.g. Raman, XAS) and microscopic techniques (SEM) as well as advanced mass-spectrometric methods (e.g. MC-ICP-MS at FZJ and LG-SIMS at Heidelberg University).

WP4: Studies on thermodynamic stability and reactivity of reference particles under storage and performance conditions (shelf-life of reference particles (in cooperation with ICSM)).

WP5: Investigations on the influence of process parameter and of liquid aerosol medium on particle formation and their properties, particularly in view of the provision of well-designed Th-doped reference particles for radiochronometry.

WP6: Reporting and publication of the results from the project at international conferences and in peer-reviewed journals.

The output from the WPs 1-6 will provide a refined understanding on important properties of the reference microparticles particularly in view of their applicability to strengthen the IAEA’s quality control system for particle analyses in nuclear safeguards.

Although most of the experiments will be conducted in the controlled area of IFN-2, the HITEC-fellowship will be integrated in cooperations already existing with renowned national and international partners, incl. the IAEA. The fellowship will significantly contribute to strengthening this network and the PhD student her-/himself will highly profit from the international educational exchange.

[1]   R. Middendorp, M. Dürr, A. Knott, F. Pointurier, D. Ferreira Sanchez, V. Samson, D. Grolimund: Characterization of the Aerosol-Based Synthesis of Uranium Particles as a Potential Reference Material for Microanalytical Methods. Anal. Chem. 89 (2017) 4721-4728. DOI: 10.1021/acs.analchem.7b00631  

[2]   S. Neumeier, R. Middendorp, A. Knott, M. Klinkenberg, F. Pointurier, D.F. Sanchez, V.-A. Samson, D. Grolimund, I. Niemeyer, D. Bosbach: Microparticle production as reference materials for particle analysis methods in safeguards. MRS Adv. 3(19) (2018). 1005-1012. https://doi.org/10.1557/adv.2018.166

[3]   P. Kegler, F. Pointurier, J. Rothe, K. Dardenne, T. Vitova, A. Beck, S. Hammerich, S. Potts, A.-L. Faure, M. Klinkenberg, F. Kreft, I. Niemeyer, D. Bosbach, S. Neumeier (2021): Chemical and Structural Investigations on Uranium Oxide based Microparticles as Reference Materials for Analytical Measurements. MRS Advances, 6, 125–130. https://doi.org/10.1557/s43580-021-00024-1

[4]   S. Richter, J. Truyens, C. Venchiarutti, Y. Aregbe, R. Middendorp, S. Neumeier, P. Kegler, M. Klinkenberg, M. Zoriy, G. Stadelmann, Z. Macsik, A. Koepf, M. Sturm, S. Konegger-Kappel, U. Repinc, L. Sangely and T. Tanpraphan (2022): Certification of the First Uranium Oxide Micro-particle Reference Materials for Nuclear Safety and Security, IRMM-2329P and IRMM-2331P. Journal of Radioanalytical and Nuclear Chemistry (JRNC), 332, (2023) 2809-2813 https://doi.org/10.1007/s10967-022-08255-8

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Research Project #14 (pdf)               Apply for Project #14

Reducing CO₂ emissions is crucial for mitigating the impacts of climate change. One promising approach to achieve this goal is to capture CO₂ and convert it into valuable fuels and commodity chemicals. Photovoltaic (PV)-driven electrochemical (EC) CO₂ reduction is a promising approach for sustainable conversion of CO₂ into valuable fuels and chemicals using renewable energy. Particularly low temperature CO₂ reduction in direct coupled PV-EC systems is of interest as high efficiency scalable versatile and material saving route[1, 2]. One of the main challenges associated with PV-driven CO₂ reduction is the intermittency of solar power and related fluctuations in the power supply, which can affect the efficiency and stability of the CO₂ reduction process. To overcome the variability of solar power, short time energy storage with batteries (B) can be introduced to PV-driven CO₂ reduction system. The system then turns to a hybrid PV-EC-B device with short- and long-term energy storage capabilities with stabilized output of electricity and EC products. In recent IMD-3 studies[3, 4] it has been demonstrated that properly designed PV-EC-B system is capable of self-sustained operation, maintains high degree of internal power coupling efficiency and exhibits higher solar-to-chemical efficiency than the reference PV-EC system without battery. This synergy puts batteries and particularly high-performance Li-ion batteries in focus of current development of the PV-driven electrochemical systems for CO₂ reduction at IMD-3.

In the first part of the work the knowhow of IMD-4 in development of novel Li-ion battery materials and devices will be combined with experience of IMD-3 in PV and PV-driven electrochemistry to develop and optimize high performance direct-coupled PV-EC-B systems for stable and sustainable conversion of CO₂ into solar fuels such as syngas, methanol and acetic acid. The second part of the work is related to coproduction of solar fuels and Li-ion electrode materials via electrochemical prelithiation processes. In this study the new approach to utilize PV electricity to simultaneously produce synthetic fuel by CO2 reduction and manufacture electrodes for Li-ion batteries in the process of electrochemical prelithiation. The new pathway for coproduction of solar fuels and prelithiated electrodes is based on the results of recent study performed at IMD-4 [5]. The study has established the formation of Li-acetylide (Li₂C₂) as a side product during prelithiation. While this side product is not necessarily beneficial for the electrode preparation, the reaction leading to the formation of Li₂C₂ can be used for conversion of CO2 into acetylene, an important precursor for polymer production.

References:

1. Kim, J., et al., Chemical Engineering Journal, 2022. 428.

2. Veenstra, F.L.P., et al., ChemSusChem, 2024. 17(4): p. e202301398.

3. Astakhov, O., et al., Journal of Power Sources, 2021. 509.

4. Kin, L.-C., et al., Solar RRL, 2022.

5. Maccio-Figgemeier, V., et al., Journal of Power Sources Advances, 2024. 28.

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Research Project #15 (pdf)                Apply for Project #15

The field of agriphotovoltaics (APV) is a quickly developing area of research. The promise of combining field crops with production of electricity is attractive, but also comes with a lot of questions. These range from fundamental questions on the functioning of crop plants when grown under solar panels and the traits these plants need to have in order to cope well, to questions on the design and practical applicability of APV and the economic consequences on the shorter and longer term.

Different APV setups have been and are being tested in experimental fields. These experiments are instrumental in getting an indication on how crops and solar panels perform for specific APV setups and environmental conditions. However, such experiments may also be limited in the extent to which different options can be explored, due to practical and financial considerations.

With 3D simulation modelling, virtual explorations can be done in which plants traits, crop configurations, solar panel setups and the characteristics of those panels can be changed at will, and the consequences for crop and panel performance can be evaluated. This can provide interesting leads for further testing in the field, potentially boosting APV research and system optimization.

In order for such 3D models to produce useful output, they would need to be calibrated to real-world data from plants grown in APV setups. Such data can be obtained from state-of-the-art phenotyping methods, that deliver 3D plant architectural and physiological data.

Within this framework, we offer a PhD thesis project related to the development, calibration and use of such 3D models, collaboratively supervised by the IMD-3 and IBG-2 with a focus on modeling and plant phenotyping respectively. This project will include the following tasks:

1. Experimental Investigation of Canopy Structure, Photosynthetic Activity, and Seasonal Development:

The first work package involves a systematic experimental investigation into the structure and photosynthetic activity of plant canopies growing under Agri-PV installations, tracked throughout a complete growth season. Through repeated measurements across time points, this phase aims to capture how canopy architecture and photosynthetic performance vary seasonally in response to modified light conditions. This time-series dataset provides insights into the impact of Agri-PV on plant development stages, enabling comparisons across selected crop types and paving the way for an integrated understanding of seasonal growth dynamics under Agri-PV shading.

2. Development of 3D Time-Series Models for Canopy Irradiance and Energy Yield Simulation:

The second work package focuses on developing comprehensive 3D models of plant canopies, incorporating time-series data to depict structural changes at different stages of growth. Using point clouds, these models will provide accurate representations of photoactive areas, such as leaves, as they evolve over the season. Integrated with the AIANA simulation package, these models will enable detailed simulations of irradiance within the canopy. AIANA, a ray-tracing tool tailored for Agri-PV applications, will be expanded to account not only for the seasonal light dynamics impacting plant growth but also for the energy yield of the PV system. By simulating energy production along with canopy irradiance, we will analyze how the light sharing between crops and PV systems affects both crop health and PV efficiency.

3. Integrated Analysis of Seasonal Canopy Development, Crop Yield, and Energy Production:

In the final work package, we will combine the time-series irradiance and energy yield simulation results with experimental data on photosynthetic activity and canopy development over the season. This analysis aims to identify relationships between canopy structure, crop yield, and energy output under Agri-PV conditions. By correlating these factors, we can pinpoint optimal Agri-PV configurations that balance crop productivity with energy yield, enhancing both agricultural output and renewable energy production. This holistic analysisprovides a basis for more refined decision-making, supporting Agri-PV designs that maximize photosynthetically active radiation for crops while optimizing energy capture.

The joint supervision of IMD-3 and IBG-2 builts upon the expertise existing in both groups. In specific IMD-3 is expert in model development and will provide the developed AIANA Agrivoltaic Irradiance ANAlyzer, https://github.com/IEK-5/aiana. IBG-2 is expert in plant phenotyping (e.g. https://doi.org/10.1146/annurev-arplant-042916-041124 ) and are coordinating the AgriPhotoVoltaics infrastructure in Alt-Morschenich (https://www.biooekonomierevier.de/Innovationslabor_APV_2_0) with integrated plant phenotyping techniques and including already joint acticivities between IMD-3 (previously IEK-5) and IBG-2 (https://www.fz-juelich.de/de/forschung/unsere-forschung/energie/agri-pv).

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Research Project #16 (pdf)               Apply for Project #16

Photovoltaic (PV) modules will become the backbone of human energy supply. To follow the "net-zero emissions by 2050" scenario, an average annual growth in PV energy generation of 25% is required until 2030. This will result in a total installed capacity of 5 TW PV modules by 2030. As the number of installed modules increases, the return of end-of-life modules will also increase. Sophisticated module recycling techniques are necessary, to handle such high amounts of PV modules.

Currently PV module recycling is typically based on shredding the whole module (with or without aluminium frame) and subsequent sorting of the fragments. Here a big issue is the strong adhesive nature of the encapsulant plastic which is used to insulate the PV cells from water vapor and to ensure a mechanical strength in the module sandwich structure. After shredding, the encapsulant still connects different materials, which makes sorting by type impossible.

The aim of this project is to explore laser-based methods to improve the recycling and the recyclability of a PV module. In a first step, methods should be developed to delaminate the sandwich structure of a PV module by laser radiation. This will allow direct collection of the glass parts of a module as well as easier access to the wafer material and metallic busbars. The second step is to investigate innovative PV module designs in which the edges of a PV module are hermetically sealed by laser welding. This would enable encapsulation materials that only structurally support the sandwich structure of a PV module, but do not have to fulfill any protection against environmental influences. Thus, the material can be designed such that it is much easier to decompose and recycle.

To summarize, the following tasks will be addressed in the PhD work:

• Development of laser delamination process for different types of PV modules
• Investigation of the influence of wavelength, processing time and spatial laser beam distribution on throughput and purity of glass substrate surface
• Development of hermetically sealing of PV module edges by laser welding
• Investigate suitability of different embedding materials for PV module manufacturing

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Research Project #17 (pdf)              Apply for Project #17

The transition towards sustainable and renewable energy sources depends not only on the production of green electricity but also on energy storage to compensate for fluctuations in production and its transport to the consumers. The production of green hydrogen from surplus green electricity and its storage in circular hydrogen carriers produced from H₂ and CO₂ allows the reuse of large parts of the current energy infrastructure to distribute green energy. Dimethyl ether (DME), a non-toxic and non-carcinogenic ether is one of the most promising circular hydrogen carriers [1].

Hydrogen is released from DME via an endothermic multi-step steam reforming process using Cu-based catalysts. After the initial hydration of DME to methanol over an acidic catalyst, steam reforming of methanol to CO₂ and H₂ is catalysed by a Cu-based catalyst [1,2]. These reactions either take place in two separated reactors or, in more recent developments, in a single reactor vessel using bifunctional catalysts containing both functionalities, i.e., acidic catalysts such as zeolites or γ-Al₂O₃ and Cu-based spinels with additions of Zn, Ce, Fe, or other metals [1]. The efficiency of the bifunctional catalysts depends on the complex interplay of reaction conditions, catalyst structure, morphology, composition, and stability [1,3,4].

The aim of the project at the newly founded Institute for a Sustainable Hydrogen Economy (INW) is to understand the relation of catalytic performance with, on the one hand, the catalyst composition and structure, and, on the other hand, the reaction conditions by in situ and operando studies in a close cooperation between INW-1 and INW-2. Catalyst materials are synthesised and their properties on the mesoscale as well as their catalytic performance are tested at INW-2. This includes the synthesis of spinel-type Cu-based catalysts with various CuO/ZnO/Al₂O₃ ratios, basic structural characterisation, surface area measurements as well as the screening of the most effective reaction conditions (feed composition, pressures, temperatures) and resulting reaction (by)-product formation. At INW-1, the catalytic interfaces and processes are studied on the nanoscale. Towards this end, in situ and operando techniques and methodologies will be developed and employed to investigate properties of the catalysts under treatment as well as reaction conditions.

The successful candidate will be based at INW-1, working on the cross-scale in situ and operando characterisation of Cu-based spinel catalysts synthesised and pre-characterised at INW-2. The relation of the catalytic process and the structural as well as chemical evolution of the catalysts, especially the active Cu-sites, will be studied by X-ray diffraction (XRD), simultaneous small- and wide-angle X-ray scattering (SAXS and WAXS), near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS), and X-ray absorption fine structure spectroscopy (XAFS) employing both, state-of-the-art laboratory devices at INW-1, and synchrotron radiation sources such as ESRF (Grenoble) and PETRA III (Hamburg). For in situ and operando studies, specially designed reaction chambers including mass-spectroscopy (MS) to monitor the reaction products will be used. Complementary, Fourier transform infrared spectroscopy (FTIR) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) at INW-2 will be employed to probe the reaction mechanism by identification of active sites (acid sites, for example), and intermediate compounds formed during catalysis [5].

The candidate will graduate from RWTH Aachen University under the supervision of Prof. Dr. Hans-Georg Steinrück and be based at the facilities of INW at the Brainergy Park in Jülich. Experiments will be carried out at the INW-1 laboratories at Brainergy Park and on the main campus of Forschungszentrum Jülich as well as at INW-2 laboratories at RWTH Aachen University, and at large scale research facilities, such as synchrotrons.

Tasks

• Structural and chemical ex situ and in situ characterization of Cu-based spinel catalysts by laboratory-based XRD, SAXS, WAXS NAP-XPS and XAFS in combination with MS at INW-1 facilities employing specially designed sample environments (i.e., both treatment and reaction conditions).
• Planning and implementation of in situ and operando experiments at synchrotron facilities to probe the structural and chemical evolution of spinel-type Cu-based catalysts by high-energy XRD, SAXS, NAP-XPS and XAFS.
• Analysis of X-ray diffraction and spectroscopy data.
• Mechanistic investigation of the DME steam reforming under various feed compositions over the Cu-based catalysts using in situ DRIFTS.
• Close collaboration with the partners at INW-2 who carry out catalyst preparation, catalytic tests and pre-characterization using physisorption and chemisorption techniques.
• Improvement of existing experimental setups and design of new in situ setups based on the needs of the PhD project.

[1]   E. Catizzone, C. Freda, G. Braccio, F. Frusteri, and G. Bonura, Dimethyl ether as circular hydrogen carrier: Catalytic aspects of hydrogenation/dehydrogenation steps, Journal of Energy Chemistry 58, 55 (2021). DOI: 10.1016/j.jechem.2020.09.040

[2]   Y. Tanaka, R. Kikuchi, T. Takeguchi, and K. Eguchi, Steam reforming of dimethyl ether over composite catalysts ofγ-Al2O3 and Cu-based spinel, Applied Catalysis B: Environmental 57, 211 (2005). DOI: 10.1016/j.apcatb.2004.11.007

[3]   K. B. Kabir, H. E. Maynard-Casely, and S. Bhattacharya, In situ studies of structural changes in DME synthesis catalyst with synchrotron powder diffraction, Applied Catalysis A: General 486, 49 (2014). DOI: 10.1021/acs.iecr.9b01214

[4]   Z. Sun, Y. Tian, P. Zhang, G. Yang, N. Tsubaki, T. Abe, A. Taguchi, J. Zhang, L. Zheng, and X. Li, Sputtered Cu-ZnO/γ-Al₂O₃ Bifunctional Catalyst with Ultra-Low Cu Content Boosting Dimethyl Ether Steam Reforming and Inhibiting Side Reactions, Industry and Engineering Chemistry Research 58, 7085 (2019). DOI: 10.1016/j.apcata.2014.08.027

[5]   I. Miletto, E. Catizzone, G. Bonura, C. Ivaldi, M. Migliori, E. Gianotti, L. Marchese, F. Frusteri and G. Giordano, In Situ FT-IR Characterization of CuZnZr/Ferrierite Hybrid Catalysts for One-Pot CO2-to-DME Conversion, Materials 11, 2275 (2018). DOI: 10.3390/ma11112275

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Research Project #18 (pdf)             Apply for Project #18

Green ammonia (NH₃) holds significant potential for renewable energy storage and transportation. Due to its high hydrogen capacity, favorable liquefaction properties, and well-established global infrastructure for distribution and handling, it is considered as one of the most promising hydrogen carriers [1-4].

Hydrogen regeneration from ammonia involves an endothermic cracking reaction:   2NH₃  N₂ + 3H₂ ΔH = 91.2 kJ/mol

This reaction is typically carried out at high temperatures (> 400 °C) and relatively high pressures (up to tens of bar) [2,3]. It is accelerated using a heterogeneous catalyst (e.g., Ru, Ni, Fe, Co, Fe–Co) [2-4]. An associated challenge is materials degradation due to nitridation. The harsh cracking environment causes atomic nitrogen to react with the steel surface of the reactor and/or the active components of the catalyst. This may result in the parasitic restructuring of the materials and the formation of metal nitride layers. Under true reaction conditions, the respective phenomena are challenging to investigate mechanistically. For example, hardly any data for rapid nitridation of steel above 600°C exists. To ensure high performance and longevity of reactors and catalysts, it is essential to gain a comprehensive understanding of these degradation processes [5].

Towards this end, this PhD project aims to investigate the atomic scale and microstructural degradation of materials during ammonia cracking through advanced in situ characterization techniques. By employing both surface- and bulk-sensitive X-ray- and neutron-based methods — such as diffraction, reflectometry, spectroscopy, and imaging [6,7] — we seek to gain detailed mechanistic insights into material behaviour under true reaction conditions. Understanding changes in (bulk) structure, surface properties, and oxidation states across scales is essential for optimizing catalysts and reactor materials for the cracking process.

A central focus of the project is to examine the nitridation of reactor walls under reaction conditions, a phenomenon that can accelerate reactor degradation. Various types of steel, including austenitic and high-strength alloys, will be tested. This information is imperative toward material selection for ammonia crackers to avoid failure. Additionally, the project will explore the effects of nitriding on the active components of catalysts, investigating both reversible and irreversible structural and surface changes that occur during cracking process. Catalysts based on Ru, Ni, Co, and Fe will be characterized across different modifications and supports. The in situ studies of catalyst behaviour under reaction conditions will provide essential information to support the development and testing of promising new catalyst candidates. We expect that we will unravel the time-scales of nitridation and long-term evolution and stability of nitride layers. This insight can be used for the proposal and selection of optimal materials for ammonia crackers.

To accomplish these goals, we will use a combination of various complementary X-ray methods to reveal structure, morphology, and chemistry of nitride layers. We will employ sample systems of systematically varied complexity, from thin films and steel sheets in gas environment to realistic reactors during operation. A specialized experimental setup will be designed to enable in situ measurements under realistic process conditions, including controlled gas flow and high temperatures and pressures. This setup will be carefully adapted to meet the unique requirements of each characterization technique and will be initially tested using state-of-the art laboratory X-ray machines on model materials such as thin iron films and bulk catalyst crystals. Upon optimization, the setup will be used to conduct experiments on actual reactors and respective realistic components and catalysts. These investigations will also be carried out using international large-scale research facilities, such as synchrotron X-ray sources and neutron reactors. These are located for example in Grenoble/France, Hamburg/Germany, Chicago/US, or Stanford/US. This will enable high time resolution and high-throughput investigations under systematically varied conditions to generate large combinatorial data sets, which are analysed using advanced big data analytics and machine learning approaches.

In summary, the PhD project will involve the following key tasks:

• Development of experimental setup for in situ X-ray-based characterization during ammonia cracking
• Investigation of reactor steel wall nitridation during reaction conditions (at synchrotron sources)
• Investigation of catalyst nitridation during reaction conditions (at synchrotron sources)
• Analysis and interpretation of experimental data, including big data analytics
• Presentation of research findings at conferences and publication in peer-reviewed scientific journals

[1] E. Spatolisano et al.: Ammonia as a Carbon-Free Energy Carrier: NH₃ Cracking to H₂. (2023) Ind. Eng. Chem. Res. 62 (28), p. 10813.

[2] S. Sun et. al: Ammonia as hydrogen carrier: Advances in ammonia decomposition catalysts for promising hydrogen production. (2022) Renew.

     SustEnerg. Rev. 169, p. 112918.

[3] M. Asif et. al: Recent advances in green hydrogen production, storage and commercial-scale use via catalytic ammonia cracking. (2023) Chem. Eng.

      J.473, p. 145381.

[4] A. Salehabadi et. al: Mixed metal oxides in catalytic ammonia cracking process for green hydrogen production: A review. (2024) Int. J. Hydrogen

      Energy 63, p. 828.

[5] N. Laws et al. Design and Performance Assessment of an Experimental Rig to Conduct Material Nitridation Studies at Extreme Ammonia Conditions

      (2023) Turbo Expo: Power for Land, Sea, and Air. Vol. 86946. American Society of Mechanical Engineers.

[6]J. Baruchel et al. (1994).Neutron and synchrotron radiation for condensed matter studies. Volume 1: theory, instruments and methods. 1^st edition,          

      Springer Berlin, Heidelberg.

[7] J. Als-Nielsen et al. (2011).Elements of Modern X-ray Physics. 2^st edition, John Wiley & Sons.

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