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Materials for a sustainable transition


Circular materials and resource chemistry

The energy transition is a materials and resource transition. In times of increasing pressure on industry and politics with respect to environmental protection and climate change, material sciences have to provide answers to the most challenging technological tasks.


The aim of the symposium is to discuss current developments in circular economy, and materials resource chemistry. Under the aspect to secure and provide indispensable materials in a limited environment, this symposium will specifically focus on applied resource chemistry and new recycling technologies. The symposium will look at the latest developments in materials science and chemistry combined with their application in recycling and regeneration technologies, in order to provide advancement in the use of secondary raw materials for high-tech applications such as energy, computing and transport technologies.

The symposium will focus on an interdisciplinary approach with research areas from the substitution of critical elements, to the development of sustainable materials, and the establishment of efficient material life cycles.

Potential speakers include scientists and experts from various fields such as resource & green chemistry, biology, environmental science & technology, as well as material sciences.

Hot topics to be covered by the symposium:

  • Circular economy
  • Green ICT
  • Defossilisation
  • Urban Mining and Recycling
  • Critical raw materials
  • Substitutional Design of Sustainable Functional Materials
  • Self-healing and Regenerative Materials
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(Bio)Polymers - Synthesis and Degradability : Andrea Gassmann
Authors : Sanjay Mathur
Affiliations : Institute of Inorganic Chemistry, University of Cologne, Greinstr. 6, 50939 Cologne, Germany

Resume : In order to develop new sustainable and reusable concepts for the degradation of omnipresent industrial plastics, immobilization of (bio) catalysts on nanocarriers offers unique opportunities for selective depolymerization and catalyst recovery. In this study, enzymes (lipase and cutinase) were covalently immobilized on carrier nanoparticles (SiO2 and Fe3O4@SiO2) through 3-(aminopropyl)trimethoxysilane linkers that provided terminal amino groups for forming a stable bond to enzyme molecules upon addition of glutaraldehyde. The presence of enzymes on the surface was confirmed by zeta potential and XPS measurements, while their degradation activity and long-term stability of up to 144 hours was demonstrated by the conversion of 4-nitrophenyl acetate to 4-nitrophenol. Furthermore, enzymatic decomposition (hydrolysis/oxidation) of electrospun polycaprolactone fiber mats was verified through morphological (SEM) and weight loss (TG) studies, which evidently showed a change in the fiber morphology due to enzymatic degradation and accordingly a weight loss.

Authors : Gina Ambrosio1,*, Guido Faglia 1,2, Stefano Tagliabue3 and Camilla Baratto1
Affiliations : 1 CNR-INO, PRISM Lab, Via Branze 45, 25123 Brescia, Italy; 2 Department of Information Engineering, University of Brescia, 25133 Brescia, Italy; 3 Corapack S.r.l., 22040 Brenna, Italy; * e-mail:;

Resume : Bio-degradable or compostable plastics, derived from renewable materials like corn, potato, starches, cellulose, and lactic acid, can tackle the environmental concerns of food packaging which is responsible for 60% of plastic waste in Europe and for micro-plastic pollution. Bioplastics stand to contribute to more sustainable commercial plastic life cycles as part of a circular economy. Enormous research has been undertaken to improve and characterize the biopolymers to bring their mechanical and physical properties comparable to that of fossil-based plastics. In our work in the framework of Spatials3, a hub of research and innovation in the field of nutrition, Raman spectroscopy (RS) was proposed as a versatile tool to investigate the degradation of biobased plastics after a stress test in water: this approach is a novelty for food packaging. Treatments at room temperature (RT) and 80°C were selected, considering that these biopolymers can be used to package ready meals. We used six different bioplastics mostly used in the food packaging applications which show different properties. The Raman spectra assigned to the pristine biopolymers have been compared to the vibrational mode of the water-treated materials at RT and 80°C and the morphological properties of polymers were analyzed by Scanning Electron Microscopy (SEM). We were able to point out the chemical structure modification of the biopolymers under the water exposure in agreement with the visual inspection. The results suggest that RS detects the specific chemical bond that was modified, helping us understand the degradation process of biobased plastics after water treatment.

Authors : Thi Nga Tran,1,* Michael Morris,2,3 Maurice Collins1
Affiliations : 1 Faculty of Science and Engineering, Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland; 2 Advanced Material and BioEngineering Research Centre (AMBER), Trinity College Dublin, The University of Dublin, Ireland; 3 School of Chemistry, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

Resume : Biocomposites made of poly(propylene carbonate) (PPC), a carbon dioxide (CO2) derived polymer, and a renewable polysaccharide are promising materials for several applications such as biomaterials and packaging. However, most of PPC-based biocomposites exhibit low mechanical and optical properties due to the inherent incompatibility between PPC and most other polymers. In this work, a novel biocomposite composed of PPC and chitosan was developed using a facile and sustainable water-based production process. This innovative synthetic route enables the formation of chitosan micron/submicron particles dispersed within the PPC matrix. This, in turn, leads to improved mechanical performance and thermal stability of these renewable and low carbon footprint materials. Furthermore, Curcumin is incorporated and its sustained release from the biocomposites results in prolonged and effective antioxidant properties. These CO2-based biocomposites are biodegradable in sea water forming non-toxic products. The developed PPC/chitosan biocomposite represents intriguing candidates for the sustainable development of biomaterials.

Authors : Niclas Solin
Affiliations : Division of Electronic and Photonic Materials, Biomolecular and Organic Electronics, Department of Physics, Chemistry, and Biology, Linköping University, Linköping, 581 83, Sweden

Resume : Proteins are highly complex molecules with a rich chemistry and self-assembly behavior. One of the most natural applications of proteins is to eat them – proteins (amino acids) are indeed required for a healthy diet. However, many of these complex molecules are available as side-streams (sometimes even waste-streams) from food production, meaning that proteins constitute a promising renewable resource for development of materials [1]. Due to their outstanding capacity for self-assembly protein molecules can be converted to advanced nanomaterials through processes more reminiscent of simple cooking than high tech manufacturing, allowing for the preparation of advanced nanomaterials without the need for energy intensive processes. While a given protein has an evolutionary optimized structure, it is of interest to be able modify the properties of proteins – both from the perspective of enabling novel functionality and being able to influence the self-assembly and structure of proteins. A plethora of such methods exist but most of them are only suitable for small scale operations related to biochemical research rather than large scale production of materials. There is accordingly a need for development of a flexible toolbox suitable for large scale production of protein materials. Herein will be discussed new methodology, based on a combination of co-milling proteins and hydrophobic materials followed by aqueous self-assembly into protein nanofibrils (PNFs) – a methodology that is easily scaled up if desired. We have recently found that the hydrophobic material can act not only as a functionalization agent (endowing novel function to the protein material) [2] but may also modify the physical behavior of the aqueous PNF dispersion – allowing access to PNF materials with unique properties and novel self-assembly characteristics [3]. The resulting PNF dispersions can be processed into solid forms such as gels and solid films. With appropriate processing nanostructured hierarchically organized films, that couple order at different length scales, can be formed [4], indicating that protein-based bioplastics with unique properties can be developed. [1]. Lendel, C. and Solin, N., 2021. Protein nanofibrils and their use as building blocks of sustainable materials. RSC Advances, 11(62), pp.39188-39215. [2]. Yuan, Y. and Solin, N., 2021. Mechanochemical Preparation and Self-Assembly of Protein: Dye Hybrids for White Luminescence. ACS applied polymer materials, 3(10), pp.4825-4836. [3]. Wang, L., Bäcklund, F.G., Yuan, Y., Nagamani, S., Hanczyc, P., Sznitko, L. and Solin, N., 2021. Air–Water Interface Assembly of Protein Nanofibrils Promoted by Hydrophobic Additives. ACS Sustainable Chemistry & Engineering, 9(28), pp.9289-9299. [4]. Yuan, Y., Wang, L. and Solin, N., 2022. Unpublished results

10:15 Coffee break    
Energy Materials for Circular Economy : Marc Widenmeyer
Authors : Patricia S. C. Schulze 1, Özde Ş. Kabaklı 1, Minasadat Heydarian 1,2, Oussama Er-Raji 1,2, Maryamsadat Heydarian 1,2, Raphael Efinger 1, Kaitlyn McMullin1, Oliver Schultz-Wittmann 1, Christoph Messmer 1,2, Alexander J. Bett 1, Oliver Fischer 1,2, Leonard Tutsch 1, Denis Erath 1, Sebastian Pingel 1, Thibaud Hatt 1, Martin Bivour 1, Martin C. Schubert 1, Jan Christoph Goldschmidt 1,3, Martin Hermle1, Stefan W. Glunz 1,2
Affiliations : 1 Fraunhofer Institute for Solar Energy Systems ISE, 79110 Freiburg, Germany; 2 University of Freiburg, Germany, 79110 Freiburg, Germany; 3 University of Marburg, Germany, 35037 Marburg, Germany.

Resume : To enable terawatt-scale photovoltaics, resource and cost efficiency are mandatory [1]. Perovskite silicon tandem solar cells can achieve both goals by exceeding the efficiency limit of 29.4% of single junction silicon solar cells [2], with only little additional production costs [3]. We aim for monolithic 2-terminal tandem devices to facilitate module integration and to avoid parasitic absorption in laterally conductive layers. Starting from a p-i-n perovskite top solar cell with a 1.68 eV absorber on p-type heterojunction silicon bottom solar cells with a pyramidal rear side texture and a planar front [4], we elaborate optimization steps to maximize the photocurrents in the sub-cells and achieve current matching. Supported by optical simulation using transfer matrix formalism and raytracing [5,6], main process adaptions are addressed, e.g., development of a more transparent front contact layer and fine-tuning the perovskite band gap. Spectral metric analysis, comprising a systematic variation of the illumination spectrum, is applied to access the individual sub-cell´s current generation and confirm current matching [7]. A certified short-circuit current density of 19.6 mA/cm2 is achieved for optimized tandem devices with planar front. For further current improvement and higher energy yield [8], fully textured tandem devices are needed. For this purpose, we investigate the dry/wet hybrid (evaporation and wet processing) route to allow perovskite deposition with tuneable band gap on μm-sized silicon texture [9]. Concerning the tandem´s open-circuit voltage, we investigate different charge transport materials and interface passivation. Implementing self-assembling molecules at the hole contact improves the surface passivation, however surface recombination at the electron contact material limits the internal voltage. Consequently, no significant VOC improvement on device level is observed. Still, an improvement in fill factor leads to a performance increase from 26.1% to 26.8% stabilized certified efficiency. To unlock the VOC potential and push efficiency further, passivating layers at the critical perovskite and electron contact interface are under investigation. Moreover, opto-electrical simulation of the full tandem stack in Sentaurus TCAD gives insight into the tandem´s band diagram and charge carrier extraction and serves as basis for further device optimization. Regarding up-scaling and metallization, we transfer our top solar cell processing from small 2.5 cm x 2.5 cm substrates to full wafer processing. Perovskite silicon tandem solar cells with an active area of up to 104.4 cm2 are realized. Low-temperature silver paste screen-printing is used for front metallization. Considering high costs of silver, electroplated copper contacts are considered as an alternative and demonstrated on semi-transparent perovskite solar cells as a proof-of-concept [10]. Further, we employ sub-cell selective characterization to analyse lateral inhomogeneities of deposition techniques and compatibility of processes [11]. References [1] J. C. Goldschmidt et al., “Technological learning for resource efficient terawatt scale photovoltaics”, Energy & Environmental Science, vol. 14, p. 5147-5160, 2021, doi: 10.1039/d1ee02497c. [2] T. Niewelt et al., “Reassessment of the intrinsic bulk recombination in crystalline silicon”, Solar Energy Materials and Solar Cells, vol. 235, p. 111467, 2022, doi: 10.1016/j.solmat.2021.111467. [3] L. A. Zafoschnig, S. Nold, and J. C. Goldschmidt, “The Race for Lowest Costs of Electricity Production: Techno-Economic Analysis of Silicon, Perovskite and Tandem Solar Cells,” IEEE Journal of Photovoltaics, vol. 10, no. 6, pp. 1632–1641, 2020, doi: 10.1109/JPHOTOV.2020.3024739. [4] P. S. C. Schulze et al., “25.1% High‐Efficient Monolithic Perovskite Silicon Tandem Solar Cell with a High Band Gap Perovskite Absorber”, Solar RRL, vol. 4, no. 7, p. 2000152, 2020, doi: 10.1002/solr.202000152. [5] C. Messmer et al., “The race for the best silicon bottom cell: Efficiency and cost evaluation of perovskite–silicon tandem solar cells”, Progress in Photovoltaics: Research and Applications, vol. 29, no. 7, pp. 744-759, 2020, doi: 10.1002/pip.3372. [6] C. Messmer et al. “Optimized front TCO and metal grid electrode for module-integrated perovskite–silicon tandem solar cells”, Progress in Photovoltaics: Research and Applications, 2021, doi: 10.1002/pip.3491. [7] M. Meusel et al., “Spectral mismatch correction and spectrometric characterization of monolithic III–V multi-junction solar cells”, Progress in Photovoltaics: Research and Applications, vol. 10, no. 4, pp. 243–255, 2002, doi: 10.1002/pip.407. [8] N. Tucher et al., “Energy yield analysis of textured perovskite silicon tandem solar cells and modules”, Optics Express, vol. 27, no. 20, pp. A1419-A1430, 2019, doi: 10.1364/OE.27.0A1419. [9] P. S. C. Schulze et al., “Perovskite hybrid evaporation/ spin coating method: From band gap tuning to thin film deposition on textures”, Thin Solid Films, vol. 704, p. 137970, 2020, doi: 10.1016/j.tsf.2020.137970. [10] T. Hatt et al, “Electroplated Copper Metal Contacts on Perovskite Solar Cells”, Solar RRL, vol. 5, no. 9, p. 2100381, 2021, doi: 10.1002/solr.202100381. [11] O. Fischer et al., “Imaging-Based Detection of Defects in Perovskite-Silicon Tandem Solar Cells”, tandemPV workshop, Freiburg, 2022. Acknowledgement This work was partially supported by the Fraunhofer Lighthouse Project MaNiTU and the German Federal Ministry for Economic Affairs and Energy (BMWi) under contract number 03EE1086A (PrEsto).

Authors : Mario Schönfeldt, Urban Rohrmann, Philipp Schreyer, Mahmudul Hasan, Konrad Opelt, Jürgen Gassmann, Anke Weidenkaff, Oliver Gutfleisch
Affiliations : Schönfeldt; Rohrmann; Schreyer; Hasan; Opelt; Gassmann; Weidenkaff: Fraunhofer IWKS, Fraunhofer Research Institution for Materials Recycling and Resource Strategies, Aschaffenburger Str. 121, 63457 Hanau, Germany Schönfeldt; Schreyer; Hasan; Opelt; Weidenkaff; Gutfleisch: TU Darmstadt, Department of Materials- and Geosciences, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany

Resume : Since its discovery in 1983, Nd-Fe-B has become the permanent magnet (PM) material with the highest energy product at ambient temperature [1]. Today Nd-Fe-B is used in many key technologies and the demand for high quality PMs will increase significantly in the near future. The required rare earths (RE) elements are considered as highly critical and the metallurgical processes to gain the RE oxides from ores have a large environmental footprint [2]. The usage of recycled material would lower the criticality and increases the sustainability of RE PMs [3]. For a viable and efficient industrial recycling process a circular economy will be necessary in which a material can be recycled multiple times. To enhance such a recycling process with reproducible outcomes the knowledge of the material behavior through every processing step or recycling cycle is mandatory. With this in mind, a Nd-Fe-B PM alloy from magnetic resonance imaging (MRI) application was multiple recycled with the so-called functional recycling approach [4] using hydrogen decrepitation. Different material properties like chemical composition, particle size, density, microstructure, magnetic values or the degree of alignment were analyzed in detail over three recycling cycles. For the determination of the degree of alignment different methods like electron backscatter diffraction (EBSD) or magnetometry were used and compared. The multiple processing and recycling of the alloy leads to a decrease in texture, orientation and the resulting magnetic properties of the recycled magnets, respectively. Meanwhile impurities and particle size of the material increase through several milling and sintering processes. Different amounts of NdH2 were mixed with the recyclate to improve the properties. With 4 wt.% NdH2 the density of recycled magnet can be fully restored. It could be shown, that magnetic properties of multiple recycled magnets meet the specification of several applications such as loudspeakers or hoverboards, however they outperform clearly magnets produced from primary materials in terms of sustainability. References: [1] O. Gutfleisch, M.A. Willard, E. Brück, C.H. Chen, S.G. Sankar, J.P. Liu, Magnetic materials and devices for the 21st century: stronger, lighter, and more energy efficient, Advanced materials (Deerfield Beach, Fla.) 23 (2011) 821–842. [2] European Commission, Study on the EU’s list of Critical Raw Materials: Final Report (2020), 2020. [3] O. Diehl, M. Schönfeldt, E. Brouwer, A. Dirks, K. Rachut, J. Gassmann, K. Güth, A. Buckow, R. Gauß, R. Stauber, O. Gutfleisch, Towards an Alloy Recycling of Nd–Fe–B Permanent Magnets in a Circular Economy, J. Sustain. Metall. 4 (2018) 163–175. [4] A. Walton, H. Yi, N.A. Rowson, J.D. Speight, V. Mann, R.S. Sheridan, A. Bradshaw, I.R. Harris, A.J. Williams, The use of hydrogen to separate and recycle neodymium–iron–boron-type magnets from electronic waste, Journal of Cleaner Production 104 (2015) 236–241.

Authors : Emanuel Ionescu1,2, Teppala D. Teja2, Ruijan Yuan2, Xingxing Xiao2, Jürgen Gassmann1, Anke Weidenkaff1,2
Affiliations : 1Fraunhofer IWKS, Brentanostr. 2a, D-63755 Alzenau, Germany; 2Technische Universität Darmstadt, Institute for Materials Science, Alarich-Weiss-Straße 2, D-64287 Darmstadt, Germany

Resume : Circular Economy (CE) represents a holistic concept and a programmatic philosophy concerning the production and consumption of goods which basically and ideally should reduce the amount of waste to a minimum. There is an obvious contradiction between on the one side the need for a circular economy and for a no-waste world and on the other side the tremendously increasing amount and complexity of consumer goods, their planned obsolescence, and consequently the massive generated amount of waste due to the take-make-waste peculiarity of their production and consumption. The Circular Economy (CE) concept has a powerful enemy when it comes to bring it to reality, and this is the second law of thermodynamics, which actually prevents that closing the production/products/material loops will lead to a full resource efficiency, i.e. equal to unity. In other words, no loops can be closed ideally, there are always irreversible losses related to material balances, materials and product quality, etc. Thus, minimizing residues and losses should be considered as important as and in addition to closing the material loops via recycling purposes. One main consequence of this will result in the stringent need to minimize the entropy increase across the various added value chains/loops. In the present paper, we will try to show however that entropy increase may not always be seen as acting against CE and that it can be used to maximize the resource efficieny and close especially materials loops in an improved manner. In our consideration, we will try to elaborate on different aspects related to the effect of entropy increase on circular economy. Firstly, we will discuss based on few representative examples the concept of structural as well as compositional disorder in tailoring and ideally maximizing the performance of materials and devices. Secondly, we will elaborate on the compositional complexity in materials as an effective way to consider highly heterogeneous waste streams as valuable secondary raw materials without the need of any (exaggerated) efforts related to materials extraction and purification. And thirdly, we will perform a prospective discussion on preparative concepts and strategies to develop materials compositions with maximized performance (as compared to that of analogous materials from primary production) and at the same time with high tolerancy for admixtures / impurities.

Authors : Susanne Wintzheimer, Karl Mandel, and The Supraparticle Group
Affiliations : S.W.: Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, D-91058 Erlangen, Germany, AND: Fraunhofer-Institute for Silicate Research ISC, Neunerplatz 2, D-97082 Würzburg, Germany; K.M.: Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, D-91058 Erlangen, Germany, AND: Fraunhofer-Institute for Silicate Research ISC, Neunerplatz 2, D-97082 Würzburg, Germany; TSG: Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, D-91058 Erlangen, Germany

Resume : The indispensable transformation to a more sustainable human society on this planet heavily relies on innovative technologies and advanced materials. The merits of nanoparticles in this context have been demonstrated widely during the last decades.[1-3] Yet, it is believed that the impact of particle-based nanomaterials on sustainability can be even further enhanced: taking NPs as building blocks enables the creation of more complex entities, so-called supraparticles.[4] Due to their evolving phenomena of coupling, emergence, and colocalization, supraparticles enable completely new material functionalities.[5] These new functionalities in supraparticles can be utilized to contribute to the sustainability of various application fields. The presented work focuses on functional supraparticles used as smart additives to either extend the materials’ lifetime or facilitate their recycling. Both approaches are essential for the establishment of a circular economy. Supraparticles indicating for example mechanical damage allow a straightforward detection and replacement of broken components to keep a product in working conditions.[6,7] Once a product cannot be repaired anymore, its recycling can be facilitated using supraparticle-based tracers. They permit the identification of marked materials by distinct optical or magnetic signals and thus an automated sorting process.[8,9] A step beyond can be taken by even combining both damage indication and an ID within a single supraparticle.[10,11] This creates truly “communicating particles” and thus, addresses both product repair and recycling with a single microscale material system. Altogether, it will be demonstrated that by combining long-known nanoparticle building blocks to form supraparticles, a new world at the “supra-nano-level” opens up and provides plenty of room for new properties and potential applications contributing to a sustainable transformation of our today’s world. [1] T. Pradeep, et al., Thin Solid Films 2009, 517, 6441; [2] X. Hu, et al., Langmuir 2010, 26, 3031. [3] M. Segev-Bar, et al., ACS Nano 2013, 7, 8366. [4] Wintzheimer S., et al., Adv. Funct. Mater., 2021, 2011089. [5] Wintzheimer S., et al., ACS Nano, 2018, 12, 5093-5120. [6] Wintzheimer S., et al., Adv. Funct. Mater. 2019, 29, 1901193. [7] Wenderoth S., et al., Small 2022, 2107513. [8] Wintzheimer S., et al., ACS Appl. Nano Mater. 2020, 3, 734-741. [9] Müssig S., et al., Small 2021, 2101588. [10] Reichstein J., et al., Adv. Funct. Mater. 2021, 2104189. [11] Wenderoth S., et al., Nano Lett. 2022, 22, 2762–2768.

12:15 Lunch break    
Resouce Strategies for a Circular Transition : Sanjay Mathur
Authors : Lukas Wagner 1, Robert Pietzcker 2, Lorenz Friedrich 3, Dmitry Bogachuk 3, Jan Christoph Goldschmidt1
Affiliations : 1 Philipps-University Marburg, 35032 Marburg, Germany; 2 Potsdam Institute for Climate Impact Research, 14412 Potsdam, Germany; 3 Fraunhofer Institute for Solar Energy Systems, 79110 Freiburg, Germany.

Resume : Cost efficient climate change mitigation requires installing up to 170 TWp photovoltaic (PV) electricity production capacity until the year 2100. The question is whether and how such growth is possible from a resource perspective. We have assessed the demand of such multi-TW-scale PV for the fundamental resources energy, greenhouse gas emissions, float-glass, and capital investments that will be necessary independently from which PV technology will dominate in the future. Furthermore, we assessed the technology specific material demand such as silver. Importantly, in our analysis we considered via a learning rate approach that PV technology is continuously improving. Conversion efficiency is increasing, while cost, and energy consumption during production are continuously decreasing. We found that without further technological learning, serious resource constraints will limit the growth of PV industry. On the other hand, continued technological learning at current rates would enable rapid growth within reasonable boundaries of resource demand. With such technological learning, energy demand for production will correspond to 2-5% of global energy consumption leading to cumulative greenhouse gas emissions of 4-11% of the 1.5°C emission budget. Glass demand will exceed current float-glass production, requiring rapid capacity expansion. Installations costs would be in the range of 300-600 billion $US2020 per year. With continued technological learning, the silver demand for PV could be contained in the range of the industry’s current consumption. Technological solutions enabling such learning are foreseeable. Especially perovskite-based (tandem) solar cells promise to reach efficiencies, energy, and costs targets that allow for staying on the development paths obtained from extrapolating current learning rates. The specific material demands of such technologies need to be analyzed carefully and the development steered towards using abundant and non-toxic materials to reach real sustainability. In this regard, we present LCA data revealing that fully printable perovskite PV modules are able to reach the lowest CO2-eq limit of PV technologies. We further assess the material demands of a future TW-scale perovskite PV industry, identifying materials used in current laboratory-type devices that my become critical and possible replacements. Finally, we present a re-manufacturing approach for perovskite PV modules to improve the integration of PV technologies into a circular economy.

Authors : Anke Weidenkaff 1,2, Andrea Gassmann 1, Emanuel Ionescu 1, Marc Widenmeyer 2, Wenji Xie 2
Affiliations : 1 Fraunhofer IWKS, Brentanostr. 2a, D-63755 Alzenau, Germany; 2 Technische Universität Darmstadt, Institute for Materials Science, Alarich-Weiss-Straße 2, D-64287 Darmstadt, Germany

Resume : Green energy conversion technologies require green materials. The development of recyclable materials and the emerging sustainable large scale production from secondary raw materials has to be based on environmental and resilience aspects as well as on performance criteria defined by a holistic life cycle assessment. The implementation of intelligent green chemistry for synthesis and scalable production processes of substitution materials from waste requires profound knowledge on environmental footprints and composition-structure -property relationship. An efficient circularity of the energy converters with a programmable lifetime and regeneration will be introduced as a suitable approach in this talk. The design of circular high performance materials uses theoretical predictions and the criticality analysis of applied elements to improve the cycle life of future energy converters such as batteries, fuel cells, electric motors, generators and solar cells.

Authors : Matthew Wei Ming Tan, Hyunwoo Bark, Gurunathan Thangavel, Pooi See Lee
Affiliations : School of Materials Science and Engineering, Nanyang Technological University, Singapore

Resume : The widespread consumption and production of electronic devices have led to 57.4 million tons of electronic waste in 2021. To avoid the repetition of this, the emerging field of soft and stretchable electronics must implement designs for a circular economy. For soft devices to have longer operational lifetimes and avoid the frequent need for new replacements, these devices can be designed with higher mechanical toughness and self-healing capabilities to resist and repair damages. In addition, recyclable soft devices potentially minimize the amount of electronic waste. However, maintaining its soft nature in pursuit of high toughness remains a challenge as rigid or hard components are typically introduced. To address this, a polyurethane elastomer with high toughness (96.5 MJ m-3), self-healing capabilities, and recyclability is designed. By judiciously tuning the molecular weight of soft segments, the elastic modulus can be reduced from 22.6 to 1.9 MPa, similar to that of soft tissues. At the same time, the introduction of carboxyl functionalities provides dynamic supramolecular interactions that can be reassociated after being broken to enable self-healing and recyclability. The advantage of attaining a low modulus is highlighted where the elastomer is utilized as a dielectric elastomer actuator that can achieve large actuation area strains of 80%. By imparting elastomers with toughness, self-healing, and recyclable properties, we can bring soft electronics closer to a circular economy.

Authors : Andrea Gassmann 1, Romy Auerbach 1, Tabea Hagedorn 2, Alice Lopes 2, Benedikt Völker 3, Carsten Binnig 3, Liselotte Schebek 1,2
Affiliations : 1 Fraunhofer IWKS, Brentanostr. 2a, D-63755 Alzenau, Germany; 2 Technische Universität Darmstadt, Chair of Material Flow Management and Resource Economy, Franziska-Braun-Straße 7, D-64287 Darmstadt, Germany; 3 Technische Universität Darmstadt, Data Management, Hochschulstr. 10, 64289 Darmstadt, Germany

Resume : The circular economy is an essential field of action for sustainability and resource efficiency as it provides high-quality secondary raw materials for the economy. This, however, requires the cooperation of the actors in the value chain from producing companies, transporters to specialized recyclers and including also buyers of secondary raw materials. Critical points for effective cooperation within this value-added network are logistical issues, minimization of cost and environmental aspects as well as quality assurance of the recyclates. The project “DigInform” addresses these requirements and develops an innovative digital information management system (IMS) in the actor chain of the circular economy. The developed IMS enables trustworthy and secure data management across company boundaries and considers the specific requirements of the user groups. Thus, existing recycling paths can be designed more efficiently and new recycling options can be derived. The chain of actors is conceptually viewed as a supply chain for secondary raw materials, i.e. the quality requirements of future buyers of the products are integrated. In the German manufacturing chemical and pharmaceutical industry, approximately 3.2 million tons of waste are generated per year, some of it continuously, others as spot batches. In the current work we focus on production-specific waste from the chemical industry and its recycling routes. The IMS is designed on the basis of real application examples: Firstly, we will present the results of the organizational and stakeholder analysis considering e.g. the state of digitalisation in companies, their needs, barriers and already implemented resource efficiency and digitization measures. This profile of requirements reflects the perspective of producing companies and waste disposal companies or recyclers. Secondly, the technical solution for the IMS will be presented that is based on the TRUSTDBLE prototype with a shared database using blockchain technology as an auditable storage to guarantee transparency and auditability of data. Finally, first results on the effects and potentials of the IMS-use on climate protection and resource efficiency will be presented.

15:15 Coffee break    
Materials Synthesis, Processing and Recovery I : Emanuel Ionescu
Authors : Gurpreet Singh
Affiliations : Kansas State University, Manhattan (Kansas), United States

Resume : Silicon containing polymer-derived ceramics (PDC) fibers, because of their intrinsic thermal stability, had enormous commercial success in the form of high-damage tolerant ceramic matrix composites. Another interesting aspect of PDCs is their amorphous microstructure which imparts them with electrochemical properties suitable for battery electrodes—nanodomains of various constituents in PDCs such as SiC, SiO or the disordered carbon phase renders PDCs with ability to cycle alkali metal-ions at room temperature without degradation or chemical corrosion for prolonged times. Here, carbon rich SiOC composite fibers were fabricated via electrospinning and pyrolysis of cyclosiloxane precursor loaded with a variety of high capacity nanofillers such as 2-D nanosheets and nanoparticles of transition metal sulfides. Investigations on structural and compositional development of the fibers were mainly conducted via Raman spectroscopy, Fourier-Transform InfraRed spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray Photoelectron Spectroscopy (XPS) to determine free carbon content, crosslinking, pyrolysis behavior and morphology of the fibers. Performance as electrode material in sodium and potassium ion rechargeable metal ion batteries will be discussed.

Authors : Marina Avena Maia, René Hauser, Laura Torrente-Murciano
Affiliations : Catalysis and Process Integration Group. Department of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS, United Kingdom; Delft IMP, Molengraaffsingel 8, 2629 JD, Delft, The Netherlands; Catalysis and Process Integration Group. Department of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS, United Kingdom

Resume : This work presents the development of ZnO core-shell materials through atomic layer deposition (ALD) for the selective adsorption of phosphate from waste aqueous solutions. Phosphate, one of the primary components in fertilizers, is a finite resource in current scarcity. Currently, it is mainly obtained by mining of phosphorous rocks, a mineral declared as one of the 30 critical resources by the European Union [1]. As such, the development and implementation of phosphate recovery systems for its reuse is urgently needed to guarantee food security worldwide. Urine-containing streams from mammal (including human waste) are one of the largest source of phosphate; offering an opportunity for its sustainable recovery aligned to the concept of circular economy [2]. However, its main challenge is associated to its low concentration in waste streams of approximately 8 mg/L [3]. Decentralized wastewater systems (i.e. no-mix toilets) collect and treat urine as a separate waste stream. This system could offer the opportunity to recover phosphate more efficiently, since through source separation urine can be collected undiluted or very low-diluted with a high concentration of phosphate. Two complementary approaches are being developed in this project for phosphate recovery from no-mix toilets streams: the development of adsorbent materials through ALD for phosphate capture and the evaluation of an integrated process of adsorption and desorption for phosphate release back into solution for fertilizer production. In this context, zinc oxide presents a high phosphate affinity. In order to increase the density of adsorption sites per mass of material, a ZnO layer was synthesized using ALD on a range of supports: TiO2, SiO2, Fe3O4 and Al2O3. ZnO was deposited on a fluidized bed reactor using diethylzinc and water as the precursor and co-reactant, respectively. In order to ensure full coverage of the support, each ALD cycle consisted of four sequential exposures of the substrate to diethylzinc vapor, N2 purge, H2O vapor, N2 purge. From the four substrates tested, ZnO deposited on SiO2 presented a phosphate adsorption capacity of 69 mg/g, whilst pristine SiO2 presented an adsorption uptake of 4 mg/g. The increase in the phosphate capture performance was due to the ZnO layer addition onto SiO2, which increased the availability of phosphate adsorption sites directly at the surface. The phosphate uptake performance of commercial ZnO was compared with the ZnO@SiO2 material. Commercial ZnO, which presents a zinc loading of 80 wt%, reached equilibrium in 30 minutes with an adsorption capacity of 62 mg/g. Even though similar phosphate uptake values were obtained for ZnO@SiO2 and commercial ZnO, the ALD material reached equilibrium in only 10 minutes with a lower zinc loading of 37.9 wt%. Since the aim is to apply the adsorbent material in decentralized systems, a faster adsorption step will allow a more efficient recovery process in no-mix toilets. In addition, ZnO@SiO2 material was exposed to five adsorption-desorption cycles, in order to obtain a highly concentrated solution of phosphate. The final solution was used as a phosphate renewable source for struvite precipitation. The obtained solid was analysed through XRD and it was possible to confirm that struvite was successfully produced from this integrated process. Thus, the extraction and recovery of phosphate from waste streams promotes a sustainable closed-loop of nutrients. [1] Henckens, T. (2021). Governance of The World’s Mineral Resources: Beyond the Foreseeable Future. Elsevier. [2] Egle, L., et al. (2015). Overview and description of technologies for recovering phosphorus from municipal wastewater. Resources, Conservation and Recycling, 105, 325-346. [3] Wilsenach, J. A., & van Loosdrecht, M. C. (2006). Integration of processes to treat wastewater and source-separated urine. Journal of Environmental Engineering, 132(3), 331-341.

Affiliations : 1Smart Materials, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy 2Dipartimento di Informatica, Bioingegneria, Robotica e Ingegneria dei Sistemi (DIBRIS), Università degli Studi di Genova, Via Opera Pia 13, 16145 Genoa, Italy

Resume : Solar steam generation is an appealing approach to compete the worldwide freshwater shortage, and for this reason, various types of materials have been developed. Herein we present a low-cost attainable alternative to the so far proposed systems, made by cattle bone waste, for steam generation and desalination. This is achieved via thermal treatment, in a controlled environment, of bone samples for their conversion into highly porous photothermal materials. The carbonized bone (CB) is not only composed of intrinsically intertwined meso and microporous channels, for productive water transportation and vapor escape, but exhibits outstanding optical absorption (99%) of the solar irradiation, solar light-to-heat conversion, and low vaporization enthalpy. The CB device demonstrates a solar evaporation rate of 1.82 kg m-2 h-1 under 1 sun illumination, and this is attributed not only to its interaction with the sunlight but also to the enhanced evaporation rate in the dark, with the solar-to-vapor conversion efficiency of 80%. Moreover, the desalination efficiency of CB reaches 99.99%. This biowaste-based highly porous photothermal system is a promising material for the efficient collection of freshwater from seawater, because of its outstanding performance coupled with the wide availability of the biosource, the straightforward fabrication approach, and the thermal and chemical stability of the final material. With such valuable alternatives, new paths for managing the continuously rising food waste are opened.

Authors : Melisa Kafali1, Güneş Kibar* 2,3,4, O. Berk Usta3,4, Batur Ercan* 1,5,6
Affiliations : 1) Department of Metallurgical and Materials Engineering, Middle East Technical University, Ankara, Turkey 2) Department of Materials Engineering, Faculty of Engineering, Adana Alparslan Turkes Science and Technology University, 01250 Adana, Turkey 3) Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA 4) Shriners Hospitals for Children, Boston, MA, 02114, US 5) Department of Biomedical Engineering, Middle East Technical University, Ankara, Turkey 6) BIOMATEN, METU Center of Excellence in Biomaterials and Tissue Engineering, Ankara, Turkey *Corresponding Author: Gunes Kibar (, Batur Ercan (

Resume : Introduction Polyhedral oligomeric silsesquioxane (POSS) particles are silica-based particles having a nanometer-sized three-dimensional architecture that is considered an organic and inorganic hybrid material[1]. Although they are proposed for various engineering applications i.e., magnetic nanodevice and drug delivery[2], there is very limited information on the antibacterial activity of POSS-based particles with or without having any surface functional groups. In this research, spherical POSS nanoparticles were synthesized in free radical mechanism in one-step emulsion polymerization of methacryl (M)–POSS monomer[3] to design antibacterial nanoparticles that targeted the infected side of the body. The POSS nanoparticles were magnetized using the co-precipitation method[4]. Silver nanoparticles were grown on the synthesized POSS nanoparticles using a polydopamine (PDA) layer[5], which provided free amine and catechol groups on POSS nanoparticles. Then, these nanoparticles were coated with a rhamnolipid (RL) layer which is widely investigated glycolipid due to its low toxicity, low critical micellar concentration, high biodegradability, and high antimicrobial activity against most microorganisms, including gram (+), gram (-) bacteria, yeast, and fungi[6]. Each coating layer combination was synthesized to investigate the antibacterial properties of these nanoparticles against Staphylococcus aureus and Pseudomonas aeruginosa strains which are harmful pathogens causing biomedical device-related infection. Experimental Procedure POSS nanoparticles were synthesized by one-step emulsion polymerization [3] 0.10g of M-POSS monomer and 0.02 g AIBN were dissolved in 300µl EtOH via sonication. The prepared solution was added to 0.25% (w/w) SDS and mixed in an oil bath at 70°C, 500 rpm for 12 h. The polymerized M-POSS nanoparticles were collected as white precipitate and rinsed with distilled water (DI) and ethanol (EtOH) various times to remove SDS and unpolymerized M-POSS monomers. Subsequently, the nano-sized particles were separated from the polymerized solution and dried at 50°C in a vacuum oven for further experiments. Magnetic-POSS nanoparticles were obtained by co-precipitation in the literature method [4]. The poly(M-POSS) nanoparticles were dispersed in a deionized water medium under a nitrogen atmosphere and placed in an ice bath. In the meantime, the iron salts FeCl2·4H2O and FeCl3·6H2O were also dissolved in a deionized water medium in N2 atmosphere. The salt solution was added to nanoparticle dispersion. The air of the mixture was removed by vacuum until no air bubble was observed. Once a light brown mixture was formed, the solution was immediately immersed in a water bath at 85°C to heat solution. Afterward, NH4OH (25% wt. /wt.) was added to this mixture, and the color of the solution turned black. The resulting dispersion was stirred mechanically at 85°C for 1h and cooled to room temperature. Superparamagnetic iron oxide nanoparticle (SPION) decorated poly(M-POSS) nanoparticles were separated from the liquid phase with a strong natural magnet and rinsed with DI water and 0.1 M HCl to remove undissolved iron salts and ammonia. Poly(M-POSS) nanoparticles were coated with PDA prior to in-situ silver growth on particles in the literature[5]. Poly(M-POSS) nanoparticles (25 mg) were dispersed in 10 ml Tris buffer solution (10 mM, pH:8.5) under magnetic stirring. DOPA-HCl (2 mg/ml) was added onto poly(M-POSS) containing buffer solution, and the dispersion was magnetically stirred for 6h of in the dark. Afterwards, PDA coated magnetic nanoparticles were added into 10 ml of 50 mM AgNO3 solution (2.5% w/v solid particle content). The solution was stirred magnetically for 12h for deposition of silver onto the POSS nanoparticles. The same protocol was aslo applied on Magnetic-Poly(M-POSS) nanoparticles. Rhamnolipid and POSS-based nanoparticles were mixed 1:5 (wt./wt.) in EtOH medium. Afterwards, the solution was sonicated for 10 min and mechanically stirred for 12h. As a final step, nanoparticles were collected by centrifuged and dried at 50°C. The multifunctional RL@Ag@SPION@poly(M-POSS) nanoparticles were fully characterized by SEM, XRD, FTIR, VSM, DLS,zeta potential analysis, antibacterial activity, and cytotoxicity of magnetic and non-magnetic POSS nanoparticles having silver, rhamnolipid and silver/rhamnolipid coatings were investigated. Results and Discussion RL-Ag-coated SPION-poly(M-POSS) nanoparticles were synthesized in five steps. The first step was poly(M-POSS) nanoparticles synthesis with precursor Methactly-POSS monomers, the second step was magnetization of POSS particles by using co-precipitation technique, the third step was PDA coating on magnetized POSS particles, the fourth step was in-situ growth of AgNO3 through the PDA layer to enhance the antibacterial property of the particles. The final step was a rhamnolipid coating on the silver-coated magnetized POSS particles. In each step, different functionality of poly(M-POSS) nanoparticles was obtained. From the first to the last step, the size of the particles varied from 100nm to 400nm in a uniform spherical morphology characterized using SEM. All synthesized poly(M-POSS) based nanoparticles possess the organic and inorganic composite structure with FTIR peaks. The peak of inorganic Si – O – Si structure at 1100 and – C= O stretching at 1736 cm-1. The weak stretching of CH3 – CH2 was observed at 2960 – 2890 cm-1. The peaks of Si – C bonds at 1260 cm-1, 850 cm-1, 755 cm-1. XRD and FTIR were done to confirm silver and RL coating on the POSS particles. POSS gave an amorphous silica peak in XRD spectra at 2θ = 23°. Polydopamine coating did not affect crystalline structure of POSS particles. The silver peaks at 2θ = 38°, 44°, 64°, 77°, and 81°. Rhamnolipid coating changed intensities of diffraction peaks, but it did not affect crystalline structure of particles. The magnetization values of silver, rhamnolipid, and silver/rhamnolipid magnetic POSS nanoparticles were examined with VSM. The values varied between 10 emu/g to 6.5 emu/g due to the thickness of coating layers on SPION. The zeta potential of poly(M-POSS) was -37mV, and coating layers changed the zeta potential of nanoparticles. RL@Ag@SPION@poly(M-POSS) nanoparticles showed strong antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. At 10 µg/ml concentration, POSS-SPION-Ag-RL particles caused nearly 3-fold reduction when compared to only POSS particles and 8-fold reduction when compared to only bacteria control. Conclusion POSS nanoparticles are silica-based structures with organic and inorganic parts and are widely used in engineering applications such as photonics, sensor, microelectronics, and biosensing. While changing the surface properties of these nanoparticles, they can also gain antibacterial properties against S. aureus and P. aeruginosa strains. Our results showed that RL@Ag@SPION@poly(M-POSS) nanoparticles had a synergistic effect against both strains and caused an 8-fold reduction in colonies. Thus, RL@Ag@SPION@poly(M-POSS) can be further studied in tissue engineering applications. References 1. Fan, L. et al., Creating biomimetic anisotropic architectures with co-aligned nanofibers and macrochannels by manipulating ice crystallization. ACS nano, 2018. 12(6): p. 5780-5790. 2. Fan, L., X. Wang, and D. Wu, Polyhedral oligomeric silsesquioxanes (POSS)‐based hybrid materials: molecular design, solution self‐assembly, and biomedical applications. Chin. J. Chem . 2021. 39(3): p. 757-774. 3. Kibar, G., Spherical shape poly (M‐POSS) micro/nano hybrid latex particles: One‐step synthesis and characterization. J. Appl. Polym. Sci., 2020. 137(41): p. 49241. 4. Kibar, G., et al., Newly designed silver coated-magnetic, monodisperse polymeric microbeads as SERS substrate for low-level detection of amoxicillin. J. Mol. Struct., 2016. 1119: p. 133-138. 5. Kibar, G. and D.Ş.Ö. Dinç, In-situ growth of Ag on mussel-inspired polydopamine@ poly (M-POSS) hybrid nanoparticles and their catalytic activity. Journal of Environmental Chemical Engineering, 2019. 7(5): p. 103435. 6. Thakur, P., et al., Rhamnolipid the Glycolipid Biosurfactant: Emerging trends and promising strategies in the field of biotechnology and biomedicine. Microbial Cell Factories, 2021. 20(1): p. 1-15.

Postersession I : Andrea Gassmann
Authors : Irinela Chilibon
Affiliations : National Institute of Research and Development for Optoelectronics, INOE 2000, Romania

Resume : Ultrasound effects on the intensification of various physical-chemical processes in solutions and liquids are presented. Ultrasound can provide an excess energy for the new interface formation, and it is possible to obtain emulsions even in the absence of surfactants. The advantages of ultrasound include lower energy consumption and production of more homogeneous emulsion than by a mechanical process. Recent breakthroughs in sonochemistry have made the ultrasound irradiation procedure more feasible for a broader range of applications. The efficacy of ultrasonic emulsification is function of irradiation time, irradiation power, oil/water ratio and physical-chemical properties of the oil. Ultrasound about 25 kHz and 40 kHz are examined in order to find the suitable work frequency to increase the cavitation efficiency. Cavitation results in the generation of hot spots, turbulence associated with liquid circulation currents contribute in the intensification of various physical-chemical operations, could contribute to the grain size decreasing of powder materials mixed into solutions. Major applications of cavitation effects could be the synthesis of biodiesel, emulsification and extraction of bio-components, in aim to increase the overall efficiency of the emulsification process. Other investigations are made at higher frequencies, for the use of ultrasound in waste water purification or improve the quality of water. The ultrasonic effects to the chemical reactions in sonochemistry involve various processes, such as: hydrolysis, oxidation, and depolymerization. Chemical and some mechanical effects are given when ultrasound irradiates liquid, and most of these effects are a result of the implosive collapse of cavitation bubbles or bubble-induced microstreaming. Liquid-powder suspensions produce high velocity interparticle collisions, which can change the surface morphology, composition, and reactivity.

Authors : K Govardhan* & J Priyanka
Affiliations : K Govardhan*, Department of Micro and NanoElectronics, School of Electronics Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, India J Priyanka, Department of Physics, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu, India

Resume : With the rapid rise of the global population and the continual increase in human mobility, the risks of epidemic outbreaks are increasing. One of the most significant pathways for the spread of respiratory infectious diseases is the airborne transmission. These airborne microorganisms may be propagated by fine dust, aerosols, or liquids, that are subsequently transported over a large region by air currents and inhaled by susceptible hosts. The use of face masks to inhibit respiratory illness or prevent pollution is a well-established method. Wearing a mask can successfully limit the spread of infectious agents from symptomatic patients. Government organizations and health institutions have made their use mandatory during the ongoing COVID-19 pandemic and face masks as a prophylactic step did restrict the spread of the novel coronavirus. However, owing to improper disposal and prolonged usage, they pose a considerable environmental threat and health risks. Inadequate management of face masks and other PPE is now being researched for its environmental impact. Face masks that have already been inappropriately disposed of, have also become a source of microplastics and nano-plastics in the environment. The presence of microplastics in masks pollutes the environment and is also hazardous to users who may inhale these components. In the year 2021, face masks alone could cause 0.15 to 0.39 MT of plastic trash to end up in the oceans due to improper waste management. An alternative and innovative solution is the need of the hour. The paper proposes the fabrication of a biodegradable face mask with infused antibacterial nanoparticles and medicinal plant extracts. A more environmentally friendly and green sourced polymer can be utilised as an effective replacement for conventionally used and highly polluting petrochemical-derived polypropylene. Poly Lactic Acid (PLA) derived from corn and wheat straws, which are otherwise discarded as bio-waste can replace polypropylene. Nanoparticles with inherent antibacterial properties like ZnO and CuO are enriched with Ag doping to enhance their antibacterial and antimicrobial properties. Medicinal plants such as Curcuma longa (turmeric), Azadirachta indica (Neem), Aloe barbadensis miller (Aloe vera), Moringa oleifera (moringa), Psidium guajava (guava) etc have been reported to exhibit excellent antimicrobial properties as well. The green extracts sourced from these plants are formulated into a nanotherapeutic emulsion. The antibacterial nanoparticles enhanced with Ag doping are mixed along with the nano-emulsion. The nano-emulsion is infused with the molten PLA are fabricated into an active layer of the face mask. The untreated PLA is used to fabricate exterior and interior particulate filters. The fabricated antibacterial face mask is subjected to various tests to conform to the stringent standards of the CDC and other statutory regulators. They are also tested for their breathability and antibacterial efficiency.

Authors : Dieu Minh Ngo, Wonseok Jo, Hyun Min Jung*
Affiliations : Department of Applied Chemistry, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Republic of Korea Department of Energy Engineering Convergence, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Republic of Korea

Resume : Polyethylene terephthalate (PET) and its derivative, poly (1,4-cyclohexylenedimethylene terephthalate) (PCT), have become attractive materials for the production of fibers, films, and food packaging, owing to their chemical resistance, durability, and good transparency. However, the massive consumption raises concerns about the waste plastics crisis. Chemical recycling processes including aminolysis, methanolysis, hydrolysis, and glycolysis have been developed to solve this issue. Among them, glycolysis, in which PET and PCT degradation occur in the presence of diols, appears to be an effective method to convert waste plastics into valuable products. Typically, ethylene glycol is added to transform PET into bis(2-hydroxyethyl) terephthalate (BHET) monomer, which can be reused for PET production. Numerous diols such as diethylene glycol (DEG), cyclohexanedimethanol (CHDM), and d-isosorbide (ISB) are utilized to expand the application of post-glycolysis products. However, a quantitative investigation of their reactivity has not yet been conducted. In our research, we systematically investigated the effect of different diols on the glycolysis rate of PET and PCT, where steric hindrance caused by the rigid structure of diols was clarified. The reaction rate of PET glycolysis involving ISB was 0.17%, and 0.28% of that observed with DEG and CHDM, respectively. In addition, due to the existence of cyclohexylene substituent in the structure, PCT showed a poor glycolysis reaction efficiency with DEG, which is one-third of that of PET. An enhanced glycolysis process was proposed and tested to overcome this low reactivity. Transesterification by the combination of zinc ions and alkoxy species efficiently improved the reaction rate by three times compared to conventional zinc catalyst. The optimal conditions were applied to directly convert PET to low-molecular-weight liquid polyols, which can be used in rigid polyurethane production.

Authors : Amanpreet Kalra1, Songhak Yoon1, Marc Widenmeyer2, Arnulf Rosspeintner3, Benjamin Balke1, Anke Weidenkaff1,2
Affiliations : 1Fraunhofer Research Institution for Materials Recycling and Resource Strategies IWKS, Aschaffenburger Straβe 121, 63457 Hanau, Germany; 2Technical University of Darmstadt, Alarich-Weiss-Straβe 2, 64287 Darmstadt, Germany; 3University of Geneva, Quai Ernest Ansermet 30, CH-1211 Geneva 4, Switzerland

Resume : Lead halide perovskites are extensively studied for various devices such as solar cells, LEDs and lasers.[1] Despite significant progress in fundamental understanding of the degradation mechanism, lead halide perovskites are currently not commercially viable due to toxicity and stability issue limiting operational lifetime. Finding potential lead substitutes in perovskites is crucial.[2] Herein, the toxic lead is replaced with manganese to synthesize CsMnBr3 perovskite. Colloidal hot-injection method is known to synthesize CsMnBr3 nanocrystals.[3,4,5] To the best of our knowledge, mechanochemical synthesis of CsMnBr3 has not been reported yet. In this study, single-phase CsMnBr3 was synthesized via mechanochemistry having the key advantages of being lead and solvent-free. The crystal structure was studied by X-ray diffraction (XRD) and Raman spectroscopy whereas thermo gravimetric analysis (TGA) was conducted to elucidate the structural stability. Two samples were successfully synthesized using solvent-free route under different milling conditions. Sample A: i) manual grinding of the precursors with mortar and pestle for 10 min in ambient atmosphere, ii) followed by automated precursor milling in a 10 ml reactor. In contrast, sample B was ball-milled in a 25 ml reactor without any prior grinding. Both samples were milled for 30 min with 25 Hz of shaking frequency. XRD patterns of both samples revealed a single-phase perovskite with P63/mmc space group. The unit cell parameters of both samples were estimated by Rietveld refinements: a = 7.6211(2) Å, c = 6.5059(2) Å for sample A; a = 7.6210(2) Å, c = 6.5102(2) Å for sample B. The estimated crystallite size of sample A (46.4 nm) was smaller than of sample B (242 nm). The lattice strain for sample A (28.65 ×10-4) was also smaller than sample B (55.94×10-4). Furthermore, Raman spectroscopy at room temperature revealed five Raman bands for both samples. Raman spectroscopy of CsMnBr3 at 2 K has been reported.[6] Thermal stability was investigated by TGA. As anticipated from the larger crystallite size sample B was thermally more stable than sample A. The results showed that the successful synthesis of CsMnBr3 reported here is challenging as Mn2+ has a strong affinity for oxygen which makes the material highly hygroscopic and unstable in ambient conditions. Mechanochemical synthesis of CsMnBr3 is a cost-effective and environmentally friendly approach that can easily be scaled up for industrial applications. As an outlook, it is anticipated to conduct further sustainability assessment of this synthesis route.[7] References [1] Y.-T. Huang, et al.,Nanotechnology2021, 32, 132004. [2] X. Wang, et al.,J. Phys. Chem. Lett.2021, 12, 10532. [3] Q. Kong, el al.,Angew. Chem. Int. Ed.2021, 60, 19653. [4] J. Almutlaq, et al.,ACS Materials Lett.2021, 3, 290. [5] T. W. Kang, et al.,Optics letters2022, 47, 1806. [6] W. Breitling, et al.,Solid State Commun.1976, 20, 525. [7] K. J. Ardila-Fierro, et al.,ChemSusChem2021, 14, 2145.

Authors : Aasir Rashid, Marc Widenmeyer, Sungho Baek, Guoxing Chen, Anke Weidenkaff
Affiliations : Technical University of Darmstadt, Department of Materials and Geo Science, Research Division Materials & Resources, Darmstadt, Germany; Technical University of Darmstadt, Department of Materials and Geo Science, Research Division Materials & Resources, Darmstadt, Germany; Technical University of Darmstadt, Department of Materials and Geo Science, Research Division Materials & Resources, Darmstadt, Germany; Fraunhofer Research Institution for Material Recycling and Resource Strategies IWKS, Alzenau, Germany; Technical University of Darmstadt, Department of Materials and Geo Science, Research Division Materials & Resources, Darmstadt, Germany and Fraunhofer Research Institution for Material Recycling and Resource Strategies IWKS, Alzenau, Germany

Resume : A challenging task for current materials science-based research is to figure out pathways that can allow for a sustainable material synthesis using secondary raw materials, while also ensuring energy and resource efficiencies and environmental friendliness. Mixed ionic–electronic conducting ceramics (MIEC) are one such material class potentially fitting this description. MIEC materials have gained prominence for their transport properties. As oxygen transport membranes, these materials have significant potential in terms of energy efficiency and circular economy of CO2-driven processes. This work is based on perovskite-type oxygen transport membrane materials namely La0.6Ca0.4Co1–xFexO3–δ (LCCF). As part of the NexPlas project1, which focusses on sustainable production of platform chemicals such as methanol by combining a CO2-fueled microwave plasma with green H2, the LCCF membranes, due to their oxygen transport capability, play a pivotal role in keeping the oxygen concentration of the plasma system in check. The tolerance of LCCF membranes in a CO2 atmosphere has already been established in our previous work2. However, in order to produce methanol, introduction of H2 to the system is required and hence H2 tolerance of the membranes has to be established as well. So far from our obtained thermogravimetric results, the LCCF membrane materials containing lower amount of cobalt e.g., La0.6Ca0.4Co0.2Fe0.8O3–δ behave rather well up to 600 oC in a 95%Ar-5%H2 atmosphere, simultaneously improving materials sustainability. However, for a longer duration, the membrane tolerance towards H2 starts to weaken which can result in membrane degradation. To ensure membrane recovery, a suitable alternative to the production of virgin membranes is needed. As the LCCF membrane materials consist of valuable rare earth and critical elements (La, Co) producing a high value waste upon reaching their end of life stage, the concept of recycling demands more attention. This can be achieved by following a sustainable and energy efficient route for the synthesis, which is enabled by the use of techniques like microwave irradiation for dissolution of LCCF during recycling and ultrasonic spray synthesis (USS) technique for material production as well as recycling. The initial results indicate a possible recycling of LCCF membrane materials using the USS technique is achievable, supported by the X-ray diffraction (XRD) and scanning electron microscopy—energy-dispersive spectroscopy (SEM-EDS) data. The current material production rate is at 340 mg/h with a recovery of 53%. A comparison between conventional synthesis techniques like reverse co-precipitation method and USS can be made based on energy and time efficiency of the latter. Similar comparisons can be drawn by adapting to microwave assisted dissolution instead of hot plate dissolution. 1 2 G. Chen et al., Chem. Eng. J. 2020, 392, 123699

Authors : Junseong Kim, Bong-Gu Kim, Janghyeok Pyeon, Tserendorj Khadaa, Hyeryang Choi, Donghyun Kim, Haeun Kim, Jung-Hun Son, Byung-il Yang, SeungCheol Yang
Affiliations : Department of Materials Convergence and System Engineering, Changwon, Gyeongnam 641-773, Republic of Korea

Resume : The thermal barrier coating has utilized a ceramic with a low thermal conductivity to protect internal materials in hot parts of gas turbine operating in extreme environments with high temperature and high pressure. Yttria-stabilized zirconia (YSZ) has been used as the most effective thermal barrier coating material because it has lower thermal conductivity, superior mechanical properties, and higher thermal expansion coefficient, compared to other ceramics. However, as YSZ coating is operated for a long time, delamination is likely to occur at the metal / ceramic interface due to the strain caused by sintering effects and detrimental phase precipitation. In this study, CeO2 was coated on the surface of YSZ powder to prepare a powder for thermal barrier coating with high thermal expansion properties compared to YSZ. CeO2 coating on YSZ was performed by wet process of the solution including Ce salt and alcohol solvent. The CeO2 coating was analyzed with various analysis tools (SEM, XRD etc.) and confirmed successfully to form on YSZ particles. Through evaluation of thermal conductivity and thermal expansion characteristics of bulk specimens made of Ce-coated YSZ powder, it was found that the core-shell structure powder prepared in this study can be applied as a next-generation thermal barrier coating material.

Authors : L.C. Cotet, A. Mihis, C. Salagean, I. Szekely, K. Magyari, M. Muresan-Pop, I. Zgura, E. Matei, M. Baibarac, I. Anghel, L. Baia, M. Baia
Affiliations : -Authors 1-5, 11, 12: “Babeș-Bolyai” University, Street Mihail Kogălniceanu, No. 1, RO-400084, Cluj-Napoca, Romania; -Authors 6-9: National Institute of Materials Physics, Bucharest-Magurele, 077125, Romania; -Author 10: Fire Officers Faculty, “Alexandru Ioan Cuza” Police Academy, Bucharest, 022451, Romania

Resume : The increase of the sustainability of materials obtained by using recycled and renewable waste materials that are involved in the fields of energy, climate protection, more safe civil materials, etc. is a priority of our days. More specifically, the enhance of the energetic efficiency of building’s thermal insulation, the increase of life time and decrease of carbon emission (i.e. CO2 footprint) for natural polymeric materials (e.g. wood, cellulosic derivatives, etc.), and a better fire resistance for construction materials in the case of extreme conditions generated by an uncontrolled fire are the themes with a real interest. In this context and taking into account “the circular-economy concept”, the goal of the present study is to involve wood wastes (e.g. sawdust of wood) for obtaining monolithic materials with improved fire resistance and increased thermal insulation properties. These new materials were prepared by modification of wood surfaces with a mixture of phosphorous (using phosphoric acids), nitrogen (using melamine) and nanocarbon (using graphene oxide, [1]). The synergetic action of these three components for fire resistance improvement of clipboard was evidenced by vertical flame burning test and thermogravimetric techniques [2]. Moreover, monolithic carbon foams (i.e. expanded carbons) with low density (i.e. 0.03-0.10 g/mL), high fire resistance (i.e. >800oC) and excellent thermal insulation properties (even at a thickness of 0.5 cm) were obtained by heating the samples at 200oC in ambient air conditions. This new yielded material type could be considered as a promising alternative for expanded polystyrene, largely used in building thermoinsulation (i.e. energetic field). Moreover, the obtained materials present an environmental-friendly character and a high fire protection degree. Morpho-structural characteristics of the samples before and after thermal treatment as well as thermal properties assessments were performed. The contribution of graphene oxide in fire protection of clipboard surface was also evidenced [2]. References [1] L.C. Coteț, et al. J. Mater. Chem. A, 5 (2017) 2132. [2] L.C. Cotet, et al., J. Nanosci. Nanotechnol., 21 (2021) 2312.

Authors : Martine Jacob, Kerstin Wissel, Oliver Clemens
Affiliations : Universität Stuttgart, Institut für Materialwissenschaft, Abteilung Chemische Materialsynthese, Stuttgart, Germany

Resume : The growing demand for safer energy storage devices has led to a significant interest in all-solid-state lithium-ion batteries (ASSLBs). Several inorganic solid-state electrolyte (SSE) classes (e.g. oxides, sulfides and halides) have been extensively studied over the years. Especially the halide-based solid electrolytes have attracted much attention due to their high ionic conductivity (10-3 Scm-1), wide electrochemical stability window and good stability towards oxide-based cathode materials [1]. These studies mainly focus on the fabrication and operation of ASSLBs, however, possible recycling strategies have not been sufficiently investigated. The halide-based SSE, Li3InCl6, has attracted attention due to its relatively easy water mediated synthesis route, coupled with a high ionic conductivity (2.04 x 10-3 Scm-1) and the ability to achieve same ionic conductivity after dissolution in water [2]. The recovery of the crystal structure after the dissolution is of particular interest, since direct recycling (or a solution-based separation route) can be used to successfully separate the SSE from the active electrode materials. In addition, through this method higher recovery rates can be expected. Here, we report first results on the development of an ecofriendly and cost-efficient recycling strategy with a high recovery rate. We will report on combinations of different anode and cathode materials with Li3InCl6. By a combination of X-ray diffraction and impedance spectroscopy, we investigate the phase purity of the recycled electrolyte for different material combinations, with impedance spectroscopy studies showing the impact of traces from electrode materials potentially influencing the conductivity. [1] Liang, Jianwen, et al. "Metal halide superionic conductors for all-solid-state batteries." Accounts of Chemical Research 54.4 (2021): 1023-1033. [2] Li, Xiaona, et al. "Water‐mediated synthesis of a superionic halide solid electrolyte." Angewandte Chemie 131.46 (2019): 16579-16584.

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Materials Synthesis, Processing and Recovery II : Anke Weidenkaff
Authors : Guowei Li, Yu Kang, Qun Yang, Uttam Gupta, Gudrun Auffermann, Yan Sun, Claudia Felser
Affiliations : Max Planck Institute Chemical Physics of Solids, Dresden, Germany

Resume : Understanding the role of electrons and surface structures is critical to the design of high-efficient heterogeneous catalysts for energy conversions such as water splitting and fuel cells. Topological materials are ideal platforms because of the symmetrically protected metallic surface states and massless high-mobility electrons. The last decade has witnessed a growing interest in experimental chemistry-heterogeneous catalysis, asymmetry synthesis, etc, but there remains a lack of understanding of how topological properties interact with the reaction processes. With high-quality topological bulk single crystals, we experimentally and theoretically confirmed the direct relationship between topological properties and surface redox reactions. Most importantly, the catalytic reaction efficiencies can be tailored effectively by external fields such as magnetic fields and stains. We believe that the manipulation of topological electronic structures would be a powerful tool for the designing of high-efficient catalysts, further, hinting at the potential for asymmetric synthesis and origin of life.

Authors : Jinxue Ding a, Wenjie Xie a, Anke Weidenkaff a,b
Affiliations : a) Materials and Resources, Department of Materials and Earth Sciences, Technical University of Darmstadt, 64287 Darmstadt, Germany; b) Fraunhofer Research Institution for Materials Recycling and Resource Strategies IWKS, 63755 Alzenau, Germany

Resume : The layered TiS2, a member of the transition-metal dichalcogenides (TMDCs) family, has been reported to be great potential thermoelectric material for room and medium temperature applications1, 2. In addition to its large Seebeck coefficient (close to -300 μV/K)3, TiS2 also exhibits obvious advantages, such as being environment-friendly, cost-effective, lightweight, etc. The Van der Waals gaps related to its layered structure can accept a variety of species as intercalants, which provides a good strategy to reduce its lattice thermal conductivity. In this work, the impact of iron intercalation on the electrical and thermal transport properties of TiS2 was investigated. Iron intercalated TiS2 with (FexTiS2) with x varying from 0 to 0.05 were prepared using a solid-liquid-vapor reaction. The iron intercalation into Van der Waals gaps between S-Ti-S slabs and the densified bulk materials were achieved by spark plasma sintering. The intercalated iron cations are served as the electron-carriers donor, leading to a substantial decrease in electrical resistivity. The lattice parameter c expands as the increase of iron content, confirming that iron particles go into the Van der Waals gaps as intercalants. Also, structural disorders caused by iron intercalation contribute to the reduction of lattice thermal conductivity. After iron intercalation, the figure of merit, ZT, is consequently improved, reaching above 0.4 at 700 K. Reference: [1] Guilmeau, E.; Maignan, A.; Wan, C.; Koumoto, K. Phys Chem Chem Phys 2015, 17, (38), 24541-55. [2] Wan, C.; Wang, Y.; Wang, N.; Norimatsu, W.; Kusunoki, M.; Koumoto, K. Sci Technol Adv Mater 2010, 11, (4), 044306. [3] Beaumale, M.; Barbier, T.; Bréard, Y.; Guelou, G.; Powell, A. V.; Vaqueiro, P.; Guilmeau, E. Acta Materialia 2014, 78, 86-92.

Authors : Melanie Johanning, Marc Widenmeyer, Giamper Escobar Cano, Vanessa Zeller, Guoxing Chen, Armin Feldhoff, Anke Weidenkaff
Affiliations : Technical University of Darmstadt, Department of Materials and Geo Science, Research Division Materials & Resources, Darmstadt, Germany; Technical University of Darmstadt, Department of Materials and Geo Science, Research Division Materials & Resources, Darmstadt, Germany; Leibniz University Hannover, Institute of Physical Chemistry and Electrochemistry, Hannover, Germany; Technical University of Darmstadt, Research Division of Material Flow Management and Resource Economy, Darmstadt, Germany; Fraunhofer Research Institution for Material Recycling and Resource Strategies IWKS, Alzenau, Germany; Leibniz University Hannover, Institute of Physical Chemistry and Electrochemistry, Hannover, Germany; Technical University of Darmstadt, Department of Materials and Geo Science, Research Division Materials & Resources, Darmstadt, Germany and Fraunhofer Research Institution for Material Recycling and Resource Strategies IWKS

Resume : Sustainable oxygen transport membrane (OTM) materials are required for the successful implementation of alternative energy conversion technologies, such as plasma-assisted carbon dioxide (CO2) splitting and conversion. For a future-oriented materials development, combined performance evaluation and sustainability assessment is highly needed. The main performance requirements for an application in plasma-assisted CO2 conversion are high oxygen permeation flux and superior life time in CO2 and reducing atmospheres. The recently developed (La0.9Ca0.1)2Ni0.75Cu0.25O4±? (LCNC) is considered as a promising candidate for such an application due to its stable oxygen permeation flux under an air/CO2 gradient at high temperature (e.g., 900 °C)1. Successful future application of LCNC additionally requires alternative production routes to reduce the environmental impact and dependency on scarce resources. One promising approach to produce secondary material with high quality and improved environmental performance is chemical recycling. We have developed a microwave-assisted chemical recycling process for LCNC. To obtain a functional precursor for further Pechini-based processing, LCNC was dissolved in an aqueous solution of citric and nitric acid using a microwave autoclave. Around 97% of LCNC input was recovered with initial properties, as confirmed by X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. A membrane prepared from recycled LCNC showed a comparable oxygen permeation flux to that of primary LCNC. In parallel, life cycle assessment (LCA) was conducted to compare the environmental impact of recycling to primary synthesis using an attributional LCA model with the cut-off approach for the secondary material. To determine direct process emissions, we have developed an emission model from comprehensive thermal analysis. CO, CO2, NO, NO2, N2O, NH3, and H2O were identified as main gaseous emissions. The environmental impact of LCNC recycling is reduced by up to 76% compared to primary synthesis in 12 of 15 impact categories. The difference is mainly caused by the high environmental impact of the production and provision of primary metal nitrates, especially lanthanum nitrate. Main levers for improving the environmental performance were identified as reduction of electricity consumption and process emissions. Due to their additional contribution to process emissions, the amount and choice of process chemicals are crucial. Bringing experimental and LCA results together, the developed recycling process is a promising method to synthesize recycled LCNC powder with primary-like properties and reduced environmental impact. The results can help to exploit the circular economy potential for oxygen transport membranes and serve as an inspiration for other gelation-based synthesis methods of functional ceramic oxides. 1 G. Chen et al., Front. Chem. Sci. Eng. 2020, 14, 405.

Authors : Lei Wang, Niclas Solin
Affiliations : Division of Electronic and Photonic Materials, Biomolecular and Organic Electronics, Department of Physics, Chemistry, and Biology, Linköping University, Linköping, 581 83, Sweden

Resume : Continuous harvesting of electricity from the ambient environment has attracted great attention as a facile approach to green and sustainable energy. We have recently developed hybrid materials between protein nanofibrils (PNFs) and low-cost graphite nanoplatelets (GNPs). These materials can be processed into thin films that can function as thermoelectric materials [1]. The same materials can also be employed for harvesting of electricity from evaporating water. Natural water evaporation-driven electricity generators with active materials from economical and environment-friendly sources are highly sought after. Devices made from hybrid materials between PNFs, and GNPs as active materials can be employed for electricity generation, simply by inserting the device into standing water. The origin of the evaporation induced electricity generation is speculated to be the ionovoltaic effect. Water from the surrounding reservoir diffuses into the active layer, and movement of water towards the top of the device leads to asymmetric ionic movement in turn leading to formation of a voltage between the electrodes at two ends of the device. The device performance can be significantly improved by addition of very small amounts of salts into the active layer. A device, with the active layer composed of a mixture of GNP:PNF:AlCl3, produces a sustained voltage of about 0.46 V, and a current of 89 nA. Moreover, the device can tolerate saline water, with only a modest decrease of voltage when operating in saline water, which provides potential for harvesting electricity from both evaporating sea water and fresh water. [1] Wang, L., et al., Mechanochemical Formation of Protein Nanofibril: Graphene Nanoplatelet Hybrids and Their Thermoelectric Properties. ACS Sustainable Chemistry & Engineering, 2020. 8(47): p. 17368-17378.

Authors : Xingxing Xiao 1, Wenjie Xie 1, Marc Widenmeyer 1, Maximilian Mellin 2, Aamir Iqbal Waidha 3, Oliver Clemens 3, Anke Weidenkaff 1,4
Affiliations : 1 Materials and Resources, Department of Materials and Earth Sciences, Technical University of Darmstadt, 64287 Darmstadt, Germany; 2 Surface Science, Department of Materials and Earth Sciences, Technical University of Darmstadt, 64287 Darmstadt, Germany; 3 Materials Synthesis Group, Institute of Material Science, University of Stuttgart, 70569 Stuttgart, Germany; 4 Fraunhofer Research Institution for Materials Recycling and Resource Strategies IWKS, 63755 Alzenau, Germany

Resume : Driven by the development of sustainable and regenerable energy conversion materials, the mineral perovskite (CaTiO3) is considered to be a potential candidate for large-scale high-temperature applications owing to its abundance, light-weight, non-toxicity, and low cost. A series of compounds with the nominal composition Ca1–xEuxTi0.9Nb0.1O3 (0 ≤ x ≤ 0.4) has been synthesized and studied. The phase purities and crystal structures were evaluated by powder X-ray diffraction (XRD) and subsequent Rietveld analysis. Through X-ray photoelectron spectroscopy (XPS) characterization, the by far dominating valence states of Ti and Nb are confirmed to be +4 and +5 in Ca1 xEuxTi0.9Nb0.1O3 compounds, respectively. Dual substitution by Nb and Eu yields a synergistic effect of improving electrical transport properties and simultaneously suppressing thermal conductivity. The former is mainly attributed to the d–f electron exchange induced by the strong hybridization of Eu 4f, Nb 4d, and Ti 3d orbitals. The latter is mostly attributed to the dominant phonon scattering by the mass fluctuation originating from the large mass contrast of Eu and Ca. The results demonstrate the evolution of insulating CaTiO3 to metallic-like conduction performance with increasing Eu content. Due to the largest power factor and lowest thermal conductivity, the sample Ca0.8Eu0.2Ti0.9Nb0.1O3 exhibits the maximum ZT of up to 0.3 at around 1173 K [1]. [1] X. Xiao et al, Mater. Today Phys. 2022, 26, 100741.

10:30 Coffee break    
Sustainability of Battery Systems : Claudia Felser
Authors : Fabian Jeschull 1, Laura Herrmann 1,2, Elif Kaymakci 2, Thomas Kölbel 2
Affiliations : 1 Karlsruhe Institute of Technology, Institute for Applied Materials – Energy Storage Systems (IAM-ESS), Eggenstein-Leopoldshafen, Germany 2 EnBW Energie Baden-Württemberg

Resume : With the proclaimed target to establish a competitive battery manufacturing value chain in Europe the European Union has embarked on a journey that will have a lasting effect in the industry landscape. Planning and building of gigafactories from established battery producers and newcomers alike were and still are announced all over the continent. It is estimated that by 2030 the total battery production capacity could lie somewhere in the 500 GWh range, creating 3-4 million jobs in the battery industry alongside. To achieve this goal, tremendous amounts of Lithium and other key raw materials, including nickel and cobalt, will be required on the hundred kilo-tonne scale annually. Specifically, for lithium amounts in the range of 100 kt scale will be needed for battery production[1]. Several recent geopolitical events have further highlighted the need of local supplies to provide this growing industry with raw materials. Most lithium today is mined either by extraction from Li-bearing clays, like spodumene (mostly Australia), or from geothermal brines (salt deserts in South America). However, lithium contents in European geothermal deposits, like the Upper Rhine Valley, do in fact exhibit sufficiently high Li contents that extraction is viable. Similarly, there are several locations in Europe, such as Serbia, with Li-rich clay deposits. In order to exploit these deposits economically-feasible extraction techniques are currently explored in joint projects between industry and academia. One example is the EU project “Lithium recovery and battery-grade materials production from European resources” (LiCORNE). In this talk we will provide an overview over different Li-extraction methods and take a deeper dive into the selective Li-extraction using inorganic absorbers[2] and electrochemical approaches[3], respectively. Currently inorganic absorbers based on spinel-type lithium-manganese-oxide compounds show the highest Li-extraction capabilities[1]. During the process the absorbed Li has to be leached out of the material in low pH aqueous media, thus leading to fast degradation of the materials by Mn-leaching as a side reaction. We will discuss how such methods can be integrated into existing infrastructure, specifically geothermal power plants, and outline the challenges and issues related to high concentrations of interfering ions as well as the rapid material degradation under the operating conditions of a geothermal power plant. References [1] European Commission (2020), Batteries Europe – Strategic Research Agenda for Batteries [2] Chitrakar et al., Recovery of lithium from seawater using manganese oxide adsorbent (H1.6Mn1.6O4) derived from Li1.6Mn1.6O4, Ind. Eng. Chem. Res. 40 (2001) 2054–2058 [3] Trócoli, Battistel, La Mantia, Selectivity of a lithium-recovery process based on LiFePO4, Chem. - A Eur. J. 20 (2014) 9888–9891

Authors : Ronja Wagner-Wenz, Jörg Zimmermann, Benjamin Balke, Emanuel Ionescu, Liselotte Schebek und Anke Weidenkaff
Affiliations : Fraunhofer-Einrichtung für Wertstoffkreisläufe und Ressourcenstrategie IWKS Brentanostraße 2a | 63755 Alzenau | Germany

Resume : The need for a holistic approach to treat waste and wastewater streams from the recycling of lithium-ion batteries is becoming ever more critical as the volume of end of life batteries rapidly increases. Both hydro-metallurgical and many direct physical recycling processes generate increasing and significant amounts of wastewater which poses direct threats to human and animal health. However, it provides a considerable opportunity to recover critical elements such as lithium, cobalt, and phosphorus. In particular, lithium is supply-constrained, but is a crucial element in the decarbonization of our society. Lithium not only has considerable solubility but is highly mobile ion and, therefore, can readily escape into the environment from municipal wastewater treatment plants. Indeed, increased lithium concentrations have already been detected in surface water in urban areas. In the present study, wastewater from direct physical lithium-ion battery recycling was investigated. 30 18650 lithium-Ion batteries are opend with electro-hydraulic fragmentation and the solid fraction is removed. The wastewater contains the electrolyte consisting of organic solvent and the conducting salt LiPF6 as well as lithium from the cathode material. It was investigated by using inductively coupled plasma optical emission spectrometry concerning the content of lithium and cobalt, (combustion) ion chromatography concerning the concentration of fluorine and concentration of organics. It was found that the lithium concentration in the studied wastewater is around 200 mg/L. The concentration is similar to that from geothermal plant operations, for which commercial recovery of lithium is already being discussed. The adsorption and electrochemical deposition processes that have been proposed to recover lithium are compared with respect to reusability, energy needed for production and recovery, and chemical needs.

Authors : David Geiß, Oleksandr Dolotko, Michael Knapp, Helmut Ehrenberg
Affiliations : Karlsruher Institut für Technologie (KIT), Institute for Applied Materials - Energy Storage Systems (IAM-ESS), D-76344 Eggenstein-Leopoldshafen, Germany

Resume : Lithium-ion batteries (LIBs) determine our everyday lives as they are used for portable electronics, vehicle propulsions, and other energy storage and distribution applications. The lithium iron phosphate (LFP) batteries have been promoted as one direction of development for cathode chemistries with an increasing amount of production and application year by year. The improvement in performance, production, and cost of LFP batteries makes them attractive for their application in electric vehicle technology. For example, the largest EV producer, Tesla, announced an increasing usage of LFP batteries, which would help to overcome cobalt and nickel supply concerns. Because of the growing use of these batteries, their recycling has become a considerable technological and ecological challenge. The pyrometallurgical recycling method, which is relatively simple in execution and used in industry, suffers from inadvertent losses of valuable elements, high energy consumption rates, and hazardous emissions. On the other hand, hydrometallurgical processes are often energy-efficient and enable to achieve high recovery rates. However, these processes are complex, expensive, and produce highly corrosive liquid waste. Since all of the existing methods have their pros and cons, there is no preferable industrial technology that offers a safe, reliable, environmentally friendly, and at the same time profitable recycling procedure. This work presents a novel approach for lithium extraction from LFP cathodes, using the chemical transformation induced by mechanical energy. The developed method combines the first three steps of conventional battery recycling workflow, namely disassembly, initial processing, and chemical conversion, into a single step, thus reducing the overall cost of the recycling process. In addition, the proposed method avoids using corrosive substances and uses low temperatures to provide an environmentally friendly alternative to currently available recycling technologies. In the developed solvent-free recycling technique, LFP material was mechanochemically treated by Al, who plays the role of a reducing agent. The use of Al reduces the overall cost of the recycling process, as it is already present in the batteries as a cathodic current collector. In order to understand the underlying reaction mechanism and optimize reaction conditions, mechanochemical reactions in the LFP-Al system were performed at different molar ratios of components and various milling times. Chemical transformations which were taking place in the process were evaluated using powder XRD analysis. Optimized conditions for reduction reaction, subsequent water leaching, and a purification step led us to produce pure Li2CO3.

Authors : Aamir Iqbal Waidha a, Amila Salihovic b, Wolfgang Ensinger a, Oliver Clemens b
Affiliations : a Institute of Materials Science, Technical University of Darmstadt, 64283, Darmstadt, Germany; b Institute of materials science, University of Stuttgart, 70569, Stuttgart, Germany

Resume : All solid-state lithium-ion batteries (ASSLIBs) are promising candidates for their use in high energy density applications like electric vehicles (EVs) [1]. With the current global projections of over 130 million EVs on road by 2030 [2], there soon will be a need for ASSLIB waste management. For ASSLIBs, various combinations of solid electrolytes and electrode materials could be imagined, especially with garnet electrolyte Li6.5La3Zr1.5Ta0.5O12 (LLZTO) since it offers high lithium ion conductivity, wide electrochemical window and stability with the electrode materials [3]. Clearly, the use such an electrolyte might shift focus on recovery of elements away from the transition metals of the electrode materials to the recovery of La/Zr/Ta or on maintaining the solid electrolyte close to its original state if possible. In this contribution, we present a green recycling approach based on hydrometallurgy to recycle a full model cell comprising of Li4Ti5O12 (LTO) anode, Li6.5La3Zr1.5Ta0.5O12 (LLZTO) garnet electrolyte and LiNi1/3Mn1/3Co1/3O2 (NMC) cathode. By dissolving the complex mixture of LTO/LLZTO/NMC in an organic acid, we manage to carry out a step wise selective leaching process enabling the separation of the battery components from one other. The phase purity of the recycled components is confirmed via X-ray diffraction and the electrochemical performance is characterized via electrochemical impedance spectroscopy. The process developed has a potential of large scale application for battery recycling, since it is continuous and cost efficient. [1] A. Masias, J. Marcicki, W. A. Paxton, Acs Energy Letters 2021, 6, 621-630. [2] A. Chitre, D. Freake, L. Lander, J. Edge, M. M. Titirici, Batteries & Supercaps 2020, 3, 1126-1136. [3] Q. Liu, Z. Geng, C. Han, Y. Fu, S. Li, Y.-b. He, F. Kang, B. Li, J. Power Sources 2018, 389, 120-134.

Authors : Kerstin Wissel 1,2, Wolfgang Ensinger 1, Oliver Clemens 2
Affiliations : 1 Technische Universität Darmstadt, Institut für Materialwissenschaft, Fachgebiet Materialanalytik, Darmstadt, Germany; 2 Universität Stuttgart, Institut für Materialwissenschaft, Abteilung Chemische Materialsynthese, Stuttgart, Germany

Resume : The vast improvements in battery technologies over the past decades, which have led to an ubiquity of Li-ion batteries in portable electronics in our daily lives, have made the development of sustainable recycling strategies for spent batteries a matter of growing urgency. This is additionally prompted by the increasing growth in the market for electric vehicles and large-scale energy storage. [1, 2] Current research efforts aim, furthermore, at the development of various next-generation battery technologies, of which all-solid-state batteries are considered highly promising due to their improved safety and both higher energy and power density compared to conventional liquid-electrolyte Li-ion batteries. The critical component in such batteries is the solid-state electrolyte. Different material classes including oxides, halides and sulfides are intensively studied with respect their potential application as solid-state electrolyte. Amongst these electrolytes, thiophosphates such as Li3PS4, Li7P3S11, Li10GeP2S12 or Li6PS5X (X=Cl, Br, I) have shown great promises owing to their high ionic conductivities in the range if 10-4 to 10 2 S/cm. [3] While recycling technologies for conventional Li-ion batteries are most often based on pyrometallurgy and hydrometallurgy, a different recycling strategy has to be pursued for thiophosphate-electrolyte-based batteries. This strategy should allow for a separation of the electrode materials from the electrolyte, while it is important to maintain the thiophosphate units in order to recover the electrolyte without chemical degradation. This also leads to improved material recovery efficiencies, since not only the electrode materials, but also the solid electrolyte can be recycled. In this contribution we show that recycling based on direct regeneration of different thiophosphate electrolytes involving the dissolution of the respective electrolyte in organic solvents, followed by the separation of the electrode materials and finally the re-precipitation of the electrolyte is feasible. Recovery of the critical metals of the electrode materials can be achieved via a hydrometallurgical treatment in an additional processing. 1. Harper, G., et al., Recycling lithium-ion batteries from electric vehicles. Nature, 2019. 575(7781): p. 75-86. 2. Thompson, D.L., et al., The importance of design in lithium ion battery recycling – a critical review. Green Chemistry, 2020. 22(22): p. 7585-7603. 3. Zhang, Q., et al., Sulfide-Based Solid-State Electrolytes: Synthesis, Stability, and Potential for All-Solid-State Batteries. 2019. 31(44): p. 1901131.

12:30 Symposium wrap-up & GSA award announcement: Andrea Gassmann    
13:00 Lunch break    

No abstract for this day

No abstract for this day

Symposium organizers
Andrea GASSMANNFraunhofer Research Institution for Materials Recycling and Resource Strategies IWKS

Brentanostraße 2a, 63755 Alzenau / Aschaffenburger Straße 121, 63457 Hanau, Germany

+49 6023 32039 878
Eckhard WEIDNERFraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT

Osterfelder Str. 3, 46047 Oberhausen, Germany

+49 208 8598 1109
Elsa OLIVETTIMIT, Department of Materials Science and engineering

77 Massachusetts Ave., Cambridge, MA, 02139, USA

+1 617 253 0877
Enrico BERNARDOUniversity of Padova, Industrial Engineering Department

Via Marzolo 9, 35131 Padova, Italy

+39 049 8275510