Ali Çoskun
Departementspräsident_in
Departement für Chemie
PER 10 bu. 319
Ch. du Musée 9
1700 Fribourg
Ch. du Musée 9
1700 Fribourg
PER 10, 319
Ordentliche_r Professor_in
Departement für Chemie
PER 10 bu. 319
Ch. du Musée 9
1700 Fribourg
Ch. du Musée 9
1700 Fribourg
PER 10, 319
Forschung und Publikationen
-
Publications
138 Publikationen
Interfacial Stabilization by Prelithiated Trithiocyanuric Acid as an Organic Additive in Sulfide‐Based All‐Solid‐State Lithium Metal Batteries
Angewandte Chemie International Edition (2024) | ArtikelPorous organic polymers with heterocyclic crown ethers for selective lithium-ion capture
Chem (2024) | ArtikelCarbon Dioxide Capture: Current Status and Future Prospects
CHIMIA (2024) | ArtikelOne-Component Nanocomposites Made from Diblock Copolymer Grafted Cellulose Nanocrystals
Biomacromolecules (2024) | ArtikelFluorinated Cyclic Ether Diluent for High-Voltage Lithium Metal Batteries
ACS Energy Letters (2024) | ArtikelDiels–Alder cycloaddition polymerization for porous poly-phenylenes with exceptional gas uptake properties
Chemical Communications (2024) | Artikel -
Forschungsprojekte
Pushing All Solid-State Batteries to Their Full Potential - Interface Engineering Guided by Advanced Diagnostics for High Performance Scalable Batteries
Status: LaufendBeginn 01.01.2022 Ende 31.12.2025 Finanzierung SNF Projektblatt öffnen All-solid-state batteries (ASSBs) are receiving considerable attention from the battery community mainly due to their capability of drastically enhancing the safety and increasing the energy density by enabling the use of metallic anodes compared to the existing lithium-ion batteries (LIBs). Despite these conspicuous advantages, ASSBs are still at research stage, leaving a substantial gap before practical adoption. Main challenge with ASSBs lies in their inferior rate performance and long-term cyclability, both primarily originating from the destabilization of electrode-electrolyte interface and the creation and propagation of mechanical stress. Energy density should also be carefully evaluated, and a well-known approach to compensate for it, is to use lithium (Li) metal anodes. Whereas individual state-of-the-art solid electrolytes offer high ionic conductivities enough for cell operation, once assembled, the cell performance is mostly not as good as expected, indicating the importance and challenge of particle-to-particle interface. Once electrolyte and active material particles are in contact, (electro-) chemical reactions take place leading to a space-charge effect build a lithium ion depleted layer, imposing a barrier for Li ion transport. The complexity of the problem necessitates an interdisciplinary research approach to tackle inferior cell performance of ASSBs and establish a fundamental understanding on the interface and morphology problems. In this direction, here, we propose a systematic strategy targeting the interface engineering of sulfide-based solid electrolytes (SEs), high voltage Ni-rich layered cathode active materials (CAMs) and Li-metal anodes. The choice of sulfide SEs arise from the consensus that sulfide SEs are suitable and a unique material for good interface contact due to their ductile mechanical properties and ability to be cold pressed. Our synergistic effort involves in-depth understanding of interfacial reactions guided by advanced diagnostics and machine-learning driven atomic scale modeling to achieve both thermodynamic and chemical stability through (1) Coskun group@UniFr, AC: the design and synthesis of elastic polymeric binders and surface stabilization of sulfide electrolytes and membrane coating on the Li-metal surface. (2) El Kazzi group@PSI, MEK: Surface and bulk operando analysis and characterization of electrochemical cells and the identification of interfacial reaction byproducts and intermediates (3) Ceriotti group@EPFL, MC: Structure, stability and reactivity of SE from machine-learning accelerated molecular simulations and (4) Choi group@SNU, JWC: the advanced electrochemical characterization of battery electrodes, optimization of cell conditions and testing battery electrodes at industrially relevant cell conditions. Accordingly, the specific five work packages (WPs) for the project involve (1) the development of solution-processed electrode coating using elastic binders and stabilization of SEs (AC) guided by machine learning (MC), (2) optimization of Ni-rich layered cathode active materials (JWC & MEK), (3) protection and interface optimization of Li-free anodes (AC, JWC), (4) characterization of electrodes using operando analytic tools (MEK, MC) and finally (5) demonstration of 2 Ah prototype cell (JWC, AC, MEK). Critically, the development of individual electrode components, machine learning and operando analyses will be intimately linked to identify interfacial issues and the solutions. In particular, the design for polymeric binders and electrolyte themselves as well as their interaction with active electrode materials will enable breakthroughs for the development of high performance ASSBs comparable to that of current LIBs. 600 MHz Nuclear Magnetic Resonance Spectrometer
Status: AbgeschlossenBeginn 01.03.2021 Ende 28.02.2022 Finanzierung SNF Projektblatt öffnen The specific aim of this proposal is to obtain funding for a 600 MHz Nuclear Magnetic Resonance (NMR) Spectrometer. The proposed AVNEO console and accessories, with 600 MHz superconducting magnet, has the capability for conducting state-of-the-art NMR experiments on liquid and solid-state samples. As for the liquid samples, the system will be equipped with prodigy N2-cooled cryoprobe to provide the researchers with very high-resolution NMR data, which was previously inaccessible. Moreover, as a solid probe, the system will be equipped with a “very fast” 1.3 mm solid-probe capable of spinning up to 67 KHz, which will provide extremely high resolution for the analysis of solid samples. The proposed 600 MHz NMR spectrometer with accessories will be equipped for conducting modern, high-resolution NMR experiments for the characterization of molecules and materials by researchers in the various subdisciplines of chemistry on a routine basis. The justification for this application rests first on the need for modern NMR instrumentation to meet the increased demand for the high-resolution NMR analysis in our department as well as in the university. As detailed in the research plan section, nine faculty will be the primary users on the 600 MHz spectrometer. Three members (Coskun, Fromm, Zobi) working on solid-state organic and inorganic materials, require modern 600 MHz capability to perform high-resolution solid-state NMR experiments. Two-dimensional NMR experiments for structural characterization for porous materials, 15N NMR for nitrogen speciation of porous materials for applications such as CO2 capture and conversion, 6Li and 7Li NMR for understanding the Li-ion transport in electrode materials and polymer electrolytes for Li-ion batteries. Weder group will develop a set-up for in-situ NMR analysis of photo-responsive supramolecular assemblies, which require the new 600 MHz NMR instrument. Bochet group will use the new NMR set-up equipped with cryoprobe to analyze complex organic molecules isolated from plant extracts with medicinal properties (generally isolated in few mg scale). In addition, isotopic labelling experiments to understand reaction mechanisms will be also performed. Kilbinger group will benefit from the cryoprobe extensively to perform 15N NMR experiments to prove the helical nature of the polymers. Moreover, increased 31P-NMR sensitivity through new cryoprobe will also allow for a more precise analysis of the new selective phosphorous reagents for the living polymerization of amino acids. Fink group will use high resolution NMR analysis extensively to determine free/surface bound PEG chains on the Au nanoparticle surface and subsequently investigate the conformation of bovine serum albumin proteins interacting with these particles, both projects will take advantage of the increased sensitivity of cryoprobe and 600 MHz NMR. Katayev group, Eccellenza Professor who will join the chemistry department in January 2021, will extensively use the high-resolution solid-state probe for the characterization of solid-phase functional group transfer reagents. Lastly, Salentinig group, with a strong expertise in food chemistry, will probe the digestion of acyl-glycerols and phospholipids via in-situ NMR. In addition, the in-situ NMR analysis of dynamic self-assembly of lipid-peptide or protein nanostructures will provide valuable information on the digestion pathways and interactions between molecules. In this context, the new 600 MHz NMR instrument will open up new research areas that were totally impossible so far, in particular state-of-the-art multidimensional NMR experiments as well as solid-state investigations. Thus, it is necessary to obtain 600 MHz instrument to meet the research and NMR time needs of the faculty. The present proposal is submitted to remedy aforementioned fundamental problems Designing Functional Polymeric Materials for High Capacity Lithium–Sulfur Batteries
Status: AbgeschlossenBeginn 01.02.2020 Ende 31.03.2024 Finanzierung SNF Projektblatt öffnen Environmental problems originating from anthropogenic CO2 emissions from large point sources, such as coal-power plants, promoted the development of eco-friendly renewable energy technologies. However, their intermittent nature necessitates the simultaneous development of high energy density, low-cost energy storage systems. The lithium-sulfur (Li-S) battery is among the most promising candidates as a next generation battery due to its exceptional theoretical gravimetric capacity of 1600 mAh g-1 and an energy density of 2600 Wh kg-1, which is 2-4 times higher compared to the conventional LIBs. Although the research on the Li-S batteries have been going for almost two decades, there are still fundamental problems yet to be tackled. The problems include (1) insulating nature of elemental sulfur, sulfur reduction intermediates and Li2S, (2) dendrite formation on the Li-metal anode surface, (3) volume expansion during lithiation up 80% and (4) the dissolution of Li-polysulfides (Li-PS) in the electrolyte, which serves as a redox shuttle leading to a severe capacity decay. Among these issues, the most critical one is the dissolution of Li-PS in the electrolyte and its diffusion as well as the side reactions with Li-metal anode and the electrolyte. Li-S battery can be considered as a liquid battery due to the dissolution of sulfur following electrochemical reduction, in which the electrolyte is acting as a “catholyte”. While the Li-PS shuttling can be managed at low sulfur loadings, it is more difficult to do so at high sulfur loadings, which is essentially required to realize full potential of Li-S battery. The strategies to mitigate Li-PS shuttling include the trapping in the electrode, blocking from interlayers and introducing catalysts capable of converting Li-PS into Li2S. While these approaches led to improved capacity within the first few cycles, subsequent fast capacity decay was also observed. In this project, in order to address these above mentioned challenges and also to establish fundamental understanding on the interaction of Li-PS with electrode components, we are proposing to develop dual targeting approach using smart polymeric materials to mitigate Li-PS shuttling. Our approach is three fold; (1) the development of defect engineered polymers via in-situ sulfur mediated polymerization, in which the defects will constitute either soft organic cations to interact with sulfur anion or glycol chains/crown ethers to target Li ions. These defects will allow us to confine the Li-PS within the active material. Importantly, the in-situ synthesized polymers will have high conductivity, thus facilitating efficient conversion of Li-PS into the insoluble Li2S due to the proximity of Li-PS to the conducting backbone. (2) We will explore catalytically active coating materials on the separator, which will act as a “smart filter” to recognize Li-PS and readily convert to insoluble Li2S. (3) Finally, we will integrate first two approaches to realize dual-capture mechanism for Li-PS at the smart polymer cathode as well as by interlayer blocking in order to realize the high performance and long life Li-S battery. For every part of this project, we will carry out detailed in-situ and ex-situ analysis to understand the operating mechanism and probe the interaction of Li-PS. These findings will allow us to establish fundamental understating on the mechanism and thus establish design principles for further development of Li-S battery components. Single Crystal Diffraction: Dual System
Status: AbgeschlossenBeginn 01.09.2019 Ende 31.08.2020 Finanzierung SNF Projektblatt öffnen Since the first installation of single crystal diffraction systems at the Chemistry Department of the University of Fribourg by the Fromm group in 2006, research at the Chemistry Department has changed significantly. Six out of eight permanent professors retired and new colleagues joined the department with new research focus. For example, the Coskun group is developing porous metal-organic frameworks, MOFs, which contain organic ligands and a large number of guest molecules in the pores as well as shape-persistent organic cages. The group relies thus on single crystal structure determination for their investigation and understanding of structure-property-relationships. Prof. Fabio Zobi is interested in medicinal chemistry and investigates metal complexes involving vitamin B12, typically leading to small single crystals with large organic ligands. The Fromm group’s research has evolved towards the bioinorganic chemistry of silver, and includes the study of peptides, small proteins as well as their coordination to silver ions. Among other users in the department, Dr. Albert Ruggi is developing catalysts for the photosplit-ting of water based on coordination compounds with large organic ligands. The group of Andreas Kilbinger uses metal-organic compounds as catalysts for polymerization reactions, which he characterizes via single crystal diffraction. We apply now for a unique combination of dual beam single crystal diffraction system with Pilatus detector, which covers on one hand the additional need, on the other allows to measure also the challenging tiny crystals of compounds containing large organic molecules. The new set-up will include X-ray sources, which have a much higher brilliance than the currently used Mo-sources in our diffraction systems, while at the same time having a lower power consumption. This dual beam line set-up will further allow to rapidly collect data on the same single crystal with different X-ray wave lengths without having to change the machine, which will be a significant advantage particularly for sensitive and easily degrading samples. A further advantage is the 4-circle goniometer, which will allow us to collect redundant data at different positions in chi, while the detector is noise-free and can hence record also very weak reflections next to strong ones. Such a detector will be extremely useful for tackling problems like twinning, superstructures or modulated structures, which can easily occur in MOF-type com-pounds and peptide based materials. Furthermore, the 20 bit dynamics of the detector will allow a short readout time of 8 milliseconds, while our current detectors (IPDS) require 90 seconds for readout. The proposed system will thus fulfill the requirements of the new colleagues and of new research projects in the department as well as in the university. Catalytic Polymeric Membranes for the Simultaneous Capture and Conversion of CO2 from Various Emission Sources
Status: AbgeschlossenBeginn 01.12.2017 Ende 28.02.2022 Finanzierung SNF Projektblatt öffnen Carbon dioxide emissions into the atmosphere accounts for the majority of environmental challenges and its global impact in the form of climate change, ocean acidification is well-documented. In this direction, absorption with amine solutions, adsorption with porous solids and cryogenic separation methods have been investigated conventionally, however, they possess major drawbacks such as high-energy penalty, environmental issues and complex operation procedures. Because of their fundamental engineering and economic advantages over competing separation technologies, membrane operations are now being explored for CO2 capture from power plants. However, the low CO2 selectivity of membrane systems is a major challenge yet to be tackled. Metal-organic frameworks (MOFs) and porous organic polymers (POPs) are emerging solid-sorbents for CO2 capture and their pore characteristics can be easily tailored by the combinational choice of building blocks. Accordingly, the incorporation of MOFs and POPs as fillers into the polymeric membranes could lead to the development of highly selective membrane systems with high gas selectivity over Knudsen diffusion. One of the great challenges for these membrane systems is, however, to realize simultaneous capture and conversion to not only use CO2 as a sustainable C1 building block, but also create an incentive for the further development of costly capture technologies. The research on these so-called “membrane reactors”, however, have been mostly limited to inorganic membranes, which are rather costly. Our main motivation in this proposal is to develop new catalytically active metal impregnated MOFs, MOF-derived core-shell porous carbons and metal impregnated POPs for the conversion of CO2 into value added products such as methanol from various emission sources at relatively low CO2 partial pressures and temperatures, which is highly important in the context of steam economy. The benchmark catalyst for the direct hydrogenation of CO2 is the Cu/ZnO/Al2O3 system. This catalyst operates at high pressures and temperatures through a widely accepted bifunctional mechanism, that is the hydrogen spillover on Cu nanoparticles and CO2 activation on ZnO to form CH3OH. However, the sintering of Cu nanoparticles and high pressures of CO2 and H2 were found to rapidly decrease the activity of the catalyst. We propose that highly CO2-philic porous materials in the form of MOFs and POPs can pre-concentrate CO2 even at very low pressures. The functionalization of pores with carbenes and amines, which can act as anchors for the chemical activation of the CO2 along with the presence of metal nanoparticles (MNPs) such as Cu, Pd for hydrogen spillover could transform these porous sorbents into efficient heterogeneous catalysts for the conversion of CO2 into MeOH. Importantly, by tuning (1) textural properties, (2) CO2-philicity and (3) catalyst loading of these porous sorbents, we will be able to obtain valuable fundamental insights for the conversion mechanism. Subsequent incorporation of these heterogeneous catalysts as fillers into the polymeric membranes will enable the realization of catalytic composite membranes for the continuous capture and conversion of CO2 at low temperature and pressures. More significantly, the ability of membranes to remove products from equilibrium reactions will further contribute the catalytic performance of these systems. Successful realization of this project will not only create economical value to the captured CO2, thus decreasing the cost of capture process, but it will also help to curb ever-increasing CO2 emissions.