423 research outputs found

    Spintronic Operations Driven by Terahertz Electromagnetic Pulses

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    Spintronic devices, supplementing and surpassing charge-based electronics by including the electron spin, have recently begun to reach the market. Information carriers such as electrons (in field-effect transistors) and photons (in optical fibers) have already reached the terahertz range (THz, 10^12 Hz). To make the electron spin compatible and competitive, spintronic operations need to be pushed to THz frequencies. So far, is is unclear whether fundamental spintronic effects such as spin accumulation or spin-orbit torque can be transferred to THz frequencies. In this respect, it is also important to note that the THz range coincides with many fundamental excitations, for instance phonons, magnons, and the relaxation of electronic currents. Strong THz electromagnetic pulses can be used to study such fundamental excitations, making use of both the electric and magnetic fields of the electromagnetic pulse. In this thesis, strong THz electromagnetic pulses are applied to spintronic thinfilm stacks to drive charge and spin currents, apply torque and manipulate magnetic order. A short optical probe pulse or a resistance probe interrogate the transient magnetic response. First, a measurement strategy is developed to simultaneously detect all components of the vector magnetization of thin film magnets in optical transmission probe experiments at normal incidence, requiring only a variation in the initial probe polarization. To this end, the magnetic circular and linear birefringence (MCB, MLB) effects are measured simultaneously and a calibration strategy for the often neglected MLB effect is presented. Second, using this detection scheme, we study the THz frequency operation of spintronic effects in ferromagnetic(FM)/non-magnetic (NM) heavy metal stacks. We find signatures of THz spin accumulation at the FM/NM interface. The spins injected into a ferromagnet relax within ∌ 100 fs, in line with electron-spin equilibration times measured by ultrafast optically induced demagnetization. Indications of the field-like spin-orbit torque (FL-SOT) are found. Third, an effective method to modulate the relative THz electric and magnetic field amplitudes in thin film samples is presented, enabling one to disentangle effects driven by the electric or the magnetic component of the THz electromagnetic pulse. A nearperfect conductor (THz mirror) quenches the THz electric field in a region close to the mirror, while doubling the THz magnetic field. Measurements with a ferromagnetic thin film confirmed a THz magnetic field increase of 1.97 ± 0.06 and a suppression of the THz electric field in the sample. Finally, we utilize the electric-field suppression effect close to metals to optically gate the THz electric field driven resistance modulation of an antiferromagnet (AFM) grown on a semiconducting substrate. An optically induced transient substrate conductance depletes the THz electric field in the AFM layer, while not perturbing the AFM magnetic order directly. A simple model of parallel conductances is presented, confirming the experimental observations. In conclusion, this thesis is an important contribution to push fundamental spintronic effects such as spin accumulation and spin-orbit torque to the THz range. The developed methodologies are helpful to advance nonlinear THz spectroscopy of magnetic materials.Da die ersten auf spintronischen Prinzipien erbauten Speicher den Markt erreichen und gleichzeitig InformationstrĂ€ger wie Elektronen (in Feldeffekttransistoren) und Photonen (in Glasfaserkabeln) in den Terahertz-Frequenzbereich (THz, 10^12 Hz) vordringen, stellt sich die Frage, ob die Spintronik, welche die Elektronik um den Elektronenspin erweitert, mit solch hohen Frequenzen kompatibel ist. Gleichzeitig ist der THz-Frequenzbereich, welcher elementare Anregungen wie Phononen und Magnonen enthĂ€lt, auch fur die Grundlagenforschung interessant. Um diese Anregungen zu untersuchen bieten sich elektromagnetische THz-Pulse mit hohen FeldstĂ€rken an, denn sie können direkt an elektrische und magnetische Resonanzen koppeln. Diese Arbeit untersucht mit THz-Lichtpulsen, die in spintronischen DĂŒnnfilmproben Spin- und Ladungsströme induzieren, ob elementare spintronische Effekte, wie die Spin-Akkumulation oder das Spin-Bahn-Drehmoment, auch bei THz-Frequenzen aktiv sind. Die magnetische Antwort wird mit kurzen optischen Pulsen oder mittels elektrischer Messungen zeitaufgelöst abgefragt. Die spintronischen Effekte werden in ferromagnetischen (FM)/nichtmagnetischen (NM) Dunnfilm-Metallmultilagen untersucht, wobei zuerst eine Messmethode erarbeitet š wird, um alle rĂ€umlichen Anteile der Probenmagnetisierung gleichzeitig zu bestimmen. Hierzu werden die magnetische zirkulĂ€re Doppelbrechung (MCB) und die, oft vernachlĂ€ssigte, magnetische lineare Doppelbrechung (MLB), welche der Abfragepuls beim Durchdringen der Probe entlang der Probennormale erfĂ€hrt, gleichzeitig bestimmt. Ein besonderes Augenmerk liegt auf der Normierung des MLB-Signals. Mithilfe dieser neuartigen Messmethode werden Indizien fur eine THz Spin-Akkumulation und das feldartige Spin- š Bahn-Drehmoment (FL-SOT) an der FM/NM GrenzflĂ€che gefunden, welche auf einen Spinaustausch zwischen dem nichtmagnetischen Schwermetall und dem FM zuruckgefĂŒhrt š werden. Die in den FM eindringenden Spins relaxieren auf einer Zeitskala von ∌ 100 fs, was mit Ergebnissen aus ultraschnellen optischen Demagnetisierungsstudien ubereinstimmt. š ZusĂ€tzlich wird die nichtlineare THz-Spektroskopie dahingehend erweitert, vom elektrischen oder magnetischen THz-Feld getriebene Signale unterscheiden zu können, indem die relativen StĂ€rken der elektromagnetischen Felder im Inneren einer Dunnfilmprobe beeinflusst werden. Hierbei unterdruckt ein elektrisch leitender THz Spiegel das THz elektrische Feld in der Probe, wĂ€hrend das THz magnetische Feld um einen Faktor 1.97±0.06 verstĂ€rkt wird. Diese Unterdruckung des THz elektrischen Feldes in der NĂ€he eines Leiters wird genutzt, um die vom THz elektrischen Feld getriebene Widerstandsmodulation in einem, auf einem (optisch angeregten) halbleitenden Substrat gewachsenen, Antiferromagneten (AFM) zu steuern. Dabei wird die Wirkung des THz elektrischen Feldes im AFM unterdruckt ohne den magnetischen Zustand des AFM zu stören. Ein einfaches Modell stutzt die Interpretation der Beobachtungen. Zusammenfassend leistet diese Arbeit einen wichtigen Beitrag, um spintronische Effekte wie die Spin-Akkumulation und das Spin-Bahn-Drehmoment im THz-Frequenzbereich zu etablieren und erweitert zusĂ€tzlich die Möglichkeiten der nichtlinearen THz-Spektroskopie an Magneten

    Jornadas Nacionales de InvestigaciĂłn en Ciberseguridad: actas de las VIII Jornadas Nacionales de InvestigaciĂłn en ciberseguridad: Vigo, 21 a 23 de junio de 2023

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    Jornadas Nacionales de InvestigaciĂłn en Ciberseguridad (8ÂȘ. 2023. Vigo)atlanTTicAMTEGA: Axencia para a modernizaciĂłn tecnolĂłxica de GaliciaINCIBE: Instituto Nacional de Cibersegurida

    Cytosolic sphingolipids and lysosome reactivation in neurodegenerative diseases

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    Glucosylceramide (GlcCer) is one of the simplest glycosphingolipids (GSLs) synthesized at the cytosolic face of cis-Golgi and translocated to the plasma membrane and organelle lumen. The glucocerebrosidases degrade GlcCer in the cytosol and lysosome. GlcCer has been suggested to be an activator of vATPase, leading to proper endolysosomal acidification. Lysosomal storage disorders (LSDs), are caused by the defective activity of lysosomal proteins, including the accumulation of unmetabolized substrates. The accumulation of substrates is thought to initiate a complex pathogenic cascade that is responsible for disease pathology, Chapter1 firstly summarizes the synthesis of glycolipids and their transportation to lysosomes for degradation and recycling back into the Golgi; however, in the case of LSDs, this is defective. Furthermore, it discusses how impaired endolysosomal acidification and lipid imbalance can be linked and common to LSDs. Chapter 2 depicts decreased lysosomal acidification and increased size in Gaucher/Parkinson's and various other LSD patient fibroblasts. Then it studies whether these defects can be corrected by altering cytosolic GlcCer. Chapter 3 shows decreased MCS between the ER/lysosomes, increased MCS between lysosomes/ the mitochondria in NPCD, and investigates if increasing cytosolic GlcCer can correct these defects. Furthermore, it tests a bank of putative cholesterol transport inhibitors in NPCD based on reports of high cholesterol levels contributing to mitochondrial dysfunction. A chemoproteomics approach has found several proteins that bind ceramides and glycolipids. Chapter 4 sought to confirm the interactions between ceramides/glycolipids and their binding proteins using molecular modelling and gene expression analysis.Schlumberger Foundation faculty for the future

    Identification and Quantification of Sperm Head Plasma Membrane Proteins Associated with Male Fertility

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    The major objective was to characterize proteins in head plasma membrane (HPM) of sperm from animals of two species to identify species’ and proteins’ differences related to fertility. HPM’s sodium/potassium-ATPase (Na+⁄K+-ATPase) acts as a receptor, inducing capacitation when bound by its hormone ouabain. Na+/K+-ATPase is an α/ÎČ dimer, each with several isoforms (α1, α2, α3, α4, ÎČ1, ÎČ2, ÎČ3) whose exact relationship to in vivo fertility and capacitation is unknown. In the first study, specific Na+/K+-ATPase isoforms in sperm HPM of boars with different Direct Boar Effects (DBEs) for farrowing rate (FR) and litter size, differed between low and high fertility boars (LF, HF, n=6/each; DBE-based). SDS-PAGE and immunoblotting detected more α3 (P or <100; Semex evaluated). Statistical analysis identified 67 differential abundance proteins (DAPs) between HF and LF (n=3/group; P<0.05), which associated by meta-analysis to BFI. Gene ontology assigned 48 up-regulated HF proteins to sperm fertilization, and 19 down-regulated to catalytic and transporter activity. 38-up-regulated DAPs (HF and LF, n=16) correlated positively (r2=0.29 to 0.66; P≀0.05) and 6 down-regulated negatively (r2=0.26 to 0.44; P≀0.05) to BFI. The third study characterized HPM Na+/K+-ATPase in 16 bulls with differing BFI but similar sperm motility kinetics. Normalized Spectral Abundance Factor (NSAF) of α1 was significantly greater in 8 higher- vs 8 lower-fertility bulls. Linear regression positively correlated BFI to NSAF of α1 and ÎČ2 (r2=0.42 and 0.47, respectively; P≀0.05), and negatively correlated BFI to α4 (r2=0.37; P≀0.05), confirmed by bioinformatics predictions. These results suggest involvement of α1 and ÎČ2 in fertilization as potential fertility biomarkers. Overall, specific Na+/K+-ATPase isoforms identified in boar and bull sperm HPM significantly correlate with in vivo fertility, as do other specific bull HPM proteins. Elucidating potential fertility biomarkers in two species improves understanding of key proteins and their roles in various, complex mechanisms that enable successful sperm fertilization

    The Fifteenth Marcel Grossmann Meeting

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    The three volumes of the proceedings of MG15 give a broad view of all aspects of gravitational physics and astrophysics, from mathematical issues to recent observations and experiments. The scientific program of the meeting included 40 morning plenary talks over 6 days, 5 evening popular talks and nearly 100 parallel sessions on 71 topics spread over 4 afternoons. These proceedings are a representative sample of the very many oral and poster presentations made at the meeting.Part A contains plenary and review articles and the contributions from some parallel sessions, while Parts B and C consist of those from the remaining parallel sessions. The contents range from the mathematical foundations of classical and quantum gravitational theories including recent developments in string theory, to precision tests of general relativity including progress towards the detection of gravitational waves, and from supernova cosmology to relativistic astrophysics, including topics such as gamma ray bursts, black hole physics both in our galaxy and in active galactic nuclei in other galaxies, and neutron star, pulsar and white dwarf astrophysics. Parallel sessions touch on dark matter, neutrinos, X-ray sources, astrophysical black holes, neutron stars, white dwarfs, binary systems, radiative transfer, accretion disks, quasars, gamma ray bursts, supernovas, alternative gravitational theories, perturbations of collapsed objects, analog models, black hole thermodynamics, numerical relativity, gravitational lensing, large scale structure, observational cosmology, early universe models and cosmic microwave background anisotropies, inhomogeneous cosmology, inflation, global structure, singularities, chaos, Einstein-Maxwell systems, wormholes, exact solutions of Einstein's equations, gravitational waves, gravitational wave detectors and data analysis, precision gravitational measurements, quantum gravity and loop quantum gravity, quantum cosmology, strings and branes, self-gravitating systems, gamma ray astronomy, cosmic rays and the history of general relativity

    Solid phase microextraction: a versatile technique for lipid analysis

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    Extensive multidisciplinary research and improvements to instrumentation and workflows are continuously enabling new insights into the role of lipids in health and disease. As with other metabolites, the accurate analysis of lipids in biological samples requires robust and efficient analytical methodologies that enable reliable quantitation. Since its introduction in the 1990s, solid phase microextraction (SPME) has proven well-suited for numerous applications in various scientific fields (environmental chemistry, forensics, clinical, and others) thanks to its many advantages and compatibility with different instruments. Despite being present on the bioanalytical landscape for a decade, SPME research aimed at lipids remains unusual and often qualitative. This thesis documents the development of three approaches for the analysis of lipids based on SPME coupled with different instrumental platforms, namely: liquid chromatography-mass spectrometry (LC-MS) (Chapter 2); mass spectrometry (MS) (Chapter 3), and Raman spectroscopy (Chapter 4). Chapter 2 details the development of an LC-MS platform, the analysis of sampling parameters crucial to SPME, the steps taken to determine the total concentration of glycerophospholipids in human plasma and strategies for the analysis of the free concentration of model lipids. The reversed-phase liquid chromatography (RPLC) method was applied to analyze exogenous lipids in human blood plasma. It was validated with respect to instrumental linearity and dynamic linear range, inter– and intra–day accuracy and precision, and limits of quantitation. The SPME method was optimized by investigating several crucial parameters, including coating chemistry, extraction time, and desorption conditions. This proposed SPME-RPLC-MS/MS platform was utilized to construct matrix-matched calibration curves for the total concentration in four plasma lots, including NISTℱ SRM¼ 1950 human blood plasma. Moreover, SPME probes were used to quantitate endogenous lipid compounds present in the NISTℱ SRM¼ 1950 plasma using a standard addition approach, which resulted in good agreement with previous studies on this sample. Furthermore, the lipidome of NISTℱ SRM¼ 1950 was qualitatively assessed via an untargeted approach using high-resolution mass spectrometry. The lipidome obtained using SPME, an unconventional technique, is in good agreement with previous studies. This chapter also proposes a simple approach for the calibration of free concentration of lipid metabolites using SPME devices and external calibration curves free of binding matrix components. To this end, this section evaluated a ‘standard generating vial’ to produce and maintain a stable free concentration in aqueous media. The standard generating vial employs a lipid laden PDMS film coated onto a carbon mesh acting as an analyte reservoir. These vials were evaluated regarding their equilibration time, short-term stability, and linearity attained at various spiking concentrations. Finally, this chapter briefly explores the binding between human serum albumin and two long-chain fatty acids using experimental and in silico approaches. This study took advantage of SPME’s extraction mechanism from the pool of unbound analytes; thus, the free concentration of fatty acids was measured with SPME fibres and used to construct Scatchard plots to estimate the binding affinities with human serum albumin. The mass uptake of fatty acids by the SPME probes under different kinetic conditions (static extraction, agitated extraction, and agitated extraction with a binding matrix component) was validated by mathematical modelling using the COMSOL Multiphysics¼ software package. In Chapter 3, solid-phase microextraction is directly coupled to mass spectrometry (SPME–MS) for the analysis of glycerophospholipids in plasma while bypassing chromatographic separation. Coated blade spray (CBS), the initial SPME–MS technology surveyed, is a sword-like device that provides the sampling/pre-concentration capabilities of SPME devices while also serving as an ion source requiring minimal additional instrumentation. While lipid detection was easily achieved through the proper selection of modifiers, CBS’s geometry and ambient nature posed a challenge regarding lipids' fast and reproducible desorption. As an alternative, the flow-isolated desorption chamber of an open microfluidic interface (MOI)—the second SPME–MS technology assessed—was employed to study the desorption of lipids with virtually no evaporation. Substantial ionization/absolute matrix effects were detected for SPME–MS technologies, mirroring the phenomena observed in other MS-based lipid analyses. Chapter 4 presents a simple, proof-of-concept approach for the on-fibre detection of unsaturated lipids based on the direct coupling of SPME probes and Raman spectroscopy. The SPME protocol was optimized by investigating various parameters influencing extraction efficiency, including coating chemistry, extraction time, extraction temperature, and washing solvent. Our findings show that the developed SPME–Raman method is suitable for detecting lipids enriched on the coating. A clear dependence is observed between the number of double bonds and the ratio of the Raman bands at 1655/1445 cm–1. Although additional studies are needed to establish how these double bonds contribute to the observed Raman bands, the proposed platform has great potential for fast profiling applications

    Fine-grained Haptics: Sensing and Actuating Haptic Primary Colours (force, vibration, and temperature)

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    This thesis discusses the development of a multimodal, fine-grained visual-haptic system for teleoperation and robotic applications. This system is primarily composed of two complementary components: an input device known as the HaptiTemp sensor (combines “Haptics” and “Temperature”), which is a novel thermosensitive GelSight-like sensor, and an output device, an untethered multimodal finegrained haptic glove. The HaptiTemp sensor is a visuotactile sensor that can sense haptic primary colours known as force, vibration, and temperature. It has novel switchable UV markers that can be made visible using UV LEDs. The switchable markers feature is a real novelty of the HaptiTemp because it can be used in the analysis of tactile information from gel deformation without impairing the ability to classify or recognise images. The use of switchable markers in the HaptiTemp sensor is the solution to the trade-off between marker density and capturing high-resolution images using one sensor. The HaptiTemp sensor can measure vibrations by counting the number of blobs or pulses detected per unit time using a blob detection algorithm. For the first time, temperature detection was incorporated into a GelSight-like sensor, making the HaptiTemp sensor a haptic primary colours sensor. The HaptiTemp sensor can also do rapid temperature sensing with a 643 ms response time for the 31°C to 50°C temperature range. This fast temperature response of the HaptiTemp sensor is comparable to the withdrawal reflex response in humans. This is the first time a sensor can trigger a sensory impulse that can mimic a human reflex in the robotic community. The HaptiTemp sensor can also do simultaneous temperature sensing and image classification using a machine vision camera—the OpenMV Cam H7 Plus. This capability of simultaneous sensing and image classification has not been reported or demonstrated by any tactile sensor. The HaptiTemp sensor can be used in teleoperation because it can communicate or transmit tactile analysis and image classification results using wireless communication. The HaptiTemp sensor is the closest thing to the human skin in tactile sensing, tactile pattern recognition, and rapid temperature response. In order to feel what the HaptiTemp sensor is touching from a distance, a corresponding output device, an untethered multimodal haptic hand wearable, is developed to actuate the haptic primary colours sensed by the HaptiTemp sensor. This wearable can communicate wirelessly and has fine-grained cutaneous feedback to feel the edges or surfaces of the tactile images captured by the HaptiTemp sensor. This untethered multimodal haptic hand wearable has gradient kinesthetic force feedback that can restrict finger movements based on the force estimated by the HaptiTemp sensor. A retractable string from an ID badge holder equipped with miniservos that control the stiffness of the wire is attached to each fingertip to restrict finger movements. Vibrations detected by the HaptiTemp sensor can be actuated by the tapping motion of the tactile pins or by a buzzing minivibration motor. There is also a tiny annular Peltier device, or ThermoElectric Generator (TEG), with a mini-vibration motor, forming thermo-vibro feedback in the palm area that can be activated by a ‘hot’ or ‘cold’ signal from the HaptiTemp sensor. The haptic primary colours can also be embedded in a VR environment that can be actuated by the multimodal hand wearable. A VR application was developed to demonstrate rapid tactile actuation of edges, allowing the user to feel the contours of virtual objects. Collision detection scripts were embedded to activate the corresponding actuator in the multimodal haptic hand wearable whenever the tactile matrix simulator or hand avatar in VR collides with a virtual object. The TEG also gets warm or cold depending on the virtual object the participant has touched. Tests were conducted to explore virtual objects in 2D and 3D environments using Leap Motion control and a VR headset (Oculus Quest 2). Moreover, a fine-grained cutaneous feedback was developed to feel the edges or surfaces of a tactile image, such as the tactile images captured by the HaptiTemp sensor, or actuate tactile patterns in 2D or 3D virtual objects. The prototype is like an exoskeleton glove with 16 tactile actuators (tactors) on each fingertip, 80 tactile pins in total, made from commercially available P20 Braille cells. Each tactor can be controlled individually to enable the user to feel the edges or surfaces of images, such as the high-resolution tactile images captured by the HaptiTemp sensor. This hand wearable can be used to enhance the immersive experience in a virtual reality environment. The tactors can be actuated in a tapping manner, creating a distinct form of vibration feedback as compared to the buzzing vibration produced by a mini-vibration motor. The tactile pin height can also be varied, creating a gradient of pressure on the fingertip. Finally, the integration of the high-resolution HaptiTemp sensor, and the untethered multimodal, fine-grained haptic hand wearable is presented, forming a visuotactile system for sensing and actuating haptic primary colours. Force, vibration, and temperature sensing tests with corresponding force, vibration, and temperature actuating tests have demonstrated a unified visual-haptic system. Aside from sensing and actuating haptic primary colours, touching the edges or surfaces of the tactile images captured by the HaptiTemp sensor was carried out using the fine-grained cutaneous feedback of the haptic hand wearable

    Actor & Avatar: A Scientific and Artistic Catalog

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    What kind of relationship do we have with artificial beings (avatars, puppets, robots, etc.)? What does it mean to mirror ourselves in them, to perform them or to play trial identity games with them? Actor & Avatar addresses these questions from artistic and scholarly angles. Contributions on the making of "technical others" and philosophical reflections on artificial alterity are flanked by neuroscientific studies on different ways of perceiving living persons and artificial counterparts. The contributors have achieved a successful artistic-scientific collaboration with extensive visual material

    Data-driven solutions to enhance planning, operation and design tools in Industry 4.0 context

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    This thesis proposes three different data-driven solutions to be combined to state-of-the-art solvers and tools in order to primarily enhance their computational performances. The problem of efficiently designing the open sea floating platforms on which wind turbines can be mount on will be tackled, as well as the tuning of a data-driven engine's monitoring tool for maritime transportation. Finally, the activities of SAT and ASP solvers will be thoroughly studied and a deep learning architecture will be proposed to enhance the heuristics-based solving approach adopted by such software. The covered domains are different and the same is true for their respective targets. Nonetheless, the proposed Artificial Intelligence and Machine Learning algorithms are shared as well as the overall picture: promote Industrial AI and meet the constraints imposed by Industry 4.0 vision. The lesser presence of human-in-the-loop, a data-driven approach to discover causalities otherwise ignored, a special attention to the environmental impact of industries' emissions, a real and efficient exploitation of the Big Data available today are just a subset of the latter. Hence, from a broader perspective, the experiments carried out within this thesis are driven towards the aforementioned targets and the resulting outcomes are satisfactory enough to potentially convince the research community and industrialists that they are not just "visions" but they can be actually put into practice. However, it is still an introduction to the topic and the developed models are at what can be defined a "pilot" stage. Nonetheless, the results are promising and they pave the way towards further improvements and the consolidation of the dictates of Industry 4.0

    Untersuchung von lithiumreichen Antiperowskiten und nanostrukturierten Übergangsmetallverbindungen fĂŒr Lithium-Ionen-Batterien

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    Die vorliegende Arbeit befasst sich mit der Untersuchung der physikalischen und elektrochemischen Eigenschaften von potenziellen Anoden- und Kathodenmaterialien fĂŒr die nĂ€chste Generation an Lithium-Ionen-Batterien. Als potenzielle Anodenmaterialien werden aufgrund ihrer Konversionsreaktionen multielektronenspeicherfĂ€hige Fe3O4-, MoO2-sowie MoS2-Nano-Kohlenstoffkomposite untersucht. Auf der Kathodenmaterialseite wirddie Klasse der lithiumreichen Antiperowskite, welche sowohl kationische als auch anionische RedoxaktivitĂ€t aufweisen, beispielhaft anhand von (Li2Fe)SeO studiert. Die physikalische Charakterisierung erfolgt mittels Röntgendiffraktometrie, Röntgenphotoelektronenspektroskopie, Rasterelektronenmikroskopie und Magnetisierungsmessungen. Zyklische Voltammetrie, galvanostatische Zyklierung und potentiostatische elektrochemische Impedanzspektroskopie geben Aufschluss ĂŒber die elektrochemischen Eigenschaften. Die vorgestellten Ergebnisse zeigen fĂŒr Fe3O4@HCS in Zyklus 250 eine KapazitĂ€t von 1050 mAh g−1, welche deutlich ĂŒber der theoretischen KapazitĂ€t von 694 mAh g−1 liegt. Der Ursprung der zusĂ€tzlichen KapazitĂ€t der Fe3O4-Nanopartikel konnte auf eine wĂ€hrend des Zyklierens sich auf- und abbauende kapazitĂ€re OberflĂ€chenschicht zurĂŒckgefĂŒhrt werden. Die vorgestellten MoO2-Kohlenstoffkomposite zeigen, dass auch mit preisgĂŒnstigen Kohlenstoffquellen eine kompetitive elektrochemische Performance erreicht werden kann und dass sowohl die PartikelgrĂ¶ĂŸe als auch der Kohlenstoffgehalt einen entscheidenden Einfluss auf die elektrochemische Performance besitzen. Studien an blumenartigen Graphen-MoS2 offenbaren die intrinsischen physikalischen und elektrochemischen Eigenschaften des Materials. Die durchgefĂŒhrten Untersuchungen am lithiumreichen Antiperowskit (Li2Fe)SeO belegen dessen vielversprechende elektrochemische Eigenschaften. Das festkörpersynthetisierte (Li2Fe)SeO erreicht eine KapazitĂ€t von 225 mAh g−1 bei einer Stromdichte von 0,1C. Des Weiteren wurde die Ursache fĂŒr die schlechte ZyklenstabilitĂ€t der lithiumreichen Antiperowskite gefunden und ein Verfahren zur Verbesserung der ZyklenstabilitĂ€t vorgestellt
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