Layered Transition Metal Thiophosphates as Anodes in Sodium-Ion Batteries: Evaluation of Electrochemical Properties and Structural Examination of Reaction Mechanisms during Sodium Uptake and Release

The subject of this thesis is the investigation of the transition metal thiophosphates (MTPs) Ni2P2S6, CrPS4 and CuCrP2S6 as anode materials in sodium-ion batteries (SIBs) with the objective of evaluating their electrochemical performance and understanding the occurring structural changes during sodium uptake and release. From an electrochemical perspective, it has been described in literature that Ni2P2S6 nanomaterials represent superior anode materials in SIBs. Interestingly, this thesis demonstrates that the corresponding bulk material provides comparable electrochemical performance. Additionally, the anode materials CuCrP2S6 and CrPS4 were investigated for the first time in SIBs. While the incorporation of Cu+ cations into electrodes often affects the electrochemical performance positively, the benefits anticipated for CuCrP2S6 are less than expected. Conversely, an excellent overall performance was demonstrated for CrPS4. From a mechanistic point of view, it was demonstrated that similar reaction pathways occur for different MTPs. During the discharge process, Na+ ions first intercalate into the layered structures, while formation of intermediate phases takes place in a second step. Lastly, the reaction proceeds according to a conversion leading to the formation of Na2S and metal nanoparticles. The previously assumed formation of NaxP phases during the discharge step therefore is disproved. It is noteworthy that each electrode material generates different intercalation compounds and intermediate phases during the discharge process. Hence, the observed reaction pathways follow similar patterns but do not display a universal reaction mechanism.Gegenstand dieser Dissertation ist die Untersuchung der Übergangsmetallthiophosphate (MTPs) Ni2P2S6, CrPS4 und CuCrP2S6 als Anodenmaterialien in Natrium-Ionen-Batterien (NIBs). Ziel der Arbeit sind die Bestimmung der elektrochemischen Leistungsfähigkeit sowie detallierte Erkenntnisse über die ablaufenden strukturellen Änderungen während der Aufnahme und Abgabe von Natrium. Aus elektrochemischer Sicht wurde bisher angenommen, dass Ni2P2S6 Nanomaterialien außergewöhnliche Elektrodenmaterialien darstellen. Interessanterweise zeigt diese Dissertation, dass Elektroden des entsprechenden Volumenmaterials vergleichbare elektrochemische Leistungsfähigkeiten aufweisen. Außerdem wurden erstmalig die Anodenmaterialien CuCrP2S6 und CrPS4 in NIBs untersucht. Der Einbau von Cu+-Kationen in Elektroden hat häufig positiven Einfluss auf die Leistungsfähigkeit. Die vermuteten Vorteile für CuCrP2S6 sind allerdings geringer als erwartet. Für CrPS4 wurde hingegen eine hervorragende Leistungsfähigkeit nachgewiesen. Untersuchungen bezüglich der Reaktionsmechanismen haben gezeigt, dass vergleichbare Prozesse für die verschiedenen MTP Materialien ablaufen. Zunächst werden Na+-Ionen in die Schichten interkaliert und anschließend bilden sich in einem zweiten Schritt intermediäre Phasen. Schließlich erfolgt eine Umwandlung der Intermeditate zu Na2S und Metallnanopartikeln. Damit wird der zuvor angenommene Mechanismus widerlegt, der die Bildung von NaxP Phasen voraussetzte. Es ist erwähnenswert, dass sich die Interkalationsverbidungen und Intermediate für jedes der Materialien unterscheiden

Etablierung eines dreidimensionalen Zellkultursystems für humane Pankreaskarzinomzellen und Behandlung von Tumorsphäroiden mit Mitoxantron beladenen supraparamagnetischen Eisenoxid-Nanopartikeln

Pancreatic ductal adenocarcinoma is a hard-to-treat, deadly malignancy. Traditional treatments, such as surgery, radiation and chemotherapy, unfortunately are still not able to significantly improve long-term survival. Three-dimensional (3D) cell cultures might be a platform to study new drug types in a highly reproducible, resource-saving model within a relevant pathophysiological cellular microenvironment. We used a 3D culture of human pancreatic ductal adenocarcinoma cell lines to investigate a potential new treatment approach using superparamagnetic iron oxide nanoparticles (SPIONs) as a drug delivery system for mitoxantrone (MTO), a chemotherapeutic agent. We established a PaCa DD183 cell line and generated PANC-1SMAD4 (-/-) cells by using the CRISPR-Cas9 system, differing in a prognostically relevant mutation in the TGF- pathway. Afterwards, we formed spheroids using PaCa DD183, PANC-1 and PANC-1SMAD4 (-/-) cells, and analyzed the uptake and cytotoxic effect of free MTO and MTO-loaded SPIONs by microscopy and flow cytometry. MTO and SPION–MTO-induced cell death in all tumor spheroids in a dose-dependent manner. Interestingly, spheroids with a SMAD4 mutation showed an increased uptake of MTO and SPION–MTO, while at the same time being more resistant to the cytotoxic effects of the chemotherapeutic agents. MTOloaded SPIONs, with their ability for magnetic drug targeting, could be a future approach for treating pancreatic ductal adenocarcinomas

A Combined Sodium Intercalation and Copper Extrusion Mechanism in the Thiophosphate Family: CuCrP2S6 as Anode Material in Sodium‐Ion Batteries

The layered hypothiophosphate CuCrP2S6 was identified as promising candidate for the application as anode in sodium-ion batteries exhibiting an appropriate electrochemical performance (409 mAh g−1 after 200 cycles @ 1 A g−1). The electrochemical long-term experiments suggest that the reaction mechanism changed upon repeated discharging and charging. The initial discharge and charge process was studied by X-ray diffraction evidencing that at the early discharge stages, Na+ was intercalated into the interlayer space accompanied by a simultaneous reduction of Cu+ to metallic Cu, which was extruded from the host. At later stages of discharge, a conversion of the intermediate phase to Cu0, amorphous Cr0 and P0 embedded in nanocrystalline Na2S occurred. After recharging, only reflections of nanocrystalline NaF could be identified, which is part of the generated solid electrolyte interphase (SEI) layer. In contrast to observation made in literature, elemental Cu seems to be oxidized during the charge process again

Influence of the Cation on the Reaction Mechanism of Sodium Uptake and Release in Bivalent Transition Metal Thiophosphate Anodes: A Case Study of Fe2_2P2_2S6_6

The layered active material Fe$_2$P$_2$S$_6$ was examined as anode material in sodium-ion batteries (SIBs) and compared to previously investigated Ni$_2$P$_2$S$_6$. A reversible specific capacity of 540 mAh g$^{−1}$ was achieved after 250 cycles, depicting similar electrochemical performance as observed for Ni$_2$P$_2$S$_6$. The rate capability and long-term behavior of these two materials are also very similar. Another objective was to elucidate the reaction mechanism during discharging and charging by applying several techniques such as X-ray diffraction, pair distribution function analysis as well as X-ray absorption and solid state NMR spectroscopy. The results clearly demonstrate that the majority of Fe$^{2+}$ is reduced to elemental Fe during the uptake of 5 Na/f.u., while an amorphous intermediate is generated, which was identified as Na$_4$P$_2$S$_6$ by solid state NMR spectroscopy. Completely discharging against a Na metal counter electrode leads to the formation of nanocrystalline Na$_2$S and indications of the formation of polymeric phosphorus were found. In sum, the Na uptake reaction process observed for Fe$_2$P$_2$S$_6$ coincides with the previously unraveled reaction pathway of Ni$_2$P$_2$S$_6$. We therefore conclude that a universal reaction takes places for bivalent transition metal thiophosphate (M$_2$P$_2$S$_6$) electrodes in SIBs

Influence of the Cation on the Reaction Mechanism of Sodium Uptake and Release in Bivalent Transition Metal Thiophosphate Anodes: A Case Study of Fe2P2S6

The layered active material Fe2P2S6 was examined as anode material in sodium-ion batteries (SIBs) and compared to previously investigated Ni2P2S6. A reversible specific capacity of 540 mAh g−1 was achieved after 250 cycles, depicting similar electrochemical performance as observed for Ni2P2S6. The rate capability and long-term behavior of these two materials are also very similar. Another objective was to elucidate the reaction mechanism during discharging and charging by applying several techniques such as X-ray diffraction, pair distribution function analysis as well as X-ray absorption and solid state NMR spectroscopy. The results clearly demonstrate that the majority of Fe2+ is reduced to elemental Fe during the uptake of 5 Na/f.u., while an amorphous intermediate is generated, which was identified as Na4P2S6 by solid state NMR spectroscopy. Completely discharging against a Na metal counter electrode leads to the formation of nanocrystalline Na2S and indications of the formation of polymeric phosphorus were found. In sum, the Na uptake reaction process observed for Fe2P2S6 coincides with the previously unraveled reaction pathway of Ni2P2S6. We therefore conclude that a universal reaction takes places for bivalent transition metal thiophosphate (M2P2S6) electrodes in SIBs

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Aqueous Flow Reactor and Vapour-Assisted Synthesis of Aluminium Dicarboxylate Metal-Organic Frameworks with Tuneable Water Sorption Properties

Energy-efficient indoors temperature and humidity control can be realised by using the reversible adsorption and desorption of water in porous materials. Stable microporous aluminium-based metal-organic frameworks (MOFs) present promising water sorption properties for this goal. The development of synthesis routes that make use of available and affordable building blocks and avoid the use of organic solvents is crucial to advance this field. In this work, two scalable synthesis routes under mild reaction conditions were developed for aluminium-based MOFs: (1) in aqueous solutions using a continuous-flow reactor and (2) through the vapour-assisted conversion of solid precursors. Fumaric acid, its methylated analogue mesaconic acid, as well as mixtures of the two were used as linkers to obtain polymorph materials with tuneable water sorption properties. The synthesis conditions determine the crystal structure and either the MIL-53 or MIL-68 type structure with square-grid or kagome-grid topology, respectively, is formed. Fine-tuning resulted in new MOF materials thus far inaccessible through conventional synthesis routes. Furthermore, by varying the linker ratio, the water sorption properties can be continuously adjusted while retaining the sigmoidal isotherm shape advantageous for heat transformation and room climatisation applications

Human Practice. Digital Ecologies. Our Future. : 14. Internationale Tagung Wirtschaftsinformatik (WI 2019) : Tagungsband

Erschienen bei: universi - Universitätsverlag Siegen. - ISBN: 978-3-96182-063-4Aus dem Inhalt: Track 1: Produktion & Cyber-Physische Systeme Requirements and a Meta Model for Exchanging Additive Manufacturing Capacities Service Systems, Smart Service Systems and Cyber- Physical Systems—What’s the difference? Towards a Unified Terminology Developing an Industrial IoT Platform – Trade-off between Horizontal and Vertical Approaches Machine Learning und Complex Event Processing: Effiziente Echtzeitauswertung am Beispiel Smart Factory Sensor retrofit for a coffee machine as condition monitoring and predictive maintenance use case Stakeholder-Analyse zum Einsatz IIoT-basierter Frischeinformationen in der Lebensmittelindustrie Towards a Framework for Predictive Maintenance Strategies in Mechanical Engineering - A Method-Oriented Literature Analysis Development of a matching platform for the requirement-oriented selection of cyber physical systems for SMEs Track 2: Logistic Analytics An Empirical Study of Customers’ Behavioral Intention to Use Ridepooling Services – An Extension of the Technology Acceptance Model Modeling Delay Propagation and Transmission in Railway Networks What is the impact of company specific adjustments on the acceptance and diffusion of logistic standards? Robust Route Planning in Intermodal Urban Traffic Track 3: Unternehmensmodellierung & Informationssystemgestaltung (Enterprise Modelling & Information Systems Design) Work System Modeling Method with Different Levels of Specificity and Rigor for Different Stakeholder Purposes Resolving Inconsistencies in Declarative Process Models based on Culpability Measurement Strategic Analysis in the Realm of Enterprise Modeling – On the Example of Blockchain-Based Initiatives for the Electricity Sector Zwischenbetriebliche Integration in der Möbelbranche: Konfigurationen und Einflussfaktoren Novices’ Quality Perceptions and the Acceptance of Process Modeling Grammars Entwicklung einer Definition für Social Business Objects (SBO) zur Modellierung von Unternehmensinformationen Designing a Reference Model for Digital Product Configurators Terminology for Evolving Design Artifacts Business Role-Object Specification: A Language for Behavior-aware Structural Modeling of Business Objects Generating Smart Glasses-based Information Systems with BPMN4SGA: A BPMN Extension for Smart Glasses Applications Using Blockchain in Peer-to-Peer Carsharing to Build Trust in the Sharing Economy Testing in Big Data: An Architecture Pattern for a Development Environment for Innovative, Integrated and Robust Applications Track 4: Lern- und Wissensmanagement (e-Learning and Knowledge Management) eGovernment Competences revisited – A Literature Review on necessary Competences in a Digitalized Public Sector Say Hello to Your New Automated Tutor – A Structured Literature Review on Pedagogical Conversational Agents Teaching the Digital Transformation of Business Processes: Design of a Simulation Game for Information Systems Education Conceptualizing Immersion for Individual Learning in Virtual Reality Designing a Flipped Classroom Course – a Process Model The Influence of Risk-Taking on Knowledge Exchange and Combination Gamified Feedback durch Avatare im Mobile Learning Alexa, Can You Help Me Solve That Problem? - Understanding the Value of Smart Personal Assistants as Tutors for Complex Problem Tasks Track 5: Data Science & Business Analytics Matching with Bundle Preferences: Tradeoff between Fairness and Truthfulness Applied image recognition: guidelines for using deep learning models in practice Yield Prognosis for the Agrarian Management of Vineyards using Deep Learning for Object Counting Reading Between the Lines of Qualitative Data – How to Detect Hidden Structure Based on Codes Online Auctions with Dual-Threshold Algorithms: An Experimental Study and Practical Evaluation Design Features of Non-Financial Reward Programs for Online Reviews: Evaluation based on Google Maps Data Topic Embeddings – A New Approach to Classify Very Short Documents Based on Predefined Topics Leveraging Unstructured Image Data for Product Quality Improvement Decision Support for Real Estate Investors: Improving Real Estate Valuation with 3D City Models and Points of Interest Knowledge Discovery from CVs: A Topic Modeling Procedure Online Product Descriptions – Boost for your Sales? Entscheidungsunterstützung durch historienbasierte Dienstreihenfolgeplanung mit Pattern A Semi-Automated Approach for Generating Online Review Templates Machine Learning goes Measure Management: Leveraging Anomaly Detection and Parts Search to Improve Product-Cost Optimization Bedeutung von Predictive Analytics für den theoretischen Erkenntnisgewinn in der IS-Forschung Track 6: Digitale Transformation und Dienstleistungen Heuristic Theorizing in Software Development: Deriving Design Principles for Smart Glasses-based Systems Mirroring E-service for Brick and Mortar Retail: An Assessment and Survey Taxonomy of Digital Platforms: A Platform Architecture Perspective Value of Star Players in the Digital Age Local Shopping Platforms – Harnessing Locational Advantages for the Digital Transformation of Local Retail Outlets: A Content Analysis A Socio-Technical Approach to Manage Analytics-as-a-Service – Results of an Action Design Research Project Characterizing Approaches to Digital Transformation: Development of a Taxonomy of Digital Units Expectations vs. Reality – Benefits of Smart Services in the Field of Tension between Industry and Science Innovation Networks and Digital Innovation: How Organizations Use Innovation Networks in a Digitized Environment Characterising Social Reading Platforms— A Taxonomy-Based Approach to Structure the Field Less Complex than Expected – What Really Drives IT Consulting Value Modularity Canvas – A Framework for Visualizing Potentials of Service Modularity Towards a Conceptualization of Capabilities for Innovating Business Models in the Industrial Internet of Things A Taxonomy of Barriers to Digital Transformation Ambidexterity in Service Innovation Research: A Systematic Literature Review Design and success factors of an online solution for cross-pillar pension information Track 7: IT-Management und -Strategie A Frugal Support Structure for New Software Implementations in SMEs How to Structure a Company-wide Adoption of Big Data Analytics The Changing Roles of Innovation Actors and Organizational Antecedents in the Digital Age Bewertung des Kundennutzens von Chatbots für den Einsatz im Servicedesk Understanding the Benefits of Agile Software Development in Regulated Environments Are Employees Following the Rules? On the Effectiveness of IT Consumerization Policies Agile and Attached: The Impact of Agile Practices on Agile Team Members’ Affective Organisational Commitment The Complexity Trap – Limits of IT Flexibility for Supporting Organizational Agility in Decentralized Organizations Platform Openness: A Systematic Literature Review and Avenues for Future Research Competence, Fashion and the Case of Blockchain The Digital Platform Otto.de: A Case Study of Growth, Complexity, and Generativity Track 8: eHealth & alternde Gesellschaft Security and Privacy of Personal Health Records in Cloud Computing Environments – An Experimental Exploration of the Impact of Storage Solutions and Data Breaches Patientenintegration durch Pfadsysteme Digitalisierung in der Stressprävention – eine qualitative Interviewstudie zu Nutzenpotenzialen User Dynamics in Mental Health Forums – A Sentiment Analysis Perspective Intent and the Use of Wearables in the Workplace – A Model Development Understanding Patient Pathways in the Context of Integrated Health Care Services - Implications from a Scoping Review Understanding the Habitual Use of Wearable Activity Trackers On the Fit in Fitness Apps: Studying the Interaction of Motivational Affordances and Users’ Goal Orientations in Affecting the Benefits Gained Gamification in Health Behavior Change Support Systems - A Synthesis of Unintended Side Effects Investigating the Influence of Information Incongruity on Trust-Relations within Trilateral Healthcare Settings Track 9: Krisen- und Kontinuitätsmanagement Potentiale von IKT beim Ausfall kritischer Infrastrukturen: Erwartungen, Informationsgewinnung und Mediennutzung der Zivilbevölkerung in Deutschland Fake News Perception in Germany: A Representative Study of People’s Attitudes and Approaches to Counteract Disinformation Analyzing the Potential of Graphical Building Information for Fire Emergency Responses: Findings from a Controlled Experiment Track 10: Human-Computer Interaction Towards a Taxonomy of Platforms for Conversational Agent Design Measuring Service Encounter Satisfaction with Customer Service Chatbots using Sentiment Analysis Self-Tracking and Gamification: Analyzing the Interplay of Motivations, Usage and Motivation Fulfillment Erfolgsfaktoren von Augmented-Reality-Applikationen: Analyse von Nutzerrezensionen mit dem Review-Mining-Verfahren Designing Dynamic Decision Support for Electronic Requirements Negotiations Who is Stressed by Using ICTs? A Qualitative Comparison Analysis with the Big Five Personality Traits to Understand Technostress Walking the Middle Path: How Medium Trade-Off Exposure Leads to Higher Consumer Satisfaction in Recommender Agents Theory-Based Affordances of Utilitarian, Hedonic and Dual-Purposed Technologies: A Literature Review Eliciting Customer Preferences for Shopping Companion Apps: A Service Quality Approach The Role of Early User Participation in Discovering Software – A Case Study from the Context of Smart Glasses The Fluidity of the Self-Concept as a Framework to Explain the Motivation to Play Video Games Heart over Heels? An Empirical Analysis of the Relationship between Emotions and Review Helpfulness for Experience and Credence Goods Track 11: Information Security and Information Privacy Unfolding Concerns about Augmented Reality Technologies: A Qualitative Analysis of User Perceptions To (Psychologically) Own Data is to Protect Data: How Psychological Ownership Determines Protective Behavior in a Work and Private Context Understanding Data Protection Regulations from a Data Management Perspective: A Capability-Based Approach to EU-GDPR On the Difficulties of Incentivizing Online Privacy through Transparency: A Qualitative Survey of the German Health Insurance Market What is Your Selfie Worth? A Field Study on Individuals’ Valuation of Personal Data Justification of Mass Surveillance: A Quantitative Study An Exploratory Study of Risk Perception for Data Disclosure to a Network of Firms Track 12: Umweltinformatik und nachhaltiges Wirtschaften Kommunikationsfäden im Nadelöhr – Fachliche Prozessmodellierung der Nachhaltigkeitskommunikation am Kapitalmarkt Potentiale und Herausforderungen der Materialflusskostenrechnung Computing Incentives for User-Based Relocation in Carsharing Sustainability’s Coming Home: Preliminary Design Principles for the Sustainable Smart District Substitution of hazardous chemical substances using Deep Learning and t-SNE A Hierarchy of DSMLs in Support of Product Life-Cycle Assessment A Survey of Smart Energy Services for Private Households Door-to-Door Mobility Integrators as Keystone Organizations of Smart Ecosystems: Resources and Value Co-Creation – A Literature Review Ein Entscheidungsunterstützungssystem zur ökonomischen Bewertung von Mieterstrom auf Basis der Clusteranalyse Discovering Blockchain for Sustainable Product-Service Systems to enhance the Circular Economy Digitale Rückverfolgbarkeit von Lebensmitteln: Eine verbraucherinformatische Studie Umweltbewusstsein durch audiovisuelles Content Marketing? Eine experimentelle Untersuchung zur Konsumentenbewertung nachhaltiger Smartphones Towards Predictive Energy Management in Information Systems: A Research Proposal A Web Browser-Based Application for Processing and Analyzing Material Flow Models using the MFCA Methodology Track 13: Digital Work - Social, mobile, smart On Conversational Agents in Information Systems Research: Analyzing the Past to Guide Future Work The Potential of Augmented Reality for Improving Occupational First Aid Prevent a Vicious Circle! The Role of Organizational IT-Capability in Attracting IT-affine Applicants Good, Bad, or Both? Conceptualization and Measurement of Ambivalent User Attitudes Towards AI A Case Study on Cross-Hierarchical Communication in Digital Work Environments ‘Show Me Your People Skills’ - Employing CEO Branding for Corporate Reputation Management in Social Media A Multiorganisational Study of the Drivers and Barriers of Enterprise Collaboration Systems-Enabled Change The More the Merrier? The Effect of Size of Core Team Subgroups on Success of Open Source Projects The Impact of Anthropomorphic and Functional Chatbot Design Features in Enterprise Collaboration Systems on User Acceptance Digital Feedback for Digital Work? Affordances and Constraints of a Feedback App at InsurCorp The Effect of Marker-less Augmented Reality on Task and Learning Performance Antecedents for Cyberloafing – A Literature Review Internal Crowd Work as a Source of Empowerment - An Empirical Analysis of the Perception of Employees in a Crowdtesting Project Track 14: Geschäftsmodelle und digitales Unternehmertum Dividing the ICO Jungle: Extracting and Evaluating Design Archetypes Capturing Value from Data: Exploring Factors Influencing Revenue Model Design for Data-Driven Services Understanding the Role of Data for Innovating Business Models: A System Dynamics Perspective Business Model Innovation and Stakeholder: Exploring Mechanisms and Outcomes of Value Creation and Destruction Business Models for Internet of Things Platforms: Empirical Development of a Taxonomy and Archetypes Revitalizing established Industrial Companies: State of the Art and Success Principles of Digital Corporate Incubators When 1+1 is Greater than 2: Concurrence of Additional Digital and Established Business Models within Companies Special Track 1: Student Track Investigating Personalized Price Discrimination of Textile-, Electronics- and General Stores in German Online Retail From Facets to a Universal Definition – An Analysis of IoT Usage in Retail Is the Technostress Creators Inventory Still an Up-To-Date Measurement Instrument? Results of a Large-Scale Interview Study Application of Media Synchronicity Theory to Creative Tasks in Virtual Teams Using the Example of Design Thinking TrustyTweet: An Indicator-based Browser-Plugin to Assist Users in Dealing with Fake News on Twitter Application of Process Mining Techniques to Support Maintenance-Related Objectives How Voice Can Change Customer Satisfaction: A Comparative Analysis between E-Commerce and Voice Commerce Business Process Compliance and Blockchain: How Does the Ethereum Blockchain Address Challenges of Business Process Compliance? Improving Business Model Configuration through a Question-based Approach The Influence of Situational Factors and Gamification on Intrinsic Motivation and Learning Evaluation von ITSM-Tools für Integration und Management von Cloud-Diensten am Beispiel von ServiceNow How Software Promotes the Integration of Sustainability in Business Process Management Criteria Catalog for Industrial IoT Platforms from the Perspective of the Machine Tool Industry Special Track 3: Demos & Prototyping Privacy-friendly User Location Tracking with Smart Devices: The BeaT Prototype Application-oriented robotics in nursing homes Augmented Reality for Set-up Processe Mixed Reality for supporting Remote-Meetings Gamification zur Motivationssteigerung von Werkern bei der Betriebsdatenerfassung Automatically Extracting and Analyzing Customer Needs from Twitter: A “Needmining” Prototype GaNEsHA: Opportunities for Sustainable Transportation in Smart Cities TUCANA: A platform for using local processing power of edge devices for building data-driven services Demonstrator zur Beschreibung und Visualisierung einer kritischen Infrastruktur Entwicklung einer alltagsnahen persuasiven App zur Bewegungsmotivation für ältere Nutzerinnen und Nutzer A browser-based modeling tool for studying the learning of conceptual modeling based on a multi-modal data collection approach Exergames & Dementia: An interactive System for People with Dementia and their Care-Network Workshops Workshop Ethics and Morality in Business Informatics (Workshop Ethik und Moral in der Wirtschaftsinformatik – EMoWI’19) Model-Based Compliance in Information Systems - Foundations, Case Description and Data Set of the MobIS-Challenge for Students and Doctoral Candidates Report of the Workshop on Concepts and Methods of Identifying Digital Potentials in Information Management Control of Systemic Risks in Global Networks - A Grand Challenge to Information Systems Research Die Mitarbeiter von morgen - Kompetenzen künftiger Mitarbeiter im Bereich Business Analytics Digitaler Konsum: Herausforderungen und Chancen der Verbraucherinformati

Long-Term Stable, High-Capacity Anode Material for Sodium-Ion Batteries: Taking a Closer Look at CrPS4_4 from an Electrochemical and Mechanistic Point of View

Electrochemical performance of the layered compound CrPS$_4$ for the usage as anode material in sodium-ion batteries (SIBs) was examined and exceptional reversible long-term capacity and capacity retention were found. After 300 cycles, an extraordinary reversible capacity of 687 mAh g$^{–1}$ at a current rate of 1 A g$^{–1}$ was achieved, while rate capability tests showed an excellent capacity retention of 100%. Detailed evaluation of the data evidence a change of the electrochemical reaction upon cycling leading to the striking long-term performance. Further investigations targeted the reaction mechanism of the first cycle by applying complementary techniques, i.e., powder X-ray diffraction (XRD), pair distribution function (PDF) analysis, X-ray absorption spectroscopy (XAS), and $^{23}$Na/$^{31}$P magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The results indicated an unexpectedly complex reaction pathway including formation of several intercalation compounds, depending on the amount of Na inserted at the early discharge states and subsequent conversion to Na$_2$S and strongly disordered metallic Cr at the completely discharged state. While XAS measurements suggest no further presence of intermediates after formation of Na intercalation compounds, several different phases are detected via MAS NMR upon continued discharging. Especially the data obtained from the MAS NMR investigations therefore point toward a very complex reaction pathway. Furthermore, solid electrolyte interphase (SEI) formation, resulting in the presence of NaF, was observed. After recharging the anode material, no structural long-range order occurred, but short-range order indeed resembled the local environment of the starting material, to a certain extent