Hybridization of electrochemical energy storage : nanohybrid materials and hybrid cell architectures for high energy, power and stability

A successful transition from fossil to renewable energy sources requires electrochemical energy storage devices that surpass current lithium-ion battery technology in specific power and performance stability. In this PhD thesis, hybrid materials containing carbon and metal oxide components are synthesized, and hybrid cell architectures employing both a Faradaic and a capacitive electrode are explored. For material hybridization, atomic layer deposition is used to deposit nanoscopic layers of metal oxide on carbon substrates. This strategy allows to combine the high capacity of Faradaic reactions with the high power enabled by the large electrode-electrolyte interface. The porosity of the carbon substrate plays a major role in the resulting electrochemical performance; ideal carbon substrates show internal mesopores (2 50 nm). Hybrid supercapacitor devices are optimized by using these hybrid materials as the cell's Faradaic electrode. It is demonstrated that the kinetics and overpotentials of the Faradaic reactions are the determining factors to enable fast and efficient cell performance. Finally, the specific energy of hybrid supercapacitor cells is drastically increased by using lithium- or sodium-containing ionic liquid electrolyte. This novel concept increases the accessible cell voltage, operation temperature window, and safety of the hybrid supercapacitor cell.Der Erfolg der Energiewende hin zu erneuerbaren Energiequellen hängt stark von der Verfügbarkeit von elektrochemischen Energiespeichern ab, welche die derzeitige Lithium-Ionen Batterietechnologie in Leistung und Stabilität übertreffen. Diese Doktorarbeit untersucht die Materialhybridisierung von Kohlenstoffen mit Metalloxiden und die Konstruktion von Hybridzellen, die aus einer kapazitiven und einer Faradayschen Elektrode bestehen. Materialhybridisierung mittels Atomlagenabscheidung erzeugt nanoskopische Lagen von Metalloxiden auf Kohlenstoffsubstraten. Dadurch kann die hohe Kapazität Faradayscher Reaktionen dank der hohen Elektrode-Elektrolyt-Grenzfläche bei erhöhter Leistung abgerufen werden. Die Porosität des Kohlenstoffsubstrats spielt dabei eine entscheidende Rolle; ideale Kohlenstoffe weisen interne Mesoporen (2-50 nm) auf. Hybridzellen können durch den Einsatz dieser Hybridmaterialien als Faradaysche Elektrode verbessert werden. Die Kinetik und das Überpotenzial der Faradayschen Reaktion sind für eine schnelle und effiziente Zellperformanz von entscheidender Bedeutung. Die spezifische Energie von Hybridzellen kann darüber hinaus durch den Einsatz lithium- bzw. natrium-haltiger ionischer Flüssigkeit deutlich erhöht werden. Dieses neuartige Zellkonzept erhöht die maximal zugängliche Zellspannung, das Einsatztemperaturfenster und die Sicherheit der Hybridzelle.Leibniz Association (SAW-2017), Carbon Metal Oxide Nanohybrid project (CarMON

Developing creative industries in northern Australia: a report on key developments and outcomes in the city of Townsville, North Queensland

Creative industries with a typically commercial focus (e.g. film, design, software) are often cited as key areas of focus for economic and workforce development. This is typically due to creative industries’ low reliance on major infrastructure (e.g. dams, roads), as well as their capacity to value add to other industry sectors given they are often at the cutting edge of technological development and innovation processes. While there are a multitude of studies that measure and assess the size and contribution of creative industries to metropolitan – and to a lesser extent regional - economies across the globe, there is very little focus on the demand side for this sector. In what is arguably the first project of its kind, this presentation reports on the overarching findings and key economic development outcomes of a major supply/demand analysis of creative industries in Townsville, northern Australia, and which was completed in 2014-15. In addition to citing the major findings and which include an estimate of the import leakage to the local economy, this presentation discusses the development of a range of key strategies and outcomes designed to build on the research findings and boost the local workforce and economic activity within the sector. These key outcomes have included the development of creative industry industries growth through Entrepreneurial/Mentoring Program, a Creative Industries Cluster, a Film Industry Development group, and the formation of Townsville City Council’s first ever Innovation and Business Advisory Group. These various strategies are discussed in terms of their formation, delivery and either intended or achieved outcomes to date. As part of ongoing research and analysis of creative industries beyond capital cities, this presentation highlights a number of key issues of relevance to not only the regions but other key centres in northern Australia, whilst also highlighting the value of university and community engagement

Vitamin C as a Potential Prophylactic Measure Against Frozen Shoulder in an In Vivo Shoulder Contracture Animal Model

BACKGROUND Frozen shoulder is a common, painful, and movement-restricting condition. Although primary frozen shoulder is idiopathic, secondary frozen shoulder can occur after trauma or surgery. Prophylactic and therapeutic options are often unsatisfactory. Vitamin C (ascorbic acid) is a potent physiological antioxidant and likely inhibits the activation of nuclear factor κB, which plays a decisive role in inflammatory reactions. HYPOTHESIS Because of its anti-inflammatory effects, vitamin C may be valuable in the prevention of secondary frozen shoulder. STUDY DESIGN Controlled laboratory study. METHODS An in vivo shoulder contracture model was conducted by fixation of the right proximal limb of Sprague-Dawley rats. A treatment group (n = 8) receiving vitamin C orally was compared with a control group (n = 9) without vitamin C. The primary outcome was capsular thickness at the shoulder joint measured on magnetic resonance imaging (MRI) examination. Further histological examination was performed but was not statistically analyzed because of variability of the cutting plane through the glenoid. RESULTS Vitamin C treatment resulted in less thickening of the axillary fold of the operated shoulder at 2 of the 3 locations measured on MRI compared with untreated controls (insertion to the glenoid, P = .074; insertion to the humerus, P = .006; middle of the axillary recess, P = .008). The observed structural changes in histological examination corroborated the significant changes obtained from the MRI measurements. CONCLUSION Prophylactic vitamin C seemed to reduce the thickening of the axillary recess in secondary frozen shoulder in this preclinical study. CLINICAL RELEVANCE Vitamin C may be helpful as a noninvasive therapeutic measure to prevent secondary frozen shoulder (eg, within the context of surgery in the shoulder region or immobilization) or to treat primary frozen shoulder at an early stage. Further studies are required to evaluate the effect of this treatment in humans and the necessary dosage in humans

Trap diversity and character evolution in carnivorous bladderworts (Utricularia, Lentibulariaceae)

Bladderworts (Utricularia, Lentibulariaceae, Lamiales) constitute the largest genus of carnivorous plants but only aquatic species (about one fifth of the genus) have so far been thoroughly studied as to their suction trap functioning. In this study, we comparatively investigated trap biomechanics in 19 Utricularia species to examine correlations between life-forms, trapping mechanisms, and functional-morphological traits. Our investigations show the existence of two functional trap principles (passive trap in U. multifida vs. active suction traps), and - in active suction traps - three main trapdoor movement types (with several subtypes). The trapdoor movement types and their corresponding functional-morphological features most presumably represent adaptations to the respective habitat. We furthermore give insights into fluid dynamics during suction in three representatives of the main types of trapdoor movement. The results on functional morphology and trapdoor movement were mapped onto a new phylogenetic reconstruction of the genus, derived from the rapidly evolving chloroplast regions trnK, rps16 and trnQ-rps16 and a sampling of 105 Utricularia species in total. We discuss potential scenarios of trap character evolution and species radiation, highlighting possible key innovations that enable such a unique carnivorous lifestyle in different habitats

Mechanistic understanding of microstructure formation during synthesis of metal oxide/carbon nanocomposites

Nanocomposite materials consisting of metal oxide and carbon are of interest as electrode materials for both high rate intercalation-type and high capacity conversion-type charge storage processes. Facile synthesis processes like the pyrolysis of an organic carbon-source can yield a well-dispersed carbon phase within the metal oxide structure. Detailed understanding of the carbon formation process is required to tailor the resulting material microstructure. Herein, both the formation and the final microstructure of a molybdenum oxide/carbon nanocomposite are studied in detail. Octylamine assembled in the interlayer space of layered MoO3 serves as a carbon source. The structural changes during pyrolysis are characterized using a combination of in situ heating X-ray diffraction with simultaneous FTIR- and mass spectroscopy-coupled thermogravimetric analysis experiments. These reveal mobility and partial desorption of octylamine and interlayer water at low temperatures, octylamine decomposition and loss of long-range order at intermediate temperatures, and carbothermic reduction of molybdenum oxide at high temperatures during pyrolysis. The resulting nanocomposite mainly contains nanocrystalline MoO2 domains surrounded by a well-dispersed carbon phase, as observed with scanning transmission electron microscopy of focus-ion beam prepared cross-sectional lamellae. The electrochemical behavior is evaluated in organic, lithium-containing electrolyte for both intercalation and conversion-type reactions, showing good intercalation kinetics and a high first cycle efficiency for the conversion-type reaction

Closed CO2 cycles in the glass production: A techno- economic evaluation

In this work, we examine the feasibility and costs of implementing CCU processes into a generic glass production, an industry responsible for the emission of about 95 million tonnes of CO2 per year. For this, we propose and analyze a process-chain to capture CO2 from the flue gas of oxy-fuel glass furnaces and further convert it into synthetic methane for its reinjection into the furnace. The process-chain is simulated using Aspen Plus® and assessed techno-economically to estimate the net production- and investment costs. We assumed the conditions of the German electricity day-ahead-market for the year 2020 to include the volatility of green energy production. Since the electricity price is crucial component of the production costs, the average purchased price was heuristically optimized based on the hydrogen production- (full load hours of the electrolyzer) and storage capacity of the plant. The influence of the hydrogen production- and storage capacity on the net production costs is exposed and the ideal result for the year 2020 is identified. Finally, the opportunities and challenges to decarbonize the glass production via CCU are presented, together with the associated costs for the process-chain

Enhanced electrochemical energy storage by nanoscopic decoration of endohedral and exohedral carbon with vanadium oxide via atomic layer deposition

Atomic layer deposition (ALD) is a facile process to decorate carbon surfaces with redox-active nanolayers. This is a particularly attractive route to obtain hybrid electrode materials for high performance electrochemical energy storage applications. Using activated carbon and carbon onions as representatives of substrate materials with large internal or external surface area, respectively, we have studied the enhanced energy storage capacity of vanadium oxide coatings. While the internal porosity of activated carbon readily becomes blocked by obstructing nanopores, carbon onions enable the continued deposition of vanadia within their large interparticle voids. Electrochemical benchmarking in lithium perchlorate in acetonitrile (1 M LiClO4) showed a maximum capacity of 122 mAh/g when using vanadia coated activated carbon and 129 mAh/g for vanadia coated carbon onions. There is an optimum amount of vanadia between 50 and 65 wt % for both substrates that results in an ideal balance between redox-activity and electrical conductivity of the hybrid electrode. Assembling asymmetric (charge balanced) full-cells, a maximum specific energy of 38 Wh/kg and 29 Wh/kg was found for carbon onions and activated carbon, respectively. The stability of both systems is promising, with a capacity retention of ∼85–91% after 7000 cycles for full-cell measurements

Carbon onion / sulfur hybrid cathodes via inverse vulcanization for lithium sulfur batteries

A sulfur–1,3-diisopropenylbenzene copolymer was synthesized by ring-opening radical polymerization and hybridized with carbon onions at different loading levels. The carbon onion mixing was assisted by shear in a two-roll mill to capitalize on the softened state of the copolymer. The sulfur copolymer and the hybrids were thoroughly characterized in structure and chemical composition, and finally tested by electrochemical benchmarking. An enhancement of specific capacity was observed over 140 cycles at higher content of carbon onions in the hybrid electrodes. The copolymer hybrids demonstrate a maximum initial specific capacity of 1150 mA h gsulfur−1 (850 mA h gelectrode−1) and a low decay of capacity to reach 790 mA h gsulfur−1 (585 mA h gelectrode−1) after 140 charge/discharge cycles. All carbon onion/sulfur copolymer hybrid electrodes yielded high chemical stability, stable electrochemical performance superior to conventional melt-infiltrated reference samples having similar sulfur and carbon onion content. The amount of carbon onions embedded in the sulfur copolymer has a strong influence on the specific capacity, as they effectively stabilize the sulfur copolymer and sterically hinder the recombination of sulfur species to the S8 configuration