The diploma thesis deals with electrode materials for lithium-ions accumulators, concretely layered materials prepared via new methods. The main objective of this work is dealing with new procedures prepare electrodes of newly developed layered electrode materials and subsequently their measure. Another challenge was a theoretical analysis of newly developed layered electrode materials for positive and negative electrodes and their preparation of new procedures. In this work the detailed procedures for the preparation of individual electrodes, electrolytes and other issues associated with these preparations. There were describing batteries of general, primary and secondary lithium cells, fuel cells, Lithium-ion batteries, layered materials forming the electrodes and of course the history these cells. Practical work is focused on separate measurements layered electrode materials prepared by new processes and assessment of results for individual layered materials. In the practical part has been made that the newly prepared layered electrode materials offer higher capacity and voltage.

This thesis is interested in new materials for lithium – ion batteries. Two different samples were investigated, one intercalation and one conversion cathode material. The theoretical part is focused to the structure of cells, their advantages and disadvantages compared to other secondary batteries. Also other materials used in batteries are described. The practical part describes the preparation of cathode materials for subsequent testing by scanning elektron microscopy and thermogravimetric analysis. In conclusions two different materials were evaluated and compared with each other.

The dissertation thesis deals with electrode materials and components for lithium-ion power sources. The thesis works with two different kinds of materials, concretely nanostructured Li4Ti5O12 with spinel basis and LiCoO2 with layered structure. The electrochemical properties, structure and element analysis and utilization possibilities in electrochemical industry of new technological electrode material Li4Ti5O12 were investigated. The influences of admixtures and electrolytes on characteristics of electrode materials with aforesaid active masses were also examined. Low cost price, environmental safety and obtained results of electrochemical measurements and structure analysis refer to wide possibilities of usage electrode material Li4Ti5O12 in the field of electrochemistry.

In this paper, we report that various kinds of active sites on graphite surface including active hydrophilic sites markedly affect the electrochemical performance of graphite anodes for lithium ion batteries under different humidity conditions. After depositing metals such as Ag and Cu by immersing and heat-treating, these active sites on the graphite surface were removed or covered and its electrochemical performance under the high humidity conditions was markedly improved. This suggests that lithium ion batteries can be assembled under less strict conditions and that it provides a valuable direction to lower the manufacturing cost for lithium ion batteries.

Development of microsized batteries plays an important role in the design of in-situ electrochemical investigation systems and portable/wearable electronics. This emerging field intimately correlates with the topics of rechargeable batteries, nanomaterials, on-chip microfabrication, flexibility with reliable mechanical properties etc. Among the various energy materials, conversion-type materials have been proposed as high-energy-density alternatives to traditional intercalation-based materials. However, these materials usually show complex reaction processes accompanied by multi-reaction intermediates, which poses a great challenge to understand the chemical mechanisms. Benefiting from the merits of microsized battery devices, we develop a novel strategy to investigate and then optimize the electrochemical performance of a specific conversion-type material: nickel-iron oxide (NFO). Subsequently, this kind of materials are employed for flexible minimized energy storage systems. Unlike traditional characterization methods based on slurry-coated electrodes, micro-platforms directly probe the intrinsic electrochemical properties of a single active material in real-time due to the elimination of other additives. In this thesis, we firstly design a micro-lithium batteries (MLBs), based on a single “Swiss-roll” microtubular nanomembrane electrode. This platform enables us to investigate the electrochemical mechanisms of electrode materials in lithium batteries by in-situ Raman spectroscopy, electrical conductivity measurements, and electrochemistry characterization. With this designed MLBs, we systematically studied NFO nanomembranes. Using in-situ Raman spectroscopy during the delithiation/lithiation process, we monitored the transition of the chemical component directly. Guided by our investigations of micro-batteries, composite NFO nanomembrane electrodes were fabricated and tested in coin cells, which showed an excellent rate performance: 440 mAh g-1 at a high rate of 20 A g-1 and a long-term stable cycling performance over 1600 cycles. One step further, a flexible energy storage micro-device is achieved using such optimized materials. We demonstrate a thin, lightweight, and flexible micro-full lithium-ion battery based on nickel-iron oxide with a high-rate performance and energy density that can be repeatedly bent to 180° without structural failure and performance loss. It delivers a stable output capacity of 140 mAh g-1 over 1000 charge/discharge cycles. Meanwhile, the excellent rate performance guarantees high energy output up to 255 W h kg-1 at a high power density of 12000 W kg-1 at the microscale.

The use of lithium-ion batteries is something that is becoming more common in today’s society. They are found in a variety of electronic equipment such as mobile phones, laptops and tools. Several incidents have been reported due to lithium-ion batteries ending up in a state called thermal runaway. This in combination with the increasing demands for environmentally friendly and sustainable energy in the form of e.g. wind turbines and solar panels, can therefore lead to unforeseen consequences. Residual energy from wind or solar power can be stored in an energy storage, often a battery system of several interconnected lithium-ion batteries. In case of an incident in these storages where a large quantity of these batteries is located, there is a risk that an explosion will occur. This further leads to the interest if it’s possible to prevent an explosion with the help of mechanical ventilation.  The purpose of this report has been to investigate the reasons why these batteries are being able to cause an explosion, what gases are emitted in the event of a thermal runaway and how explosive they are. With the results given it’s possible to then perform calculations on ventilation capacity needed to maintain a non-explosive atmosphere. This was carried out through a literature study of currently available research combined with information from various authorities, hand calculations and calculations in Excel.  With the results of the literature study, it can be stated that the battery cell consisting of the cathode material lithium-nickel-manganese-cobalt oxide (NMC) is most reactive. The most common gases emitted from these cells during thermal runaway are hydrogen, carbon monoxide, carbon dioxide, methane, ethylene and ethane. These gases are also the most common gases during thermal runaway when the battery consists of a different cathode material, but the distribution may look different. All of these gases, with the exception of carbon dioxide, are flammable and can contribute to an explosive atmosphere.  Three different scenarios are developed where thermal runaway is assumed to take place at a battery cell inside battery storages of different sizes: two container-based energy storage and one battery storage for home use located in a garage space. In these respective scenarios, a certain number of cells are assumed to be in thermal runaway. The lower flammability limit for the ventilated gas mixture is determined to 8,53% based on the amount of emitted gas and the distribution of it due to thermal runaway. With the knowledge of the lower flammability limit of the emitted gas mixture, as well as other available data from each scenario, the desired capacity for ventilation is calculated at 0,23 m3/s for the two container-based battery storages and at 0,035 m3/s for the battery storage located in the garage space. If this capacity of the ventilation is present when thermal runaway occurs, it means that the concentration of combustible gases should remain below the lower flammability limit. It is worth noting that these calculations were performed to some extent based on assumptions and may therefore be judged more as approximate rather than exact.  The conclusions drawn by the performed calculations are that mechanical ventilation is a potential alternative to ensure that the atmosphere in a battery storage doesn’t become explosive if a thermal runaway occurs in the battery cells.

Ökad miljömedvetenhet ökar anpassningen till ett klimatsmart samhälle där helt eller delvis elektriska bilar blivit populära. Med ökat antal elektriska bilar på vägarna tillkommer risker, som tidigare inte funnits, i form av litium-jonbatterier. Elfordon målas upp som en stor brandrisk men är det korrekt?  Vid brand i ett parkeringsgarage under mark finns flera försvårande förutsättningar när räddningstjänsten ska utföra insats. Vid elfordonsbrand i parkeringsgarage under mark ökar komplexiteten ytterligare. På grund av begränsad forskning är osäkerheten fortfarande stor exempelvis om räddningstjänstens larmställ står emot toxisk brandrök, speciellt det farliga ämnet vätefluorid, som bildas vid elfordonsbrand.  Räddningstjänsten saknar tydliga riktlinjer för elfordonsbrand i parkeringsgarage under mark vilket är ett problem som behöver belysas och utredas. Arbetet omfattar en litteraturstudie, enkätundersökning och intervjustudie.  Medvetenheten om eventuella risker med elfordonsbrand i parkeringsgarage under mark är stor. Kunskapen hur riskerna ska hanteras vid insats är däremot bristfällig. Med högre befattning på räddningstjänsten och utbildningskrav höjs generellt kunskapsnivån. Oberoende om en person arbetar på räddningstjänstförbund, enskild kommuns räddningstjänst eller arbetsbefattning har individuellt intresse stor inverkan på personens kunskapsnivå kring elfordonsbrand. Resultatet av enkätundersökning och intervjustudie åskådliggjorde att riktlinjer för elfordonsbrand i parkeringsgarage under mark förekom i mindre utsträckning inom svensk räddningstjänst. Istället uppgav vissa räddningstjänster att allmänna riktlinjer för elfordonsbrand förekom och dessa kan appliceras på efterfrågat scenario.  Slutsatsen av utfört arbete är att nationell riktlinje för elfordonsbrand behöver upprättas. Riktlinjen bör inte vara specificerad till elfordonsbrand i parkeringsgarage under mark utan allmänt skriven. Myndigheten för samhällsskydd och beredskap bör som styrande organ leda samverkan med svensk räddningstjänst för upprättandet av nationell riktlinje.  Önskan med arbetets resultat är att belysa kunskapsbristen med förhoppning att berörda parter tar ansvar för att höja befintlig kunskapsnivå. Vidare att framtagandet av nationell riktlinje kring elfordonsbrand genomförs. För att möjliggöra detta behövs mer och ny forskning.  På grund av arbetet omfattning fanns inte möjlighet att undersöka innehåll och utformning av eventuell framtida riktlinje. Vid fortsatt arbete är detta något som bör undersökas. Befintliga riktlinjer kring elfordonsbrand i parkeringsgarage under mark bör också studeras vidare. / With increased environmental awareness the adaption to a more sustainable society with electrical and part-electrical vehicles have become more popular. With an increasing number of electrical vehicles, new risks have appeared on the roads in the form of lithium-ion batteries. Electrical vehicles are considered a major risk, but is this assumption completely true?  There are several aggravating conditions for the fire department in the event of underground parking garage fires. The involvement of an electrical vehicle will make the firefighting event more complex. Due to limited research there still is a great deal of uncertainties about the toxic fumes from fires in electrical vehicles. One example the performance of the fire fighters' clothing to resist the toxic gas hydrogen fluoride; many others exist.  The lack of guidelines for the fire department regarding electrical vehicle fires in underground parking garages needs to be highlighted and investigated further. The methods used in the report include literature studies, surveys, and interviews.  Awareness of the potential risks when electrical vehicles are burning in underground parking garages is satisfactory. On the other hand, the knowledge of how to manage these incidents is inadequate. The level of knowledge is generally higher when personnel on the fire department have a higher position with associated qualification requirements. It does not matter if a person works in a fire department in a union or if it’s driven by one county for the level of knowledge. Each individual's interest in the subject have influence over a person’s knowledge.  The survey and interviews illustrated that specific guidelines regarding fire in electrical vehicles in underground parking garages have minimal occurrence in the Swedish Fire Department. Instead, some fire departments declared that general guidelines for fires in electrical vehicles exists. These general guidelines can therefore be adapted to address fires in electrical vehicles in underground parking garages.  This study concludes that national guidelines need to be established. The guidelines should not be specific to electrical vehicle fires in underground parking garages. Instead they should be written in a general and broad representation to encompass electric vehicle fires. National guidelines should be developed by The Swedish Civil Contingencies Agency (MSB) in cooperation with the Swedish rescue services.  The desire with this report is to highlight the perceived lack of knowledge amongst stakeholders and for those involved to take responsibility to improve the existing knowledge platform. Further, it is suggested that national guidelines to be considered and potentially developed for fires involving electrical vehicles. To accomplish this additional research is needed as well as a broader understanding of electric car components and the considerations for firefighting.  The intention of this report was not to analyze the implementation of a national guideline regarding firefighting, building and parking design standards, fire mitigation efforts, etc. related to electric vehicles. As mentioned above, additional research for adapting a national study would be worthy for further consideration. Lastly, existing guidelines and standards should be further studied in order to modify and adopt to the changing landscape impacting electric vehicle use.

<p>Electrospinning has gained immense interests in recent years due to its potential application in various fields, including energy storage application. The V₂O₅/GO as a layered crystal structure has been demonstrated to fabricate nanofibers with diameters within a range of ~300nm through electrospinning technique. The porous, hollow, and interconnected nanostructures were produced by electrospinning formed by polymers such as Polyvinylpyrrolidone (PVP) and Polyvinyl alcohol (PVA), separately, as solvent polymers with electrospinning technique. </p> <p> </p> <p>In this study, we investigated the synthesis of a graphene-modified nanostructured V₂O₅ through modified sol-gel method and electrospinning of V₂O₅/GO hybrid. Electrochemical characterization was performed by utilizing Arbin Battery cycler, Field Emission Scanning Electron Microscopy (FESEM), X-ray powder diffraction (XRD), Thermogravimetric analysis (TGA), Mercury Porosimetery, and BET surface area measurement. </p> <p> </p> <p>As compared to the other conventional fabrication methods, our optimized sol-gel method, followed by the electrospinning of the cathode material achieved a high initial capacity of <b>342 mAh/g</b> at a high current density of 0.5C (171 mA/g) and the capacity retention of ~80% after 20 cycles. Also, the prepared sol-gel method outperforms the pure V₂O₅cathode material, by obtaining the capacity almost two times higher.</p> <p>The results of this study showed that post-synthesis treatment of cathode material plays a prominent role in electrochemical performance of the nanostructured vanadium oxides. By controlling the annealing and drying steps, and time, a small amount of pyrolysis carbon can be retained, which improves the conductivity of the V₂O₅ nanorods. Also, controlled post-synthesis helped us to prevent aggregation of electro-spun twisted nanostructured fibers which deteriorates the lithium diffusion process during charge/discharge of batteries.</p>

The physics of transition metal oxides is controlled by the combination and competition of several degrees of freedom, in particular the charge, the spin and the orbital state of the electrons. One important parameter responsible for the physical properties is the density of charge carriers which determines the oxidization state of the transition metal ions. The central objective in this work is the study of transition metal oxides in which the charge carrier density is adjusted and controlled via lithium intercalation/deintercalation using electrochemical methods. Lithium exchange can be achieved with a high degree of accuracy by electrochemical methods. The magnetic properties of various intermediate compounds are studied. Among the materials under study the mixed valent vanadium-oxide multiwall nanotubes represent a potentially technologically relevant material for lithium-ion batteries. Upon electron doping of VOx-NTs, the data confirm a higher number of magnetic V4+ sites. Interestingly, room temperature ferromagnetism evolves after electrochemical intercalation of Li, making VOx-NTs a novel type of self-assembled nanoscaled ferromagnets. The high temperature ferromagnetism was attributed to formation of nanosize interacting ferromagnetic spin clusters around the intercalated Li ions. This behavior was established by a complex experimental study with three different local spin probe techniques, namely, electron spin resonance (ESR), nuclear magnetic resonance (NMR) and muon spin relaxation spectroscopies. Sr2CuO2Br2 was another compound studied in this work. The material exhibits CuO4 layers isostructural to the hole-doped high-Tc superconductor La2-xSr2CuO4. Electron doping is realized by Li-intercalation and superconductivity was found below 9K. Electrochemical treatment hence allows the possibility of studying the electronic phase diagram of LixSr2CuO2Br2, a new electron doped superconductor. The effect of electrochemical lithium doping on the magnetic properties was also studied in tunnel-like alpha-MnO2 nanostructures. Upon lithium intercalation, Mn4+ present in alpha-MnO2 will be reduced to Mn3+, resulting in a Mn mixed valency in this compound. The mixed valency and different possible interactions arising between magnetic spins give a complexity to the magnetic properties of doped alpha-MnO2.

Die wachsende Weltbevölkerung und die stetigen Entwicklungen in der Industrie benötigen einerseits immer größere Mengen an Grundchemikalien und führen andererseits zu einem ständig steigenden Energiebedarf. Die Dissertation behandelt daher die Themen Zeolithe und Kathodenmaterialien, welche zwei aktuelle Forschungsschwerpunkte der chemischen Industrie darstellen. Der Fokus der Arbeit lag in der Steuerung der Partikelgröße durch die hydrothermale und mikrowellenunterstützte Kristallisation.