This thesis project solve problematic of thermal proces in lead-acid batteries. There are decribed history of lead – acid batteries, distributions of batteries, overview of construction lead – acid batteries and VRLA batteries and is decribed thermal runaway proces and basic termal process. They are listed here practical results and the measurements is concluded.

This diploma thesis deals with materials used by production ofcathodes of Lithium-ion batteries. Primary this thesis deals with LiCoO2material and its subsidizing of alkali metals. The first part deals with the charakteristic of Lithium-ion batteries, used materials, possibilities of doping and charging. The practical part concentrates on production of active substance of cathode and doping this substance by sodium and potassium. The methods of evaluation were used galvanostaticcycling and x-ray analysis (XRD).

This diploma thesis focuses on study of positive electrode materials for Li-Ion batteries. Our aim are intercalation materials whose are really perspective materials whose are widely used in this case. The theoretical part of my thesis focus on basic study of Li-ion batteries and their parameters. We studied charging and discharging processes. AFM and SEM were used as additional techniques for study LiCoO2 a Li0,975K0,025CoO2. We tested lifetime and stability of electrode as a perspective material for electrode for Li-ion batteries.

This diploma thesis deals with concept design of electric car with electric in-wheel motors. The designing work starts with modeling of dynamic through acceleration and range of electric car. This was necessary to choose important components. These components were placed based on given criteria. The full model of electric car was designed in program Creo Parametric. In the final chapter stress analysis via program Ansys is presented.

The purpose of this diploma thesis is to describe the impact of compaction pressure on the electrochemical parameters of lithium-sulfur batteries. Theoretical part of this thesis contains briefly described terminology and general issues of batteries and their division. Every kind of battery is provided with a closer description of a specific battery type. A separate chapter is dedicated to lithium cells, mainly lithium-ion batteries. Considering various composition of lithium-ion batteries, this chapter deeply analyzes mostly used active materials of electrodes, used electrolytes and separators. Considering that the electrochemical principle of Li-S and Li-O batteries is different to Li-ion batteries, these accumulators of new generation are included in individual subhead. In the experimental part of this thesis are described methods used to measure electrochemical parameters of Li-S batteries. Next chapter contains description of preparing individual electrodes and their composition. Rest of the experimental part of my thesis is dedicated to the description of individual experiments and achieved results.

<div>Metal nanoparticles have long been of paramount importance in many areas such as: emission reduction in cars, hydrogen production via the water-gas shift reaction, and lithium-ion storage in batteries. For these purposes, the size and shape of the nanoparticles have been shown to play a crucial role in improving nanoparticle performance. </div><div><br></div><div>For characterization of nanostructures, the use of transmission electron microscopy (TEM) has been shown to be extremely useful. Via a TEM instrument, one can learn about nanoparticle properties such as: particle size, 3D morphology, chemical composition, fine structure, crystallography, even to atomic resolution. No other technique boasts such ability at such a high xyz resolution. This work includes TEM work for many different applications within catalysis and energy storage fields.</div><div><br></div><div>In catalytic applications, the <1 nm particle sizes often sought after generally lead to higher activity per unit mass of the catalyst, but also have the tendency to sinter due to concomitant increases in the surface free energy, leading to catalyst deactivation especially at elevated temperatures. To investigate the sintering, (Pt,Au)-iron oxide heterodimer nanoparticles were heated in the microscope with simultaneous imaging. For that purpose, the sample was irradiated with a 532 nm pulsed laser, with laser powers of 4-25 mW within a TEM microscope to investigate particle sintering as it happens. The Au and Pt phases were both found to wet over the Fe₃O₄ phase, a behavior opposite to the Strong Metal Support Interactions (SMSI - caused by oxide wetting the metal) which were expected from well-known literature reports. This new behavior demonstrates that not only nanoparticle size, but also the support particle size can affect catalytic properties. This is shown by the fact that the size of the support oxide in these heterodimer nanoparticles is only 3 times the diameter of the active metal nanoparticles, compared to a greater than 20 times size difference for a standard metal oxide supported nanoparticle system. </div><div> </div><div>Nanoparticle metal catalysts can also undergo significant catalytic improvement via the addition of promoting metals. Kinetics were measured on a series of Pt/Co on carbon nanotube support catalysts, and addition of Co was seen to improve the turnover frequency by 10 times. Leaching of the bulk Co phases, while preserving PtCo alloy structures, reduced activity by more than 18 times demonstrating the need for a Pt/CoO_xH_y interface for catalytic promotion, and showing that PtCo alloying did not produce the promotion effect.</div><div><br></div><div>Although, for the PtCo catalysts for WGS, the formation of a Co-oxyhydroxide phase was proved to be vital, nanoparticle alloying is also well-known to improve dehydrogenation kinetics. This was shown for a series of PtM catalysts with core/shell structures, which were found to be highly selective for propane dehydrogenation as a result of the PtM intermetallic phase. XAS studies of these materials led to the discovery that formation of a continuous PtM alloy surface layer that is 2–3 atomic layers thick was sufficient to obtain identical catalytic properties between those of the core–shell and full alloy catalysts. TEM characterization was also performed to determine the core/shell nature of these catalysts.</div><div><br></div><div>Another interesting morphological "tuning knob" of nanoparticle catalysts is related to Reactive metal–support interactions (RMSI). RMSI can have electronic, geometric and compositional effects that can be used to tune catalytic active sites. Generally, non-oxide supports are disregarded as unable to undergo RMSI. However, we report an example of non-oxide-based RMSI between platinum and Nb₂CT_x MXenes--a recently developed, two-dimensional metal carbide, with a dopant labeled as T. The surface functional groups can be reduced, and a Pt–M surface alloy is formed. WGS reaction kinetics reveal that these RMSI supports stabilize the relevant nanoparticles and generate higher H₂O activation ability and thus higher rates compared with a non-reducible support or a bulk niobium carbide. This RMSI between platinum and the niobium MXene support can be extended to other members of the MXene family and opens new avenues for the facile design and manipulation of functional bimetallic nanoparticle catalysts.</div><div><br></div><div>Other important catalytic nanostructures are Au/TS-1 (Titanosilicalite-1, a zeolite with the MFI structure) catalysts which can be used to make propylene oxide (PO), an important industrial intermediate, and are extremely interesting due to the potential for one-pot chemical reactions, which will save on capital costs. The kinetics of propylene epoxidation over these Au/TS-1 catalysts were measured in a continuous stirred tank reactor (CSTR) free from temperature and concentration gradients. Apparent reaction orders were measured at 473 K for H₂ (0.7 order), O₂ (0.2), and C₃H₆ (0.2) for a series of Au/TS-1 catalysts with varied Au (0.02–0.09 wt%) and Ti (Si/Ti: 75–143) contents. These measured orders were consistent with those reported previously. Co-feeding propylene oxide enabled measurement of the apparent reaction order in propylene oxide (−0.4 to −0.8 order), showing, for the first time, and it was found that relevant pressures of propylene oxide reversibly inhibit propylene epoxidation over Au/TS-1, while co-feeding carbon dioxide and water has no effect on the propylene epoxidation rate. Analysis of previously proposed two-site reaction mechanisms in light of these new reaction orders for O₂ (0.4), H₂ (1), and C₃H₆ (0.4), corrected to account for propylene oxide inhibition, provides further evidence that propylene epoxidation over Au/TS-1 occurs via a simultaneous mechanism requiring two distinct, but adjacent, types of sites, and not by a sequential mechanism that invokes migration of H₂O₂ formed on Au sites to PO forming Ti sites. H₂ oxidation rates are not inhibited by propylene oxide, implying that the sites required for hydrogen oxidation are distinct from those required for propylene epoxidation. Those who intend on performing kinetics in the future are encouraged to perform a simple conversion-based tau-test, outlined in the relevant chapter of this thesis, to determine whether products inhibit reaction rates.</div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div>Yet another important field in which nanoparticle morphology research is essential is that of development of lithium-ion batteries. The current commercial graphite anode for lithium batteries is unfortunately prone to formation of lithium plating during use, from which well-documented safety issues arise. We demonstrated the use of an alternative anode, antimony, to have a measured specific capacity that is 1.6x higher than the theoretical capacity of graphite. Antimony, however, suffers from low cyclability due to large volumetric changes (~150%) upon the expansion caused by lithiation. To combat this problem, several different synthesis methods to produce nanoparticles of differing structures were tested and it was found that amine boranes produce a unique 3D nanochain structure with stable particle sizes of ~30 nm. These “3D nanochains” were found to have a stable charge capacity retention (98%) after 100 cycles due to their unique morphology which accommodates the lithiation expansion.</div><div><br></div><div>The role of sulfur nanostructures in lithium–sulfur batteries was also examined. Carbon–sulfur composites without crystalline sulfur demonstrate a high specific capacity of ≈1000 Ah kg⁻¹after 100 cycles with a gravimetric current of 557 A kg⁻¹. This high rate capacity is found to depend on sulfur distribution which, in turn, is controlled by the synthesis pathway.</div><div><br></div><div>In conclusion, the morphology of nanostructures affects many different aspects of performance, rate, and stability. Further study into these details are expected to generate additional knowledge of a wide variety of interesting nanomaterials.</div>

Binder free vertical aligned (VA) CNT/sulfur composite electrodes with high sulfur loadings up to 70 wt% were synthesized delivering discharge capacities higher than 800 mAh g−1 of the total composite electrode mass. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Lithium-ion batteries(LIBs) have dominated the energy storage market in the past two decades. The high specific energy, low self-discharge, relatively high power and low maintenance of LIBs enabled the revolution of electronic devices and electric vehicle industry, changed the communication and transportation styles of the modern world. Although the specific energy of LIBs has increased significantly since first commercialized in 1991, it has reached a bottleneck with current electrode materials. To meet the increasing market demand, it is necessary to develop high capacity electrode materials.<div><br></div><div>Current commercial anode material for LIB is graphite which has a specific capacity of 372 mAh g-1. Other group IV elements (silicon (Si), germanium (Ge), tin (Sn)) have much higher capacities. However, group IV elements have large volume change during lithiation/delithiation, leading to pulverization of active materials and disconnection between electrode particles and current collector, resulting in fast capacity fading. To address this issue, it is essential to understand the microstructural evolution of Si, Ge and Sn during cycling.<br></div><div><br></div><div>This dissertation is mainly focused on the morphological and structural evolution of Sn and Ge based materials. In this dissertation, anin situ focused ion beam-scanning electron microscopy (FIB-SEM) method is developed to investigate the microstructuralevolution of a single electrode particle and correlate with its electrochemical performance. This method is applied toall projects. The first project is to investigate the microstructural evolution of a Sn particle during cycling. Surface structures of Sn particles are monitored and correlated with different states of charge. The second project is to investigate the morphological evolution of Ge particles at different conditions. Different structures (nanopores, cracks, intact surface) appear at different cycling rates. The third project is to study selenium doped Ge (GeSe) anodes. GeSe and Ge particles are tested at the same condition. Se doping forms Li-Ge-Se network, provides fast Li transport and buffers volume change. The fourth project is to study the reaction front of Ge particle during lithiation. Micron-sized Ge particles have two reaction fronts and a wedge shape reaction interface, which is different from the well-known core-shell mode. The fifth project is to investigate antimony (Sb)-coated porous Ge particles. The Sb coating suppresses electrolyte decomposition and porous structure alleviates volume change. The results in this dissertation reveal fundamental information about the reaction mechanism of Sn and Ge anode. The results also show the effects of doping, porous structuring and surface coating of anode materials.</div>

Mathematical modelling using differential equations is an important tool to predict the behaviorof vanadium redox batteries, since it may contribute to improve the device performance and leadto a better understanding of the principles of its operation. Modelling can be complementedby asymptotic analysis as a mean to promote reductions or simplifications that make modelsless complex. Such simplifications are useful in this context, whereas these models usuallyaddresses one cell only – the smallest operating unit – while real applications demand tensor hundreds cells implying on larger computational requirements. In this research, severaloptions for asymptotic reductions were investigated and, applied to different models, were ableto speed up the processing time in 2.46× or reduce the memory requirements up to 11.39%. Thecomputational simulations were executed by COMSOL Multiphysics v.4.4, also by in-housecode developed in MATLAB. The validation of results was done by comparing it to experimentalresults available in literature. Additionally, correlating the results provided by COMSOL withthe ones arising from the implemented sub-routines allowed to validate the developed algorithm.Key-words: / A modelagem matemática por meio de equações diferenciais é uma importante ferramenta paraprever o comportamento de baterias redox de vanádio, pois ela pode contribuir para o aperfeiçoamentodo produto e melhor entendimento dos princípios da sua operação. Os estudos demodelagem podem ser aliados à análise assintótica no intuito de promover reduções ou simplificaçõesque tornem os modelos menos complexos, isso é feito a partir da observação da importânciaque cada termo exerce sobre as equações. Tais simplificações são úteis neste contexto, visto queos modelos geralmente abordam uma célula apenas - a menor unidade operacional da bateria- enquanto aplicações reais exigem o uso de dezenas ou centenas delas implicando em umamaximização do uso de recursos computacionais. Neste trabalho, foram investigadas múltiplasformas de reduções assintóticas que empregadas na construção dos modelos puderam acelerar otempo de processamento em até 2,46 vezes ou reduzir os requisitos de memória principal em até11,39%. As simulações computacionais foram executadas pelo software COMSOL Multiphysicsv. 4.4, e também por scripts desenvolvidos em ambiente de programação MATLAB. A validaçãodos resultados foi feita comparando-os a dados experimentais presentes na literatura. Talabordagem permitiu também validar as rotinas implementadas para a simulação dos modeloscomparando suas soluções com aquelas providas pelo COMSOL.

The aim of this project was to find a recycling route for Prussian white. During the experimental part, one recycling method was tested using sodium hydroxide and from this a method for re-synthesis of Prussian white was conducted as well as a method for re-crystallisation of sodium ferrocyanide. The method that proved most successful was the re-crystallisation of sodium ferrocyanide. Furthermore, the conditions needed to conduct a proper re-synthesis of Prussian white was not available during this research. Therefore, it was not possible to produce Prussian white of the right structure. The analysis was performed through XRD analysis and it was concluded that it is possible to re-crystallise sodium ferrocyanide from Prussian white.