京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22456号 / 工博第4717号 / 新制||工||1737(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 安部 武志, 教授 作花 哲夫, 教授 阿部 竜 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

The recent discovery of layered transition metal carbides (MXenes) is one of the most important developments in two-dimensional (2D) materials. Preliminary theoretical and experimental studies suggest a wide range of potential applications for MXenes. The MXenes are prepared by chemically etching ‘A’-layer element from layered ternary metal carbides, nitrides and carbonitrides (MAX phases) through aqueous acid treatment, which results in various surface terminations such as hydroxyl, oxygen or fluorine. It has been found that surface terminations play a critical role in defining MXene properties and affects MXene performance in different applications such as electrochemical energy storage, electromagnetic interference shielding, water purification, sensors and catalysis. Also, the electronic, thermoelectric, structural, plasmonic and optical properties of MXenes largely depend upon surface terminations. Thus, controlling the surface chemistry if MXenes can be an efficient way to improve their properties. This research mainly aims to perform surface modifications of two commonly studied MXenes; Ti2C and Ti3C2, via chemical, thermal or physical processes to enhance electrochemical energy storage properties. The as-prepared and surface modified MXenes have been studied as electrode materials in Li-ion batteries (LIBs) and supercapacitors (SCs). In pursuit of desirable MXene surface, we have developed an in-situ room temperature oxidation process, which resulted in TiO2/MXene nanocomposite and enhanced Li-ion storage. The idea of making metal oxide and MXene nanocomposites was taken to the next level by combining a high capacity anode materials – SnO2 – and MXene. By taking advantage of already existing surface functional groups (–OH), we have developed a composite of SnO2/MXene by atomic layer deposition (ALD) which showed enhanced capacity and excellent cyclic stability. Thermal annealing of MXene at elevated temperature under different atmospheres was carried out and detailed surface chemistry was studied to analyze the change in surface functional groups and its effect on electrochemical performance. Also, we could replace surface functional groups with desirable heteroatoms (e.g., nitrogen) by plasma processing and studied their effect on energy storage properties. This work provides an experimental baseline for surface modification of MXene and helps to understand the role of various surface functional groups in MXene electrode electrochemical performance.

In this thesis is written a brief history of electric cars up to the present. Hybrid vehicles are described and particular attention is given to the description of electric vehicles. A method for accumulating electrical energy by electrochemical accumulators is provided. Finally, there are operation costs of electric cars.

The master's thesis is devoted to the comparison of different types of lithium-ion batteries. Primarily, an introduction to electrochemical power sources and their division is described. Furthermore, the thesis deals only with lithium-ion batteries. In the theoretical part, the chapters discuss the history, the principle of operation and a detailed description of the main battery parts, including used materials. A comparison of commercially available lithium-ion cells with each other as well as with other types of batteries is also included in the theoretical part. The practical part deals with the cyclinf of lithium-ion cells and subsequent evaluation of the effect of temperature on the capacitance and current characteristics of these lithium-ion batteries.

This work deals with problems of degradation mechanisms of lead-acid batteries. For a better understanding of the diverse effects that cause the degradation are analyzed and the physical explanation of each of the degradation mechanisms. The paper describes the measuring method by which they examined the different manifestations of degradation mechanisms. At the conclusion of works are carried out measurements in which it is possible to trace the manifestations of the various degradation mechanisms in lead battery taking place mainly on the active surface electrodes.

This thesis deals with the preparation and characterization of electrode materials for Li-ion batteries based on elemental sulfur. The theoretical part is focused on the characteristics of Li-ion batteries, electrochemical reactions, the process of electrochemical lithiation of sulfur and solubility properties of intermediate polysulfides. The practical part of the thesis deals with the preparation of cathode materials for Li-ion cells with an active substance in the form of elemental sulfur. The prepared electrodes were investigated using cyclic voltammetry and galvanostatic cycling. Physical characterization by SEM and XRD was provided.

Le développement rapide des batteries lithium-ion nécessite des études de vieillissement précises. L'objectif de la thèse est de préciser sur une nouvelle chimie de cellule (NMC) l'impact des paramètres sur le vieillissement, à savoir la température, l'intensité du courant et l'état de charge, et de le mettre en œuvre dans un modèle prédictif et reparamétrable.Une campagne de tests permet de quantifier l'impact unitaire des paramètres de vieillissement sur la perte de capacité de chaque batterie. Nous intégrons les résultats dans un modèle de fatigue. Celui-ci module l'impact d'un ampère-heure échangé par les conditions d’échange de cet ampère-heure au moyen de fonctions de pondération. Ce modèle est ensuite implémenté dans un logiciel, muni de son interface homme machine. Il permet à l'utilisateur de se familiariser avec le vieillissement et de faire des calculs de prédiction de perte de capacité de la batterie.Cependant, ce modèle peut dériver avec le temps en raison de sollicitations répétées. Par conséquent, ses paramètres doivent être mis à jour au moyen de mesures sur le terrain, afin de rester précis. Ces mesures sur le terrain sont soumises à la méthode dite d'analyse incrémentielle des capacités (ICA), consistant à analyser la quantité dQ/dV en fonction de V. Nous avons montré que l’évolution des pics observables sur l’ICA peut être corrélée à la cinétique du premier modèle de fatigue, ce qui permet de se servir de cette mesure pour le recalibrer. Cette mesure permet de réaliser le couplage avec le modèle de fatigue. Enfin, des tests applicatifs permettent de valider la méthode développée. / Reliable development of LIBs requires accurate aging studies. The objective of the thesis is to clarify on a new cell chemistry (NMC) the impact of the parameters on aging, namely the temperature, the rated current intensity and the state of charge, and to implement it in a predictive and updatable model.A test campaign makes it possible to quantify the unit impact of the aging parameters on the loss of capacity of each battery cell. We integrate the results into a fatigue model. The latter modulates the impact of an exchanged ampere-hour by the exchange conditions of this ampere-hour by means of weighting functions. This model is then implemented in a software, equipped with its man/machine interface. It allows the user to become familiar with aging and to make prediction calculations of loss of battery capacity.This model can drift with time due to repeated solicitation, so its parameters need to be updated by on-field measurements, to remain accurate. These on-field measurements are submitted to the so-called Incremental Capacity Analysis method (ICA), consisting in the analysis of dQ/dV as a function of V. We have shown that the evolution of the peaks observable on the ICA can be correlated with the kinetics of the first fatigue model. This measurement makes it possible to couple with the fatigue model. Finally, application tests validate the method developed.

abstract: In recent years, many school districts, community colleges, and universities in California have implemented energy management-as-a-service (EMaaS). The purpose of this study was to analyzes how EMaaS has been realized in California schools, including how performance expectations and service guarantees have been met, how value is created and captured, and which trends are emerging in the pay-for-performance models. This study used a qualitative research design to identify patterns in the collected data and allow theories to be drawn from the emergent categories and themes. Ten in-depth interviews were conducted with a diverse pool of facility managers, energy practitioners, superintendents, and associate superintendents working with EMaaS. Four themes emerged (1) peak shaving overperformance, (2) low risk/reward, (3) performance exactly as expected, and (4) hope in future flexibility. This study reveals medium to high levels of performance satisfaction from the customers of cloud-enabled and battery-based EMaaS in California schools. Value has been captured primarily through peak shaving and intelligent bill management. Large campuses with higher peaks are especially good at delivering energy savings, and in some instances without pairing batteries and solar. Where demand response participation is permitted by the utility companies, the quality of demand response performance is mixed, with performance being exactly as expected to slightly less than expected. The EMaaS business model is positioned to help California schools implement and achieve many of their future sustainability goals in a cost-effective way. / Dissertation/Thesis / Masters Thesis Construction Management 2020

In this thesis, the diffusion of lithium was studied on boron-doped diamond (BDD) as a potential anode material in lithium ion batteries (LIB). The initial interaction between deposited lithium and BDD thin films was studied using X-ray Photoelectron Spectroscopy (XPS). Diffusion is directly linked to reactions between lithium and carbon atoms in the BDD-lithium interface. By measuring binding energies of core-electrons of carbon and lithium before and after deposition, these reactions can be analyzed. Scanning Electron Microscopy (SEM) was used to study the BDD surface and the behaviour of deposited lithium. Experiments show that a chemical interaction occurs between lithium and carbon atoms in the surfacelayers of the BDD. The diffusion of lithium is discussed from spectroscopic data and suggests that surface diffusion is occurring and no proof of bulk diffusion was found. The results do not exclude bulk diffusion in later states but it was not found in the initial interaction at the interface after depositing lithium. SEM images show that lithium clusters in the nanometer range are formed on the BDD surface. The results of this study give insights in the initial diffusion behaviour of lithium at the BDD interface and possible following events are discussed.

Integrating renewable energy and energy storage systems provides a way of operating the electrical grid system more energy efficiently and stably. Thermal storage and batteries are the most common devices for integration. One approach to integrating thermal storage on site is to use ice in combination with the cooling system. The use of ice storage can enable a change in the time variation of electrical usage for cooling in response to variations in PV availability, utility prices, and cooling requirements.A number of studies can be found in the literature that address optimal operation of onsite PV systems with batteries or ice storage. However, although it is a natural and practical question, it is not clear which integrated storage system performs better in terms of overall economics. Ice storage has low initial and maintenance costs, but there is an efficiency penalty for charging of storage and it can only shift electrical loads associated with building cooling requirements. A battery’s round-trip efficiency,on the other hand, is quite consistent and batteries can be used to shift both HVAC and non-HVAC loads. However, batteries have greater initial costs and a significantly shorter life. This research presents a tool and provides a case study for comparing life-cycle economics of battery and ice storage systems for a commercial building that has chillers for cooling and an on-site photovoltaic system. A model predictive control algorithm was developed and implemented in simulation for the two systems in order to compare optimal costs. The effect of ice storage and battery sizing were studied in order to determine the best storage sizes from an economic perspective and to provide a fair comparison